The dissolved organic matter(DOM)with high mobility and reactivity plays a crucial role in soil.In this study,the characteristics and phytotoxicity ofDOMreleased fromthe hydrochars prepared from different feedstocks(c...The dissolved organic matter(DOM)with high mobility and reactivity plays a crucial role in soil.In this study,the characteristics and phytotoxicity ofDOMreleased fromthe hydrochars prepared from different feedstocks(cowmanure,corn stalk and Myriophyllum aquaticum)under three hydrothermal carbonization(HTC)temperatures(180,200 and 220°C)were evaluated.The results showed that the hydrochars had high dissolved organic carbon content(20.15 to 37.65 mg/g)and its content showed a gradual reduction as HTC temperature increased.Three fluorescent components including mixed substance of fulvic acid-like and humic acid-like substances(C1,30.92%-58.32%),UVA humic acid-like substance(C2,25.27%-29.94%)and protein-like substance(C3,11.74%-41.92%)were identified in hydrochar DOM by excitation emission matrix spectra coupled with parallel factor analysis.High HTC temperature increased the relative proportion of aromatic substances(C1+C2)and humification degree of hydrochar DOM from cow manure,while it presented adverse effects on the hydrochar DOM from corn stalk and Myriophyllum.aquaticum.The principal component analysis suggested that feedstock type and HTC temperature posed significant effects on the characteristics of hydrochar DOM.Additionally,seed germination test of all hydrochar DOM demonstrated that the root length was reduced by 8.88%-26.43%in contrast with control,and the germination index values were 73.57%-91.12%.These findings provided new insights into the potential environmental effects for hydrochar application in soil.展开更多
The copper complexing of dissolved organic matter released from hydrochar(HDOM)affects the former’s environmental behavior.In this study,how hydrothermal temperatures(180,220 and 260℃)influence the molecular-level c...The copper complexing of dissolved organic matter released from hydrochar(HDOM)affects the former’s environmental behavior.In this study,how hydrothermal temperatures(180,220 and 260℃)influence the molecular-level constitutions and Cu(II)binding features of HDOM were elucidated via fourier transform ion cyclotron resonance mass spectrometry and multi-spectroscopic analysis.The findings demonstrated that the almost HDOM molecules had the traits of lower polarity and higher hydrophobicity.As the hydrothermal temperature increased,the molecules with particularly high relative strength gradually disappeared,average molecular weight,percentages of CHON and aliphatic compounds of HDOM reduced while the percentages of CHO and aromatic compounds increased.In general,the fluorescence quenching of Cu(II)weakened as hydrothermal temperature rose and the Cu(II)binding stability constants of fluorophores in HDOM were 4.50–5.31.In addition,the Cu(II) binding order of fluorophores in HDOM showed temperature heterogeneities, andpolysaccharides or aromatic rings of non-fluorescent substances had the fastest responsesto Cu(II) binding. Generally, fluorescent components tend to bind Cu(II) at relatively traceconcentrations (0–40 μmol/L), whereas non-fluorescent substances tend to the bind Cu(II)at relatively higher concentrations (50–100 μmol/L). This study contributed to the predictionof the potential environmental behaviors and risks of Cu(II) at the molecular level afterhydrochar application.展开更多
The effectiveness of using vegetation to stabilise shallow soil slopes heavily depends on the survival of vegetation,yet the amplification of extreme events induced by climate change threatens the health of plants cov...The effectiveness of using vegetation to stabilise shallow soil slopes heavily depends on the survival of vegetation,yet the amplification of extreme events induced by climate change threatens the health of plants covering slopes.Hydrochar is an environmentally friendly soil amender that can achieve the potential benefits of promoting plant growth for slope stabilisation and facilitation of waste upcycling.The mechanism underlying the hydrochar effects on the mechanical behaviour of unsaturated soils remains unclear.This study investigated the influence of grass-derived hydrochar on the water retention,compressibility,and shear strength of a compacted siltyeclay sand.Soil microstructural changes due to hydrochar amendment were measured to explain the soilehydrochar hydromechanical interaction.The increase in suction resulted in a less significant increase in yield stress and a negligible reduction in compressibility of the hydrochar-amended soil compared with the unamended case.This phenomenon was observed because hydrochar addition reduced the large pores with diameters greater than the macropore peak of 60 mm due to pore filling by hydrochar particles,resulting in a less substantial volume contraction during drying.Hydrochar introduced more significant effects on the soil’s shear strength in an unsaturated state compared to a saturated case.Despite the similarity of the unsaturated amended soil with the critical-state friction angle to the saturated case,the former exhibited a greater shear strength because the hydrochar addition improved water retention capability.As a result,the degree of saturation and,hence,Bishop’s effective stress were higher than those for the unamended case for a given suction.展开更多
The function-led design of porous hydrochar from mineral-rich biowaste for environmental applications inevitably suffers from carbon-ash recalcitrance.However,a method to alter the original carbon skeleton with ash re...The function-led design of porous hydrochar from mineral-rich biowaste for environmental applications inevitably suffers from carbon-ash recalcitrance.However,a method to alter the original carbon skeleton with ash remains elusive and hinders the availability of hydrochar.Herein,we propose a facile strategy for breaking the rigid structure of carbon-ash coupled hydrochar using phase-tunable molten carbonates.A case system was designed in which livestock manure and NaHCO3 were used to prepare the activated hydrochar,and NH3 served as the target contaminant.Due to the redox effect,we found that organic fractions significantly advanced the melting temperature of Na2CO3 below 800℃.The Na species steadily broke the carbon-ash interaction as the thermal intensity increased and transformed inorganic constituents to facilitate ash dissolution,rebuilding the hydrochar skeleton with abundant hierarchical channels and active defect edges.The surface polarity and mesopore distribution collectively governed the five cycles NH3 adsorption attenuation process.Manure hydrochar delivered favorable potential for application with a maximum overall adsorption capacity of 100.49 mg·g^(-1).Integrated spectroscopic characterization and theoretical computations revealed that incorporating NH3 on the carbon surface could transfer electrons to chemisorbed oxygen,which promoted the oxidation of pyridine-N during adsorption.This work offers deep insight into the structure function correlation of hydrochar and inspires a more rational design of engineered hydrochar from high-ash biowaste.展开更多
The Response Surface Methodology (RSM) was used to optimise the conditions of preparation of activated hydrochar from tannery solid waste by hydrothermal carbonisation (HTC). The main factors such as residence time, m...The Response Surface Methodology (RSM) was used to optimise the conditions of preparation of activated hydrochar from tannery solid waste by hydrothermal carbonisation (HTC). The main factors such as residence time, moisture content and final carbonisation temperature were investigated during the optimisation of hydrochar preparation conditions. The three responses investigated are hydrochar yield, iodine and methylene blue indices. The results of experimental analyses showed that the yield of hydrochar decreases with increasing final temperature, leading to the formation of micropores inside the carbonaceous solid. The optimum conditions for preparing the following hydrochar were obtained: 83.10%, 390.44 mg∙g−1 and 259.63 mg∙g−1 respectively for the hydrochar yield, the iodine and methylene blue indices. The specific surface area of prepared hydrochar is 849.160 m2/g, SEM micrographs showed a porous heterogeneous surface and particularly, the hydrochar surface also revealed external pores on the hydrochar surface which acted as a pathway to the micropores. Fourier transform infrared (FTIR), however, showed a predominance of acid functions on the surface of the carbonaceous solids. Tests were carried out to eliminate indigo carmine in aqueous media. Activated hydrochar showed a high level of activity, with the Langmuir and Freundlich isotherms giving an adsorption quantity of 354.610 mol/g and a KF constant of 468.2489, respectively. The findings of the research revealed that hydrochar produced is well adapted for dyes removal.展开更多
