A UV-activated room temperature chemiresistive gas sensor based on ZnO nanocrystals film was fabricated. Its gas sensing properties under various conditions were also investigated in detail. The results shed new insig...A UV-activated room temperature chemiresistive gas sensor based on ZnO nanocrystals film was fabricated. Its gas sensing properties under various conditions were also investigated in detail. The results shed new insight into the adsorption behaviors of gas molecules on the surface of ZnO nanocrystals under UV irradiation. The chemisorbed oxygen species(O^-2(ads)(hv)) induced by UV light govern the adsorption and desorption ways of other gas molecules on the surface of ZnO nanocrystals, which is dependent on the electron affinity of gas molecules. Gas molecules with higher electron affinity than oxygen molecules can be adsorbed on the surface by the competitive adsorption way, extracting electrons from the surface. Gas molecules with lower electron affinity than oxygen molecules are attracted by the adsorbed O^-2(ads)(hv)layer, releasing electrons to the surface. These processes can influence the gas sensing properties of the sensor. Our findings will pave the way for the fundamental understanding and design of UV-activated gas sensor in the future.展开更多
Graphene oxide(GO) channels exhibit unique mass transport behaviors due to their flexibility, controllable thinness and extraordinary physicochemical properties, enabling them to be widely used for adsorption and memb...Graphene oxide(GO) channels exhibit unique mass transport behaviors due to their flexibility, controllable thinness and extraordinary physicochemical properties, enabling them to be widely used for adsorption and membrane separation. Nevertheless, the adsorption behavior of nanosized contaminants within the channels of GO membrane has not been fully discussed. In this study, we fabricated a GO membrane(PGn, where n represents the deposition cycles of GO) with multi channels via the crosslinking of GO and multibranched poly(ethyleneimine)(PEI). Phenol was used as molecular probe to determine the correlations between dynamic adsorption behavior and structural parameters of the multilevel GO/PEI membrane. PG8 shows higher adsorption capacities and affinity, which is predominantly attributed to the multichannel structure providing a large specific surface for phenol adsorption, enhancing the accessibility of active sites for phenol molecules and the transport of phenol. Density functional theory calculations demonstrate that the adsorption mechanism of phenol within GO channel is energetically oriented by hydrogen bonds, which is dominated by oxygen-containing groups compared to amino groups. Particularly, the interfaces which facilitate strong π-π interaction and hydrogen bonds maybe the most active regions. Moreover, the as-prepared PG8 membrane showed outstanding performance for other contaminants such as methyl orange and Cr(VI). It is anticipated that this study will have implications for design of GO-related environmental materials with enhanced efficiency.展开更多
Naturally occurring radium(^(223)Ra,^(224)Ra,^(226)Ra,and^(228)Ra)isotopes have been widely applied as geochemical tracers in marine environments,especially when estimating the submarine groundwater discharge(SGD).In ...Naturally occurring radium(^(223)Ra,^(224)Ra,^(226)Ra,and^(228)Ra)isotopes have been widely applied as geochemical tracers in marine environments,especially when estimating the submarine groundwater discharge(SGD).In this sense,the influencing factors and transport mechanism of radium isotope activity in aquifers can be key information for SGD estimation.This work evaluates the adsorption/desorption behavior of^(224)Ra and^(226)Ra in the solid-liquid phase through a leaching experiment and analysis of field data.The results suggested that radium isotope activity was positively correlated with salinity and grain size,in the case of abundant sediments.Through ion analysis,we found that the ions(Na^(+),Ca^(2+),Mg^(2+),and Ba^(2+))exchanged with radium isotopes in the process of transport.A 1-D reactive transport model was established to simulate the transport process of radium isotope in aquifers.The model successfully simulated the variation of radium isotope desorption activity with salinity and was subsequently verified in the field.This study contributes to the understanding of the geochemical behavior of radium isotopes in aquifers and provides guidance for selecting a suitable groundwater endmember in SGD estimation.展开更多
