Phosphorus(P)in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment.The mobility and bioavailability of P primarily depend on the contents of different P forms,w...Phosphorus(P)in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment.The mobility and bioavailability of P primarily depend on the contents of different P forms,which in turn depend on the sedimentary environment.Here,sediment samples from Baiyangdian(BYD)lake were collected and measured by the Standards,Measurements,and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy(31P NMR)to characterize different P forms and their relationships with sediment physicochemical properties.The P content in the sediments varied in different areas and had characteristics indicative of exogenous river input.Inorganic P(334–916 mg/kg)was the dominant form of P.The 31P NMR results demonstrated that orthophosphate monoesters(16–110 mg/kg),which may be a source of P when redox conditions change,was the dominant form of organic P(20–305 mg/kg).The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities,and the regions affected by exogenous river input had a higher content of P and a higher risk of P release.Principal component analysis indicated that P bound to Fe,Al,and Mn oxides and hydroxides(NaOH-P)and organic P were mainly derived from industrial and agricultural pollution,respectively.Redundancy analysis indicated that increases in pH lead to the release of NaOH-P.Organic matter plays an important role in the organic P biogeochemical cycle,as it acts as a sink and source of organic P.展开更多
As safe byproducts of drinking water treatment processes,ferric and alum water treatment residuals（FARs） have the potential to be new phosphate（P） immobilization materials.In this study,batch experiments were cond...As safe byproducts of drinking water treatment processes,ferric and alum water treatment residuals（FARs） have the potential to be new phosphate（P） immobilization materials.In this study,batch experiments were conducted to investigate and compare the adsorption characteristics of three P species by FARs.The results showed that the kinetic processes of different P species＇ adsorption by FARs could be described by a pseudo second-order model.The ranking list of the initial adsorption rates with respect to different phosphates was pyrophosphate,phytate,orthophosphate,hexametaphosphate and glycerophosphate.Of the six models considered,the two-site Langmuir model most effectively described the adsorption characteristics of the various P species.Upon fitting the results,the maximum adsorption capacities were determined to be 40.24 mg/g for phytate,18.04 mg/g for pyrophosphate,17.14 mg/g for orthophosphate,15.86 mg/g for hexametaphosphate and 10.81 mg/g for glycerophosphate.In addition,the adsorption processes of the different P species were spontaneous endothermic processes and were favored at lower pH values.The pH dependency was found to be especially true for orthophosphate,where the adsorption capacity decreased by 1.22 mg/g with an increase in pH from 5 to 9.Fractionation of the adsorbed P species from the FARs demonstrated that Al-P and Fe-P were the dominating forms,constituting approximately 80%-90% of the total P fractions,which indicated that the adsorbed P species had a low leaching risk and could stably exist in the FARs.Therefore,the FARs could be effective in controlling pollution in water caused by different P species.展开更多
Batch experiments were conducted to investigate the phosphorus（P） adsorption and desorption on five drinking water treatment residuals（WTRs） collected from different regions in China. The physical and chemical cha...Batch experiments were conducted to investigate the phosphorus（P） adsorption and desorption on five drinking water treatment residuals（WTRs） collected from different regions in China. The physical and chemical characteristics of the five WTRs were determined. Combined with rotated principal component analysis, multiple regression analysis was used to analyze the relationship between the inherent properties of the WTRs and their P adsorption capacities. The results showed that the maximum P adsorption capacities of the five WTRs calculated using the Langmuir isotherm ranged from 4.17 to8.20 mg/g at a p H of 7 and further increased with a decrease in p H. The statistical analysis revealed that a factor related to Al and 200 mmol/L oxalate-extractable Al（Alox） accounted for 36.5% of the variations in the P adsorption. A similar portion（28.5%） was attributed to an integrated factor related to the p H, Fe, 200 mmol/L oxalate-extractable Fe（Feox）, surface area and organic matter（OM） of the WTRs. However, factors related to other properties（Ca,P and 5 mmol/L oxalate-extractable Fe and Al） were rejected. In addition, the quantity of P desorption was limited and had a significant negative correlation with the（Feox＋ Alox） of the WTRs（p 〈 0.05）. Overall, WTRs with high contents of Alox, Feoxand OM as well as large surface areas were proposed to be the best choice for P adsorption in practical applications.展开更多