Innovative measure is a urgent requirement for managing the huge volume of municipal sewage sludge. The hydrothermal carbonation （HTC） shows some potential advantages for using hydrochar as a soil conditioner. The a...Innovative measure is a urgent requirement for managing the huge volume of municipal sewage sludge. The hydrothermal carbonation （HTC） shows some potential advantages for using hydrochar as a soil conditioner. The aim of this work was to investigate the properties of hydrochars, by means of the HTC of municipal sewage sludge under different temperatures （190 and 260~C） and reaction hours （1, 6, 12, 18 and 24 h）. The HTC led to the decreases of N, O and H contents by more than 54.6, 37.9 and 10.0%, respectively, and slight changes of C content. The Py-GC-MS analysis showed that a large proportion of fatty acids, in particular hexadecanoic acid, transferred into alkenes, olefins and aromatic compounds. The 13C-NMR and fourier transform infrared spectra （FTIR） confirmed the transformation and changes in chemical structure in which hydrochar contained lower oxygen-containing organic C of O-alkyl, carboxylic and carbonyl C and aliphaticity, but higher aromatic C and aromaticity. The rich hydrophobic functions induced in high positive charges in the charred sludge. The HTC facilitated the pore structure development, proved by higher specific surface area and specific pore volume, with a maximum of 17.30 and 0.83 cm^3 g^-1, respectively. The availabilities of N, P and K markedly reduced during HTC treatment. The activities of most heavy metals were depressed though they accumulated in the hydrochar. Further work is required to investigate the values and risk of the charred sludge amended to soil.展开更多
In this paper,a novel compound was developed by mixing H_(3)PO_(4)-modified cauliflower leaves hydrochar(CLH)and coal gangue-based Na-X zeolite(ZL).An alkaline soil contaminated with cadmium(Cd)and lead(Pb)was amended...In this paper,a novel compound was developed by mixing H_(3)PO_(4)-modified cauliflower leaves hydrochar(CLH)and coal gangue-based Na-X zeolite(ZL).An alkaline soil contaminated with cadmium(Cd)and lead(Pb)was amended through the individual and synergistic application of CLH and ZL(1%CLH,2%CLH,1%ZL,2%ZL and 1%CLH+1%ZL),and Chinese cabbage was grown on it.Individual application of CLH was superior to ZL on decreasing the pH of alkaline soil and increasing soil available phosphorus(Olsen-P)and soil organic matter(SOM).In contrast,their combined application significantly improved the soil cation exchange capacity(CEC).Besides,the 1%CLH+1%ZL was the most efficient treatment in decreasing diethylenetriamine pentaacetate(DTPA)-extractable Cd/Pb and concentrations of these two metals in cabbage root and shoot.Their synergistic application could better increase Cd and Pb immobilization and cabbage yield than their alone application.Furthermore,the immobilization of Pb for all treatments was higher than that of Cd.The synergistic immobilization mechanism of CLH and ZL reflected that the CLH precipitated and complexed with these two metals,which may block the pores of hydrochar or wrap on the surface of hydrochar.So the continuous adsorption and complexation were prevented.Nevertheless,ZL could probably alleviate this obstacle.This finding provides helpful information about using CLH combined with ZL as a soil stabilizer to immobilize heavy metals in contaminated alkaline soil.展开更多
A rising global population and aspirational higher living standards has driven a step change in resource utilization and concomitant anthropogenic pollution across the biosphere.Low-cost and scalable technologies for ...A rising global population and aspirational higher living standards has driven a step change in resource utilization and concomitant anthropogenic pollution across the biosphere.Low-cost and scalable technologies for environmental remediation are therefore urgently sought,with an emphasis on trash-to-treasure strategies that exploit abundant but underutilized waste by-products of existing sectors.Biochars are carbon-rich,porous solids produced by biomass pyrolysis under anaerobic or oxygen-scarce conditions at high temperature(350–700°C),while hydrochars are produced by hydrothermal biomass carbonization at lower temperature(130–250°C)and high autogenous pressures(0.3–4.0 MPa).Bio/hydrochars possess unique physicochemical properties,notably high surface areas(100–1500 m2 g-1)and porosity(0.25–2.5 cm^(3)g^(-1))and rich surface chemistry featuring carboxylic,phenolic,hydroxyl,and carbonyl functions,amenable to chemical,physical,or biochemical modification,rendering them ideal sorbents for pollutants such as heavy metals(e.g.As and Cr),and toxic organic(e.g.,dyes and xenobiotics)and inorganic(e.g.,SO_(2))molecules.Bio/hydrochars are attractive for environmental remediation of pollutant mixtures by surface complexation,redox chemistry,electrostatic interactions/ion exchange,or coprecipitation.This review discusses recent opportunities and challenges in creating bio/hydrochar sorbents and their nanocomposites through grafting,doping,and chemical/physical activation,for the depollution of aquatic and atmospheric environments.展开更多
The corncob hydrochar is prepared by using a stainless autoclave at 230?C for 8 h.The products are characterized by elemental analyzer,Fourier Transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and scanning ...The corncob hydrochar is prepared by using a stainless autoclave at 230?C for 8 h.The products are characterized by elemental analyzer,Fourier Transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and scanning electron microscope(SEM).The effects of hydrochar dosage,pH,adsorption time and phenol concentration on the adsorption performance of hydrochar are investigated by means of single-factor experimental analysis.Based on the experiments the adsorption thermodynamic and kinetics are tentatively discussed.The results show that abundant oxygen-containing functional groups are scattered on the surface of the corncob hydrochar.The adsorption kinetics of phenol on the hydrochar corresponds well with pseudo-second-order kinetic model.Thermodynamic studies indicate that Freundlich adsorption isotherm model is much better than Langmuir model in describing the adsorption of phenol on the corncob hydrochar at 25?C-45?C.This study provides scientific basis for the development of cheap and efficient adsorbents for the removal of phenols derived from oilfield wastewater.展开更多
Hydrothermal carbonization is highly applicable to high moisture biomass upgrading due to the fact that moist-ure involved can be directly used as reaction media under the subcritical-water region.With this,value-adde...Hydrothermal carbonization is highly applicable to high moisture biomass upgrading due to the fact that moist-ure involved can be directly used as reaction media under the subcritical-water region.With this,value-added utilization of hydrochar as solid fuel with high carbon and energy density is one of the important pathways for biomass conversion.In this review,the dewatering properties of hydrochar after the hydrothermal carbonization of biowaste,coalification degree with elemental composition and evolution,pelletization of hydrochar to enhance the mechanical properties and density,coupled with the combustion properties of hydrochar biofuel were discussed with various biomass and carbonization parameters.Potential applications for the co-combustion with coal,cleaner properties and energy balance for biowaste hydrothermal carbonization were presented as well as the challenges.展开更多
Hydrochar prepared with four typical biowastes,pine wood,food waste,digested sewage sludge,and Chlorella were applied for the promotion of anaerobic digestion.The gas production and substrate composition were analyzed...Hydrochar prepared with four typical biowastes,pine wood,food waste,digested sewage sludge,and Chlorella were applied for the promotion of anaerobic digestion.The gas production and substrate composition were analyzed associated with the hydrochar characteristics.The results suggested that Chlorella hydrochar(C-C)showed the highest cumulative yield of methane(approximately 345 mL)with high total organic carbon(TOC)removal efficiency and low volatile fatty acids(VAFs)concentration.Especially,food waste hydrochar(F-C)showed a poor effect on anaerobic digestion and aroused 1.4–1.6 g/L accumulation of VAFs,in which the toxic components may account for the low efficiency.The C-C and sludge hydrochar(S-C)may develop direct interspecific electron transport(DIET)to facilitate the generation of methane by both surface groups and conductivity of the body structure,unlike pinewood hydrochar(P-C),which mainly depended on the aromatic matrix structure of hydrochar body.This work suggested that C-C can be the best candidate for the facilitation of anaerobic digestion,and N-containing biowaste like algae and lignocellulose like pine wood may establish different DIET pathways based on the physicochemical characteristics of hydrochar.展开更多
