The application of industrial solid wastes as environmentally functional materials for air pollutants control has gained much attention in recent years due to its potential to reduce air pollution in a cost-effective ...The application of industrial solid wastes as environmentally functional materials for air pollutants control has gained much attention in recent years due to its potential to reduce air pollution in a cost-effective manner.In this review,we investigate the development of industrialwaste-based functional materials for various gas pollutant removal and consider the relevant reaction mechanism according to different types of industrial solid waste.We see a recent effort towards achieving high-performance environmental functional materials via chemical or physical modification,in which the active components,pore size,and phase structure can be altered.The review will discuss the potential of using industrial solid wastes,these modified materials,or synthesized materials from raw waste precursors for the removal of air pollutants,including SO_(2),NO_(x),Hg^(0),H_(2)S,VOCs,and CO_(2).The challenges still need to be addressed to realize this potential and the prospects for future research fully.The suggestions for future directions include determining the optimal composition of these materials,calculating the real reaction rate and turnover frequency,developing effective treatment methods,and establishing chemical component databases of raw industrial solid waste for catalysts/adsorbent preparation.展开更多
In this study,a novel Pt-loaded Cu Pc/g-C_(3)N_(4)(Pt Cu CN)composite was synthesized for the selective photocatalytic reduction of CO_(2)to CH_(4)under visible light.The Pt Cu CN catalyst achieved a CH_(4)yield of 3...In this study,a novel Pt-loaded Cu Pc/g-C_(3)N_(4)(Pt Cu CN)composite was synthesized for the selective photocatalytic reduction of CO_(2)to CH_(4)under visible light.The Pt Cu CN catalyst achieved a CH_(4)yield of 39.8μmol g^(-1)h^(-1),significantly outperforming bulk g-C_(3)N_(4)and Cu Pc alone by factors of 2.5 and 3.1,respectively,with a high selectivity of 90%.In comparison with other commonly studied photocatalysts,such as g-C_(3)N_(4)-based catalysts,the Pt Cu CN composite exhibited superior CH_(4)yield and product selectivity,demonstrating its potential as a more efficient photocatalyst for CO_(2)reduction.X-ray photoelectron spectroscopy(XPS),density functional theory(DFT)calculations,and in-situ infrared(IR)analysis revealed that the Pt^(0)species effectively lower the activation energy for CH_(4)formation,while Cu Pc extends the light absorption range and enhances charge separation.The combined effects of these components in a Z-scheme heterojunction provide new insights into designing highly selective CO_(2)-to-CH_(4)photocatalysts.This work demonstrates the potential of Pt Cu CN as a highly efficient and stable catalyst for CO_(2)reduction to CH_(4)under visible light.展开更多
Corn stover,an agricultural waste,was used to prepare nitrogen self-doped carbon quantum dots(CQDs)through a simple hydrothermal method with only water at near room temperature for the first time.The surface,electroch...Corn stover,an agricultural waste,was used to prepare nitrogen self-doped carbon quantum dots(CQDs)through a simple hydrothermal method with only water at near room temperature for the first time.The surface,electrochemical,and photovoltaic characteristics of CQDs doped TiO_(2)in dye-sensitized solar cells(DSSCs)were thoroughly and systematically examined.The average diameter of blue-fluorescence CQDs measured by a high-resolution transmission electron microscope(HR-TEM)was 4.63±0.87 nm,which consisted of polar functional groups.The highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)energy of the biomass-derived CQDs,determined by the cyclic voltammetry(CV)test,were,−5.48 eV and−3.89 eV,respectively.The negative shift of flat band potential(Vfb)in CQDs incorporated photoanode implies the fermi level shifted upward.Experimental results revealed that the improved performance of DSSCs was due to charge transport enhancement and separation,which resulted in the improved energy level configuration between TiO_(2),CQDs,and electrolytes.In this regard,the CQDs serve as a mediator that enables charge carrier transport without hindrance.In this study,CQDs added to TiO_(2)+N719,increased short circuit current density(JSC)and power conversion efficiency(PCE)value by∼26.00%(10.13 to 12.69 mA/cm^(2))and 27.20%(4.78%to 6.08%),respectively.展开更多
Functionalization has emerged as a pivotal endeavor to tailor the surface properties of photocatalysts.We propose a facile amine functionalization strategy to establish a Cu−In−Zn−S(CIZS)/NiSx hybrid with covalent bon...Functionalization has emerged as a pivotal endeavor to tailor the surface properties of photocatalysts.We propose a facile amine functionalization strategy to establish a Cu−In−Zn−S(CIZS)/NiSx hybrid with covalent bonds using individual ethylenediamine(EDA)molecules.Our approach witnesses a remarkable photocatalytic hydrogen evolution(PHE)competence of 65.93 mmol g^(−1)h^(−1)driven by visible light,the highest value yielded by CIZS to date.X-ray absorption spectra of CIZS and density functional theory(DFT)calculations confirm the crucial amine N→Cu coordination after amine functionalization.The new emerging coordination via lone-pair electron donation profitably accesses the regulation of the coordination environment,electronic structures,and carrier behavior.Moreover,individual EDA molecule with two-terminal−NH2 group serves as a molecular bridge to hybrid CIZS and NiS_(x)cocatalyst via N→Cu and N→Ni coordination,favorably promoting efficient charge transport.This study provides advances in practical functionalizing photocatalysts.展开更多
Three large π-conjugated and imine-based COFs,named TFP-TAB,TFP-TTA,and TTA-TTB,were synthesized via the ordered incorporation of benzene and triazine rings in the same host framework to study how the structural unit...Three large π-conjugated and imine-based COFs,named TFP-TAB,TFP-TTA,and TTA-TTB,were synthesized via the ordered incorporation of benzene and triazine rings in the same host framework to study how the structural units affect the efficiency of CO_(2)photoreduction.Results from both experiments and density-functional theory(DFT)calculations indicate the separation and transfer of the photoinduced charges is highly related to the triazine-N content and the conjugation degree in the skeletons of COFs.High-efficiency CO_(2)photoreduction can be achieved by rationally adjusting the number and position of both benzene and triazine rings in the COFs.Specifically,TTA-TTB,with orderly interlaced triazine-benzene heterojunctions,can suppress the recombination probability of electrons and holes,which effectively immobilizes the key species(COOH)and lowers the free energy change of the potential-determining step,and thus exhibits a superior visible-light-induced photocatalytic activity that yields 121.7 μmol HCOOH g^(-1)h^(-1).This research,therefore,helps to elucidate the effects of the different structural blocks in COFs on inherent heterogeneous photocatalysis for CO_(2)reduction at a molecular level.展开更多
