摘要
为优化提升天然硅藻土对水体中重金属的吸附性能,采用“煅烧-钙化-柱撑”三步法对天然硅藻土进行纯化改性,合成制备硅藻土基改性吸附剂(CMODE)。利用响应面法的Box-Behnken设计优化CMODE吸附剂的制备条件,结果表明对CMODE制备影响顺序为:煅烧温度(X1)>Ca^(2+)浓度(X2)>OH^(-)/Al^(3+)比(X3),且在煅烧温度350℃、Ca^(2+)浓度5%、柱化液OH^(-)/Al^(3+)比2.2的优化条件下,CMODE对Pb(II)吸附去除率预测值可达93.45%,验证试验得到Pb(II)去除率为92.83%,与模型预测值的偏差仅为0.62%,说明实验值与模型预测值之间拟合良好,回归拟合得到的二次多项式模型能够有效预测CMODE吸附性能。CMODE对Pb(II)的吸附过程与二级动力学模型和Langmuir等温吸附模型拟合良好,表明CMODE对Pb(II)的吸附为单分子层化学吸附,且CMODE对Pb(II)的吸附作用以静电吸引、离子交换和表面络合为主。
To optimize and enhance the adsorption performance of natural diatomaceous earth for heavy metals in water,a three-step method of"calcination calcification column support"was used to purify and modify diatomaceous earth,and a diatomaceous earth-based modified adsorbent(CMODE)was synthesized.The Box Behnken design using response surface methodology was used to optimize the preparation conditions of diatomaceous earth based modified adsorbents.The results showed that the order of influence of various factors on the preparation of CMODE was as follows:calcination temperature(X1)>Ca^(2+)concentration(X2)>OH^(-)/Al^(3+)ratio(X3).Under the optimized conditions of calcination temperature was 350℃,Ca^(2+)concentration was 5%,and column liquid OH^(-)/Al^(3+)ratio was 2.2,the predicted adsorption performance of CMODE could reach 93.45%,and the validation experiment obtained a Pb(II)removal rate of 92.83%.The deviation from the predicted value of the model is only 0.62%,indicating a good fit between the experimental value and the predicted value of the model.The quadratic polynomial model obtained by regression fitting can effectively predict the adsorption performance of CMODE.The adsorption process of Pb(II)by CMODE is well fitted with the second-order kinetic model and Langmuir isotherm adsorption model,indicating the adsorption of Pb(II)by CMODE is monolayer chemical adsorption,and the adsorption effect of CMODE on Pb(II)is mainly electrostatic attraction,ion exchange,and surface complexation.
作者
张占梅
陈熙琳
张毅
黄紫然
石瑞琦
ZHANG Zhanmei;CHEN Xilin;ZHANG Yi;HUANG Ziran;SHI Ruiqi(College of River and Ocean Engineering,Chongqing Jiaotong University;Key Laboratory of Water Conservancy and Water Transport Engineering,Ministry of Education:Chongqing 400074,China)
出处
《水处理技术》
CAS
CSCD
北大核心
2023年第9期58-63,95,共7页
Technology of Water Treatment
基金
国家自然科学基金项目(21906012)
重庆交通大学研究生科研创新项目(2023S0040)。
关键词
响应面
硅藻土
重金属
吸附
response surface methodology
diatomite
heavy metals
adsorbent