Hydrochar has potential applications in soil improvement and heavy metal remediation.Hydrochar would undergo the process of aging when introduced into the soil,altering its properties.However,recent studies have focus...Hydrochar has potential applications in soil improvement and heavy metal remediation.Hydrochar would undergo the process of aging when introduced into the soil,altering its properties.However,recent studies have focused mainly on the artificial aging of hydrochar,which could not reveal the cumulative effect of multiple environmental factors.Therefore,the periodical monitoring of the property and sorption behavior of hydrochar after amending soils is necessary to better understand the multifaceted mechanisms associated with the natural aging of hydrochar.This study selected the sludge-derived hydrochar(SLHC)as a typical hydrochar and applied a 16-month rice-wheat-rice rotation to mimic the natural aging of hydrochar,focusing on changing properties and cadmium(Cd)sorption and literature contrast between aging strategies and biochar types.The porosity,O abundance,and ash content of 16-month aged SLHC increased by 37%,47%,and 8.5%,respectively,facilitating Cd sorption due to surface complexation,pore sorption,and precipitation.The sorption percentage of Cd to SLHC was in the range of 11-14%for SLHC-A0 and increased to 17-31%for SLHC-A4 and 20-32%for SLHC-A16 after natural aging.The natural aging of SLHC induced by ash content played an essential role in Cd sorption site heterogeneity.Linear regression analysis showed that aging strategies on sorption behavior significantly differed between biochars.Thus,studies involving natural aging with multiple environmental factors are preferred over those involving chemical or biological aging.Future studies should continue to explore the mechanisms of natural aging-induced heavy metal sorption between hydrochar and pyrochar.These results improve insights to appraise the potential of SLHC as soil amendments to alleviate the adverse effects of heavy metal contamination and provide an essential basis for researchers and staff in soil management and environmental prevention.展开更多
Hydrothermal carbonization(HTC)has been regarded as a promising technique for turning wet biomass into hydrochar due to its low energy consumption,low exhaust gas emissions,etc.In addition,hydrochar is an important so...Hydrothermal carbonization(HTC)has been regarded as a promising technique for turning wet biomass into hydrochar due to its low energy consumption,low exhaust gas emissions,etc.In addition,hydrochar is an important source of dissolved organic matter(DOM),which plays a crucial part in the migration and destiny of pollutants in the environmental medium.However,there are limited studies that focus on the factors that influence the formation of DOM in hydrochar,such as hydrothermal temperature.Therefore,the current study comprehensively characterized the optical properties of DOM within hydrochar derived from sawdust(HDOM)under different hydrothermal temperatures(150-300℃)by Ultraviolet-visible(UV-Vis)and fluorescence spectroscopy,as well as its complexation characteristic with Cu(II).The findings revealed that the organic carbon content of HDOM reached a peak of 37.3 mg L^(−1)when the temperature rose to 240℃and then decreased as the temperature increased.UV-Vis spectroscopy analysis showed that the absorption capacity of HDOM at 275 nm increases with temperature and reaches a maximum value at 240℃,indicating that high temperature promotes the formation of monocyclic aromatic compounds.High temperature enhances the aromaticity,hydrophobicity,and humification degree of HDOM,thus improving its stability and aromaticity.The E3/E4 ratios are all greater than 3.5,confirming that the main component of HDOM is fulvic acid,which corresponds to 3D-EEM and Pearson’s correlation coefficient analysis.The humification index(HIX)of HDOM increased with the rise in hydrothermal temperature(150-240℃),as observed by the three-dimensional excitation-emission matrix spectroscopy(3D-EEMs).After reaching its peak at 240℃,the HIX value gradually dropped in line with the trend of the DOC change.Moreover,the bioavailability(BIX)value of DOM was all high and greater than 1,indicating all the HDOM are readily bioavailable.Two microbial humic substances(C1 and C4),a humic-like substance(C2),and a protein-like substance(C3)were discovered in DOM by integrating 3D-EEMs with parallel factor analysis(PARAFAC).Their fluorescence intensity decreases as the Cu(II)concentration increases,indicating the formation of complexes with Cu(II).As the temperature rises,the binding ability of DOM and Cu(II)changes significantly,reaching the optimum at 300℃.Meanwhile,the substance C2 has the strongest binding ability with Cu(II).This research emphasizes the significance of spectroscopy analysis in determining the evolution of hydrochar-derived DOM,the potential for heavy metal binding and migration,and its characteristics and features.展开更多
Lignin,an abundant aromatic polymer in nature,has received significant attention for its potential in the production of bio-oils and chemicals owing to increased resource availability and environmental issues.The hydr...Lignin,an abundant aromatic polymer in nature,has received significant attention for its potential in the production of bio-oils and chemicals owing to increased resource availability and environmental issues.The hydrodeoxygenation of guaiacol,a lignin-derived monomer,can produce cyclohexanol,a nylon precursor,in a carbon-negative and environmentally friendly manner.This study explored the porous properties and the effects of activation methods on the Ru-based catalyst supported by environmentally friendly and cost-effective hydrochar.Highly selective cleavage of C_(ary)-O bonds was achieved under mild conditions(160°C,0.2 MPa H_(2),and 4 h),and alkali activation further improved the catalytic activity.Various characterization methods revealedthat hydrothermal treatment and alkali activation relatively contributed to the excellent performance of the catalysts and influenced their porous structure and Ru dispersion.X-ray photoelectron spectroscopy results revealed an increased formation of metallic ruthenium,indicating the effective regulation of interaction between active sites and supports.This synergistic approach used in this study,involving the valorization of cellulose-derived hydrochar and the selective production of nylon precursors from lignin-derived guaiacol,indicated the comprehensive and sustainable utilization of biomass resources.展开更多
This study investigates the simultaneous production of hydrochar and bioactive compounds from Ulva lactuca via a hydrothermal process.The experiment was carried out using a batch reaction vessel at different reaction ...This study investigates the simultaneous production of hydrochar and bioactive compounds from Ulva lactuca via a hydrothermal process.The experiment was carried out using a batch reaction vessel at different reaction temperatures of 180-220◦C and various holding times of 30-90 min.As expected,both temperature and time vigorously influenced hydrochar and bioactive compound production.The maximum hydrochar yield was at 32.4 wt%.The higher heating value(HHV)of hydrochar was observed in the range of 17.68-21.07 MJ kg^(-1),near the energy content of low-rank coals.The hydrochars exhibited contact angles higher than 90°(i.e.,94-108°)for a longer time,confirming their hydrophobic surfaces.The scanning electron microscope analysis(SEM)showed that the hydrothermal process enables cracks in the spherical shape of raw U.lactuca into small and porous particles.Besides producing hydrochar,the hydrothermal process of U.lactuca also gives promising antioxidants and phenolics as bioactive compounds.The highest total phenolic content and antioxidant activity could be achieved in hydrolysate at 200℃and 30 min with the value of 1.20±0.12 mg/g and 71.6±1.3%,respectively.展开更多
Hydrothermal carbonization(HTC)stands out as an eco-friendly,cost-effective method for generating renewable carbon-based materials from biomass.The HTC process yields products such as hydrochars and carbon dots(CDs),p...Hydrothermal carbonization(HTC)stands out as an eco-friendly,cost-effective method for generating renewable carbon-based materials from biomass.The HTC process yields products such as hydrochars and carbon dots(CDs),possessed of notable photocatalytic capabilities due to their unique physicochemical features.Additionally,pairing traditional photocatalysts with hydrochar derivatives elevates their performance,rendering them more effective.Recent times have witnessed a surge in interest in these hydrochar based photocatalysts(HC-photocatalysts).Their appeal stems from multiple attributes:impeccable performance,adaptability to visible light,and adjustable physicochemical properties.This review delves deep into the evolving landscape of these HC-photocatalysts,segmenting them into three distinct categories:hydrochars,hydrochar-based CDs(HC-CDs),and hydrochar-based composites(HC-composites).For each category,we dissect their synthesis routes,unravel the photocatalytic mechanisms,and explore various enhancement strategies.We further traverse their versatile applications,spanning environmental treatment,disinfection,energy conversion,and organic synthesis.In the end,we spotlight the prevailing challenges and uncharted territories in the domain of HC-photocatalysts.In essence,this review serves as a guide,furnishing a theoretical foundation and steering directions for future explorations and tangible implementations of HC-photocatalysts.展开更多