This article reviews the progress made in CO2 separation and capture research and engineering. Various technologies, such as absorption, adsorption, and membrane separation, are thoroughly discussed. New concepts such...This article reviews the progress made in CO2 separation and capture research and engineering. Various technologies, such as absorption, adsorption, and membrane separation, are thoroughly discussed. New concepts such as chemical-looping combustion and hydrate-based separation are also introduced briefly. Future directions are suggested. Sequestration methods, such as forestation, ocean fertilization and mineral carbonation techniques are also covered. Underground injection and direct ocean dump are not covered.展开更多
The advancement and increasing interests in green energy production and environmental protection technologies have spurred the demand for rare earth elements.On the other hand,the U.S.has to rely 100% on import of the...The advancement and increasing interests in green energy production and environmental protection technologies have spurred the demand for rare earth elements.On the other hand,the U.S.has to rely 100% on import of these materials as the industry was crashed because of the environmental issues associated with mining and processing,and more importantly lack competitiveness.As rare earth elements have many applications in defense and national security sectors,some of the elements were listed as strategic materials or critical materials because of the uncertainties in supply and prices.Therefore,it has become imperative in searching for alternative resources for supplying rare earth elements including unconventional resources.With the strong incentive,coal fly ash is identified as one of the candidates among them.In this study,we present rare earth element data for the 42 ash samples(all derived from Powder River Basin coal) that we collected from seven states(UT,WY,10,WI,ND,CO,and MI) representing 158 million tons of fly ash.The results indicate scattered distributions of rare earth elements with concentration ranging from 156 to 590 ppm although all the ash samples originated from the same coal basin(Powder River Basin).The rare earth element resource in these ashes is estimated between 74000 and 106000 t.The ash samples were also characterized by elemental analysis,XRD,SEM-EDS and BET surface area.The characterizations of the ashes were discussed as they might have implications in the subsequent rare earth element extraction processes.In summary,fly ash may represent a potential resource for rare earth element production.展开更多
Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments.A series of FeMn binary oxide with different Fe：Mn molar ratios was synthesized by a simultaneous...Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments.A series of FeMn binary oxide with different Fe：Mn molar ratios was synthesized by a simultaneous oxidation and coprecipitation process for TC removal.Results showed that Fe-Mn binary oxide had higher removal efficiency than that of hydrous iron oxide and hydrous manganese oxide,and that the oxide with a Fe：Mn molar ratio of 5：1 was the best in removal than other molar ratios.The tetracycline removal was highly pH dependent.The removal of tetracycline decreased with the increase of initial concentration,but the absolute removal quantity was more at high concentration.The presence of cations and anions such as Ca2＋,Mg2＋,CO32-and SO42-had no significant effect on the tetracycline removal in our experimental conditions,while SiO32-and PO43-had hindered the adsorption of tetracycline.The mechanism investigation found that tetracycline removal was mainly achieved by the replacement of surface hydroxyl groups by the tetracycline species and formation of surface complexes at the water/oxide interface.This primary study suggests that Fe-Mn binary oxide with a proper Fe：Mn molar ratio will be a very promising material for the removal of tetracycline from aqueous solutions.展开更多
With the shape selective zeolite catalyst,toluene alkylation with methanol to para-xylene(MTPX)technology could produce highly pure para-xylene(PX)in one step.The lower feedstock cost and less energy consumption in pr...With the shape selective zeolite catalyst,toluene alkylation with methanol to para-xylene(MTPX)technology could produce highly pure para-xylene(PX)in one step.The lower feedstock cost and less energy consumption in products separation make it more competitive compared to the current toluene disproportionation route.Thus,MTPX is regarded as the most reasonable production route for PX production.This article reviews the strategies that applied to the preparation of high-performance catalysts for MTPX,with special focus on the precise control of pore dimension and acid sites distribution in zeolite to achieve the highest selectivity to PX.The outlook of the MTPX catalyst is also proposed to guide the catalyst development in the field.展开更多
Elevated arsenic and selenium concentrations in water cause health problems to both humans and wildlife. Natural and anthropogenic activities have caused contamination of these elements in waters worldwide, making the...Elevated arsenic and selenium concentrations in water cause health problems to both humans and wildlife. Natural and anthropogenic activities have caused contamination of these elements in waters worldwide, making the development of efficient cost-effective methods in their removal essential. In this work, removal of arsenate and selenite from water by adsorption onto a natural goethite(α-FeO OH) sample was studied at varying conditions. The data was then compared with other arsenate, selenite/goethite adsorption systems as much of literature shows discrepancies due to varying adsorption conditions. Characterization of the goethite was completed using inductively coupled plasma mass spectrometry, X-ray diffraction, Fouriertransform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller surface area analysis. Pseudo-first order(PFO) and pseudo-second order(PSO) kinetic models were applied; including comparisons of different regression methods. Various adsorption isotherm models were applied to determine the best fitting model and to compare adsorption capacitates with other works. Desorption/leaching of arsenate and selenite was studied though the addition of phosphate and hydroxyl ions. Langmuir isotherm modeling resulted in maximum adsorption capacities of 6.204 and 7.740 mg/g for arsenate and selenite adsorption,respectively. The PSO model applied with a non-linear regression resulted in the best kinetic fits for both adsorption and desorption of arsenate and selenite. Adsorption decreased with increasing pH. Phosphate induced desorption resulted in the highest percentage of arsenate and selenite desorbed, while hydroxide induced resulted in the fastest desorption kinetics.展开更多