Economicdevelopment and population growth havedeeplydamaged the urbanwater environment of Guilin City, China. Main problems involved structuraldamage and functionaldeterioration of the urbanwaters. An integrated techn...Economicdevelopment and population growth havedeeplydamaged the urbanwater environment of Guilin City, China. Main problems involved structuraldamage and functionaldeterioration of the urbanwaters. An integrated technical schemewasdeveloped to rehabilitate the urbanwater environment and to enhance thewaters＇ functionsduring 1998-2008. Improvement ofwaters＇ functions includedwater system reconstruction,water pollution control,water safety assurance, and aquatic ecological restoration. Thewater systemwas reconstructed to connectdifferentwaters and cleanwater supplies to the lakes. Moreover,water pollutionwas controlled to improvewater quality by endogenous pollutant elimination and extraneous pollutant interception. In addition, ecological measures put in place serve to enhancewater system functions and better benefit both nature and humans. The project has brought about sound ecological, economic and social benefits in Guilin City,which can potentially be extended to similar cities.展开更多
A study on the removal of Co（Ⅱ） from aqueous solutions by water treatment residuals（WTR） was conducted in batch conditions. The sorption process of Co（Ⅱ） followed pseudosecondorder kinetics, with 30 hr require...A study on the removal of Co（Ⅱ） from aqueous solutions by water treatment residuals（WTR） was conducted in batch conditions. The sorption process of Co（Ⅱ） followed pseudosecondorder kinetics, with 30 hr required to reach equilibrium. Using the Langmuir adsorption isotherm model, a relatively high maximum sorption capacity of 17.31 mg/g Co（Ⅱ） was determined. The adsorption of Co（Ⅱ） was dependent on pH values and was affected by the ionic strength. Results show that Co（Ⅱ） adsorption was a spontaneous endothermic process and was favorable at high temperature. Most of the adsorbed Co（Ⅱ） stayed on the WTR permanently, whereas only small amounts of adsorbed Co（Ⅱ） were desorbed. The shifting of peaks in FT-IR spectra indicated that Co（Ⅱ） interacted with the WTR surface through strong covalent bond formation with Fe（Al）–O functional groups. It was concluded that WTR can be a suitable material from which to develop an efficient adsorbent for the removal of Co（Ⅱ） from wastewater.展开更多
Fe/Al drinking water treatment residuals（WTRs）, ubiquitous and non-hazardous by-products of drinking water purification, are cost-effective adsorbents for glyphosate. Given that repeated glyphosate applications coul...Fe/Al drinking water treatment residuals（WTRs）, ubiquitous and non-hazardous by-products of drinking water purification, are cost-effective adsorbents for glyphosate. Given that repeated glyphosate applications could significantly decrease glyphosate retention by soils and that the adsorbed glyphosate is potentially mobile, high sorption capacity and stability of glyphosate in agricultural soils are needed to prevent pollution of water by glyphosate.Therefore, we investigated the feasibility of reusing Fe/Al WTR as a soil amendment to enhance the retention capacity of glyphosate in two agricultural soils. The results of batch experiments showed that the Fe/Al WTR amendment significantly enhanced the glyphosate sorption capacity of both soils（p 〈 0.001）. Up to 30% of the previously adsorbed glyphosate desorbed from the non-amended soils, and the Fe/Al WTR amendment effectively decreased the proportion of glyphosate desorbed. Fractionation analyses further demonstrated that glyphosate adsorbed to non-amended soils was primarily retained in the readily labile fraction（Na HCO3-glyphosate）. The WTR amendment significantly increased the relative proportion of the moderately labile fraction（HCl-glyphosate） and concomitantly reduced that of the Na HCO3-glyphosate, hence reducing the potential for the release of soil-adsorbed glyphosate into the aqueous phase. Furthermore, Fe/Al WTR amendment minimized the inhibitory effect of increasing solution p H on glyphosate sorption by soils and mitigated the effects of increasing solution ionic strength. The present results indicate that Fe/Al WTR is suitable for use as a soil amendment to prevent glyphosate pollution of aquatic ecosystems by enhancing the glyphosate retention capacity in soils.展开更多