Limited information is available about potential physicochemical changes that can occur in hydrochar post-production,e.g.during drying and storage.Understanding these changes is crucial not just for shaping future res...Limited information is available about potential physicochemical changes that can occur in hydrochar post-production,e.g.during drying and storage.Understanding these changes is crucial not just for shaping future research plans,but also for future practical applications.Here we studied the effect of moisture(69.2%and 2.4%)and three storage temperatures(−18,4,and 20°C)over a year on selected organic and inorganic compounds in hydrochar produced from the Hydrothermal carbonization(HTC)of digested cow manure.Comparison of the control wet hydrochars(WHs)and dry hydrochars(DHs)showed changes in organic compound composition due to drying.Overall,the total amount of the selected organic compounds was notably greater in WH(15.2 g kg−1 DM)compared to DH(11.8 g kg−1 DM),with variations observed in individual compound concentrations.Drying,however,had no significant influence on the identified inorganic compounds.Storage caused significant changes in both WH and DH,particularly in organic compounds after 12 weeks.Sugars(2-sevenfold),acids(36-371%),and aromatics(58-120%)in stored samples at week 52 were significantly higher than their control values.Changes in the inorganic elements(e.g.,Co,K,Mg,Mn,P,S,Sr,and Zn)occurred faster in WH,with significant differences starting from week 1 compared to their control values,while DH showed fewer changes.Based on these changes in both organic and inorganic content,we recommend the optimal storage conditions for future HTC studies to preserve hydrochar properties.Finally,we discussed potential applications for stored hydrochars,with DH showing greater stability,especially at−18°C,making it suitable for various applications.展开更多
Hydrochar from waste biomass is a promising material for removing emerging contaminants(e.g.,antibiotics)in water/soil environment.Abundant small-sized hydrochar particles(HPs)with a high content of reactive functiona...Hydrochar from waste biomass is a promising material for removing emerging contaminants(e.g.,antibiotics)in water/soil environment.Abundant small-sized hydrochar particles(HPs)with a high content of reactive functional groups and high mobility are easily released into ecosystems through hydrochar applications.However,the photodegradation ability and corresponding structures of HPs are largely unknown,which hinder accurate estimation of the remediation effect of hydrochar in ecosystems.Herein,photodegradation performance of HP towards targeted norfloxacin(NOR,a typical antibiotic)under light irradiation(visible and UV light)were investigated after adsorption processes upon release into soil/water,and its reactive species and photoactive structures were clarified and compared with those of residual bulk hydrochar(BH)comprehensively.The results showed that:(1)photodegradation percentages of HPs were 4.02 and 4.48 times higher than those of BHs under UV and visible light,in which reactive species of both HPs and BHs were·OH and·O2−;(2)density functional theory(DFT)results identified that the main photoactive structure of graphitic-N decreased the energy gap(Eg)of HPs,and C=O,COOH groups improved electron donating ability of BHs;(3)well-developed graphitization structure of HP resulted from higher polymerization reaction was an significant photoactive structure involving its superior photodegradation ability relative to that of BH.The distinct heterogeneities of photodegradation ability in HP and BH and underlying photoactive structures provide an in-depth understanding of hydrochar application for removing emerging contaminants in soil/water environment.Identifying photoactive structures is helpful to predict photodegradation ability of hydrochar according to their abundance.展开更多
Hydrothermal carbonization(HTC)is a thermochemical conversion technology to produce hydrochar from wet biomass without drying,but it is time-consuming and expensive to experimentally determine the optimal HTC operatio...Hydrothermal carbonization(HTC)is a thermochemical conversion technology to produce hydrochar from wet biomass without drying,but it is time-consuming and expensive to experimentally determine the optimal HTC operational conditions of specific biomass to produce desired hydrochar.Therefore,a machine learning(ML)approach was used to predict and optimize hydrochar properties.Specifically,biochemical components(proteins,lipids,and carbohydrates)of biomass were predicted and analyzed first via elementary composition.Then,accurate single-biomass(no mixture)based ML multi-target models(average R^(2)=0.93 and RMSE=2.36)were built to predict and optimize the hydrochar properties(yield,elemental composition,elemental atomic ratio,and higher heating value).Biomass composition(elemental and biochemical),proximate analyses,and HTC conditions were inputs herein.Interpretation of the model results showed that ash,temperature,and the N and C content of biomass were the most critical factors affecting the hydrochar properties,and that the relative importance of biochemical composition(25%)for the hydrochar was higher than that of operating conditions(19%).Finally,an intelligent system was constructed based on a multi-target model,verified by applying it to predict the atomic ratios(N/C,O/C,and H/C).It could also be extended to optimize hydrochar production from the HTC of single-biomass samples with experimental validation and to predict hydrochar from the co-HTC of mixed biomass samples reported in the literature.This study advances the field by integrating predictive modeling,intelligent systems,and mechanistic insights,offering a holistic approach to the precise control and optimization of hydrochar production through HTC.展开更多
To reveal the influence of the diversity of precursors on the formation of environmental persistent free radicals(EPFRs),pomelo peel(PP)and its physically divided portion,pomelo cuticle(PC),and white fiber(WF)were use...To reveal the influence of the diversity of precursors on the formation of environmental persistent free radicals(EPFRs),pomelo peel(PP)and its physically divided portion,pomelo cuticle(PC),and white fiber(WF)were used as precursors to prepare six hydrochars:PPH-Fe,PCH-Fe,WFH-Fe,PPH,PCH,and WFH with and without Fe(III)addition during hydrothermal carbonization(HTC).PPH-Fe and WFH-Fe had higher EPFRs content(9.11×10^(18)and 8.25×10^(18)spins·g^(−1))compared to PPH and WFH(3.33×10^(18)and 2.96×10^(18)spins·g^(−1)),indicating that iron-doping favored EPFRs formation.However,PCH-Fe had lower EPFRs content(2.78×10^(18)spins·g^(−1))than PCH(7.95×10^(18)spins·g^(−1)),possibly due to excessive iron leading to the consumption of the generated EPFRs.For another reason,the required Fe(III)amount for EPFRs formation might vary among different precursors.PC has a lower concentration of phenolic compounds but 68-97%fatty acids,while WF and PP are rich in cellulose and lignin.In the Fenton-like reaction,oxygen-centered radicals of hydrochar played a significant role in activating H_(2)O_(2)and efficiently degrading bisphenol A(BPA).Mechanisms of reactive oxygen species(ROS)generation in hydrochar/H_(2)O_(2)system were proposed.EPFRs on hydrochar activate H_(2)O_(2)via electron transfer,creating·OH and 1O2,leading to BPA degradation.More importantly,the embedded EPFRs on the hydrochar’s inner surface contributed to the prolonged Fenton-like reactivity of PPH-Fe stored for 45 days.This study demonstrates that by optimizing precursor selection and iron doping,hydrochars can be engineered to maximize their EPFRs content and reactivity,providing a cost-effective solution for the degradation of hazardous pollutants.展开更多
基金supported by the Director Fund Project provided by the Institute of Plant Nutrition,Resources and Environment,Beijing Academy of Agriculture and Forestry Sciences(No.YZS202101)the Youth Fund Project provided by Beijing Academy of Agriculture and Forestry Sciences(No.QNJJ202125)China Agriculture Research System of MOF and MARA.