The use of trichlorphon in large quantities causes a large number of organic pollutants to enter water, sediments, and soils. Phyllosilicate minerals are considered effective adsorbents for organic pollutants. However...The use of trichlorphon in large quantities causes a large number of organic pollutants to enter water, sediments, and soils. Phyllosilicate minerals are considered effective adsorbents for organic pollutants. However, the adsorption behavior of organic pollutants on soil minerals affected by low-molecular-weight organic acids(LMWOAs) is not fully understood. In this study, the effect of LMWOAs on the adsorption behavior of trichlorphon on phyllosilicate minerals was investigated using a combination of adsorption measurements and molecular spectroscopic techniques(attenuated total reflection-Fourier transform infrared spectroscopy(ATR-FTIR) and X-ray photoelectron spectroscopy(XPS)). The adsorption of trichlorphon onto kaolinite(KAO) and montmorillonite(MON) was suppressed by increasing pH, indicating that electrostatic interaction played a key role in adsorption, especially at low pH. In the presence of citric acid(CA), there was an obvious promotion of trichlorphon adsorption on KAO and MON. In the presence of oxalic acid(OA), the adsorption of trichlorphon on KAO was promoted, whereas the adsorption on MON was inhibited, especially at pH 4.0. The presence of CA and OA increased the adsorption by increasing the exposure of hydrophobic sites of KAO and MON. The results from ATR-FTIR and XPS also indicated that the hydrophobic Si–O sites of phyllosilicate minerals were the preferred adsorption sites for trichlorphon in the presence of CA and OA, probably driven by the hydrophobic effect. However, the weak effect of OA on MON caused an increase in the electrostatic repulsion between MON and trichlorphon molecules, thus inhibiting adsorption. This study is significant for a deeper understanding of self-purification of soil and sediment systems in the presence of organic pollutants.展开更多
Flotation is a complex process that occurs in solid-liquid-gas multiphase systems,and its main factors include the minerals,separation medium,as well as various flotation reagents.The study of mineral properties and i...Flotation is a complex process that occurs in solid-liquid-gas multiphase systems,and its main factors include the minerals,separation medium,as well as various flotation reagents.The study of mineral properties and interactions with other components such as reagents and water lays the basic theoretical foundation for flotation.Density functional theory(DFT) calculations can qualitatively evaluate the exchange of matter and energy between the mineral system and the surroundings and quantitatively characterize these behaviors,which greatly expands the breadth and depth of flotation studies.This review systematically summarizes the advances of flotation research based on DFT studies,including the study of mineral crystal chemistry represented by the theory of lattice defects,mineral surface hydration such as hydrophilicity and hydrophobicity,surface regulation mechanism,and collecting mechanism based on surface adsorption theory.More significantly,it systematically elaborates different types of collectors according to their characteristics and emphatically explains the mechanism of some typical collectors in detail.展开更多
Probing the relationship between the adsorption of superoxide species and the kinetics of Li-O_(2) chemistry is critical for designing superior oxygen electrodes for the Li-O_(2) battery,yet the modulation essence,esp...Probing the relationship between the adsorption of superoxide species and the kinetics of Li-O_(2) chemistry is critical for designing superior oxygen electrodes for the Li-O_(2) battery,yet the modulation essence,especially at the atomic level,remains little understood.Herein,we reveal that the adsorption behaviors of superoxide species can be effectively regulated via a core-induced interfacial charge interaction,and we find that moderate adsorption strength can enable superior rate capability in a Li-O_(2) battery.More importantly,operando X-ray absorption near-edge structure and surface-enhanced Raman spectroscopy provide tools to monitor in situ the evolution of the superoxide intermediates and the electronic states of the catalyst's metal sites during the discharge and charge processes,and correlate these with the surface adsorption states.The concept of tuning adsorption behavior through interfacial charge engineering could open up new opportunities to further advance the development of the Li-O_(2) battery and beyond.展开更多
