The adsorption of Pb(II)on silica gel synthesized from chemical glass bottle waste has been studied.The effect of independent variables(adsorbent dose,initial concentration of Pb(II),contact time,and pH)on the Pb(II)r...The adsorption of Pb(II)on silica gel synthesized from chemical glass bottle waste has been studied.The effect of independent variables(adsorbent dose,initial concentration of Pb(II),contact time,and pH)on the Pb(II)removal from water was evaluated and optimized using the Response Surface Methodology(RSM).Under optimized conditions(adsorbent dose:20 mg;contact time:30 min;initial Pb(II)concentration:120 mg.L^(−1);and pH:8),the removal of Pb(II)was 99.77%.The adsorption equilibrium data obtained from the batch experiment were investigated using different isotherm models.The Langmuir isotherm model fits the experimental data.This shows that the surface of the silica gel synthesized from chemical bottles waste was covered by a Pb(II)monolayer.XRF analysis showed that the synthesized silica gel had a SiO_(2) content of 75.63%.Amorphous silica was observed from XRD analysis.SEM-EDX characterization showed that Pb was adsorbed on the silica gel surface.SEM analysis showed that silica gel has irregular particles with a surface area of 297.08 m2.g^(−1) with a pore radius of 15.74 nm calculated from BET analysis.展开更多
In order to improve the anaerobic digestion efficiency of waste activated sludge(WAS),a pretreatment procedure should be carried out so as to disrupt the microbial cell structure,thus releasing intracellular organic...In order to improve the anaerobic digestion efficiency of waste activated sludge(WAS),a pretreatment procedure should be carried out so as to disrupt the microbial cell structure,thus releasing intracellular organic matters.In this paper,a corona discharge triggered by a DC voltage was employed to pre-treat WAS for various time periods under different temperatures.The magnitude of the DC voltage was 4 k V at both negative and positive polarities.The changes in the soluble chemical oxygen demand,phosphorus and nitrogen content,and p H value within the WAS were utilized to estimate the pretreatment performance of the DC corona.It was found that with increasing treatment time,the pretreatment efficiency tends to be reduced.With increased temperature,the pretreatment efficiency appears to be better.It is suggested that the oxidative species and the active particles generated in the corona discharge play an important role in disrupting the microbial cell structure,which is dependent upon the treatment time and the temperature.展开更多
The international environmental conventions have become the main effective ways to solve the global environmental issues,which are also the most active convention mechanisms in the world.This paper studies development...The international environmental conventions have become the main effective ways to solve the global environmental issues,which are also the most active convention mechanisms in the world.This paper studies development trend and the implementation of the international environmental conventions on chemicals and wastes in China,such as Basel Convention,Rotterdam Convention,Stockholm Convention and Minamata Convention.Based on the Multilateral Synergy of International Conventions on Chemicals and Wastes,gaps and needs of the management of chemicals and wastes in China,this article put forward proposals for China to implement the coordinated development of these four conventions in the future..展开更多
The chemical stability of simulated waste forms Zr_(1–x)Nd_xSiO_(4–x/2) was investigated using the static leach test(MCC-1) with lixiviants of three pH values(pH=4, 6.7 and 10) at three temperature points(4...The chemical stability of simulated waste forms Zr_(1–x)Nd_xSiO_(4–x/2) was investigated using the static leach test(MCC-1) with lixiviants of three pH values(pH=4, 6.7 and 10) at three temperature points(40, 90 and 150 oC) for periods ranging from 1 to 42 d, and the influence of temperature, pH, as well as their combined effects were explored in detail. The results showed that all the normalized release rate of Nd firstly decreased with leaching time and closed to equilibrium after 14 d. As the temperature increased, the normalized release rate of Nd also increased, but it was no more than 3×10^(–5) g/(m^2·d). And, the normalized release rate of Nd reached the highest values(~5×10^(–5) g/(m^2·d)) when pH=4, whilst the normalized release rate of Nd remained the lowest value(~1×10^(–5) g/(m^2·d)) near neutral environment(pH=6.7).展开更多
Zircon was employed to immobilize simulated tetravalentactinide nuclide(Ce^4+). Zr_(1–x)Ce_xSiO_4(0≤x≤0.10) ceramics were synthesized and their chemical durabilities were investigated systematically. The eff...Zircon was employed to immobilize simulated tetravalentactinide nuclide(Ce^4+). Zr_(1–x)Ce_xSiO_4(0≤x≤0.10) ceramics were synthesized and their chemical durabilities were investigated systematically. The effects of p H and temperature on the chemical durability of the as-prepared compounds were investigated using the MCC-1 static leaching test, and their coupling effects were also explored. It was found that the normalized release rates of Ce in deionized water and alkaline solutions(pH=10) were smaller than those in acid solutions(p H=4). At a certain p H value, the normalized release rate of Ce(LR Ce) increased with the temperature in the initial period. However, the leaching progress almost reached a balance after 14 days, and both of the p H and the temperature had slight impact on the leaching of Ce element. Moreover, the LR_(Ce) were below 10^(–5)g/m^2/d after 42 days, which was lower than those of other nuclear waste forms in all discussed leachates.展开更多
