摘要
在环境岩土工程领域中,重金属污染土修复成为重要方向。工业发展加剧了铅污染,同时产生了大量副产品零价铁屑。铁屑的来源广、价格低、吸附性能优良,是一种较理想的铅污染处理材料。因此笔者采用零价铁粉处理Pb^(2+) 污染土,通过开展单因素实验考察吸附剂设计剂量、初始污染物浓度、处理时间、溶液p H对Pb^(2+) 去除效果的影响,对平衡状态进行等温吸附研究、对反应过程进行吸附动力学研究。结果表明,Pb^(2+) 去除率与吸附剂设计剂量、处理时间长度正相关,与初始污染浓度负相关,与p H不明显相关;在Pb^(2+) 初始浓度为300 mg/L、铁粉设计剂量为10 g/L、处理时间为48 h的条件下,实验中Pb^(2+) 去除率可达98%,吸附剂的单位吸附量可达25.35mg/g; Freundlich等温吸附模型、准二级动力学模型较符合本反应;结合反应前后XRD图谱分析固相成分及含量,零价铁去除Pb^(2+) 主要通过化学吸附与物理吸附,并以化学吸附为主,具体作用形式包括铅离子被零价铁还原固定,污染物与含铁胶体共沉淀,以及静电作用;实验结果为零价铁去除重金属污染物技术的应用提供参考。
Remediation of heavy metal contaminated soil has been wildly studied in the field of environmental geotechnology.Industrialization has increasingly brought Pb^2+pollution,and produced a mass of zero-valent iron scurf as a by-product at the same time.zero-valent iron is produced in a variety of industries.Besides,it has low prices and good adsorption properties,and thus is considered as a desirable adsorption material for the remediation of Pb^2+and other heavy metal pollutants.Due to the reasons above,in this study,zero-valent iron powder was used in the remediation of Pb^2+contaminated soil.We conducted single-factor experiments to evaluate how experimental parameters influenced adsorption properties of zero-valent iron,as well as the removal efficiency of Pb^2+in the process,including zero-valent iron powder dosage,initial concentration of Pb^2+in solution,reaction time,as well as initial solution pH.Based on the experimental data,we carried out study on isothermal properties of the states of equilibrium,also studied adsorption kinetics during the reaction.According to the above results,Pb^2+removal efficiency had a positive correlation with iron powder dosage and reaction time,but it had a negative correlation with initial concentration of Pb^2+solution.Additionally,there was no obvious correlation between initial solution pH and the removal efficiency of Pb^2+.Under the condition that the initial concentration of Pb^2+was 300 mg/L,the iron dosage was 10 g/L,the duration was 48 h,the adsorption capacity of zero-valent iron reached 25.35 mg/g,and the removal efficiency of Pb^2+was over 98%.We fitted the experimental data with Freundlich equation and Langmuir equation for thermodynamic study,so the pseudo first order model and pseudo second order model were used for adsorption kinetic discussion.As the fitting results indicated,the reduction process was better coincident with pseudo second order kinetic model and Freundlich equation.The solid adsorbents and residual solid were characterized by X-ray diffraction(
作者
徐晓晶
魏闻语
张宇
李亭
唐强
XU Xiaojing;WEI Wenyu;ZHANG Yu;LI Ting;TANG Qiang(Tonghe Environmental Engineering Co.Ltd.,Suzhou 215011,Jiangsu,China;School of Rail Transportation,Soochow University,Suzhou 215131,Jiangsu,China;Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210098,China;Jiangsu Research Center for Geotechnical Engineering Technology,Hohai University,Nanjing 210098,China)
出处
《林业工程学报》
北大核心
2018年第6期142-148,共7页
Journal of Forestry Engineering
基金
国家自然科学基金(51708377)
江苏省自然科学基金青年项目(BK20170339)
江苏省高等学校自然科学研究面上项目(17KJB560008)
江苏省建设系统科技项目(2016ZD18,2017ZD002)。
关键词
零价铁
重金属污染
吸附
吸附特性
共沉淀
zero-valent iron
heavy metal pollution
adsorption
complexation