文摘The dissolved organic matter(DOM)with high mobility and reactivity plays a crucial role in soil.In this study,the characteristics and phytotoxicity ofDOMreleased fromthe hydrochars prepared from different feedstocks(cowmanure,corn stalk and Myriophyllum aquaticum)under three hydrothermal carbonization(HTC)temperatures(180,200 and 220°C)were evaluated.The results showed that the hydrochars had high dissolved organic carbon content(20.15 to 37.65 mg/g)and its content showed a gradual reduction as HTC temperature increased.Three fluorescent components including mixed substance of fulvic acid-like and humic acid-like substances(C1,30.92%-58.32%),UVA humic acid-like substance(C2,25.27%-29.94%)and protein-like substance(C3,11.74%-41.92%)were identified in hydrochar DOM by excitation emission matrix spectra coupled with parallel factor analysis.High HTC temperature increased the relative proportion of aromatic substances(C1+C2)and humification degree of hydrochar DOM from cow manure,while it presented adverse effects on the hydrochar DOM from corn stalk and Myriophyllum.aquaticum.The principal component analysis suggested that feedstock type and HTC temperature posed significant effects on the characteristics of hydrochar DOM.Additionally,seed germination test of all hydrochar DOM demonstrated that the root length was reduced by 8.88%-26.43%in contrast with control,and the germination index values were 73.57%-91.12%.These findings provided new insights into the potential environmental effects for hydrochar application in soil.
基金supported by the National Natural Science Foundation of China(No.42307090)the Open Subject from State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in theMiddle and Lower Reaches of Yangtze River(No.AEHKF2023008).
文摘The copper complexing of dissolved organic matter released from hydrochar(HDOM)affects the former’s environmental behavior.In this study,how hydrothermal temperatures(180,220 and 260℃)influence the molecular-level constitutions and Cu(II)binding features of HDOM were elucidated via fourier transform ion cyclotron resonance mass spectrometry and multi-spectroscopic analysis.The findings demonstrated that the almost HDOM molecules had the traits of lower polarity and higher hydrophobicity.As the hydrothermal temperature increased,the molecules with particularly high relative strength gradually disappeared,average molecular weight,percentages of CHON and aliphatic compounds of HDOM reduced while the percentages of CHO and aromatic compounds increased.In general,the fluorescence quenching of Cu(II)weakened as hydrothermal temperature rose and the Cu(II)binding stability constants of fluorophores in HDOM were 4.50–5.31.In addition,the Cu(II) binding order of fluorophores in HDOM showed temperature heterogeneities, andpolysaccharides or aromatic rings of non-fluorescent substances had the fastest responsesto Cu(II) binding. Generally, fluorescent components tend to bind Cu(II) at relatively traceconcentrations (0–40 μmol/L), whereas non-fluorescent substances tend to the bind Cu(II)at relatively higher concentrations (50–100 μmol/L). This study contributed to the predictionof the potential environmental behaviors and risks of Cu(II) at the molecular level afterhydrochar application.
基金supported by grants funded by the Hong Kong Research Grants Council(Grant No.CRF/C6006-20G)a grant provided by the Joint NSFC/RGC Joint Research Scheme(Grant No.N_HKUST603/22)the Fundamental Research Funds for the Central Universities(Grant No.Z1090125018).
文摘The effectiveness of using vegetation to stabilise shallow soil slopes heavily depends on the survival of vegetation,yet the amplification of extreme events induced by climate change threatens the health of plants covering slopes.Hydrochar is an environmentally friendly soil amender that can achieve the potential benefits of promoting plant growth for slope stabilisation and facilitation of waste upcycling.The mechanism underlying the hydrochar effects on the mechanical behaviour of unsaturated soils remains unclear.This study investigated the influence of grass-derived hydrochar on the water retention,compressibility,and shear strength of a compacted siltyeclay sand.Soil microstructural changes due to hydrochar amendment were measured to explain the soilehydrochar hydromechanical interaction.The increase in suction resulted in a less significant increase in yield stress and a negligible reduction in compressibility of the hydrochar-amended soil compared with the unamended case.This phenomenon was observed because hydrochar addition reduced the large pores with diameters greater than the macropore peak of 60 mm due to pore filling by hydrochar particles,resulting in a less substantial volume contraction during drying.Hydrochar introduced more significant effects on the soil’s shear strength in an unsaturated state compared to a saturated case.Despite the similarity of the unsaturated amended soil with the critical-state friction angle to the saturated case,the former exhibited a greater shear strength because the hydrochar addition improved water retention capability.As a result,the degree of saturation and,hence,Bishop’s effective stress were higher than those for the unamended case for a given suction.
基金supported by the National Natural Science Foundation of China(52261145701 and U21A20162)the 2115 Talent Development Program of China Agricultural University.
文摘The function-led design of porous hydrochar from mineral-rich biowaste for environmental applications inevitably suffers from carbon-ash recalcitrance.However,a method to alter the original carbon skeleton with ash remains elusive and hinders the availability of hydrochar.Herein,we propose a facile strategy for breaking the rigid structure of carbon-ash coupled hydrochar using phase-tunable molten carbonates.A case system was designed in which livestock manure and NaHCO3 were used to prepare the activated hydrochar,and NH3 served as the target contaminant.Due to the redox effect,we found that organic fractions significantly advanced the melting temperature of Na2CO3 below 800℃.The Na species steadily broke the carbon-ash interaction as the thermal intensity increased and transformed inorganic constituents to facilitate ash dissolution,rebuilding the hydrochar skeleton with abundant hierarchical channels and active defect edges.The surface polarity and mesopore distribution collectively governed the five cycles NH3 adsorption attenuation process.Manure hydrochar delivered favorable potential for application with a maximum overall adsorption capacity of 100.49 mg·g^(-1).Integrated spectroscopic characterization and theoretical computations revealed that incorporating NH3 on the carbon surface could transfer electrons to chemisorbed oxygen,which promoted the oxidation of pyridine-N during adsorption.This work offers deep insight into the structure function correlation of hydrochar and inspires a more rational design of engineered hydrochar from high-ash biowaste.
文摘The Response Surface Methodology (RSM) was used to optimise the conditions of preparation of activated hydrochar from tannery solid waste by hydrothermal carbonisation (HTC). The main factors such as residence time, moisture content and final carbonisation temperature were investigated during the optimisation of hydrochar preparation conditions. The three responses investigated are hydrochar yield, iodine and methylene blue indices. The results of experimental analyses showed that the yield of hydrochar decreases with increasing final temperature, leading to the formation of micropores inside the carbonaceous solid. The optimum conditions for preparing the following hydrochar were obtained: 83.10%, 390.44 mg∙g−1 and 259.63 mg∙g−1 respectively for the hydrochar yield, the iodine and methylene blue indices. The specific surface area of prepared hydrochar is 849.160 m2/g, SEM micrographs showed a porous heterogeneous surface and particularly, the hydrochar surface also revealed external pores on the hydrochar surface which acted as a pathway to the micropores. Fourier transform infrared (FTIR), however, showed a predominance of acid functions on the surface of the carbonaceous solids. Tests were carried out to eliminate indigo carmine in aqueous media. Activated hydrochar showed a high level of activity, with the Langmuir and Freundlich isotherms giving an adsorption quantity of 354.610 mol/g and a KF constant of 468.2489, respectively. The findings of the research revealed that hydrochar produced is well adapted for dyes removal.