Drinking water treatment residuals（WTRs） have a potential to realize eutrophication control objectives by reducing the internal phosphorus（P） load of lake sediments. Information regarding the ecological risk of de...Drinking water treatment residuals（WTRs） have a potential to realize eutrophication control objectives by reducing the internal phosphorus（P） load of lake sediments. Information regarding the ecological risk of dewatered WTR reuse in aquatic environments is generally lacking, however. In this study, we analyzed the eco-toxicity of leachates from sediments with or without dewatered WTRs toward algae Chlorella vulgaris via algal growth inhibition testing with algal cell density, chlorophyll content, malondialdehyde content, antioxidant enzyme superoxide dismutase activity, and subcellular structure indices. The results suggested that leachates from sediments unanimously inhibited algal growth, with or without the addition of different WTR doses（10% or 50% of the sediment in dry weight） at different p H values（8–9）, as well as from sediments treated for different durations（10 or 180 days）. The inhibition was primarily the result of P deficiency in the leachates owing to WTR P adsorption, however, our results suggest that the dewatered WTRs were considered as a favorable potential material for internal P loading control in lake restoration projects, as it shows acceptably low risk toward aquatic plants.展开更多
Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene(TCE).In this work,the liquid-phase hydrogenation of TCE by Raney Ni(R-Ni)and Pd/C under an open syste...Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene(TCE).In this work,the liquid-phase hydrogenation of TCE by Raney Ni(R-Ni)and Pd/C under an open system have been studied,in which nascent H_(2)(Nas-H_(2))generated in situ from the cathode acted as a hydrogen source.Experimental results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H_(2)bubbles from the cathode.Furthermore,the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated,respectively.The results showed that NO_(3)^(-) and acetonitrile can form a competitive reaction with TCE;Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts,and have a stronger inhibitory effect on Pd/C.This work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system.展开更多
基金supported by the Beijing Municipal Science and Technology Plan Project (No. Z181100005518005)the National Natural Science Foundation of China (Nos. 51579009, 51879012)the Major Science and Technology Program for Water Pollution Control and Treatment (No. 2018ZX07110004)
文摘Phosphorus(P)in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment.The mobility and bioavailability of P primarily depend on the contents of different P forms,which in turn depend on the sedimentary environment.Here,sediment samples from Baiyangdian(BYD)lake were collected and measured by the Standards,Measurements,and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy(31P NMR)to characterize different P forms and their relationships with sediment physicochemical properties.The P content in the sediments varied in different areas and had characteristics indicative of exogenous river input.Inorganic P(334–916 mg/kg)was the dominant form of P.The 31P NMR results demonstrated that orthophosphate monoesters(16–110 mg/kg),which may be a source of P when redox conditions change,was the dominant form of organic P(20–305 mg/kg).The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities,and the regions affected by exogenous river input had a higher content of P and a higher risk of P release.Principal component analysis indicated that P bound to Fe,Al,and Mn oxides and hydroxides(NaOH-P)and organic P were mainly derived from industrial and agricultural pollution,respectively.Redundancy analysis indicated that increases in pH lead to the release of NaOH-P.Organic matter plays an important role in the organic P biogeochemical cycle,as it acts as a sink and source of organic P.
