Hydrothermal treatment(HTT)can efficiently valorize the digestate after anaerobic digestion.However,the disposal of the HTT liquid is challenging.This paper proposes a method to recover energy through the anaerobic co...Hydrothermal treatment(HTT)can efficiently valorize the digestate after anaerobic digestion.However,the disposal of the HTT liquid is challenging.This paper proposes a method to recover energy through the anaerobic co-digestion of food waste and HTT liquid fraction.The effect of HTT liquid recirculation on anaerobic co-digestion performance was investigated.This study focused on the self-generated hydrochars that remained in the HTT supernatant after centrifugation.The effect of the self-generated hydrochars on the methane(CH_(4))yield and microbial communities were discussed.After adding HTT liquids treated at 140 and 180C,the maximum CH4 production increased to 309.36 and 331.61 mL per g COD,respectively.The HTT liquid exhibited a pH buffering effect and kept a favorable pH for the anaerobic co-digestion.In addition,the self-generated hydrochars with higher carbon content and large oxygen-containing functional groups remained in HTT liquid.They increased the electron transferring rate of the anaerobic co-digestion.The increased relative abundance of Methanosarcina,Syntrophomonadaceae,and Synergistota was observed with adding HTT liquid.The results of the principal component analysis indicate that the electron transferring rate constant had positive correlationships with the relative abundance of Methanosarcina,Syntrophomonadaceae,and Synergistota.This study can provide a good reference for the disposal of the HTT liquid and a novel insight regarding the mechanism for the anaerobic co-digestion.展开更多
Oxidative magnetization has attracted great attention as an efficient strategy for modulating physiochemical properties of magnetic biochar.In this paper,a K_(2)FeO_(4)-involving hydrothermal oxidative magnetization w...Oxidative magnetization has attracted great attention as an efficient strategy for modulating physiochemical properties of magnetic biochar.In this paper,a K_(2)FeO_(4)-involving hydrothermal oxidative magnetization was explored to regulate multiple micro-structures for manufacture magnetic hydrochar(MHC)for Fenton-like degradation of tetracycline in aqueous solution.Diverse shapes of Fe_(3)O_(4) and nano zero-valent iron(nZVI)were doped with abundant oxygen containing groups and persistent free radicals(PFRs).Multiple catalysis sites including iron species,PFRs,oxygen containing groups,and graphite defects contributed to accelerate the Fenton-like degradation with synergistic effect.Notably,MHC achieved a tetracycline removal rate of 99% within 60 min at 50 mg/L,with a total organic carbon(TOC)removal rate of 35%.Furthermore,after four cycles of reuse,the degradation efficiency slightly decreased to 93%.This study highlights the potential of magnetic hydrochar with multiple catalytic sites in the effective and sustainable degradation of pollutants.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
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
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
Hydrothermal carbonization(HTC) of lignocellulosic biomass is a promising technology for the production of carbon materials with negative carbon emissions. However, the high reaction temperature and energy consumption...Hydrothermal carbonization(HTC) of lignocellulosic biomass is a promising technology for the production of carbon materials with negative carbon emissions. However, the high reaction temperature and energy consumption have limited the development of HTC technology. In conventional batch reactors, the temperature and pressure are typically coupled at saturated states. In this study, a decoupled temperature and pressure hydrothermal(DTPH) reaction system was developed to decrease the temperature of the HTC reaction of lignocellulosic biomass(rice straw and poplar leaves). The properties of hydrochars were analyzed by scanning electron microscopy(SEM), Fourier transform infrared(FTIR) spectroscopy, X-ray photoelectron spectroscopy(XPS), Raman spectroscopy, X-ray diffraction(XRD), thermogravimetric analyzer(TGA), etc. to propose the reaction mechanism. The results showed that the HTC reaction of lignocellulosic biomass could be realized at a low temperature of 200℃ in the DTPH process, breaking the temperature limit(230℃) in the conventional process. The DTPH method could break the barrier of the crystalline structure of cellulose in the lignocellulosic biomass with high cellulose content, realizing the carbonization of cellulose and hemicellulose with the dehydration, unsaturated bond formation, and aromatization. The produced hydrochar had an appearance of carbon microspheres, with high calorific values, abundant oxygen-containing functional groups, a certain degree of graphitization, and good thermal stability. Cellulose acts not only as a barrier to protect itself and hemicellulose from decomposition, but also as a key precursor for the formation of carbon microspheres. This study shows a promising method for synthesizing carbon materials from lignocellulosic biomass with a carbon-negative effect.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
