Mg2+ and PO43+ were added into the synthetic wastewater, leading to the dissociation of the complex ions in the wastewater, and resulting in removal of copper and ammonia therein. The effects of agents addition amo...Mg2+ and PO43+ were added into the synthetic wastewater, leading to the dissociation of the complex ions in the wastewater, and resulting in removal of copper and ammonia therein. The effects of agents addition amount, pH, and reaction time on the removal efficiency of copper and ammonia were investigated. In particular, two-sectional struvite formation (TSSF) process was established for copper and ammonia removal. MgCl2 and Na2HPO4 were added by following 90% addition in the first section and remained 10% in the second during the TSSF process. Compared with one sectional struvite formation, TSSF possessed much better performance. Under condition of n(NH3-N):n(Mg):n(P)=1:1.2:1.5 (molar ratio), pH=9, and reaction time of 30 min, the removal efficiencies of copper and ammonia were 98.9% and 99.96%, respectively. The enhanced performance of TSSF is explained by the competition of ammonia by copper?ammonia complexes and struvite. The dissociation of copper-ammonia complexes is further demonstrated by thermodynamic equilibrium analysis, on the basis of calculations and establishment of predominance phases diagram. Moreover, XRD and EDS analyses further confirmed the formation of struvite and precipitation of copper, which prove the transmission of copper and ammonia from liquid phase into solid phase.展开更多
Air stripping was adopted to treat nickel ammonia complex ion-containing wastewater in order to remove nickel and ammonia simultaneously in one technological process.The relationship among pH,the concentration of nick...Air stripping was adopted to treat nickel ammonia complex ion-containing wastewater in order to remove nickel and ammonia simultaneously in one technological process.The relationship among pH,the concentration of nickel ammonia complex ion and total ammonia concentration was analyzed theoretically.Influence of pH value,water temperature,airflow rate and time on air stripping was studied in detail by static experiment in laboratory.The results show that at pH 11,temperature of 60℃and airflow rate of 0.12 m3/h,NH3 and Ni 2+concentrations remained in wastewater are less than 2 and 0.2 mg/L,respectively,after blowing for 75 min,which reaches the standard of the state discharge.When the tail gas is absorbed by 0.5 mol/L H2SO4 in order to avoid the secondary pollution,the absorption rate can achieve 70%.展开更多
Unlike natural organic matter(NOM), wastewater organic matter(WWOM) from wastewater treatment plant effluents has not been extensively studied with respect to complexation reactions with heavy metals such as copper or...Unlike natural organic matter(NOM), wastewater organic matter(WWOM) from wastewater treatment plant effluents has not been extensively studied with respect to complexation reactions with heavy metals such as copper or zinc. In this study, organic matter from surface waters and a wastewater treatment plant effluent were concentrated by reverse osmosis(RO) method. The samples were treated in the laboratory to remove trace metals and major cations. The zinc complexing properties of both NOM and the WWOM were studied by square wave anodic stripping voltammetry(SWASV). Experimental data were compared to predictions using the Windermere Humic Aqueous Model(WHAM) Version VI. We found that the zinc binding of WWOM was much stronger than that of NOM and not well predicted by WHAM. This suggests that in natural water bodies that receive wastewater treatment plant effluents the ratio of WWOM to NOM must be taken into account in order to accurately predict free zinc activities.展开更多
The coordination structure of cupric tartrate(Cu−TA)complex was investigated by ultraviolet−visible(UV-Vis)and liquid chromatography/mass spectrometer(LC-MS)firstly;furthermore,effective coordination configurations an...The coordination structure of cupric tartrate(Cu−TA)complex was investigated by ultraviolet−visible(UV-Vis)and liquid chromatography/mass spectrometer(LC-MS)firstly;furthermore,effective coordination configurations and electronic properties of Cu−TA in aqueous solution were systematically revealed by density functional theory(DFT)calculations.Consistently,Job plots show the possible existence of[Cu(TA)]and[Cu(TA)_(2)]^(2-)at 230 and 255 nm based on UV-Vis results.LC-MS results confirm the existence of the single and high coordination complexes[Cu_(2)(TA)_(2)]^(+),[Cu(TA)_(2)]^(+)and[Cu_(2)(TA)_(3)(H_(2)O)_(2)(OH)_(2)]^(2+).DFT calculation results show that carboxylic oxygen and hydroxyl oxygen of tartaric acid(TA)are preferred sites for Cu(Ⅱ)coordination.[Cu(TA)](1H,3H sites O of TA coordinated with Cu(Ⅱ)),[Cu(TA)_(2)]^(2-)(two 1^(C),2^(H) sites O of TA coordinated with Cu(Ⅱ)),and[Cu(TA)_(3)]^(4-)(three 2H,3H sites O of TA coordinated with Cu(Ⅱ))should be dominant coordination configurations of Cu−TA.The corresponding Gibbs reaction energies are-170.1,-136.2,and-90.2 kJ/mol,respectively.展开更多