基金financially supported by the National Natural Science Foundation of China (41071206)
文摘Innovative measure is a urgent requirement for managing the huge volume of municipal sewage sludge. The hydrothermal carbonation （HTC） shows some potential advantages for using hydrochar as a soil conditioner. The aim of this work was to investigate the properties of hydrochars, by means of the HTC of municipal sewage sludge under different temperatures （190 and 260~C） and reaction hours （1, 6, 12, 18 and 24 h）. The HTC led to the decreases of N, O and H contents by more than 54.6, 37.9 and 10.0%, respectively, and slight changes of C content. The Py-GC-MS analysis showed that a large proportion of fatty acids, in particular hexadecanoic acid, transferred into alkenes, olefins and aromatic compounds. The 13C-NMR and fourier transform infrared spectra （FTIR） confirmed the transformation and changes in chemical structure in which hydrochar contained lower oxygen-containing organic C of O-alkyl, carboxylic and carbonyl C and aliphaticity, but higher aromatic C and aromaticity. The rich hydrophobic functions induced in high positive charges in the charred sludge. The HTC facilitated the pore structure development, proved by higher specific surface area and specific pore volume, with a maximum of 17.30 and 0.83 cm^3 g^-1, respectively. The availabilities of N, P and K markedly reduced during HTC treatment. The activities of most heavy metals were depressed though they accumulated in the hydrochar. Further work is required to investigate the values and risk of the charred sludge amended to soil.
基金This work was financially supported by the National Natural Science Foundation of China(No.21701099)the Science and Technology Innovation Project of Colleges and Universities of Shanxi Province in 2020(No.2020L0721)the Basic Research Project of Shanxi Province,China(No.201801D121267).
文摘In this paper,a novel compound was developed by mixing H_(3)PO_(4)-modified cauliflower leaves hydrochar(CLH)and coal gangue-based Na-X zeolite(ZL).An alkaline soil contaminated with cadmium(Cd)and lead(Pb)was amended through the individual and synergistic application of CLH and ZL(1%CLH,2%CLH,1%ZL,2%ZL and 1%CLH+1%ZL),and Chinese cabbage was grown on it.Individual application of CLH was superior to ZL on decreasing the pH of alkaline soil and increasing soil available phosphorus(Olsen-P)and soil organic matter(SOM).In contrast,their combined application significantly improved the soil cation exchange capacity(CEC).Besides,the 1%CLH+1%ZL was the most efficient treatment in decreasing diethylenetriamine pentaacetate(DTPA)-extractable Cd/Pb and concentrations of these two metals in cabbage root and shoot.Their synergistic application could better increase Cd and Pb immobilization and cabbage yield than their alone application.Furthermore,the immobilization of Pb for all treatments was higher than that of Cd.The synergistic immobilization mechanism of CLH and ZL reflected that the CLH precipitated and complexed with these two metals,which may block the pores of hydrochar or wrap on the surface of hydrochar.So the continuous adsorption and complexation were prevented.Nevertheless,ZL could probably alleviate this obstacle.This finding provides helpful information about using CLH combined with ZL as a soil stabilizer to immobilize heavy metals in contaminated alkaline soil.
基金the National Natural Science Foundation of China(NNSFC21706134)the Young Natural Science Foundation of Jiangsu Province(BK20170918)for financial supportsupport from the“Advanced analysis and testing center of Nanjing Forestry University.”
文摘A rising global population and aspirational higher living standards has driven a step change in resource utilization and concomitant anthropogenic pollution across the biosphere.Low-cost and scalable technologies for environmental remediation are therefore urgently sought,with an emphasis on trash-to-treasure strategies that exploit abundant but underutilized waste by-products of existing sectors.Biochars are carbon-rich,porous solids produced by biomass pyrolysis under anaerobic or oxygen-scarce conditions at high temperature(350–700°C),while hydrochars are produced by hydrothermal biomass carbonization at lower temperature(130–250°C)and high autogenous pressures(0.3–4.0 MPa).Bio/hydrochars possess unique physicochemical properties,notably high surface areas(100–1500 m2 g-1)and porosity(0.25–2.5 cm^(3)g^(-1))and rich surface chemistry featuring carboxylic,phenolic,hydroxyl,and carbonyl functions,amenable to chemical,physical,or biochemical modification,rendering them ideal sorbents for pollutants such as heavy metals(e.g.As and Cr),and toxic organic(e.g.,dyes and xenobiotics)and inorganic(e.g.,SO_(2))molecules.Bio/hydrochars are attractive for environmental remediation of pollutant mixtures by surface complexation,redox chemistry,electrostatic interactions/ion exchange,or coprecipitation.This review discusses recent opportunities and challenges in creating bio/hydrochar sorbents and their nanocomposites through grafting,doping,and chemical/physical activation,for the depollution of aquatic and atmospheric environments.
基金financial support by the National Natural Science Foundation of China(No.41472095)the Open Fund of Key Laboratory of Exploration Technologies for Oil and Gas Resources(Yangtze University)+1 种基金Ministry of Education(No.K2018-05)the Foundation of Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals,Shandong University of Science and Technology(Grant No.DMSM2018041).
文摘The corncob hydrochar is prepared by using a stainless autoclave at 230?C for 8 h.The products are characterized by elemental analyzer,Fourier Transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and scanning electron microscope(SEM).The effects of hydrochar dosage,pH,adsorption time and phenol concentration on the adsorption performance of hydrochar are investigated by means of single-factor experimental analysis.Based on the experiments the adsorption thermodynamic and kinetics are tentatively discussed.The results show that abundant oxygen-containing functional groups are scattered on the surface of the corncob hydrochar.The adsorption kinetics of phenol on the hydrochar corresponds well with pseudo-second-order kinetic model.Thermodynamic studies indicate that Freundlich adsorption isotherm model is much better than Langmuir model in describing the adsorption of phenol on the corncob hydrochar at 25?C-45?C.This study provides scientific basis for the development of cheap and efficient adsorbents for the removal of phenols derived from oilfield wastewater.
基金supported by the Fundamental Research Funds for the Central Universities of Southwest Jiaotong University,supported by Sichuan Science and Technology Program(2021YFS0284).
文摘Hydrothermal carbonization is highly applicable to high moisture biomass upgrading due to the fact that moist-ure involved can be directly used as reaction media under the subcritical-water region.With this,value-added utilization of hydrochar as solid fuel with high carbon and energy density is one of the important pathways for biomass conversion.In this review,the dewatering properties of hydrochar after the hydrothermal carbonization of biowaste,coalification degree with elemental composition and evolution,pelletization of hydrochar to enhance the mechanical properties and density,coupled with the combustion properties of hydrochar biofuel were discussed with various biomass and carbonization parameters.Potential applications for the co-combustion with coal,cleaner properties and energy balance for biowaste hydrothermal carbonization were presented as well as the challenges.
基金supported by the Opening Project of Key Laboratory of Agricultural Renewable Resource Utilization Technology (No.HLJHDNY2104)Funding for the National Natural Science Foundation of China (NSFC U21A20162)+2 种基金Heilongjiang Postdoctoral Financial Assistance (LBH-Z21042)University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (UNPYSCT-2020106)Sichuan Science and Technology Program (2022NSFSC1162).
文摘Hydrochar prepared with four typical biowastes,pine wood,food waste,digested sewage sludge,and Chlorella were applied for the promotion of anaerobic digestion.The gas production and substrate composition were analyzed associated with the hydrochar characteristics.The results suggested that Chlorella hydrochar(C-C)showed the highest cumulative yield of methane(approximately 345 mL)with high total organic carbon(TOC)removal efficiency and low volatile fatty acids(VAFs)concentration.Especially,food waste hydrochar(F-C)showed a poor effect on anaerobic digestion and aroused 1.4–1.6 g/L accumulation of VAFs,in which the toxic components may account for the low efficiency.The C-C and sludge hydrochar(S-C)may develop direct interspecific electron transport(DIET)to facilitate the generation of methane by both surface groups and conductivity of the body structure,unlike pinewood hydrochar(P-C),which mainly depended on the aromatic matrix structure of hydrochar body.This work suggested that C-C can be the best candidate for the facilitation of anaerobic digestion,and N-containing biowaste like algae and lignocellulose like pine wood may establish different DIET pathways based on the physicochemical characteristics of hydrochar.