Excessive waste production has led to the concept of a circular bioeconomy to deliver valuable by-products and improve environmental sustainability.The annual worldwide rice production accounts for more than 750 milli...Excessive waste production has led to the concept of a circular bioeconomy to deliver valuable by-products and improve environmental sustainability.The annual worldwide rice production accounts for more than 750 million tons of grain and 150 million tons of husk.Rice husk(RH)contains valuable biomaterials with extensive applications in various fields.The proportions of each component depend primarily on rice genotype,soil chemistry,and climatic conditions.RH and its derivatives,including ash,biochar,hydrochar,and activated carbon have been placed foreground of applications in agriculture and other industries.While the investigation on RH’s compositions,microstructures,and by-products has been done copiously,owing to its unique features,it is still an open-ended area with enormous scope for innovation,research,and technology.Here,we reviewed the latest applications of RH and its derivatives,including fuel and other energy resources,construction materials,pharmacy,medicine,and nanobiotechnology to keep this versatile biomaterial in the spotlight.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 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
Nonylphenol polyethoxylates (NPEOs) are widely used as nonionic surfactants in many industry fields. High concentration NPEOs waste water is produced in some production processes. It is often treated to realize reduct...Nonylphenol polyethoxylates (NPEOs) are widely used as nonionic surfactants in many industry fields. High concentration NPEOs waste water is produced in some production processes. It is often treated to realize reduction by distillation. Therefore, NPEOs waste liquid with higher concentration is produced and it is difficult to be treated by traditional water treatment process. In this study, hydrothermal carbonization process was used to convert NPEOs waste liquid to carbonaceous product (hydrochar) with sulfuric acid as additive in 24 h at 200°C. The hydrochar was characterized by scanning electron microscope, Fourier-transform infrared spectrometer and thermogravimetric analysis. The element composition and the high heat value of the hydrochar were similar to lignite, showing that it could be used as an alternative fuel.展开更多
Thermal treatment of biomass has been attracting attention for a decade or so, especially torrefaction. However, for the past few years, wet pyrolysis, also known as hydrothermal carbonization (HTC), has been getting ...Thermal treatment of biomass has been attracting attention for a decade or so, especially torrefaction. However, for the past few years, wet pyrolysis, also known as hydrothermal carbonization (HTC), has been getting some attention. Hydrothermal carbonization is a thermal treatment of biomass in the presence of water in a temperature range of 180°C - 260°C. This method of treating biomass has some benefits which others do not, such as it can handle extremely wet biomass. However, treating biomass may not be enough for practical use. It may need to be transported and stored. Thus, this study explored the idea of pelletizing the HTC biomass. The mechanical strength of the HTC pellets was found to be 93%, whereas, higher heating value (HHV) (dry basis) was found to be 4% higher than the corresponding white pellets. The initial results with some limited parameters indicated that it would be possible to pelletize without binder. However, extensive research on energy balance and economic assessment would be necessary to achieve economic feasibility.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
Biomass is a resourcewhose organic carbon is formed from atmospheric carbon dioxide.It has numerous characteristics such as low carbon emissions,renewability,and environmental friendliness.The efficient utilization of...Biomass is a resourcewhose organic carbon is formed from atmospheric carbon dioxide.It has numerous characteristics such as low carbon emissions,renewability,and environmental friendliness.The efficient utilization of biomass plays a significant role in promoting the development of clean energy,alleviating environmental pressures,and achieving carbon neutrality goals.Among the numerous processing technologies of biomass,hydrothermal carbonization(HTC)is a promising thermochemical process that can decompose and convert biomass into hydrochar under relatively mild conditions of approximately 180℃–300℃,thereby enabling its efficient resource utilization.In addition,HTC can directly process feedstocks with high moisture content without the need for high-temperature drying,resulting in lower energy consumption.Based on a systematic analysis of the