The adsorption behavior, antibacterial, and corrosion properties of a Ti-3 Cu alloy were studied in a phosphate-buffered saline solution containing 0, 1, 3, and 6 gL^(-1) bovine serum albumin protein at 37℃ and pH = ...The adsorption behavior, antibacterial, and corrosion properties of a Ti-3 Cu alloy were studied in a phosphate-buffered saline solution containing 0, 1, 3, and 6 gL^(-1) bovine serum albumin protein at 37℃ and pH = 7.4(±0.2). The protein adsorption behavior was examined via cyclic voltammetry, secondary ions mass spectroscopy(SIMS), and angle-resolved X-ray photoelectron spectroscopy(ARXPS). The corrosion property was analyzed by the open circuit potential(OCP), potentiodynamic polarization(PD),and electrochemical impedance spectroscopy(EIS) examinations. The antibacterial test was conducted according to the GB/T 21510 China Standard. It was observed that the surface charge density(QA DS) was directly proportional to the amount of the adsorbed BSA protein, signifying that the protein adsorption was accompanied by the charge transfer, pointing to chemisorptions phenomena. BSA amino groups and other organic species were observed in the surface analysis examinations. It was shown that the formation of barrier complexes between the TiO_(2) oxide-layer and PBS solution resulted in decreasing the release of Cu-ions, which consequently reduced the antibacterial activity. On the other hand, these barrier complexes improved the corrosion resistance by increasing the charge transfer resistance and double-layer capacitance of the Ti-3 Cu alloy.展开更多
Unraveling the substrate adsorption structure–performance relationship is pivotal for heterogeneous carbon supported metal single-atom catalysts(M_(1)/C SACs).However,due to the complexity of the functional groups on...Unraveling the substrate adsorption structure–performance relationship is pivotal for heterogeneous carbon supported metal single-atom catalysts(M_(1)/C SACs).However,due to the complexity of the functional groups on carbon material surface,it is still a great challenge.Herein,inspired by structure of enzymes,we used activated carbon(AC),which has adjustable surface oxygen functional groups(OFGs),supported atomically dispersed Fe-N_(4) sites as heme-like catalyst.And based on a combination of scanning transmission electron microscopy(STEM),X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),Mössbauer spectroscopy,Fourier transform infrared(FT-IR)characterizations,kinetics experiments and density functional theory(DFT)calculations,we revealed the effect of substrate adsorption behavior on AC support surface,that is,with the increase of carboxyl group in OFGs,the adsorbed 3,3',5,5'-tetramethylbenzidine(TMB)molecular increased,and consequently the substrate enriched on AC surface.Such carboxyl group as well as Fe-N_(4) active sites synergistically realized high-efficiency peroxidase-like activity,just like the heme.This work suggests that simultaneously constructing metal single-atom active sites and specific functional groups on carbon support surface may open an avenue for engineering metal-support synergistic catalysis in M_(1)/C SACs,which can further improve catalytic performance.展开更多
This study focused on the adsorptive behaviors of humic acid onto freshly prepared hydrous MnO_(2)(s)(δMnO_(2)),and investigated the feasibility of employingδMnO2 for humic acid removal from drinking water.Effects o...This study focused on the adsorptive behaviors of humic acid onto freshly prepared hydrous MnO_(2)(s)(δMnO_(2)),and investigated the feasibility of employingδMnO2 for humic acid removal from drinking water.Effects of such parameters as molecular mass of humic acid,kinds of diva-lent cations on adsorptive behaviors and possible mechanisms involved were investigated.This study indicated that humic acid with higher molecular mass exhibited more tendency of adsorbing ontoδMnO2 than that with lower molecular mass.Ca^(2+)facilitated more humic acid adsorption than Mg^(2+);UV-Vis spectra analysis indicated higher capabilities of Ca^(2+)coordinating with acidic functional groups of humic acid than that of Mg2+.Additionally,ζpotential characterization indicated that Ca^(2+)showed higher potential of increasingζpotential ofδMnO_(2) than Mg^(2+).Ca^(2+)of 1.0 mmol/L increasedζpotential ofδMnO2 from−37 mV(pH 7.9)to+7 mV(pH 7.2),while 1.0 mmol/L Mg^(2+)^increased to lower value as−9 mV(pH 6.5),correspondingly.Fourier transform infrared(FTIR)spectra demonstrated the adsorption of humic acid ontoδMnO_(2),showing the important roles of-COO−function-al groups and surface Mn-OH in the adsorption of humic acid ontoδMnO_(2).展开更多