To study how global warming and eutrophication affect water ecosystems, a multiplicative growth Monod model, modified by incorporating the Arrhenius equation, was applied to Lake Taihu to quantitatively study the rela...To study how global warming and eutrophication affect water ecosystems, a multiplicative growth Monod model, modified by incorporating the Arrhenius equation, was applied to Lake Taihu to quantitatively study the relationships between algal biomass and both nutrients and temperature using long-term data. To qualitatively assess which factor was a limitation of the improved model, temperature variables were calculated using annual mean air temperature （AT）, water temperature （WT）, and their average temperature （ST）, while substrate variables were calculated using annual mean total nitrogen （TN）, total phosphorus （TP）, and their weighted aggregate （R）, respectively. The nine fitted curves showed that TN and AT were two important factors influencing algal growth; AT limited growth as algal photosynthesis is mainly carried out near the water surface; N leakage of phytoplankton and internal phosphorus load from sediment explains why TN was the best predictor of peak biomass using the Monod model. The fitted results suggest that annual mean algal biomass increased by 0.145 times when annual mean AT increased by 1.0℃. Results also showed that the more eutrophic the lake, the greater the effect AT had on algal growth. Subsequently, the long-term joint effect of annual temperature increase and eutrophication to water ecosystems can be quantitatively assessed and predicted.展开更多
Methanol （CH3OH） is an important industrial chemical with a wide variety of uses. Industrial methanol synthesis catalysts are typically composed of Cu, Zn, and AI, but the use of catalysts incorporating rare earth e...Methanol （CH3OH） is an important industrial chemical with a wide variety of uses. Industrial methanol synthesis catalysts are typically composed of Cu, Zn, and AI, but the use of catalysts incorporating rare earth elements has been shown to improve the catalytic performance. Due to their unique chemical and physical properties, the use of rare earth elements （scandium, yttrium, and the lanthanides） in catalysis in general has continued to increase over the past few decades, while the use of rare earth in methanol synthesis catalysts has not, despite often improving pertbrmance. The ability of several of the rare earth elements （Pr, Ce, Eu, Tb, Yb） to easily switch between oxidation states makes them beneficial for many different types of catalysts. However, for methanol synthesis the surface basicity is an important property, and the basic nature of the rare earth elements can be used to tune the basicity of catalysts. A small number of correlations between rare earth properties and catalytic performance have been observed, but often do not apply to other catalysts. Properties such as strength of basic sites, ionic radius, and etec- tronegativity have been found to correlate with performance results such as activity or selectivity.展开更多
Methanol,a versatile chemical,fuel additive and potential H_(2) carrier,has attracted great attention.Despite of the wide industrialization,improvement of Cu-based methanol-synthesis catalysts is highly anticipated.Ac...Methanol,a versatile chemical,fuel additive and potential H_(2) carrier,has attracted great attention.Despite of the wide industrialization,improvement of Cu-based methanol-synthesis catalysts is highly anticipated.Accordingly,a series of Cu/ZnO/Al_(2)O_(3) with designed precursor structures were prepared,and its structure-function relationship was investigated to make progress on this area.Results showed the catalyst derived from highly zinc-substituted malachite demonstrated the best catalytic performance in this work.It was found that the well-behaved catalyst possessed relatively high Cu specific surface area and exposed Cu concentration,and the well Cu/ZnO synergy.CuZn alloy was found by In-situ XRD tests,and its effect on the catalyst's thermostability was discussed.Fractional precipitation,which facilitated the Cu^(2+) substitution by Zn^(2+) in malachite lattice,could be an efficient preparation method of the Cu/ZnO/Al_(2)O_(3) catalyst.展开更多
Sodium percarbonate(SPC)and peroxymonocarbonate(PMC)have been widely used in modified Fenton reactions because of their multiple superior features,such as a wide pH range and environmental friendliness.This broad revi...Sodium percarbonate(SPC)and peroxymonocarbonate(PMC)have been widely used in modified Fenton reactions because of their multiple superior features,such as a wide pH range and environmental friendliness.This broad review is intended to provide the fundamental information,status and progress of SPC and PMC based decontamination technologies according to the peer-reviewed papers in the last two decades.Both SPC and PMC can directly decompose various pollutants.The degradation efficiency will be enhanced and the target contaminants will be expanded after the activation of SPC and PMC.The most commonly used catalysts for SPC activation are iron compounds while cobalt composi-tions are applied to activate PMC in homogenous and heterogeneous catalytical systems.The generation and participation of hydroxyl,superoxide and/or carbonate radicals are involved in the activated SPC and PMC system.The reductive radicals,such as carbon dioxide and hydroxyethyl radicals,can be generated when formic acid or methanol is added in the Fe(II)/SPC system,which can reduce target contaminants.SPC can also be activated by energy,tetraacetylethylenediamine,ozone and buffered alkaline to generate different reactive radicals for pollutant decomposition.The SPC and activated SPC have been assessed for application in-situ chemical oxidation and sludge dewatering treatment.The challenges and prospects of SPC and PMC based decontamination technologies are also addressed in the last section.展开更多
TiO2 nanomaterial is promising with its high potential and outstanding performance in photocatalytic environmental applications, such as CO2 conversion, water treatment, and air quality control. For many of these appl...TiO2 nanomaterial is promising with its high potential and outstanding performance in photocatalytic environmental applications, such as CO2 conversion, water treatment, and air quality control. For many of these applications, the particle size, crystal structure and phase, porosity, and surface area influence the activity of TiO2 dramatically. TiO2 nanomaterials with special structures and morphologies, such as nanospheres, nanowires, nanotubes, nanorods, and nanoflowers are thus synthesized due to their desired characteristics. With an emphasis on the different morphologies of TiO2 and the influence factors in the synthesis, this review summarizes fourteen TiO2 preparation methods, such as the sol-gel method, solvothermal method, and reverse micelle method. The TiO2 formation mechanisms, the advantages and disadvantages of the preparation methods, and the photocatalytic environmental application examples are proposed as well.展开更多