critical articles mainly published in 2011-2025 related to biomass,HTC,and hydrochar applications,in this review,the category of biomass was first classified and the chemical compositions were summarized.Then,the main chemical reaction pathways involved in biomass decomposition and transformation during the HTC process were introduced.Meanwhile,the roles of key process parameters,including reaction temperature,residence time,pH,feedstock type,pressure,mass ratio of biomass to water,and the use of catalysts on HTC,were carefully discussed.Finally,the applications of hydrochar in energy utilization,environmental remediation,soil improvement,adsorbent,microbial fermentation,and phosphorus recovery fields were highlighted.The future directions of the HTC process were also provided,which would respond to climate change by promoting the development of the sustainable carbon materials field.展开更多
Application of advanced techniques and machine learning(ML)for designing and predicting the properties of engineered hydrochar/biochar is of great agro-environmental concern.Carbon(C)stability and phosphorus(P)availab...Application of advanced techniques and machine learning(ML)for designing and predicting the properties of engineered hydrochar/biochar is of great agro-environmental concern.Carbon(C)stability and phosphorus(P)availability in hydrochar(HC)are among the key limitations as they cannot be accurately predicted by traditional one-factor tests and might be overcome by engineering the pristine HC.Therefore,the aims of this study were(1)to determine the optimal production conditions of engineered swine manure HC with high C stability and P availability,and(2)to develop the best ML models to predict the properties of HC derived from different feedstocks.Pristine-(HC)and FeCl_(3)impregnated swine manure-derived HC(HC-Fe)were produced by hydrothermal carbonization under different pH(4,7,and 10),reaction temperature(180,220,and 260℃),and residence time(60,120,and 180 min)and characterized using thermo-gravimetric,microscopic,and spectroscopic analyses.Also,different ML algorithms were used to model and predict the hydrochar solid yield,properties,and nutrients content.FeCl_(3)impregnation increased Fe-phosphate content,while it reduced H/C and O/C ratios and hydroxyapatite P content,and therefore improved C stability and P availability in the HC-Fe as compared to HC,particularly under lower pH(4),temperature of 220℃,and at 120 min.The generalized additive ML model outperformed the other models for predicting the HC properties with a correlation coefficient of 0.86.The ML analysis showed that the most influential features on the hydrochar C stability were the H and O contents in the biomass,while P availability in HC was more dependent on the C,N and O contents in biomass.These results provided optimal production conditions for Fe-engineered manure hydrochar and identified the best performing ML model for predicting hydrochar properties.The main implication of this study is that it offers a high potential to improve the utilization of biowastes and produce biowastederived engineered hydrochar with high C stability and P availability on a large scale.展开更多
基金supported by the Shenzhen Fundamental Research Program(No.GXWD20201231165807007-20220724202837001).
文摘Hydrothermal treatment(HTT)can efficiently valorize the digestate after anaerobic digestion.However,the disposal of the HTT liquid is challenging.This paper proposes a method to recover energy through the anaerobic co-digestion of food waste and HTT liquid fraction.The effect of HTT liquid recirculation on anaerobic co-digestion performance was investigated.This study focused on the self-generated hydrochars that remained in the HTT supernatant after centrifugation.The effect of the self-generated hydrochars on the methane(CH_(4))yield and microbial communities were discussed.After adding HTT liquids treated at 140 and 180C,the maximum CH4 production increased to 309.36 and 331.61 mL per g COD,respectively.The HTT liquid exhibited a pH buffering effect and kept a favorable pH for the anaerobic co-digestion.In addition,the self-generated hydrochars with higher carbon content and large oxygen-containing functional groups remained in HTT liquid.They increased the electron transferring rate of the anaerobic co-digestion.The increased relative abundance of Methanosarcina,Syntrophomonadaceae,and Synergistota was observed with adding HTT liquid.The results of the principal component analysis indicate that the electron transferring rate constant had positive correlationships with the relative abundance of Methanosarcina,Syntrophomonadaceae,and Synergistota.This study can provide a good reference for the disposal of the HTT liquid and a novel insight regarding the mechanism for the anaerobic co-digestion.
基金supported byHainan Provincial Natural Science Foundation of China(Nos.422RC600,519QN175)National Natural Science Foundation ofChina(Nos.52160018,21801053,52400206,52500209)High-Level Talent Program of Hainan Province(Nos.XJ2400008202,XJ2400011473).
