硝酸改性污泥基生物炭除U(Ⅵ)效果及机理分析  

U(Ⅵ)removal efficiency and mechanism by acidified sewage sludge-derived biochar

作　　者：莫官海 农海杜 胡青 谢水波[1] 刘红娟[2] 曾涛涛[1] MO Guanhai;NONG Haidu;HU Qing;XIE Shuibo;LIU Hongjuan;ZENG Taotao(Hunan Province Key Laboratoiy of Pollution Control and Resource Reuse Technology,University of South China,Hengyang 421001,Hunan,China;School of Nuclear Science and Technology,University of South China,Hengyang 421001,Hunan,China)

机构地区：[1]南华大学污染控制与资源化技术湖南省高校重点实验室,湖南衡阳421001 [2]南华大学核科学技术学院,湖南衡阳421001

出　　处：《精细化工》2021年第2期395-403,共9页Fine Chemicals

基　　金：湖南省教育厅创新平台开放基金项目(19K081)。

摘　　要：以城市污泥为原料制备出污泥基生物炭(SSB),并通过硝酸酸化处理得到硝酸改性污泥基生物炭(SSB-AO),探究了SSB-AO投加量、溶液初始pH、离子强度、吸附时间、U(Ⅵ)初始质量浓度以及吸附温度对SSB-AO去除U(Ⅵ)的影响,通过SEM-EDS、FTIR及XPS分析SSB-AO对U(Ⅵ)的去除机理。结果表明:SSB-AO对U(Ⅵ)的吸附符合拟二级动力学模型,吸附过程以化学吸附为主;等温吸附过程符合Langmuir模型。在30℃、NaNO_(3)浓度为0.01 mol/L、吸附时间300 min、初始pH=6、U(Ⅵ)初始质量浓度为10~100 mg/L及SSB-AO投加量为0.6 g/L的条件下,SSB-AO去除U(Ⅵ)的理论最大吸附量为80.34 mg/g;通过5次吸附-解吸实验,SSB-AO对U(Ⅵ)的去除率保持在88%以上,说明SSB-AO具有良好的重复使用性;SSB-AO去除U(Ⅵ)的机理为SSB-AO内层络合作用、静电作用以及离子交换。SSB-AO能有效地提高对U(Ⅵ)的吸附能力,该研究为处理含U(Ⅵ)废水提供借鉴。Sewage sludge-derived biochar(SSB)was prepared from sewage sludge and then modified by nitric acid to obtain acidified sewage sludge-derived biochar(SSB-AO).The effects of SSB-AO dosage,initial pH of solution,coexisting ions strength,adsorption time,initial mass concentration of U(Ⅵ)and adsorption temperature on the removal of U(Ⅵ)by SSB-AO were investigated.The removal mechanism was analyzed by SEM-EDS,FTIR and XPS.The results showed that the adsorption of U(Ⅵ)by SSB-AO was in accordance with the pseudo second-order kinetic model,and the adsorption progress was mainly chemical adsorption.The isotherm adsorption process was conformed to Langmuir model.Under the conditions of 30℃,0.01 mol/L NaNO3,adsorption time of 300 min,initial pH of 6,initial U(Ⅵ)mass concentration in range of 10~100 mg/L and SSB-AO dosage of 0.6 g/L,the theoretical maximum adsorption capacity of SSB-AO to U(Ⅵ)was 80.34 mg/g.The adsorption efficiency of SSB-AO was more than 88%after five adsorption desorption tests,indicating that SSB-AO had excellent reusability.The mechanism of U(Ⅵ)removal by SSB-AO included inner surface complexation,electrostatic adsorption and ion exchange.SSB-AO can effectively improve the adsorption capacity of U(Ⅵ),which provides a reference for the treatment of wastewater containing U(Ⅵ).

关 键 词：酸化 污泥基生物炭 放射性废水 U(Ⅵ) 机理 水处理技术 

分 类 号：X703[环境科学与工程—环境工程]