A convenient method for methane(CH_(4))direct conversion to methanol(CH_(3)OH)is of great significance to use methane-rich resources,especially clathrates and stranded shale gas resources located in remote regions.The...A convenient method for methane(CH_(4))direct conversion to methanol(CH_(3)OH)is of great significance to use methane-rich resources,especially clathrates and stranded shale gas resources located in remote regions.Theoretically,the activation of CH_(4) and the selectivity to the CH_(3)OH product are challenging due to the extreme stability of CH_(4) and relatively high reactivity of CH_(3)OH.The state-of-the-art‘methane reforming-methanol synthesis’process adopts a two-step strategy to avoid the further reaction of CH_(3)OH under the harsh conditions required for CH_(4) activation.In the electrochemical field,researchers are trying to develop conversion pathways under mild conditions.They have found suitable catalysts to activate the C–H bonds in methane with the help of external charge and have designed the electrode reactions to continuously generate certain active oxygen species.These active oxygen species attack the activated methane and convert it to CH_(3)OH,with the benefit of avoiding over-oxidation of CH_(3)OH,and thus obtain a high conversion efficiency of CH_(4) to CH_(3)OH.This mini-review focuses on the advantages and challenges of electrochemical conversion of CH4 to CH_(3)OH,especially the strategies for supplying electro-generated active oxygen species in-situ to react with the activated methane.展开更多
The purpose of this work is to remove Pb（II） from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-m...The purpose of this work is to remove Pb（II） from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy（FTIR）, Solid carbon nuclear magnetic resonance spectroscopy（CNMR））, silicon-29 nuclear magnetic resonance spectroscopy（Si NMR））, and X-ray diffraction spectroscope（（XRD） were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb（II） from the aqueous solution. The Pb（II）-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy（FTIR））,scanning electron microscopy（SEM））, and X-ray photoelectron spectroscopy（（XPS））. From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb（II）. Kinetic studies indicated that the adsorption of Pb（II）followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb（II） ions was 430 mg/g. Thus, the waste linear low-density polyethylene-g-poly（acrylic acid）-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb（II） adsorbent.展开更多
Olivine, one of the most abundant minerals existing in nature, is explored as a C02 carbonation agent for direct carbonation of C02 in flue gas. Olivine based C02 capture is thermodynamically favorable and can form a ...Olivine, one of the most abundant minerals existing in nature, is explored as a C02 carbonation agent for direct carbonation of C02 in flue gas. Olivine based C02 capture is thermodynamically favorable and can form a stable carbonate for long-term storage. Experimental results have shown that water vapor plays an important role in improving CO/carbonation rate and capacities. Other operation conditions including reaction temperature, initial C02 concentration, residence time corresponding to the flow rate of C02 gas stream, and water vapor concentration also considerably affect the performance of the technology.展开更多
While carbon dioxide(CO_(2))is a major greenhouse gas,it is also an important C1 resource.In the trend of energy conservation and emission reduction,electrocatalytic reduction has become a very promising strategy for ...While carbon dioxide(CO_(2))is a major greenhouse gas,it is also an important C1 resource.In the trend of energy conservation and emission reduction,electrocatalytic reduction has become a very promising strategy for CO_(2)utilization because it can convert CO_(2)directly to high-valued chemicals and fuels under mild conditions.In particular,the product CO and by-product H_(2)can be combined into syngas by an electrocatalytic CO_(2)reduction reaction(CO_(2)RR)in an aqueous medium.Different molar ratios of CO and H_(2)may be used to produce essential bulk chemicals or liquid fuels such as methanol,alkanes,and olefins through thermochemical catalysis,Fischer-Tropsch synthesis,microbial fermentation,and other techniques.This work discusses the latest strategies in controlling the molar ratio of CO/H_(2)and improving the yield of CO_(2)RR-to-syngas.The challenges of electrocatalytic syngas production are analyzed from an industrial application perspective,and the possible measures to overcome them are proposed in terms of new catalyst design,electrolyte innovation,flow reactor optimization,anodic reaction coupling,and operando technique application.展开更多
The catalyst layers(CLs) electrode is the key component of the membrane electrode assembly(MEA) in proton exchange membrane fuel cells(PEMFCs). Conventional electrodes for PEMFCs are composed of carbon-supported, iono...The catalyst layers(CLs) electrode is the key component of the membrane electrode assembly(MEA) in proton exchange membrane fuel cells(PEMFCs). Conventional electrodes for PEMFCs are composed of carbon-supported, ionomer, and Pt nanoparticles, all immersed together and sprayed with a micron-level thickness of CLs. They have a performance trade-off where increasing the Pt loading leads to higher performance of abundant triple-phase boundary areas but increases the electrode cost. Major challenges must be overcome before realizing its wide commercialization. Literature research revealed that it is impossible to achieve performance and durability targets with only high-performance catalysts, so the controllable design of CLs architecture in MEAs for PEMFCs must now be the top priority to meet industry goals. From this perspective, a 3D ordered electrode circumvents this issue with a support-free architecture and ultrathin thickness while reducing noble metal Pt loadings. Herein, we discuss the motivation in-depth and summarize the necessary CLs structural features for designing ultralow Pt loading electrodes. Critical issues that remain in progress for 3D ordered CLs must be studied and characterized. Furthermore, approaches for 3D ordered CLs architecture electrode development, involving material design, structure optimization, preparation technology, and characterization techniques, are summarized and are expected to be next-generation CLs for PEMFCs. Finally, the review concludes with perspectives on possible research directions of CL architecture to address the significant challenges in the future.展开更多
基金supported by National Natural Science Foundation of China(Grant No.52270106 and 22266021)Yunnan Major Scientific and Technological Projects(grant No.202202AG050005)Yunnan Fundamental Research Projects(grant No.202201AT070116).