At present,as the majority of nursing homes, resorts,villages,villas and other decentralized living areas are far away from municipal sewer system,it is difficult to transport municipal waste water to city sewage trea...At present,as the majority of nursing homes, resorts,villages,villas and other decentralized living areas are far away from municipal sewer system,it is difficult to transport municipal waste water to city sewage treatment plants for processing.If the large quantity of decentralized wastewater were directly discharged to the rivers,lakes or other receiving water body without treatment,seriously contaminate to surface water and groundwater occurred.According to the analysis on characteristics of distributed展开更多
Filters filled with a micelle-clay complex mixed with sand were employed to investigate their purification capability of tertiary treated wastewater with loose UF-membranes. The UF membrane was hollow fiber with a mol...Filters filled with a micelle-clay complex mixed with sand were employed to investigate their purification capability of tertiary treated wastewater with loose UF-membranes. The UF membrane was hollow fiber with a molecular weight cutoff of 100 kD. The complex was prepared from the organic cation octadecyltrimethylammonium (ODTMA) and the negatively charged clay-mineral, montmoriIIonite. This complex has a very large surface area, which includes large hydrophobic domains and is positively charged, about half of the cation exchange capacity of the clay. Two sets of filtration experiments were carried out at flow rates of 1.2 and 50 mL/min, which correspond to flow velocities of 3.7 and 153 cm/h, respectively. In the first case, after a passage of 1 L, the turbidity, total suspended solids (TSS), fecal coliforms (FC), and total coliforms (TC) were reduced to zero from 14 NTU, 6 ppm, 350 and 10,000 counts per 100 mL, respectively. In the second case, the numbers of FC and TC were reduced from 50,000/100 mL to zero after the passage of 14 L. The values of COD and BOD were reduced several-fold. The conclusion is that the incorporation of micelle-clay filters in the sewage treatment system with loose tertiary capability is promising and warrants larger scale experiments for optimization of the overall system.展开更多
Heavy metals usually exist stably as the species of organic complexes in high-salinity wastewater.Therefore,their effective removal is challenging,especially when the initial p H is neutral.Herein,a novel nitrogen dop...Heavy metals usually exist stably as the species of organic complexes in high-salinity wastewater.Therefore,their effective removal is challenging,especially when the initial p H is neutral.Herein,a novel nitrogen doped biomass-based composite(N-CMCS)was synthesized to remove the complexed heavy metal of Cr(Ⅲ)-carboxyl.The maximum adsorption capacity of Cr(Ⅲ)-Citrate(Cr-Cit)by N-CMCS under neutral p H(7.0)and high-salinity(200 mmol/L NaCl)condition was up to 2.50 mmol/g.And the removal performance remained stable after 6 times of regeneration.Combined with species and characterizations analysis,electrostatic attraction and hydrogen bonding were the main mechanisms for N-CMCS to remove Cr(Ⅲ)-carboxyl complexes.Dynamic adsorption indicated N-CMCS column could treat about 1300BV simulated wastewater and 350 BV actual wastewater with the concentration of effluent lower than1.0 mg/L.Furthermore,N-CMCS could remove a variety of complexed heavy metal ions under neutral p H,indicating the great potential in practical application.展开更多
Realizing fast and continuous generation of reactive oxygen species(ROSs)via iron-based advanced oxidation processes(AOPs)is significant in the environmental and biological fields.However,current AOPs assisted by co-c...Realizing fast and continuous generation of reactive oxygen species(ROSs)via iron-based advanced oxidation processes(AOPs)is significant in the environmental and biological fields.However,current AOPs assisted by co-catalysts still suffer from the poor mass/electron transfer and non-durable promotion effect,giving rise to the sluggish Fe^(2+)/Fe^(3+)cycle and low dynamic concentration of Fe^(2+)for ROS production.Herein,we present a three-dimensional(3D)macroscale co-catalyst functionalized with molybdenum disulfide(MoS_(2))to achieve ultra-efficient Fe^(2+)regeneration(equilibrium Fe^(2+)ratio of 82.4%)and remarkable stability(more than 20 cycles)via a circulating flow-through process.Unlike the conventional batch-type reactor,experiments and computational fluid dynamics simulations demonstrate that the optimal utilization of the 3D active area under the flow-through mode,initiated by the convectionenhanced mass/charge transfer for Fe^(2+)reduction and then strengthened by MoS_(2)-induced flow rotation for sufficient reactant mixing,is crucial for oxidant activation and subsequent ROS generation.Strikingly,the flow-through co-catalytic system with superwetting capabilities can even tackle the intricate oily wastewater stabilized by different surfactants without the loss of pollutant degradation efficiency.Our findings highlight an innovative co-catalyst system design to expand the applicability of AOPs based technology,especially in large-scale complex wastewater treatment.展开更多