Dioxin production is a worldwide concern because of its persistence and carcinogenic,teratogenic, and mutagenic effects. The pyrolysis-chemical looping combustion process of disposing solid waste is an alternative to ...Dioxin production is a worldwide concern because of its persistence and carcinogenic,teratogenic, and mutagenic effects. The pyrolysis-chemical looping combustion process of disposing solid waste is an alternative to traditional solid waste incineration developed to reduce the dioxin production. Based on the equilibrium composition of the Deacon reaction,pyrolysis gas oxidized by seven common oxygen carriers, namely, Cu O, Ni O, Ca SO4, Co O,Fe2O3, Mn3O4, and Fe Ti O3, is studied and compared with the pyrolysis gas directly combusted by air. The result shows that the activity of the Deacon reaction for oxygen carriers is lower than that for air. For four typical oxygen carriers(Cu O, Ni O, Fe2O3, and Fe Ti O3), the influences of temperature, pressure, gas composition, and tar on the Deacon reaction are discussed in detail. According to these simulation results, the dioxin production in China, Europe, the United States, and Japan is predicted for solid waste disposal by the pyrolysis-chemical looping combustion process. Thermodynamic analysis results in this paper show that chemical looping combustion can reduce dioxin production in the disposal of solid waste.展开更多
Rapid industrial developments coupled with surging population growth have complicated issues dealing with water scarcity as the quest for clean and sanitized water intensifies globally. Existing flesh water supplies c...Rapid industrial developments coupled with surging population growth have complicated issues dealing with water scarcity as the quest for clean and sanitized water intensifies globally. Existing flesh water supplies could be contaminated with organic, inorganic and biological matters that have potential harm to the society. Turbidity in general is a measure of water cloudiness induced by such colloidal and suspended matters and is also one of the major criteria in raw water monitoring to meet the stipulated water quality guidelines. Turbidity reduction is often accomplished using chemical coagulants such as alum. The use of alum is widely associated with potential development of health issues and generation of voluminous sludge. Natural coagulants that are available in abundance can certainly be considered in addressing the drawbacks associated with the use of chemical coagulants. Twenty one types of plant-based natural coagulants categorized as fruit waste and others are identified and presented collectively with their research summary in this review. The barriers and prospects of commercialization of natural coagulants in near future are also discussed.展开更多
文摘The adsorption of Pb(II)on silica gel synthesized from chemical glass bottle waste has been studied.The effect of independent variables(adsorbent dose,initial concentration of Pb(II),contact time,and pH)on the Pb(II)removal from water was evaluated and optimized using the Response Surface Methodology(RSM).Under optimized conditions(adsorbent dose:20 mg;contact time:30 min;initial Pb(II)concentration:120 mg.L^(−1);and pH:8),the removal of Pb(II)was 99.77%.The adsorption equilibrium data obtained from the batch experiment were investigated using different isotherm models.The Langmuir isotherm model fits the experimental data.This shows that the surface of the silica gel synthesized from chemical bottles waste was covered by a Pb(II)monolayer.XRF analysis showed that the synthesized silica gel had a SiO_(2) content of 75.63%.Amorphous silica was observed from XRD analysis.SEM-EDX characterization showed that Pb was adsorbed on the silica gel surface.SEM analysis showed that silica gel has irregular particles with a surface area of 297.08 m2.g^(−1) with a pore radius of 15.74 nm calculated from BET analysis.
基金financially supported by National Natural Science Foundation of China(Grant No.51677127)
文摘In order to improve the anaerobic digestion efficiency of waste activated sludge(WAS),a pretreatment procedure should be carried out so as to disrupt the microbial cell structure,thus releasing intracellular organic matters.In this paper,a corona discharge triggered by a DC voltage was employed to pre-treat WAS for various time periods under different temperatures.The magnitude of the DC voltage was 4 k V at both negative and positive polarities.The changes in the soluble chemical oxygen demand,phosphorus and nitrogen content,and p H value within the WAS were utilized to estimate the pretreatment performance of the DC corona.It was found that with increasing treatment time,the pretreatment efficiency tends to be reduced.With increased temperature,the pretreatment efficiency appears to be better.It is suggested that the oxidative species and the active particles generated in the corona discharge play an important role in disrupting the microbial cell structure,which is dependent upon the treatment time and the temperature.
基金supported by the National Key Research and Development Project of China(2019YFC1805600)the Global Environment Facility(Project 5383)the contributions are appreciated.
文摘The international environmental conventions have become the main effective ways to solve the global environmental issues,which are also the most active convention mechanisms in the world.This paper studies development trend and the implementation of the international environmental conventions on chemicals and wastes in China,such as Basel Convention,Rotterdam Convention,Stockholm Convention and Minamata Convention.Based on the Multilateral Synergy of International Conventions on Chemicals and Wastes,gaps and needs of the management of chemicals and wastes in China,this article put forward proposals for China to implement the coordinated development of these four conventions in the future..