To remove antibiotics from waste water,an alkali active porous biochar,850BC,was prepared from corncob xylose residue.In preparation,NaOH dipping was used for silicon removal and KOH activation was operated at 850℃.F...To remove antibiotics from waste water,an alkali active porous biochar,850BC,was prepared from corncob xylose residue.In preparation,NaOH dipping was used for silicon removal and KOH activation was operated at 850℃.Further characterization containing BET,SEM,and FTIR were confirmed.850BC possessed a huge specific surface area of 3043 m^(2)·g^(−1),developed pore structure and abundant oxygen functional groups.The adsorption performance of sulfamethoxazole on 850BC was quick and efficient,and the adsorption capacity reached 1429 mg·g^(−1),which was significantly higher than other adsorbents reported previously.While pseudo-second-order kinetic model and Langmuir model could better describe the adsorption,chemisorp-tion dominated the SMX adsorption onto 850BC.In virtue of pore-filling andπ-πinteraction as major mechanism,a large surface area and rich oxygen-containing functional groups led to an excellent adsorption performance.Thus,this preparation method provided a biochar-based adsorbent with enhanced specific surface for efficient removal of antibiotic pollutants.展开更多
Isomerism is an essential and widespread phenomenon in organic chemistry but rarely observed in covalent organic frameworks(COFs),a novel class of crystalline porous organic polymers with versatile applications.Herein...Isomerism is an essential and widespread phenomenon in organic chemistry but rarely observed in covalent organic frameworks(COFs),a novel class of crystalline porous organic polymers with versatile applications.Herein,we give an account of the first example of a controllable synthesis of constitutional isomers of a COF.The two isomers exhibited marked differences in their gas/vapor adsorption behaviors and chemical stability in various solvents.Furthermore,structure transformation from one isomer to the other was realized.This work not only paves the way for rational design and synthesis of COF isomers but also provides a vivid example of structure–property relationship in crystalline porous polymers.展开更多
基金supported by the Funds for Creative Research Groups of China(Grant No.61421002)the National Natural Science Foundation of China(Grant Nos.61571097,61604033,61671115)the National Postdoctoral Program for Innovative Talents(Grant No.BX201600026)
文摘A UV-activated room temperature chemiresistive gas sensor based on ZnO nanocrystals film was fabricated. Its gas sensing properties under various conditions were also investigated in detail. The results shed new insight into the adsorption behaviors of gas molecules on the surface of ZnO nanocrystals under UV irradiation. The chemisorbed oxygen species(O^-2(ads)(hv)) induced by UV light govern the adsorption and desorption ways of other gas molecules on the surface of ZnO nanocrystals, which is dependent on the electron affinity of gas molecules. Gas molecules with higher electron affinity than oxygen molecules can be adsorbed on the surface by the competitive adsorption way, extracting electrons from the surface. Gas molecules with lower electron affinity than oxygen molecules are attracted by the adsorbed O^-2(ads)(hv)layer, releasing electrons to the surface. These processes can influence the gas sensing properties of the sensor. Our findings will pave the way for the fundamental understanding and design of UV-activated gas sensor in the future.
基金supported by the National Natural Science Foundation of China(22078269 and 51708406).
文摘Graphene oxide(GO) channels exhibit unique mass transport behaviors due to their flexibility, controllable thinness and extraordinary physicochemical properties, enabling them to be widely used for adsorption and membrane separation. Nevertheless, the adsorption behavior of nanosized contaminants within the channels of GO membrane has not been fully discussed. In this study, we fabricated a GO membrane(PGn, where n represents the deposition cycles of GO) with multi channels via the crosslinking of GO and multibranched poly(ethyleneimine)(PEI). Phenol was used as molecular probe to determine the correlations between dynamic adsorption behavior and structural parameters of the multilevel GO/PEI membrane. PG8 shows higher adsorption capacities and affinity, which is predominantly attributed to the multichannel structure providing a large specific surface for phenol adsorption, enhancing the accessibility of active sites for phenol molecules and the transport of phenol. Density functional theory calculations demonstrate that the adsorption mechanism of phenol within GO channel is energetically oriented by hydrogen bonds, which is dominated by oxygen-containing groups compared to amino groups. Particularly, the interfaces which facilitate strong π-π interaction and hydrogen bonds maybe the most active regions. Moreover, the as-prepared PG8 membrane showed outstanding performance for other contaminants such as methyl orange and Cr(VI). It is anticipated that this study will have implications for design of GO-related environmental materials with enhanced efficiency.