基金supported by the National Natural Science Foundation of China (No. 51278055,51179008)
文摘As safe byproducts of drinking water treatment processes,ferric and alum water treatment residuals（FARs） have the potential to be new phosphate（P） immobilization materials.In this study,batch experiments were conducted to investigate and compare the adsorption characteristics of three P species by FARs.The results showed that the kinetic processes of different P species＇ adsorption by FARs could be described by a pseudo second-order model.The ranking list of the initial adsorption rates with respect to different phosphates was pyrophosphate,phytate,orthophosphate,hexametaphosphate and glycerophosphate.Of the six models considered,the two-site Langmuir model most effectively described the adsorption characteristics of the various P species.Upon fitting the results,the maximum adsorption capacities were determined to be 40.24 mg/g for phytate,18.04 mg/g for pyrophosphate,17.14 mg/g for orthophosphate,15.86 mg/g for hexametaphosphate and 10.81 mg/g for glycerophosphate.In addition,the adsorption processes of the different P species were spontaneous endothermic processes and were favored at lower pH values.The pH dependency was found to be especially true for orthophosphate,where the adsorption capacity decreased by 1.22 mg/g with an increase in pH from 5 to 9.Fractionation of the adsorbed P species from the FARs demonstrated that Al-P and Fe-P were the dominating forms,constituting approximately 80%-90% of the total P fractions,which indicated that the adsorbed P species had a low leaching risk and could stably exist in the FARs.Therefore,the FARs could be effective in controlling pollution in water caused by different P species.
基金supported by the National Key Technology R&D Program(No.2012BAJ21B08)the National Natural Science Foundation of China(No.5127805551179008)
文摘Batch experiments were conducted to investigate the phosphorus（P） adsorption and desorption on five drinking water treatment residuals（WTRs） collected from different regions in China. The physical and chemical characteristics of the five WTRs were determined. Combined with rotated principal component analysis, multiple regression analysis was used to analyze the relationship between the inherent properties of the WTRs and their P adsorption capacities. The results showed that the maximum P adsorption capacities of the five WTRs calculated using the Langmuir isotherm ranged from 4.17 to8.20 mg/g at a p H of 7 and further increased with a decrease in p H. The statistical analysis revealed that a factor related to Al and 200 mmol/L oxalate-extractable Al（Alox） accounted for 36.5% of the variations in the P adsorption. A similar portion（28.5%） was attributed to an integrated factor related to the p H, Fe, 200 mmol/L oxalate-extractable Fe（Feox）, surface area and organic matter（OM） of the WTRs. However, factors related to other properties（Ca,P and 5 mmol/L oxalate-extractable Fe and Al） were rejected. In addition, the quantity of P desorption was limited and had a significant negative correlation with the（Feox＋ Alox） of the WTRs（p 〈 0.05）. Overall, WTRs with high contents of Alox, Feoxand OM as well as large surface areas were proposed to be the best choice for P adsorption in practical applications.
基金supported by the National Natural Science Foundation of China(No.51278055,51179008)the National Key Technology R&D Program(No.2012BAJ21B08)
文摘Economicdevelopment and population growth havedeeplydamaged the urbanwater environment of Guilin City, China. Main problems involved structuraldamage and functionaldeterioration of the urbanwaters. An integrated technical schemewasdeveloped to rehabilitate the urbanwater environment and to enhance thewaters＇ functionsduring 1998-2008. Improvement ofwaters＇ functions includedwater system reconstruction,water pollution control,water safety assurance, and aquatic ecological restoration. Thewater systemwas reconstructed to connectdifferentwaters and cleanwater supplies to the lakes. Moreover,water pollutionwas controlled to improvewater quality by endogenous pollutant elimination and extraneous pollutant interception. In addition, ecological measures put in place serve to enhancewater system functions and better benefit both nature and humans. The project has brought about sound ecological, economic and social benefits in Guilin City,which can potentially be extended to similar cities.
基金supported by the National Natural Science Foundation of China(No.51278055)the National Science and Technology Major Project(No.2012ZX07203-003)
文摘A study on the removal of Co（Ⅱ） from aqueous solutions by water treatment residuals（WTR） was conducted in batch conditions. The sorption process of Co（Ⅱ） followed pseudosecondorder kinetics, with 30 hr required to reach equilibrium. Using the Langmuir adsorption isotherm model, a relatively high maximum sorption capacity of 17.31 mg/g Co（Ⅱ） was determined. The adsorption of Co（Ⅱ） was dependent on pH values and was affected by the ionic strength. Results show that Co（Ⅱ） adsorption was a spontaneous endothermic process and was favorable at high temperature. Most of the adsorbed Co（Ⅱ） stayed on the WTR permanently, whereas only small amounts of adsorbed Co（Ⅱ） were desorbed. The shifting of peaks in FT-IR spectra indicated that Co（Ⅱ） interacted with the WTR surface through strong covalent bond formation with Fe（Al）–O functional groups. It was concluded that WTR can be a suitable material from which to develop an efficient adsorbent for the removal of Co（Ⅱ） from wastewater.