基金the National Natural Science Foundation of China(Nos.41877090 and 42107398)Natural Science Foundation of Jiangsu Province(BK20181165 and BK20210358)+1 种基金China Postdoctoral Science Foundation(2020M68618)Yunnan Branch of China National Tobacco Corporation(2022530000241022).
文摘Hydrochar has potential applications in soil improvement and heavy metal remediation.Hydrochar would undergo the process of aging when introduced into the soil,altering its properties.However,recent studies have focused mainly on the artificial aging of hydrochar,which could not reveal the cumulative effect of multiple environmental factors.Therefore,the periodical monitoring of the property and sorption behavior of hydrochar after amending soils is necessary to better understand the multifaceted mechanisms associated with the natural aging of hydrochar.This study selected the sludge-derived hydrochar(SLHC)as a typical hydrochar and applied a 16-month rice-wheat-rice rotation to mimic the natural aging of hydrochar,focusing on changing properties and cadmium(Cd)sorption and literature contrast between aging strategies and biochar types.The porosity,O abundance,and ash content of 16-month aged SLHC increased by 37%,47%,and 8.5%,respectively,facilitating Cd sorption due to surface complexation,pore sorption,and precipitation.The sorption percentage of Cd to SLHC was in the range of 11-14%for SLHC-A0 and increased to 17-31%for SLHC-A4 and 20-32%for SLHC-A16 after natural aging.The natural aging of SLHC induced by ash content played an essential role in Cd sorption site heterogeneity.Linear regression analysis showed that aging strategies on sorption behavior significantly differed between biochars.Thus,studies involving natural aging with multiple environmental factors are preferred over those involving chemical or biological aging.Future studies should continue to explore the mechanisms of natural aging-induced heavy metal sorption between hydrochar and pyrochar.These results improve insights to appraise the potential of SLHC as soil amendments to alleviate the adverse effects of heavy metal contamination and provide an essential basis for researchers and staff in soil management and environmental prevention.
基金supported by the Outstanding Youth Research Project in Anhui Provincial Scientific Research Plan Project(2022AH020089)Anhui Province University Top Talent Funding Project(gxbjZD2021069)+1 种基金Excellent Scientific Research and Innovation Team of Universities in Anhui Province(2023AH010062)Commissioned R&D project(ZHEP2021001,BOFA202007).
文摘Hydrothermal carbonization(HTC)has been regarded as a promising technique for turning wet biomass into hydrochar due to its low energy consumption,low exhaust gas emissions,etc.In addition,hydrochar is an important source of dissolved organic matter(DOM),which plays a crucial part in the migration and destiny of pollutants in the environmental medium.However,there are limited studies that focus on the factors that influence the formation of DOM in hydrochar,such as hydrothermal temperature.Therefore,the current study comprehensively characterized the optical properties of DOM within hydrochar derived from sawdust(HDOM)under different hydrothermal temperatures(150-300℃)by Ultraviolet-visible(UV-Vis)and fluorescence spectroscopy,as well as its complexation characteristic with Cu(II).The findings revealed that the organic carbon content of HDOM reached a peak of 37.3 mg L^(−1)when the temperature rose to 240℃and then decreased as the temperature increased.UV-Vis spectroscopy analysis showed that the absorption capacity of HDOM at 275 nm increases with temperature and reaches a maximum value at 240℃,indicating that high temperature promotes the formation of monocyclic aromatic compounds.High temperature enhances the aromaticity,hydrophobicity,and humification degree of HDOM,thus improving its stability and aromaticity.The E3/E4 ratios are all greater than 3.5,confirming that the main component of HDOM is fulvic acid,which corresponds to 3D-EEM and Pearson’s correlation coefficient analysis.The humification index(HIX)of HDOM increased with the rise in hydrothermal temperature(150-240℃),as observed by the three-dimensional excitation-emission matrix spectroscopy(3D-EEMs).After reaching its peak at 240℃,the HIX value gradually dropped in line with the trend of the DOC change.Moreover,the bioavailability(BIX)value of DOM was all high and greater than 1,indicating all the HDOM are readily bioavailable.Two microbial humic substances(C1 and C4),a humic-like substance(C2),and a protein-like substance(C3)were discovered in DOM by integrating 3D-EEMs with parallel factor analysis(PARAFAC).Their fluorescence intensity decreases as the Cu(II)concentration increases,indicating the formation of complexes with Cu(II).As the temperature rises,the binding ability of DOM and Cu(II)changes significantly,reaching the optimum at 300℃.Meanwhile,the substance C2 has the strongest binding ability with Cu(II).This research emphasizes the significance of spectroscopy analysis in determining the evolution of hydrochar-derived DOM,the potential for heavy metal binding and migration,and its characteristics and features.
基金The financial support from the National Natural Science Foundation of China(Grant No.52276202)the National Key R&D Program of China(Grant No.2020YFC1910100)+4 种基金the Tsinghua University-Shanxi Clean Energy Research Institute Innovation Project Seed FundHuaneng Group Science and Technology Research Project(Grant No.KTHT-U22YYJC12)the International Joint Mission On Climate Change and Carbon NeutralityTsinghua-Toyota Joint Research Fundand State Key Laboratory of Chemical Engineering(Grant No.SKL-ChE-22A03)are gratefully acknowledged.
文摘Lignin,an abundant aromatic polymer in nature,has received significant attention for its potential in the production of bio-oils and chemicals owing to increased resource availability and environmental issues.The hydrodeoxygenation of guaiacol,a lignin-derived monomer,can produce cyclohexanol,a nylon precursor,in a carbon-negative and environmentally friendly manner.This study explored the porous properties and the effects of activation methods on the Ru-based catalyst supported by environmentally friendly and cost-effective hydrochar.Highly selective cleavage of C_(ary)-O bonds was achieved under mild conditions(160°C,0.2 MPa H_(2),and 4 h),and alkali activation further improved the catalytic activity.Various characterization methods revealedthat hydrothermal treatment and alkali activation relatively contributed to the excellent performance of the catalysts and influenced their porous structure and Ru dispersion.X-ray photoelectron spectroscopy results revealed an increased formation of metallic ruthenium,indicating the effective regulation of interaction between active sites and supports.This synergistic approach used in this study,involving the valorization of cellulose-derived hydrochar and the selective production of nylon precursors from lignin-derived guaiacol,indicated the comprehensive and sustainable utilization of biomass resources.
基金financially by the Indonesian Endowment Fund for Education(LPDP)through“RISPRO KI”the International Research Collaboration(Grant No.RISPRO/KI/B1/KOM/12/11684/1/2020).
文摘This study investigates the simultaneous production of hydrochar and bioactive compounds from Ulva lactuca via a hydrothermal process.The experiment was carried out using a batch reaction vessel at different reaction temperatures of 180-220◦C and various holding times of 30-90 min.As expected,both temperature and time vigorously influenced hydrochar and bioactive compound production.The maximum hydrochar yield was at 32.4 wt%.The higher heating value(HHV)of hydrochar was observed in the range of 17.68-21.07 MJ kg^(-1),near the energy content of low-rank coals.The hydrochars exhibited contact angles higher than 90°(i.e.,94-108°)for a longer time,confirming their hydrophobic surfaces.The scanning electron microscope analysis(SEM)showed that the hydrothermal process enables cracks in the spherical shape of raw U.lactuca into small and porous particles.Besides producing hydrochar,the hydrothermal process of U.lactuca also gives promising antioxidants and phenolics as bioactive compounds.The highest total phenolic content and antioxidant activity could be achieved in hydrolysate at 200℃and 30 min with the value of 1.20±0.12 mg/g and 71.6±1.3%,respectively.
基金funded by Shandong Province Major Scientific and Techno-logical Innovation Project(2021CXGC010803)the National Natural Science Foundation of China(21876188).