基金Project supported by the National Natural Science Foundation of China(41302028,41302029,21507105)Thousand Youth Talents Plan(Y42H831301)+3 种基金Key Project of Sichuan Education Department(14ZA0099,15ZB0116)Foundation of Laboratory of National Defense Key Discipline for Nuclear Waste and Environmental Safety,Southwest University of Science and Technology(15yyhk10)the Doctor Foundation in Southwest University of Science and Technology(10zx7126)Hebei Science and Technology Support Program(15211121)
文摘The chemical stability of simulated waste forms Zr_(1–x)Nd_xSiO_(4–x/2) was investigated using the static leach test(MCC-1) with lixiviants of three pH values(pH=4, 6.7 and 10) at three temperature points(40, 90 and 150 oC) for periods ranging from 1 to 42 d, and the influence of temperature, pH, as well as their combined effects were explored in detail. The results showed that all the normalized release rate of Nd firstly decreased with leaching time and closed to equilibrium after 14 d. As the temperature increased, the normalized release rate of Nd also increased, but it was no more than 3×10^(–5) g/(m^2·d). And, the normalized release rate of Nd reached the highest values(~5×10^(–5) g/(m^2·d)) when pH=4, whilst the normalized release rate of Nd remained the lowest value(~1×10^(–5) g/(m^2·d)) near neutral environment(pH=6.7).
基金Project supported by the National Natural Science Foundation of China(21507105,41302029)Thousand Youth Talents Plan(Y42H831301)+3 种基金Key Project of Sichuan Education Department(15ZB0116)Foundation of Laboratory of National Defense Key Discipline for Nuclear Waste and Environmental Safety,Southwest University of Science and Technology(15yyhk10)the Doctor Foundation in Southwest University of Science and Technology(10zx7126)Sichuan’s Training Program of Innovation and Entrepreneurship for Undergraduate(201610619039)
文摘Zircon was employed to immobilize simulated tetravalentactinide nuclide(Ce^4+). Zr_(1–x)Ce_xSiO_4(0≤x≤0.10) ceramics were synthesized and their chemical durabilities were investigated systematically. The effects of p H and temperature on the chemical durability of the as-prepared compounds were investigated using the MCC-1 static leaching test, and their coupling effects were also explored. It was found that the normalized release rates of Ce in deionized water and alkaline solutions(pH=10) were smaller than those in acid solutions(p H=4). At a certain p H value, the normalized release rate of Ce(LR Ce) increased with the temperature in the initial period. However, the leaching progress almost reached a balance after 14 days, and both of the p H and the temperature had slight impact on the leaching of Ce element. Moreover, the LR_(Ce) were below 10^(–5)g/m^2/d after 42 days, which was lower than those of other nuclear waste forms in all discussed leachates.
基金supported by the National Basic Research Program of China (973 Program) (No. 2011CB201502)the National Key Technology R&D Program of China (No. 2010BAC66B03)
文摘Dioxin production is a worldwide concern because of its persistence and carcinogenic,teratogenic, and mutagenic effects. The pyrolysis-chemical looping combustion process of disposing solid waste is an alternative to traditional solid waste incineration developed to reduce the dioxin production. Based on the equilibrium composition of the Deacon reaction,pyrolysis gas oxidized by seven common oxygen carriers, namely, Cu O, Ni O, Ca SO4, Co O,Fe2O3, Mn3O4, and Fe Ti O3, is studied and compared with the pyrolysis gas directly combusted by air. The result shows that the activity of the Deacon reaction for oxygen carriers is lower than that for air. For four typical oxygen carriers(Cu O, Ni O, Fe2O3, and Fe Ti O3), the influences of temperature, pressure, gas composition, and tar on the Deacon reaction are discussed in detail. According to these simulation results, the dioxin production in China, Europe, the United States, and Japan is predicted for solid waste disposal by the pyrolysis-chemical looping combustion process. Thermodynamic analysis results in this paper show that chemical looping combustion can reduce dioxin production in the disposal of solid waste.
基金Monash University Malaysia for providing the research scholarship
文摘Rapid industrial developments coupled with surging population growth have complicated issues dealing with water scarcity as the quest for clean and sanitized water intensifies globally. Existing flesh water supplies could be contaminated with organic, inorganic and biological matters that have potential harm to the society. Turbidity in general is a measure of water cloudiness induced by such colloidal and suspended matters and is also one of the major criteria in raw water monitoring to meet the stipulated water quality guidelines. Turbidity reduction is often accomplished using chemical coagulants such as alum. The use of alum is widely associated with potential development of health issues and generation of voluminous sludge. Natural coagulants that are available in abundance can certainly be considered in addressing the drawbacks associated with the use of chemical coagulants. Twenty one types of plant-based natural coagulants categorized as fruit waste and others are identified and presented collectively with their research summary in this review. The barriers and prospects of commercialization of natural coagulants in near future are also discussed.