文摘The application of industrial solid wastes as environmentally functional materials for air pollutants control has gained much attention in recent years due to its potential to reduce air pollution in a cost-effective manner.In this review,we investigate the development of industrialwaste-based functional materials for various gas pollutant removal and consider the relevant reaction mechanism according to different types of industrial solid waste.We see a recent effort towards achieving high-performance environmental functional materials via chemical or physical modification,in which the active components,pore size,and phase structure can be altered.The review will discuss the potential of using industrial solid wastes,these modified materials,or synthesized materials from raw waste precursors for the removal of air pollutants,including SO_(2),NO_(x),Hg^(0),H_(2)S,VOCs,and CO_(2).The challenges still need to be addressed to realize this potential and the prospects for future research fully.The suggestions for future directions include determining the optimal composition of these materials,calculating the real reaction rate and turnover frequency,developing effective treatment methods,and establishing chemical component databases of raw industrial solid waste for catalysts/adsorbent preparation.
基金financial support from the National Natural Science Foundation of China(Grant NO.22466023,52470119,52260013)the Applied Basic Research Foundation of Yunnan Province(Grant NO.202401AT070408)+1 种基金Yunnan Provincial Key Laboratory of Energy Saving in Phosphorus Chemical Engineering and New Phosphorus Materials(Grant NO.202205AG070067)Yunnan Technological Innovation Center of Phosphorus Resources(Grant NO.202305AK340002)。
文摘In this study,a novel Pt-loaded Cu Pc/g-C_(3)N_(4)(Pt Cu CN)composite was synthesized for the selective photocatalytic reduction of CO_(2)to CH_(4)under visible light.The Pt Cu CN catalyst achieved a CH_(4)yield of 39.8μmol g^(-1)h^(-1),significantly outperforming bulk g-C_(3)N_(4)and Cu Pc alone by factors of 2.5 and 3.1,respectively,with a high selectivity of 90%.In comparison with other commonly studied photocatalysts,such as g-C_(3)N_(4)-based catalysts,the Pt Cu CN composite exhibited superior CH_(4)yield and product selectivity,demonstrating its potential as a more efficient photocatalyst for CO_(2)reduction.X-ray photoelectron spectroscopy(XPS),density functional theory(DFT)calculations,and in-situ infrared(IR)analysis revealed that the Pt^(0)species effectively lower the activation energy for CH_(4)formation,while Cu Pc extends the light absorption range and enhances charge separation.The combined effects of these components in a Z-scheme heterojunction provide new insights into designing highly selective CO_(2)-to-CH_(4)photocatalysts.This work demonstrates the potential of Pt Cu CN as a highly efficient and stable catalyst for CO_(2)reduction to CH_(4)under visible light.
基金the Department of Energy(DOE,Award Number:DE-FE0031997)for providing funds to support our research.
文摘Corn stover,an agricultural waste,was used to prepare nitrogen self-doped carbon quantum dots(CQDs)through a simple hydrothermal method with only water at near room temperature for the first time.The surface,electrochemical,and photovoltaic characteristics of CQDs doped TiO_(2)in dye-sensitized solar cells(DSSCs)were thoroughly and systematically examined.The average diameter of blue-fluorescence CQDs measured by a high-resolution transmission electron microscope(HR-TEM)was 4.63±0.87 nm,which consisted of polar functional groups.The highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)energy of the biomass-derived CQDs,determined by the cyclic voltammetry(CV)test,were,−5.48 eV and−3.89 eV,respectively.The negative shift of flat band potential(Vfb)in CQDs incorporated photoanode implies the fermi level shifted upward.Experimental results revealed that the improved performance of DSSCs was due to charge transport enhancement and separation,which resulted in the improved energy level configuration between TiO_(2),CQDs,and electrolytes.In this regard,the CQDs serve as a mediator that enables charge carrier transport without hindrance.In this study,CQDs added to TiO_(2)+N719,increased short circuit current density(JSC)and power conversion efficiency(PCE)value by∼26.00%(10.13 to 12.69 mA/cm^(2))and 27.20%(4.78%to 6.08%),respectively.
基金supported by the National Natural Science Foundation of China(No.62304219)the Strategic Priority Research Program of theChinese Academy of Sciences(No.XDB43000000)+1 种基金the CAS Project for Young Scientists in Basic Research(YSBR−090)the National Natural ScienceFoundation of China(Nos.21975245,U20A20206,and 51972300)。
文摘Functionalization has emerged as a pivotal endeavor to tailor the surface properties of photocatalysts.We propose a facile amine functionalization strategy to establish a Cu−In−Zn−S(CIZS)/NiSx hybrid with covalent bonds using individual ethylenediamine(EDA)molecules.Our approach witnesses a remarkable photocatalytic hydrogen evolution(PHE)competence of 65.93 mmol g^(−1)h^(−1)driven by visible light,the highest value yielded by CIZS to date.X-ray absorption spectra of CIZS and density functional theory(DFT)calculations confirm the crucial amine N→Cu coordination after amine functionalization.The new emerging coordination via lone-pair electron donation profitably accesses the regulation of the coordination environment,electronic structures,and carrier behavior.Moreover,individual EDA molecule with two-terminal−NH2 group serves as a molecular bridge to hybrid CIZS and NiS_(x)cocatalyst via N→Cu and N→Ni coordination,favorably promoting efficient charge transport.This study provides advances in practical functionalizing photocatalysts.