文摘Hydrothermal carbonization(HTC)stands out as an eco-friendly,cost-effective method for generating renewable carbon-based materials from biomass.The HTC process yields products such as hydrochars and carbon dots(CDs),possessed of notable photocatalytic capabilities due to their unique physicochemical features.Additionally,pairing traditional photocatalysts with hydrochar derivatives elevates their performance,rendering them more effective.Recent times have witnessed a surge in interest in these hydrochar based photocatalysts(HC-photocatalysts).Their appeal stems from multiple attributes:impeccable performance,adaptability to visible light,and adjustable physicochemical properties.This review delves deep into the evolving landscape of these HC-photocatalysts,segmenting them into three distinct categories:hydrochars,hydrochar-based CDs(HC-CDs),and hydrochar-based composites(HC-composites).For each category,we dissect their synthesis routes,unravel the photocatalytic mechanisms,and explore various enhancement strategies.We further traverse their versatile applications,spanning environmental treatment,disinfection,energy conversion,and organic synthesis.In the end,we spotlight the prevailing challenges and uncharted territories in the domain of HC-photocatalysts.In essence,this review serves as a guide,furnishing a theoretical foundation and steering directions for future explorations and tangible implementations of HC-photocatalysts.
文摘Limited information is available about potential physicochemical changes that can occur in hydrochar post-production,e.g.during drying and storage.Understanding these changes is crucial not just for shaping future research plans,but also for future practical applications.Here we studied the effect of moisture(69.2%and 2.4%)and three storage temperatures(−18,4,and 20°C)over a year on selected organic and inorganic compounds in hydrochar produced from the Hydrothermal carbonization(HTC)of digested cow manure.Comparison of the control wet hydrochars(WHs)and dry hydrochars(DHs)showed changes in organic compound composition due to drying.Overall,the total amount of the selected organic compounds was notably greater in WH(15.2 g kg−1 DM)compared to DH(11.8 g kg−1 DM),with variations observed in individual compound concentrations.Drying,however,had no significant influence on the identified inorganic compounds.Storage caused significant changes in both WH and DH,particularly in organic compounds after 12 weeks.Sugars(2-sevenfold),acids(36-371%),and aromatics(58-120%)in stored samples at week 52 were significantly higher than their control values.Changes in the inorganic elements(e.g.,Co,K,Mg,Mn,P,S,Sr,and Zn)occurred faster in WH,with significant differences starting from week 1 compared to their control values,while DH showed fewer changes.Based on these changes in both organic and inorganic content,we recommend the optimal storage conditions for future HTC studies to preserve hydrochar properties.Finally,we discussed potential applications for stored hydrochars,with DH showing greater stability,especially at−18°C,making it suitable for various applications.
基金supported by the National Natural Science Foundation of China(No.42207276)National Key Research and Development Program of China(2021YFD1700805).
文摘Hydrochar from waste biomass is a promising material for removing emerging contaminants(e.g.,antibiotics)in water/soil environment.Abundant small-sized hydrochar particles(HPs)with a high content of reactive functional groups and high mobility are easily released into ecosystems through hydrochar applications.However,the photodegradation ability and corresponding structures of HPs are largely unknown,which hinder accurate estimation of the remediation effect of hydrochar in ecosystems.Herein,photodegradation performance of HP towards targeted norfloxacin(NOR,a typical antibiotic)under light irradiation(visible and UV light)were investigated after adsorption processes upon release into soil/water,and its reactive species and photoactive structures were clarified and compared with those of residual bulk hydrochar(BH)comprehensively.The results showed that:(1)photodegradation percentages of HPs were 4.02 and 4.48 times higher than those of BHs under UV and visible light,in which reactive species of both HPs and BHs were·OH and·O2−;(2)density functional theory(DFT)results identified that the main photoactive structure of graphitic-N decreased the energy gap(Eg)of HPs,and C=O,COOH groups improved electron donating ability of BHs;(3)well-developed graphitization structure of HP resulted from higher polymerization reaction was an significant photoactive structure involving its superior photodegradation ability relative to that of BH.The distinct heterogeneities of photodegradation ability in HP and BH and underlying photoactive structures provide an in-depth understanding of hydrochar application for removing emerging contaminants in soil/water environment.Identifying photoactive structures is helpful to predict photodegradation ability of hydrochar according to their abundance.
基金supported by the National Key Research and Development Program of China(2021YFE0104900)the Open Project of Xiangjiang Laboratory(22xj03003)the Science and Technology Innovation Program of Hunan Province(2021RC4005,2021GK1210).
文摘Hydrothermal carbonization(HTC)is a thermochemical conversion technology to produce hydrochar from wet biomass without drying,but it is time-consuming and expensive to experimentally determine the optimal HTC operational conditions of specific biomass to produce desired hydrochar.Therefore,a machine learning(ML)approach was used to predict and optimize hydrochar properties.Specifically,biochemical components(proteins,lipids,and carbohydrates)of biomass were predicted and analyzed first via elementary composition.Then,accurate single-biomass(no mixture)based ML multi-target models(average R^(2)=0.93 and RMSE=2.36)were built to predict and optimize the hydrochar properties(yield,elemental composition,elemental atomic ratio,and higher heating value).Biomass composition(elemental and biochemical),proximate analyses,and HTC conditions were inputs herein.Interpretation of the model results showed that ash,temperature,and the N and C content of biomass were the most critical factors affecting the hydrochar properties,and that the relative importance of biochemical composition(25%)for the hydrochar was higher than that of operating conditions(19%).Finally,an intelligent system was constructed based on a multi-target model,verified by applying it to predict the atomic ratios(N/C,O/C,and H/C).It could also be extended to optimize hydrochar production from the HTC of single-biomass samples with experimental validation and to predict hydrochar from the co-HTC of mixed biomass samples reported in the literature.This study advances the field by integrating predictive modeling,intelligent systems,and mechanistic insights,offering a holistic approach to the precise control and optimization of hydrochar production through HTC.
基金supported by the National Key Research and Development Program of China(No.2020YFC1808103)Science&Technology Commission of Shanghai Municipality(No.22002400500)+1 种基金National Natural Science Foundation of China(20907029 and 21577085)Natural Science Fund Projects of Shanghai Municipal Science and Technology Commission(No.14ZR1415600).
文摘To reveal the influence of the diversity of precursors on the formation of environmental persistent free radicals(EPFRs),pomelo peel(PP)and its physically divided portion,pomelo cuticle(PC),and white fiber(WF)were used as precursors to prepare six hydrochars:PPH-Fe,PCH-Fe,WFH-Fe,PPH,PCH,and WFH with and without Fe(III)addition during hydrothermal carbonization(HTC).PPH-Fe and WFH-Fe had higher EPFRs content(9.11×10^(18)and 8.25×10^(18)spins·g^(−1))compared to PPH and WFH(3.33×10^(18)and 2.96×10^(18)spins·g^(−1)),indicating that iron-doping favored EPFRs formation.However,PCH-Fe had lower EPFRs content(2.78×10^(18)spins·g^(−1))than PCH(7.95×10^(18)spins·g^(−1)),possibly due to excessive iron leading to the consumption of the generated EPFRs.For another reason,the required Fe(III)amount for EPFRs formation might vary among different precursors.PC has a lower concentration of phenolic compounds but 68-97%fatty acids,while WF and PP are rich in cellulose and lignin.In the Fenton-like reaction,oxygen-centered radicals of hydrochar played a significant role in activating H_(2)O_(2)and efficiently degrading bisphenol A(BPA).Mechanisms of reactive oxygen species(ROS)generation in hydrochar/H_(2)O_(2)system were proposed.EPFRs on hydrochar activate H_(2)O_(2)via electron transfer,creating·OH and 1O2,leading to BPA degradation.More importantly,the embedded EPFRs on the hydrochar’s inner surface contributed to the prolonged Fenton-like reactivity of PPH-Fe stored for 45 days.This study demonstrates that by optimizing precursor selection and iron doping,hydrochars can be engineered to maximize their EPFRs content and reactivity,providing a cost-effective solution for the degradation of hazardous pollutants.