基金Project(51674305)supported by the National Natural Science Foundation of ChinaProject(2013WK2007)supported by the Key Project of Science and Technology of Hunan Province,China+1 种基金Project(2015CX001)supported by the Innovation Stimulating Program of Central South University,ChinaKey Project(1602FKDC007)supported by Science and Technology Program of Gansu Province,China
文摘Mg2+ and PO43+ were added into the synthetic wastewater, leading to the dissociation of the complex ions in the wastewater, and resulting in removal of copper and ammonia therein. The effects of agents addition amount, pH, and reaction time on the removal efficiency of copper and ammonia were investigated. In particular, two-sectional struvite formation (TSSF) process was established for copper and ammonia removal. MgCl2 and Na2HPO4 were added by following 90% addition in the first section and remained 10% in the second during the TSSF process. Compared with one sectional struvite formation, TSSF possessed much better performance. Under condition of n(NH3-N):n(Mg):n(P)=1:1.2:1.5 (molar ratio), pH=9, and reaction time of 30 min, the removal efficiencies of copper and ammonia were 98.9% and 99.96%, respectively. The enhanced performance of TSSF is explained by the competition of ammonia by copper?ammonia complexes and struvite. The dissociation of copper-ammonia complexes is further demonstrated by thermodynamic equilibrium analysis, on the basis of calculations and establishment of predominance phases diagram. Moreover, XRD and EDS analyses further confirmed the formation of struvite and precipitation of copper, which prove the transmission of copper and ammonia from liquid phase into solid phase.
基金Project(08SK1002)supported by the Major Project of Scientific and Technological Department of Hunan Province,ChinaProject(50508044)supported by the National Natural Science Foundation of China
文摘Air stripping was adopted to treat nickel ammonia complex ion-containing wastewater in order to remove nickel and ammonia simultaneously in one technological process.The relationship among pH,the concentration of nickel ammonia complex ion and total ammonia concentration was analyzed theoretically.Influence of pH value,water temperature,airflow rate and time on air stripping was studied in detail by static experiment in laboratory.The results show that at pH 11,temperature of 60℃and airflow rate of 0.12 m3/h,NH3 and Ni 2+concentrations remained in wastewater are less than 2 and 0.2 mg/L,respectively,after blowing for 75 min,which reaches the standard of the state discharge.When the tail gas is absorbed by 0.5 mol/L H2SO4 in order to avoid the secondary pollution,the absorption rate can achieve 70%.
文摘Unlike natural organic matter(NOM), wastewater organic matter(WWOM) from wastewater treatment plant effluents has not been extensively studied with respect to complexation reactions with heavy metals such as copper or zinc. In this study, organic matter from surface waters and a wastewater treatment plant effluent were concentrated by reverse osmosis(RO) method. The samples were treated in the laboratory to remove trace metals and major cations. The zinc complexing properties of both NOM and the WWOM were studied by square wave anodic stripping voltammetry(SWASV). Experimental data were compared to predictions using the Windermere Humic Aqueous Model(WHAM) Version VI. We found that the zinc binding of WWOM was much stronger than that of NOM and not well predicted by WHAM. This suggests that in natural water bodies that receive wastewater treatment plant effluents the ratio of WWOM to NOM must be taken into account in order to accurately predict free zinc activities.
基金the National Key Research and Development Program of China(No.2019YFC0408303)the Natural Science Foundation of Hunan Province,China(No.2021JJ20069)+2 种基金the Changsha Science and Technology Project,China(Nos.kq2106016,kq2009005)Higher Education Discipline Innovation Project(111 Project),China(No.B14034)the Fundamental Research Funds for the Central Universities of Central South University,China(No.2021zzts0887).
文摘The coordination structure of cupric tartrate(Cu−TA)complex was investigated by ultraviolet−visible(UV-Vis)and liquid chromatography/mass spectrometer(LC-MS)firstly;furthermore,effective coordination configurations and electronic properties of Cu−TA in aqueous solution were systematically revealed by density functional theory(DFT)calculations.Consistently,Job plots show the possible existence of[Cu(TA)]and[Cu(TA)_(2)]^(2-)at 230 and 255 nm based on UV-Vis results.LC-MS results confirm the existence of the single and high coordination complexes[Cu_(2)(TA)_(2)]^(+),[Cu(TA)_(2)]^(+)and[Cu_(2)(TA)_(3)(H_(2)O)_(2)(OH)_(2)]^(2+).DFT calculation results show that carboxylic oxygen and hydroxyl oxygen of tartaric acid(TA)are preferred sites for Cu(Ⅱ)coordination.[Cu(TA)](1H,3H sites O of TA coordinated with Cu(Ⅱ)),[Cu(TA)_(2)]^(2-)(two 1^(C),2^(H) sites O of TA coordinated with Cu(Ⅱ)),and[Cu(TA)_(3)]^(4-)(three 2H,3H sites O of TA coordinated with Cu(Ⅱ))should be dominant coordination configurations of Cu−TA.The corresponding Gibbs reaction energies are-170.1,-136.2,and-90.2 kJ/mol,respectively.