基金support from the Scientific Research Fund of Zhejiang Provincial Education Department(Y202353855)the Zhejiang Provincial Key R&D Project(2021C01056)+1 种基金the Programme of Introducing Talents of Discipline to Universities(No.D17008)the National Natural Science Foundation of China(22208312).
文摘Three large π-conjugated and imine-based COFs,named TFP-TAB,TFP-TTA,and TTA-TTB,were synthesized via the ordered incorporation of benzene and triazine rings in the same host framework to study how the structural units affect the efficiency of CO_(2)photoreduction.Results from both experiments and density-functional theory(DFT)calculations indicate the separation and transfer of the photoinduced charges is highly related to the triazine-N content and the conjugation degree in the skeletons of COFs.High-efficiency CO_(2)photoreduction can be achieved by rationally adjusting the number and position of both benzene and triazine rings in the COFs.Specifically,TTA-TTB,with orderly interlaced triazine-benzene heterojunctions,can suppress the recombination probability of electrons and holes,which effectively immobilizes the key species(COOH)and lowers the free energy change of the potential-determining step,and thus exhibits a superior visible-light-induced photocatalytic activity that yields 121.7 μmol HCOOH g^(-1)h^(-1).This research,therefore,helps to elucidate the effects of the different structural blocks in COFs on inherent heterogeneous photocatalysis for CO_(2)reduction at a molecular level.
文摘This article reviews the progress made in CO2 separation and capture research and engineering. Various technologies, such as absorption, adsorption, and membrane separation, are thoroughly discussed. New concepts such as chemical-looping combustion and hydrate-based separation are also introduced briefly. Future directions are suggested. Sequestration methods, such as forestation, ocean fertilization and mineral carbonation techniques are also covered. Underground injection and direct ocean dump are not covered.
基金supported by the U.S. Department of Energy through “Rare Earth Elements from Coal and Coal By-Products” program(DE-FE00027069).
文摘The advancement and increasing interests in green energy production and environmental protection technologies have spurred the demand for rare earth elements.On the other hand,the U.S.has to rely 100% on import of these materials as the industry was crashed because of the environmental issues associated with mining and processing,and more importantly lack competitiveness.As rare earth elements have many applications in defense and national security sectors,some of the elements were listed as strategic materials or critical materials because of the uncertainties in supply and prices.Therefore,it has become imperative in searching for alternative resources for supplying rare earth elements including unconventional resources.With the strong incentive,coal fly ash is identified as one of the candidates among them.In this study,we present rare earth element data for the 42 ash samples(all derived from Powder River Basin coal) that we collected from seven states(UT,WY,10,WI,ND,CO,and MI) representing 158 million tons of fly ash.The results indicate scattered distributions of rare earth elements with concentration ranging from 156 to 590 ppm although all the ash samples originated from the same coal basin(Powder River Basin).The rare earth element resource in these ashes is estimated between 74000 and 106000 t.The ash samples were also characterized by elemental analysis,XRD,SEM-EDS and BET surface area.The characterizations of the ashes were discussed as they might have implications in the subsequent rare earth element extraction processes.In summary,fly ash may represent a potential resource for rare earth element production.
基金supported by the Fund for the Creative Research Groups of China (No. 50921064)the Special Co-construction Project of Beijing Municipal Commission of Education
文摘Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments.A series of FeMn binary oxide with different Fe：Mn molar ratios was synthesized by a simultaneous oxidation and coprecipitation process for TC removal.Results showed that Fe-Mn binary oxide had higher removal efficiency than that of hydrous iron oxide and hydrous manganese oxide,and that the oxide with a Fe：Mn molar ratio of 5：1 was the best in removal than other molar ratios.The tetracycline removal was highly pH dependent.The removal of tetracycline decreased with the increase of initial concentration,but the absolute removal quantity was more at high concentration.The presence of cations and anions such as Ca2＋,Mg2＋,CO32-and SO42-had no significant effect on the tetracycline removal in our experimental conditions,while SiO32-and PO43-had hindered the adsorption of tetracycline.The mechanism investigation found that tetracycline removal was mainly achieved by the replacement of surface hydroxyl groups by the tetracycline species and formation of surface complexes at the water/oxide interface.This primary study suggests that Fe-Mn binary oxide with a proper Fe：Mn molar ratio will be a very promising material for the removal of tetracycline from aqueous solutions.
基金the funding support(Project No.:CF9300172922)from National Institute of Clean-and-low-carbon Energy.
文摘With the shape selective zeolite catalyst,toluene alkylation with methanol to para-xylene(MTPX)technology could produce highly pure para-xylene(PX)in one step.The lower feedstock cost and less energy consumption in products separation make it more competitive compared to the current toluene disproportionation route.Thus,MTPX is regarded as the most reasonable production route for PX production.This article reviews the strategies that applied to the preparation of high-performance catalysts for MTPX,with special focus on the precise control of pore dimension and acid sites distribution in zeolite to achieve the highest selectivity to PX.The outlook of the MTPX catalyst is also proposed to guide the catalyst development in the field.
基金the United States Geological Survey (USGS) (No.1003073E)the State of Wyoming(No.1002727A) for providing funding
文摘Elevated arsenic and selenium concentrations in water cause health problems to both humans and wildlife. Natural and anthropogenic activities have caused contamination of these elements in waters worldwide, making the development of efficient cost-effective methods in their removal essential. In this work, removal of arsenate and selenite from water by adsorption onto a natural goethite(α-FeO OH) sample was studied at varying conditions. The data was then compared with other arsenate, selenite/goethite adsorption systems as much of literature shows discrepancies due to varying adsorption conditions. Characterization of the goethite was completed using inductively coupled plasma mass spectrometry, X-ray diffraction, Fouriertransform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller surface area analysis. Pseudo-first order(PFO) and pseudo-second order(PSO) kinetic models were applied; including comparisons of different regression methods. Various adsorption isotherm models were applied to determine the best fitting model and to compare adsorption capacitates with other works. Desorption/leaching of arsenate and selenite was studied though the addition of phosphate and hydroxyl ions. Langmuir isotherm modeling resulted in maximum adsorption capacities of 6.204 and 7.740 mg/g for arsenate and selenite adsorption,respectively. The PSO model applied with a non-linear regression resulted in the best kinetic fits for both adsorption and desorption of arsenate and selenite. Adsorption decreased with increasing pH. Phosphate induced desorption resulted in the highest percentage of arsenate and selenite desorbed, while hydroxide induced resulted in the fastest desorption kinetics.
