ldentification work of solid wastes ’ risks is a kind of improvement and amendment for environmental impact assessment document of constructed projectss. ln the research, waste identification is classified as per ent...ldentification work of solid wastes ’ risks is a kind of improvement and amendment for environmental impact assessment document of constructed projectss. ln the research, waste identification is classified as per entrustment source and the characteristics of pol ution accidents are analyzed, with major problems of National Catalogue of Hazardous Wastes and countermeasures proposed.展开更多
Scorodite（FeAsO4·2H2O）is the most popular phase for arsenic（As）immobilization while the reductive dissolution of Fe（Ⅲ）to Fe（Ⅱ）will promote As release.In the present study,an equilibrium between Fe（Ⅲ）...Scorodite（FeAsO4·2H2O）is the most popular phase for arsenic（As）immobilization while the reductive dissolution of Fe（Ⅲ）to Fe（Ⅱ）will promote As release.In the present study,an equilibrium between Fe（Ⅲ）and Fe（Ⅱ）was achieved in scorodite preparation system by introducing certain alcohol（methanol,ethanol,isopropanol or tert-butanol）,and thus a new mixed-valent iron arsenate black crystal formulated as Fe（Ⅱ）（5.2）Fe（Ⅲ）（8.8）（HAsO4）4（AsO4）8·H2O was prepared.In comparison with scorodite,the black crystal has higher As content（36.4%,mass fraction）and lower crystal water content（0.73%,mass fraction）.Additionally,the leaching concentration of As can be lower than the threshold value（5 mg/L）regulated by identification standards for hazardous wastes of China（GB 5080.3-2007）.Therefore,this new mixed-valent iron arsenate crystal could be classified as a non-hazardous and promising As-bearing phase in environmental applications.展开更多
The zeolite synthesis using waste as silicon source is a promising low-cost process. Sugarcane bagasse ash is a hazardous solid waste generated in large amounts in the sugar industry. Thus, development of new procedur...The zeolite synthesis using waste as silicon source is a promising low-cost process. Sugarcane bagasse ash is a hazardous solid waste generated in large amounts in the sugar industry. Thus, development of new procedures for its productive reuse is relevant. Therefore, this waste was used to prepare a new ZCNT （zeolite/carbon nanotube material）. In this work, ZCNT was applied in a CO2/CH4 separation. The adsorption took place at 303 K under pressure of 0.1 until 20 bar and the data were fitted by Langmuir, Toth and Freundlich equations. The adsorbed amount at 20 bar found was 4.7 mmol of CO2/g and 4.1 mmol of CH4/g; at 3 bar the adsorbed amount was 4.1 mmol of COJg and 1.2 mmol of CHa/g. This result indicates that ZCNT has potential application in COJCH4 separation at low pressures.展开更多
文摘ldentification work of solid wastes ’ risks is a kind of improvement and amendment for environmental impact assessment document of constructed projectss. ln the research, waste identification is classified as per entrustment source and the characteristics of pol ution accidents are analyzed, with major problems of National Catalogue of Hazardous Wastes and countermeasures proposed.
基金Project(51634010)supported by the Key Project of National Natural Science Foundation of ChinaProject(51304251)supported by the National Natural Science Foundation of ChinaProject(201509050)supported by Special Program on Environmental Protection for Public Welfare of China
文摘Scorodite（FeAsO4·2H2O）is the most popular phase for arsenic（As）immobilization while the reductive dissolution of Fe（Ⅲ）to Fe（Ⅱ）will promote As release.In the present study,an equilibrium between Fe（Ⅲ）and Fe（Ⅱ）was achieved in scorodite preparation system by introducing certain alcohol（methanol,ethanol,isopropanol or tert-butanol）,and thus a new mixed-valent iron arsenate black crystal formulated as Fe（Ⅱ）（5.2）Fe（Ⅲ）（8.8）（HAsO4）4（AsO4）8·H2O was prepared.In comparison with scorodite,the black crystal has higher As content（36.4%,mass fraction）and lower crystal water content（0.73%,mass fraction）.Additionally,the leaching concentration of As can be lower than the threshold value（5 mg/L）regulated by identification standards for hazardous wastes of China（GB 5080.3-2007）.Therefore,this new mixed-valent iron arsenate crystal could be classified as a non-hazardous and promising As-bearing phase in environmental applications.
文摘The zeolite synthesis using waste as silicon source is a promising low-cost process. Sugarcane bagasse ash is a hazardous solid waste generated in large amounts in the sugar industry. Thus, development of new procedures for its productive reuse is relevant. Therefore, this waste was used to prepare a new ZCNT （zeolite/carbon nanotube material）. In this work, ZCNT was applied in a CO2/CH4 separation. The adsorption took place at 303 K under pressure of 0.1 until 20 bar and the data were fitted by Langmuir, Toth and Freundlich equations. The adsorbed amount at 20 bar found was 4.7 mmol of CO2/g and 4.1 mmol of CH4/g; at 3 bar the adsorbed amount was 4.1 mmol of COJg and 1.2 mmol of CHa/g. This result indicates that ZCNT has potential application in COJCH4 separation at low pressures.
