BP-PSO优化改性凹凸棒土吸附Pb(Ⅱ)条件及其机制研究  

Research on Optimization Pb(Ⅱ) Adsorption Conditions Using Modified Attapulgite by BP-PSO and Its Adsorption Mechanism

作　　者：谢伟芳[1] 韩承辉[1] XIE Wei-fang;HAN Cheng-hui(School of Environment and Ecology,Jiangsu City Vocational College,Nanjing 210017,China)

机构地区：[1]江苏城市职业学院生态环境学院

出　　处：《硅酸盐通报》2019年第12期3822-3832,共11页Bulletin of the Chinese Ceramic Society

基　　金：江苏省高等学校自然科学研究面上项目(17KJB610002);江苏省环境工程重点实验室科研开放基金课题(KF2015005)

摘　　要：为探究Keggin离子改性凹凸棒土对Pb(Ⅱ)的吸附性能及获得Pb(Ⅱ)最大去除率,采用响应面(RSM)及反向传播神经网络结合粒子群算法(BP-PSO)对去除条件进行优化,利用X射线光电子能谱仪表征、动力学、等温吸附及热力学研究对吸附机理进行探讨,采用可渗透反应墙对Pb(Ⅱ)去除进行动态模拟。XPS表征结果显示Pb(Ⅱ)被吸附到改性土表面,该吸附过程并未发现氧化还原反应。RSM优化下,预测和实际Pb(Ⅱ)最大去除率分别为83. 85%和81. 24%,相对应的去除条件:反应时间为50. 02 min、初始Pb(Ⅱ)浓度为150 mg/L、温度为20℃及初始p H值为7。BP-PSO优化下最大去除率为85. 68%,对应的实验条件:温度为20℃,反应时间为52. 28 min,初始Pb(Ⅱ)浓度为250 mg/L,初始p H值为7,在此条件下验证实验值为84. 41%。BP-PSO更合适用于优化改性凹凸棒土吸附水溶液中Pb(Ⅱ)。改性凹凸棒土对Pb(Ⅱ)的吸附为吸热、自发及熵驱动的过程。可渗透反应墙中对Pb(Ⅱ)去除率的去除效果不理想。In order to investigate the mechanism of Pb( Ⅱ) adsorption using Keggin ion-modified attapulgite and obtain the maximum Pb( Ⅱ) removal efficiency, response surface methodology( RSM) and back-propagation neural network combined with particle swarm optimization( BP-PSO) were used to optimize the removal conditions. X-ray photoelectron spectroscopy( XPS), kinetics, isothermal adsorption and thermodynamics were employed to explore the adsorption mechanism. The dynamic simulation of Pb( Ⅱ) removal by permeable reactive barrier( PRB) was carried out. XPS characterization showes that Pb( Ⅱ) is adsorbed on the surface of Keggin ion-modified attapulgite,and no redox reaction is found during the adsorption process. Under RSM optimization,the maximum removal rates of predicted and actual Pb( Ⅱ)are 83. 85% and 81. 24% under reaction time is 50. 02 min,initial Pb( Ⅱ) concentration is 150 mg/L,temperature is20 ℃ and initial p H is 7,respectively. The maximum removal efficiency is 85. 68% under the optimized BP-PSO conditions. The corresponding experimental conditions were as follows: temperature was 20 ℃,reaction time was 52. 28 min,initial Pb( Ⅱ) concentration was 250 mg/L,initial p H value was 7,and the experimental value was 84. 41% under these conditions. BP-PSO is more suitable for optimizing the adsorption of Pb( Ⅱ) in aqueous solution by modified attapulgite.The Pb( Ⅱ) adsorption by Keggin ion-modified attapulgite is an endothermic,spontaneous and entropy-driven process. The Pb( Ⅱ) removal efficiency in PRB is not well.

关 键 词：Keggin离子 凹凸棒土 Pb(Ⅱ) 响应面 反向传播神经网络结合粒子群算法 

分 类 号：X53[环境科学与工程—环境工程]