文摘Oxidative magnetization has attracted great attention as an efficient strategy for modulating physiochemical properties of magnetic biochar.In this paper,a K_(2)FeO_(4)-involving hydrothermal oxidative magnetization was explored to regulate multiple micro-structures for manufacture magnetic hydrochar(MHC)for Fenton-like degradation of tetracycline in aqueous solution.Diverse shapes of Fe_(3)O_(4) and nano zero-valent iron(nZVI)were doped with abundant oxygen containing groups and persistent free radicals(PFRs).Multiple catalysis sites including iron species,PFRs,oxygen containing groups,and graphite defects contributed to accelerate the Fenton-like degradation with synergistic effect.Notably,MHC achieved a tetracycline removal rate of 99% within 60 min at 50 mg/L,with a total organic carbon(TOC)removal rate of 35%.Furthermore,after four cycles of reuse,the degradation efficiency slightly decreased to 93%.This study highlights the potential of magnetic hydrochar with multiple catalytic sites in the effective and sustainable degradation of pollutants.
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.
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The financial support from the Key-Area Research and Development Program of Guangdong Province (2020B1111380001)the Beijing Municipal Natural Science Foundation (2222012)+1 种基金the National Natural Science Foundation of China (Grant No.52070116)the Tsinghua University-Shanxi Clean Energy Research Institute Innovation Project Seed Fund。
文摘Hydrothermal carbonization(HTC) of lignocellulosic biomass is a promising technology for the production of carbon materials with negative carbon emissions. However, the high reaction temperature and energy consumption have limited the development of HTC technology. In conventional batch reactors, the temperature and pressure are typically coupled at saturated states. In this study, a decoupled temperature and pressure hydrothermal(DTPH) reaction system was developed to decrease the temperature of the HTC reaction of lignocellulosic biomass(rice straw and poplar leaves). The properties of hydrochars were analyzed by scanning electron microscopy(SEM), Fourier transform infrared(FTIR) spectroscopy, X-ray photoelectron spectroscopy(XPS), Raman spectroscopy, X-ray diffraction(XRD), thermogravimetric analyzer(TGA), etc. to propose the reaction mechanism. The results showed that the HTC reaction of lignocellulosic biomass could be realized at a low temperature of 200℃ in the DTPH process, breaking the temperature limit(230℃) in the conventional process. The DTPH method could break the barrier of the crystalline structure of cellulose in the lignocellulosic biomass with high cellulose content, realizing the carbonization of cellulose and hemicellulose with the dehydration, unsaturated bond formation, and aromatization. The produced hydrochar had an appearance of carbon microspheres, with high calorific values, abundant oxygen-containing functional groups, a certain degree of graphitization, and good thermal stability. Cellulose acts not only as a barrier to protect itself and hemicellulose from decomposition, but also as a key precursor for the formation of carbon microspheres. This study shows a promising method for synthesizing carbon materials from lignocellulosic biomass with a carbon-negative effect.
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.
文摘Excessive waste production has led to the concept of a circular bioeconomy to deliver valuable by-products and improve environmental sustainability.The annual worldwide rice production accounts for more than 750 million tons of grain and 150 million tons of husk.Rice husk(RH)contains valuable biomaterials with extensive applications in various fields.The proportions of each component depend primarily on rice genotype,soil chemistry,and climatic conditions.RH and its derivatives,including ash,biochar,hydrochar,and activated carbon have been placed foreground of applications in agriculture and other industries.While the investigation on RH’s compositions,microstructures,and by-products has been done copiously,owing to its unique features,it is still an open-ended area with enormous scope for innovation,research,and technology.Here,we reviewed the latest applications of RH and its derivatives,including fuel and other energy resources,construction materials,pharmacy,medicine,and nanobiotechnology to keep this versatile biomaterial in the spotlight.
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.
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.
文摘Nonylphenol polyethoxylates (NPEOs) are widely used as nonionic surfactants in many industry fields. High concentration NPEOs waste water is produced in some production processes. It is often treated to realize reduction by distillation. Therefore, NPEOs waste liquid with higher concentration is produced and it is difficult to be treated by traditional water treatment process. In this study, hydrothermal carbonization process was used to convert NPEOs waste liquid to carbonaceous product (hydrochar) with sulfuric acid as additive in 24 h at 200°C. The hydrochar was characterized by scanning electron microscope, Fourier-transform infrared spectrometer and thermogravimetric analysis. The element composition and the high heat value of the hydrochar were similar to lignite, showing that it could be used as an alternative fuel.