基金The Joint Funds of the National Natural Science Foundation of China under contract Nos U22A20580 and U2106203the National Natural Science Foundation of China under contract No.41706067the Open Project Program of Key Laboratory of Ecological Warning,Protection&Restoration for Bohai Sea,Ministry of Natural Resources under contract No.2022108.
文摘Naturally occurring radium(^(223)Ra,^(224)Ra,^(226)Ra,and^(228)Ra)isotopes have been widely applied as geochemical tracers in marine environments,especially when estimating the submarine groundwater discharge(SGD).In this sense,the influencing factors and transport mechanism of radium isotope activity in aquifers can be key information for SGD estimation.This work evaluates the adsorption/desorption behavior of^(224)Ra and^(226)Ra in the solid-liquid phase through a leaching experiment and analysis of field data.The results suggested that radium isotope activity was positively correlated with salinity and grain size,in the case of abundant sediments.Through ion analysis,we found that the ions(Na^(+),Ca^(2+),Mg^(2+),and Ba^(2+))exchanged with radium isotopes in the process of transport.A 1-D reactive transport model was established to simulate the transport process of radium isotope in aquifers.The model successfully simulated the variation of radium isotope desorption activity with salinity and was subsequently verified in the field.This study contributes to the understanding of the geochemical behavior of radium isotopes in aquifers and provides guidance for selecting a suitable groundwater endmember in SGD estimation.
基金financially supported by the National Natural Science Foundation of China(Nos.41825021,42007020,and 21876097)the National Natural Science Foundation Project of International Cooperation and Exchange,China(No.41961144010)。
文摘The use of trichlorphon in large quantities causes a large number of organic pollutants to enter water, sediments, and soils. Phyllosilicate minerals are considered effective adsorbents for organic pollutants. However, the adsorption behavior of organic pollutants on soil minerals affected by low-molecular-weight organic acids(LMWOAs) is not fully understood. In this study, the effect of LMWOAs on the adsorption behavior of trichlorphon on phyllosilicate minerals was investigated using a combination of adsorption measurements and molecular spectroscopic techniques(attenuated total reflection-Fourier transform infrared spectroscopy(ATR-FTIR) and X-ray photoelectron spectroscopy(XPS)). The adsorption of trichlorphon onto kaolinite(KAO) and montmorillonite(MON) was suppressed by increasing pH, indicating that electrostatic interaction played a key role in adsorption, especially at low pH. In the presence of citric acid(CA), there was an obvious promotion of trichlorphon adsorption on KAO and MON. In the presence of oxalic acid(OA), the adsorption of trichlorphon on KAO was promoted, whereas the adsorption on MON was inhibited, especially at pH 4.0. The presence of CA and OA increased the adsorption by increasing the exposure of hydrophobic sites of KAO and MON. The results from ATR-FTIR and XPS also indicated that the hydrophobic Si–O sites of phyllosilicate minerals were the preferred adsorption sites for trichlorphon in the presence of CA and OA, probably driven by the hydrophobic effect. However, the weak effect of OA on MON caused an increase in the electrostatic repulsion between MON and trichlorphon molecules, thus inhibiting adsorption. This study is significant for a deeper understanding of self-purification of soil and sediment systems in the presence of organic pollutants.
基金financially supported by the Natural Science Foundation of China under grants: U20A20269, 51874106, and 51574092。
文摘Flotation is a complex process that occurs in solid-liquid-gas multiphase systems,and its main factors include the minerals,separation medium,as well as various flotation reagents.The study of mineral properties and interactions with other components such as reagents and water lays the basic theoretical foundation for flotation.Density functional theory(DFT) calculations can qualitatively evaluate the exchange of matter and energy between the mineral system and the surroundings and quantitatively characterize these behaviors,which greatly expands the breadth and depth of flotation studies.This review systematically summarizes the advances of flotation research based on DFT studies,including the study of mineral crystal chemistry represented by the theory of lattice defects,mineral surface hydration such as hydrophilicity and hydrophobicity,surface regulation mechanism,and collecting mechanism based on surface adsorption theory.More significantly,it systematically elaborates different types of collectors according to their characteristics and emphatically explains the mechanism of some typical collectors in detail.
