摘要
硫酸厂污泥中砷(As)的含量和浸出毒性高,环境危害大,处理难度高.以9家硫酸厂的污泥为研究对象,探究污泥中As的赋存形态、浸出毒性和来源,探讨污泥中As的浸出机制,以期为含砷污泥的处置提供理论依据和数据支撑.结果表明,9家硫酸厂污泥中As含量高达2.61×10^(4)~1.50×10^(5)mg·kg^(-1),浸出浓度为73.6~1.47×10^(4)mg·L^(-1),属于危险废弃物.污泥中As主要以三价砷(As(Ⅲ))和五价砷(As(V))的形态存在,As(Ⅲ)的赋存形态包括铁(氢)氧化物表面吸附态和As_(2)O_(3),而As(V)主要赋存于Ca-As(V)沉淀和吸附在铁(氢)氧化物上.污泥中As的浸出受Ca和Fe含量的显著影响,与Ca/Fe比呈显著负相关,Ca/Fe从0.206增加到6.67,As浸出率从80.5%降到1.85%.As(Ⅲ)的浸出率比As(V)浸出率高0.477~7.03倍.铁(氢)氧化物表面吸附态As(Ⅲ)解吸和As_(2)O_(3)溶解是导致As(Ⅲ)溶解的主要原因,Ca-As(V)沉淀的溶解和吸附态As(V)的解吸导致了As(V)的释放.
Sludge from sulfuric acid plants has high contents and leaching toxicity of arsenic(As).Its disposal is of great challenge and also has extremely high environmental risks.The chemical composition,toxicity,As sources of sludges from 9 sulfuric acid plants were studied.The leaching mechanism of As in sludge was discussed to provide theoretical and technical information for sludge disposal.The contents of As in sludge samples from sulfuric acid plants were in the range of 2.61×10^(4)~1.50×10^(5)mg·kg^(-1),with high leaching concentrations of 73.6~1.47×10^(4)mg·L^(-1),making it classified as hazardous waste.As in sludge was in the form of Arsenite(As(Ⅲ))and arsenate(As(V)).As(Ⅲ)was predominately adsorbed by iron(hydro)oxides and formed As_(2)O_(3)minerals,whereas As(V)was captured by Ca-As(V)precipitates and iron(hydro)oxides.Thus,the leaching toxicity of As was significantly affected by the contents of Ca and Fe in sludge,and a significant negative correlation between the leaching efficiency of As and Ca/Fe ratio was observed,with the leaching efficiencies of As decreasing from 80.5%to 1.85%with the increase of Ca/Fe from 0.206 to 6.67.The leaching efficiencies of As(Ⅲ)were 0.477-fold to 7.03-fold higher than those of As(V),which were attributed to the desorption of As(Ⅲ)from iron(hydr)oxides and the dissolution of As_(2)O_(3).Moreover,the leaching of As(V)was mainly induced from the dissolution of Ca-As(V)precipitates and the desorption of As(V)from iron(hydr)oxides.
作者
石瑶
王鑫
陈静
齐宇彤
芦柏年
侯慧杰
吴晓晖
娄伟
刘平波
肖劲光
肖武
王琳玲
SHI Yao;WANG Xin;CHEN Jing;QI Yutong;LU Bonian;HOU Huijie;WU Xiaohui;LOU Wei;LIU Pingbo;XIAO Jinguang;XIAO Wu;WANG Linling(School of Environmental Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074;Hunan Provincial Engineering Research Center for Resource Recovery and Safe Disposal of Industrial Solid Waste(Hunan Heqing Environmental Technology Co.,Ltd.),Changsha 410032;China Urban Construction Design&Research Institute Co.,Ltd.,Wuhan 430040;PowerChina Environmental Engineering Co.,Ltd.,Changsha 410027;PowerChina Zhongnan Engineering Co.,Ltd.,Changsha 410014)
出处
《环境科学学报》
CAS
CSCD
北大核心
2022年第3期237-245,共9页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.22076053)
国家重点研发计划(No.2019YFC1805202)
中央高校基本科研业务费专项资金资助项目(No.HUST:2020JYCXJJ048)。
关键词
含砷污泥
亚砷酸盐
砷酸盐
浸出毒性
危险固废
arsenic-containing sludge
arsenite
arsenate
leaching toxicity
hazardous waste