文摘Thermal treatment of biomass has been attracting attention for a decade or so, especially torrefaction. However, for the past few years, wet pyrolysis, also known as hydrothermal carbonization (HTC), has been getting some attention. Hydrothermal carbonization is a thermal treatment of biomass in the presence of water in a temperature range of 180°C - 260°C. This method of treating biomass has some benefits which others do not, such as it can handle extremely wet biomass. However, treating biomass may not be enough for practical use. It may need to be transported and stored. Thus, this study explored the idea of pelletizing the HTC biomass. The mechanical strength of the HTC pellets was found to be 93%, whereas, higher heating value (HHV) (dry basis) was found to be 4% higher than the corresponding white pellets. The initial results with some limited parameters indicated that it would be possible to pelletize without binder. However, extensive research on energy balance and economic assessment would be necessary to achieve economic feasibility.
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supported by National Natural Science Foundation of China(22578155,22478147)the Natural Science Foundation of Huaian City(HAB2024051).
文摘Biomass is a resourcewhose organic carbon is formed from atmospheric carbon dioxide.It has numerous characteristics such as low carbon emissions,renewability,and environmental friendliness.The efficient utilization of biomass plays a significant role in promoting the development of clean energy,alleviating environmental pressures,and achieving carbon neutrality goals.Among the numerous processing technologies of biomass,hydrothermal carbonization(HTC)is a promising thermochemical process that can decompose and convert biomass into hydrochar under relatively mild conditions of approximately 180℃–300℃,thereby enabling its efficient resource utilization.In addition,HTC can directly process feedstocks with high moisture content without the need for high-temperature drying,resulting in lower energy consumption.Based on a systematic analysis of the critical articles mainly published in 2011-2025 related to biomass,HTC,and hydrochar applications,in this review,the category of biomass was first classified and the chemical compositions were summarized.Then,the main chemical reaction pathways involved in biomass decomposition and transformation during the HTC process were introduced.Meanwhile,the roles of key process parameters,including reaction temperature,residence time,pH,feedstock type,pressure,mass ratio of biomass to water,and the use of catalysts on HTC,were carefully discussed.Finally,the applications of hydrochar in energy utilization,environmental remediation,soil improvement,adsorbent,microbial fermentation,and phosphorus recovery fields were highlighted.The future directions of the HTC process were also provided,which would respond to climate change by promoting the development of the sustainable carbon materials field.
基金sustained by a grant from the National Key Research and Development Program of China“Intergovernmental Cooperation in International Science and Technology Innovation”[Grant number 2023YFE0104700]the National Natural Science Foundation of China[Grant Number 31401944]The author Esmat F.Ali extends his appreciation to Taif University,Saudi Arabia for supporting this work through project number(TU-DSPP-2024-27).
文摘Application of advanced techniques and machine learning(ML)for designing and predicting the properties of engineered hydrochar/biochar is of great agro-environmental concern.Carbon(C)stability and phosphorus(P)availability in hydrochar(HC)are among the key limitations as they cannot be accurately predicted by traditional one-factor tests and might be overcome by engineering the pristine HC.Therefore,the aims of this study were(1)to determine the optimal production conditions of engineered swine manure HC with high C stability and P availability,and(2)to develop the best ML models to predict the properties of HC derived from different feedstocks.Pristine-(HC)and FeCl_(3)impregnated swine manure-derived HC(HC-Fe)were produced by hydrothermal carbonization under different pH(4,7,and 10),reaction temperature(180,220,and 260℃),and residence time(60,120,and 180 min)and characterized using thermo-gravimetric,microscopic,and spectroscopic analyses.Also,different ML algorithms were used to model and predict the hydrochar solid yield,properties,and nutrients content.FeCl_(3)impregnation increased Fe-phosphate content,while it reduced H/C and O/C ratios and hydroxyapatite P content,and therefore improved C stability and P availability in the HC-Fe as compared to HC,particularly under lower pH(4),temperature of 220℃,and at 120 min.The generalized additive ML model outperformed the other models for predicting the HC properties with a correlation coefficient of 0.86.The ML analysis showed that the most influential features on the hydrochar C stability were the H and O contents in the biomass,while P availability in HC was more dependent on the C,N and O contents in biomass.These results provided optimal production conditions for Fe-engineered manure hydrochar and identified the best performing ML model for predicting hydrochar properties.The main implication of this study is that it offers a high potential to improve the utilization of biowastes and produce biowastederived engineered hydrochar with high C stability and P availability on a large scale.