基金This work was supported by the National Key Research and Development Program of China(2017YFA0206703)Natural Science Fund of China(No.21771169,11722543)the Collaborative Innovation program of Hefei Science Center,CAS,and the Fundamental Research Funds for the Central Universities(WK2060000016).We also thank the Soft X-ray Microscope at beamline BL07W,the Photoemission Endstations at BL10B of National Synchrotron Radiation Laboratory,and the Shanghai Synchrotron Radiation Facility(BL14W1,SSRF)for nano CT,XPS and XAFS characterizations.The numerical calculations in this paper have been done on the supercomputing system in the Supercomputing Center of University of Science and Technology of China.
文摘Probing the relationship between the adsorption of superoxide species and the kinetics of Li-O_(2) chemistry is critical for designing superior oxygen electrodes for the Li-O_(2) battery,yet the modulation essence,especially at the atomic level,remains little understood.Herein,we reveal that the adsorption behaviors of superoxide species can be effectively regulated via a core-induced interfacial charge interaction,and we find that moderate adsorption strength can enable superior rate capability in a Li-O_(2) battery.More importantly,operando X-ray absorption near-edge structure and surface-enhanced Raman spectroscopy provide tools to monitor in situ the evolution of the superoxide intermediates and the electronic states of the catalyst's metal sites during the discharge and charge processes,and correlate these with the surface adsorption states.The concept of tuning adsorption behavior through interfacial charge engineering could open up new opportunities to further advance the development of the Li-O_(2) battery and beyond.
基金financially supported by the National Key Research and Development Program of China(2018YFC1106601)Liaoning Revitalization Talents Program(XLYC1807069)+1 种基金National Natural Science Foundation(No.51631009,31870954)support of the CSC scholarship。
文摘The adsorption behavior, antibacterial, and corrosion properties of a Ti-3 Cu alloy were studied in a phosphate-buffered saline solution containing 0, 1, 3, and 6 gL^(-1) bovine serum albumin protein at 37℃ and pH = 7.4(±0.2). The protein adsorption behavior was examined via cyclic voltammetry, secondary ions mass spectroscopy(SIMS), and angle-resolved X-ray photoelectron spectroscopy(ARXPS). The corrosion property was analyzed by the open circuit potential(OCP), potentiodynamic polarization(PD),and electrochemical impedance spectroscopy(EIS) examinations. The antibacterial test was conducted according to the GB/T 21510 China Standard. It was observed that the surface charge density(QA DS) was directly proportional to the amount of the adsorbed BSA protein, signifying that the protein adsorption was accompanied by the charge transfer, pointing to chemisorptions phenomena. BSA amino groups and other organic species were observed in the surface analysis examinations. It was shown that the formation of barrier complexes between the TiO_(2) oxide-layer and PBS solution resulted in decreasing the release of Cu-ions, which consequently reduced the antibacterial activity. On the other hand, these barrier complexes improved the corrosion resistance by increasing the charge transfer resistance and double-layer capacitance of the Ti-3 Cu alloy.
基金The authors wish to acknowledge the support of National Natural Science Foundation of China(NSFC,Nos.21802094,22002118,22172119,and 22102167)Postdoctoral Research Foundation of China(Nos.2020TQ0245 and 2021M693060)Natural Science Basic Research Plan in Shaanxi Province of China(No.2021JM047).