文摘At present,as the majority of nursing homes, resorts,villages,villas and other decentralized living areas are far away from municipal sewer system,it is difficult to transport municipal waste water to city sewage treatment plants for processing.If the large quantity of decentralized wastewater were directly discharged to the rivers,lakes or other receiving water body without treatment,seriously contaminate to surface water and groundwater occurred.According to the analysis on characteristics of distributed
文摘Filters filled with a micelle-clay complex mixed with sand were employed to investigate their purification capability of tertiary treated wastewater with loose UF-membranes. The UF membrane was hollow fiber with a molecular weight cutoff of 100 kD. The complex was prepared from the organic cation octadecyltrimethylammonium (ODTMA) and the negatively charged clay-mineral, montmoriIIonite. This complex has a very large surface area, which includes large hydrophobic domains and is positively charged, about half of the cation exchange capacity of the clay. Two sets of filtration experiments were carried out at flow rates of 1.2 and 50 mL/min, which correspond to flow velocities of 3.7 and 153 cm/h, respectively. In the first case, after a passage of 1 L, the turbidity, total suspended solids (TSS), fecal coliforms (FC), and total coliforms (TC) were reduced to zero from 14 NTU, 6 ppm, 350 and 10,000 counts per 100 mL, respectively. In the second case, the numbers of FC and TC were reduced from 50,000/100 mL to zero after the passage of 14 L. The values of COD and BOD were reduced several-fold. The conclusion is that the incorporation of micelle-clay filters in the sewage treatment system with loose tertiary capability is promising and warrants larger scale experiments for optimization of the overall system.
基金the support provided by the National Natural Science Foundation of China(No.51522805)。
文摘Heavy metals usually exist stably as the species of organic complexes in high-salinity wastewater.Therefore,their effective removal is challenging,especially when the initial p H is neutral.Herein,a novel nitrogen doped biomass-based composite(N-CMCS)was synthesized to remove the complexed heavy metal of Cr(Ⅲ)-carboxyl.The maximum adsorption capacity of Cr(Ⅲ)-Citrate(Cr-Cit)by N-CMCS under neutral p H(7.0)and high-salinity(200 mmol/L NaCl)condition was up to 2.50 mmol/g.And the removal performance remained stable after 6 times of regeneration.Combined with species and characterizations analysis,electrostatic attraction and hydrogen bonding were the main mechanisms for N-CMCS to remove Cr(Ⅲ)-carboxyl complexes.Dynamic adsorption indicated N-CMCS column could treat about 1300BV simulated wastewater and 350 BV actual wastewater with the concentration of effluent lower than1.0 mg/L.Furthermore,N-CMCS could remove a variety of complexed heavy metal ions under neutral p H,indicating the great potential in practical application.
基金supported by National Natural Science Foundation of China(52003240)Zhejiang Provincial Natural Science Foundation of China(LQ21B070007)China Postdoctoral Science Foundation(2022M722818).
文摘Realizing fast and continuous generation of reactive oxygen species(ROSs)via iron-based advanced oxidation processes(AOPs)is significant in the environmental and biological fields.However,current AOPs assisted by co-catalysts still suffer from the poor mass/electron transfer and non-durable promotion effect,giving rise to the sluggish Fe^(2+)/Fe^(3+)cycle and low dynamic concentration of Fe^(2+)for ROS production.Herein,we present a three-dimensional(3D)macroscale co-catalyst functionalized with molybdenum disulfide(MoS_(2))to achieve ultra-efficient Fe^(2+)regeneration(equilibrium Fe^(2+)ratio of 82.4%)and remarkable stability(more than 20 cycles)via a circulating flow-through process.Unlike the conventional batch-type reactor,experiments and computational fluid dynamics simulations demonstrate that the optimal utilization of the 3D active area under the flow-through mode,initiated by the convectionenhanced mass/charge transfer for Fe^(2+)reduction and then strengthened by MoS_(2)-induced flow rotation for sufficient reactant mixing,is crucial for oxidant activation and subsequent ROS generation.Strikingly,the flow-through co-catalytic system with superwetting capabilities can even tackle the intricate oily wastewater stabilized by different surfactants without the loss of pollutant degradation efficiency.Our findings highlight an innovative co-catalyst system design to expand the applicability of AOPs based technology,especially in large-scale complex wastewater treatment.