基金supported by the State Technology Major Special Project on Water Pollution Control(No.2008ZX07101-009,2009ZX07101-015)the National Natural Science Foundation of China(No. 90510009)
文摘To study how global warming and eutrophication affect water ecosystems, a multiplicative growth Monod model, modified by incorporating the Arrhenius equation, was applied to Lake Taihu to quantitatively study the relationships between algal biomass and both nutrients and temperature using long-term data. To qualitatively assess which factor was a limitation of the improved model, temperature variables were calculated using annual mean air temperature （AT）, water temperature （WT）, and their average temperature （ST）, while substrate variables were calculated using annual mean total nitrogen （TN）, total phosphorus （TP）, and their weighted aggregate （R）, respectively. The nine fitted curves showed that TN and AT were two important factors influencing algal growth; AT limited growth as algal photosynthesis is mainly carried out near the water surface; N leakage of phytoplankton and internal phosphorus load from sediment explains why TN was the best predictor of peak biomass using the Monod model. The fitted results suggest that annual mean algal biomass increased by 0.145 times when annual mean AT increased by 1.0℃. Results also showed that the more eutrophic the lake, the greater the effect AT had on algal growth. Subsequently, the long-term joint effect of annual temperature increase and eutrophication to water ecosystems can be quantitatively assessed and predicted.
文摘Methanol （CH3OH） is an important industrial chemical with a wide variety of uses. Industrial methanol synthesis catalysts are typically composed of Cu, Zn, and AI, but the use of catalysts incorporating rare earth elements has been shown to improve the catalytic performance. Due to their unique chemical and physical properties, the use of rare earth elements （scandium, yttrium, and the lanthanides） in catalysis in general has continued to increase over the past few decades, while the use of rare earth in methanol synthesis catalysts has not, despite often improving pertbrmance. The ability of several of the rare earth elements （Pr, Ce, Eu, Tb, Yb） to easily switch between oxidation states makes them beneficial for many different types of catalysts. However, for methanol synthesis the surface basicity is an important property, and the basic nature of the rare earth elements can be used to tune the basicity of catalysts. A small number of correlations between rare earth properties and catalytic performance have been observed, but often do not apply to other catalysts. Properties such as strength of basic sites, ionic radius, and etec- tronegativity have been found to correlate with performance results such as activity or selectivity.
基金supported by the National Key R&D Program of China(2018YFB0604701)the CHN ENERGY Group Corp.Ltd.(CF9300200004)。
文摘Methanol,a versatile chemical,fuel additive and potential H_(2) carrier,has attracted great attention.Despite of the wide industrialization,improvement of Cu-based methanol-synthesis catalysts is highly anticipated.Accordingly,a series of Cu/ZnO/Al_(2)O_(3) with designed precursor structures were prepared,and its structure-function relationship was investigated to make progress on this area.Results showed the catalyst derived from highly zinc-substituted malachite demonstrated the best catalytic performance in this work.It was found that the well-behaved catalyst possessed relatively high Cu specific surface area and exposed Cu concentration,and the well Cu/ZnO synergy.CuZn alloy was found by In-situ XRD tests,and its effect on the catalyst's thermostability was discussed.Fractional precipitation,which facilitated the Cu^(2+) substitution by Zn^(2+) in malachite lattice,could be an efficient preparation method of the Cu/ZnO/Al_(2)O_(3) catalyst.
基金supported by the Beijing Natural Science Foun-dation(No.8202029)the National Key R&D Program of China(No.2018YFD0900805)+1 种基金the National Natural Science Founda-tion of China(Nos.U19A20107 and 21307005)Beijing Ad-vanced Innovation Program for Land Surface Science.
文摘Sodium percarbonate(SPC)and peroxymonocarbonate(PMC)have been widely used in modified Fenton reactions because of their multiple superior features,such as a wide pH range and environmental friendliness.This broad review is intended to provide the fundamental information,status and progress of SPC and PMC based decontamination technologies according to the peer-reviewed papers in the last two decades.Both SPC and PMC can directly decompose various pollutants.The degradation efficiency will be enhanced and the target contaminants will be expanded after the activation of SPC and PMC.The most commonly used catalysts for SPC activation are iron compounds while cobalt composi-tions are applied to activate PMC in homogenous and heterogeneous catalytical systems.The generation and participation of hydroxyl,superoxide and/or carbonate radicals are involved in the activated SPC and PMC system.The reductive radicals,such as carbon dioxide and hydroxyethyl radicals,can be generated when formic acid or methanol is added in the Fe(II)/SPC system,which can reduce target contaminants.SPC can also be activated by energy,tetraacetylethylenediamine,ozone and buffered alkaline to generate different reactive radicals for pollutant decomposition.The SPC and activated SPC have been assessed for application in-situ chemical oxidation and sludge dewatering treatment.The challenges and prospects of SPC and PMC based decontamination technologies are also addressed in the last section.