文摘Unraveling the substrate adsorption structure–performance relationship is pivotal for heterogeneous carbon supported metal single-atom catalysts(M_(1)/C SACs).However,due to the complexity of the functional groups on carbon material surface,it is still a great challenge.Herein,inspired by structure of enzymes,we used activated carbon(AC),which has adjustable surface oxygen functional groups(OFGs),supported atomically dispersed Fe-N_(4) sites as heme-like catalyst.And based on a combination of scanning transmission electron microscopy(STEM),X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),Mössbauer spectroscopy,Fourier transform infrared(FT-IR)characterizations,kinetics experiments and density functional theory(DFT)calculations,we revealed the effect of substrate adsorption behavior on AC support surface,that is,with the increase of carboxyl group in OFGs,the adsorbed 3,3',5,5'-tetramethylbenzidine(TMB)molecular increased,and consequently the substrate enriched on AC surface.Such carboxyl group as well as Fe-N_(4) active sites synergistically realized high-efficiency peroxidase-like activity,just like the heme.This work suggests that simultaneously constructing metal single-atom active sites and specific functional groups on carbon support surface may open an avenue for engineering metal-support synergistic catalysis in M_(1)/C SACs,which can further improve catalytic performance.
基金This work was supported by the National Natural Science Foundation of China(Grant No.50678007).
文摘This study focused on the adsorptive behaviors of humic acid onto freshly prepared hydrous MnO_(2)(s)(δMnO_(2)),and investigated the feasibility of employingδMnO2 for humic acid removal from drinking water.Effects of such parameters as molecular mass of humic acid,kinds of diva-lent cations on adsorptive behaviors and possible mechanisms involved were investigated.This study indicated that humic acid with higher molecular mass exhibited more tendency of adsorbing ontoδMnO2 than that with lower molecular mass.Ca^(2+)facilitated more humic acid adsorption than Mg^(2+);UV-Vis spectra analysis indicated higher capabilities of Ca^(2+)coordinating with acidic functional groups of humic acid than that of Mg2+.Additionally,ζpotential characterization indicated that Ca^(2+)showed higher potential of increasingζpotential ofδMnO_(2) than Mg^(2+).Ca^(2+)of 1.0 mmol/L increasedζpotential ofδMnO2 from−37 mV(pH 7.9)to+7 mV(pH 7.2),while 1.0 mmol/L Mg^(2+)^increased to lower value as−9 mV(pH 6.5),correspondingly.Fourier transform infrared(FTIR)spectra demonstrated the adsorption of humic acid ontoδMnO_(2),showing the important roles of-COO−function-al groups and surface Mn-OH in the adsorption of humic acid ontoδMnO_(2).
基金the National Key Research and Development Program of China[2017YFA0207201]the National Natural Science Foundation of China(Grant No.2197020577).
文摘To remove antibiotics from waste water,an alkali active porous biochar,850BC,was prepared from corncob xylose residue.In preparation,NaOH dipping was used for silicon removal and KOH activation was operated at 850℃.Further characterization containing BET,SEM,and FTIR were confirmed.850BC possessed a huge specific surface area of 3043 m^(2)·g^(−1),developed pore structure and abundant oxygen functional groups.The adsorption performance of sulfamethoxazole on 850BC was quick and efficient,and the adsorption capacity reached 1429 mg·g^(−1),which was significantly higher than other adsorbents reported previously.While pseudo-second-order kinetic model and Langmuir model could better describe the adsorption,chemisorp-tion dominated the SMX adsorption onto 850BC.In virtue of pore-filling andπ-πinteraction as major mechanism,a large surface area and rich oxygen-containing functional groups led to an excellent adsorption performance.Thus,this preparation method provided a biochar-based adsorbent with enhanced specific surface for efficient removal of antibiotic pollutants.
基金the National Science Fund for Distinguished Young Scholars of China(no.21725404)Shanghai Scientific and Technological Innovation Project(18JC1410600)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB20000000)for financial support.
文摘Isomerism is an essential and widespread phenomenon in organic chemistry but rarely observed in covalent organic frameworks(COFs),a novel class of crystalline porous organic polymers with versatile applications.Herein,we give an account of the first example of a controllable synthesis of constitutional isomers of a COF.The two isomers exhibited marked differences in their gas/vapor adsorption behaviors and chemical stability in various solvents.Furthermore,structure transformation from one isomer to the other was realized.This work not only paves the way for rational design and synthesis of COF isomers but also provides a vivid example of structure–property relationship in crystalline porous polymers.