基金supported by the National Natural Science Foundation of China (Nos.51278055, 51179008)the National Key Technology R&D Program (No.2012BAJ21B08)the National Public Benefit (Environmental) Research Foundation of China (No.201109009)
文摘Fe/Al drinking water treatment residuals（WTRs）, ubiquitous and non-hazardous by-products of drinking water purification, are cost-effective adsorbents for glyphosate. Given that repeated glyphosate applications could significantly decrease glyphosate retention by soils and that the adsorbed glyphosate is potentially mobile, high sorption capacity and stability of glyphosate in agricultural soils are needed to prevent pollution of water by glyphosate.Therefore, we investigated the feasibility of reusing Fe/Al WTR as a soil amendment to enhance the retention capacity of glyphosate in two agricultural soils. The results of batch experiments showed that the Fe/Al WTR amendment significantly enhanced the glyphosate sorption capacity of both soils（p 〈 0.001）. Up to 30% of the previously adsorbed glyphosate desorbed from the non-amended soils, and the Fe/Al WTR amendment effectively decreased the proportion of glyphosate desorbed. Fractionation analyses further demonstrated that glyphosate adsorbed to non-amended soils was primarily retained in the readily labile fraction（Na HCO3-glyphosate）. The WTR amendment significantly increased the relative proportion of the moderately labile fraction（HCl-glyphosate） and concomitantly reduced that of the Na HCO3-glyphosate, hence reducing the potential for the release of soil-adsorbed glyphosate into the aqueous phase. Furthermore, Fe/Al WTR amendment minimized the inhibitory effect of increasing solution p H on glyphosate sorption by soils and mitigated the effects of increasing solution ionic strength. The present results indicate that Fe/Al WTR is suitable for use as a soil amendment to prevent glyphosate pollution of aquatic ecosystems by enhancing the glyphosate retention capacity in soils.
基金supported by the National Natural Science Foundation of China(No.51278055)the Specialized Research Fund for the Doctoral Program of Higher Education(No.2012003110027)the National Key Technology R&D Program(No.2012BAJ21B08)
文摘Drinking water treatment residuals（WTRs） have a potential to realize eutrophication control objectives by reducing the internal phosphorus（P） load of lake sediments. Information regarding the ecological risk of dewatered WTR reuse in aquatic environments is generally lacking, however. In this study, we analyzed the eco-toxicity of leachates from sediments with or without dewatered WTRs toward algae Chlorella vulgaris via algal growth inhibition testing with algal cell density, chlorophyll content, malondialdehyde content, antioxidant enzyme superoxide dismutase activity, and subcellular structure indices. The results suggested that leachates from sediments unanimously inhibited algal growth, with or without the addition of different WTR doses（10% or 50% of the sediment in dry weight） at different p H values（8–9）, as well as from sediments treated for different durations（10 or 180 days）. The inhibition was primarily the result of P deficiency in the leachates owing to WTR P adsorption, however, our results suggest that the dewatered WTRs were considered as a favorable potential material for internal P loading control in lake restoration projects, as it shows acceptably low risk toward aquatic plants.
基金supported by the National Natural Science Foundation of China(No.51878169)the Guangdong Innovation Team Project for Colleges and Universities(No.2016KCXTD023)+1 种基金Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2017)Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110497)。
文摘Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene(TCE).In this work,the liquid-phase hydrogenation of TCE by Raney Ni(R-Ni)and Pd/C under an open system have been studied,in which nascent H_(2)(Nas-H_(2))generated in situ from the cathode acted as a hydrogen source.Experimental results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H_(2)bubbles from the cathode.Furthermore,the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated,respectively.The results showed that NO_(3)^(-) and acetonitrile can form a competitive reaction with TCE;Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts,and have a stronger inhibitory effect on Pd/C.This work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system.