基金the supports from the Clean Coal ProgramSchool of Energy Resources in Wyoming
文摘TiO2 nanomaterial is promising with its high potential and outstanding performance in photocatalytic environmental applications, such as CO2 conversion, water treatment, and air quality control. For many of these applications, the particle size, crystal structure and phase, porosity, and surface area influence the activity of TiO2 dramatically. TiO2 nanomaterials with special structures and morphologies, such as nanospheres, nanowires, nanotubes, nanorods, and nanoflowers are thus synthesized due to their desired characteristics. With an emphasis on the different morphologies of TiO2 and the influence factors in the synthesis, this review summarizes fourteen TiO2 preparation methods, such as the sol-gel method, solvothermal method, and reverse micelle method. The TiO2 formation mechanisms, the advantages and disadvantages of the preparation methods, and the photocatalytic environmental application examples are proposed as well.
基金support from National Science Foundation of China(No.22075012).
文摘A convenient method for methane(CH_(4))direct conversion to methanol(CH_(3)OH)is of great significance to use methane-rich resources,especially clathrates and stranded shale gas resources located in remote regions.Theoretically,the activation of CH_(4) and the selectivity to the CH_(3)OH product are challenging due to the extreme stability of CH_(4) and relatively high reactivity of CH_(3)OH.The state-of-the-art‘methane reforming-methanol synthesis’process adopts a two-step strategy to avoid the further reaction of CH_(3)OH under the harsh conditions required for CH_(4) activation.In the electrochemical field,researchers are trying to develop conversion pathways under mild conditions.They have found suitable catalysts to activate the C–H bonds in methane with the help of external charge and have designed the electrode reactions to continuously generate certain active oxygen species.These active oxygen species attack the activated methane and convert it to CH_(3)OH,with the benefit of avoiding over-oxidation of CH_(3)OH,and thus obtain a high conversion efficiency of CH_(4) to CH_(3)OH.This mini-review focuses on the advantages and challenges of electrochemical conversion of CH4 to CH_(3)OH,especially the strategies for supplying electro-generated active oxygen species in-situ to react with the activated methane.
基金supported by the USM short-term grant (Ac No.: 8044043)by the USM fellowship scheme for PhD study (to M. Irani)Water Program at University of Wyoming
文摘The purpose of this work is to remove Pb（II） from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy（FTIR）, Solid carbon nuclear magnetic resonance spectroscopy（CNMR））, silicon-29 nuclear magnetic resonance spectroscopy（Si NMR））, and X-ray diffraction spectroscope（（XRD） were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb（II） from the aqueous solution. The Pb（II）-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy（FTIR））,scanning electron microscopy（SEM））, and X-ray photoelectron spectroscopy（（XPS））. From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb（II）. Kinetic studies indicated that the adsorption of Pb（II）followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb（II） ions was 430 mg/g. Thus, the waste linear low-density polyethylene-g-poly（acrylic acid）-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb（II） adsorbent.
基金supported by the Caterpillar, Siemens,and the School of Energy Resource at University of Wyoming
文摘Olivine, one of the most abundant minerals existing in nature, is explored as a C02 carbonation agent for direct carbonation of C02 in flue gas. Olivine based C02 capture is thermodynamically favorable and can form a stable carbonate for long-term storage. Experimental results have shown that water vapor plays an important role in improving CO/carbonation rate and capacities. Other operation conditions including reaction temperature, initial C02 concentration, residence time corresponding to the flow rate of C02 gas stream, and water vapor concentration also considerably affect the performance of the technology.
基金the financial support from the National Natural Science Foundation of China(22233006,22273018)the Project of Henan International Joint Laboratory of Green Chemistrythe 111 Project(D17007)。
文摘While carbon dioxide(CO_(2))is a major greenhouse gas,it is also an important C1 resource.In the trend of energy conservation and emission reduction,electrocatalytic reduction has become a very promising strategy for CO_(2)utilization because it can convert CO_(2)directly to high-valued chemicals and fuels under mild conditions.In particular,the product CO and by-product H_(2)can be combined into syngas by an electrocatalytic CO_(2)reduction reaction(CO_(2)RR)in an aqueous medium.Different molar ratios of CO and H_(2)may be used to produce essential bulk chemicals or liquid fuels such as methanol,alkanes,and olefins through thermochemical catalysis,Fischer-Tropsch synthesis,microbial fermentation,and other techniques.This work discusses the latest strategies in controlling the molar ratio of CO/H_(2)and improving the yield of CO_(2)RR-to-syngas.The challenges of electrocatalytic syngas production are analyzed from an industrial application perspective,and the possible measures to overcome them are proposed in terms of new catalyst design,electrolyte innovation,flow reactor optimization,anodic reaction coupling,and operando technique application.
基金funded by the Natural Science Foundation of Shandong Province, China (ZR2023MB049)the China Postdoctoral Science Foundation (2020M670483)the Science Foundation of Weifang University (2023BS11)。
文摘The catalyst layers(CLs) electrode is the key component of the membrane electrode assembly(MEA) in proton exchange membrane fuel cells(PEMFCs). Conventional electrodes for PEMFCs are composed of carbon-supported, ionomer, and Pt nanoparticles, all immersed together and sprayed with a micron-level thickness of CLs. They have a performance trade-off where increasing the Pt loading leads to higher performance of abundant triple-phase boundary areas but increases the electrode cost. Major challenges must be overcome before realizing its wide commercialization. Literature research revealed that it is impossible to achieve performance and durability targets with only high-performance catalysts, so the controllable design of CLs architecture in MEAs for PEMFCs must now be the top priority to meet industry goals. From this perspective, a 3D ordered electrode circumvents this issue with a support-free architecture and ultrathin thickness while reducing noble metal Pt loadings. Herein, we discuss the motivation in-depth and summarize the necessary CLs structural features for designing ultralow Pt loading electrodes. Critical issues that remain in progress for 3D ordered CLs must be studied and characterized. Furthermore, approaches for 3D ordered CLs architecture electrode development, involving material design, structure optimization, preparation technology, and characterization techniques, are summarized and are expected to be next-generation CLs for PEMFCs. Finally, the review concludes with perspectives on possible research directions of CL architecture to address the significant challenges in the future.
