摘要
探讨了初始浓度、接触时间、pH、离子强度等因素对针铁矿对去除水溶液中Cd(Ⅱ)的影响。利用X射线粉末衍射仪(XRD)对针铁矿进行表征,并通过批量实验研究了针铁矿对Cd(Ⅱ)吸附动力学和等温吸附机理。结果表明:针铁矿比表面积为82.36m^2/g;准二级动力学和Langmuir等温吸附适用于针铁矿对Cd(Ⅱ)的吸附,相关系数分别为0.9535和0.9915;当25℃、pH为5时,用Langmuir等温线计算得到其最大吸附量为35.29mg/g;针铁矿吸附Cd(Ⅱ)能力随pH增大而增大;随着CaCl2的浓度增大,针铁矿对Cd(Ⅱ)的吸附量减小,随着MgCl2的浓度增大,针铁矿对Cd(Ⅱ)的吸附量先减小后上升,总体有抑制作用。
The effect of initial aqueous concentration,contact time,pH and ionic strength on Cd(Ⅱ) removal by goethite from aqueous solution were studied.Goethite was characterized by X-ray powder diffraction (XRD).The goethite surface area was determined to be 82.36 m^2/g.Batch experiments were carried out to determine the adsorption kinetics and isothermal mechanism of Cd (Ⅱ) by goethite.Pseudo-second kinetic equation and Langmuir isotherm were found to fit the experimental data well (r =0.9535 and 0.9915,respectively).The maximum adsorption capacity (Q m) calculated from Langmuir isotherm was found to be 35.29 mg/g for Cd(Ⅱ) with pH 5.0 and 25 ℃.The adsorption process was found to be dependent with pH value.The adsorption capacity of Cd(Ⅱ) increased with the increase of aqueous pH.In CaCl2 and MgCl 2 solutions,Cd(Ⅱ) adsorption decreased with increasing ionic strength.With the increase of CaCl2 concentration,the adsorptive capacity of goethite to Cd(Ⅱ) decreased.With the increase of MgCl 2 concentration,the adsorptive capacity of goethite to Cd(Ⅱ) decreased at first,then increased,which had an inhibitory effect generally.
作者
郑骁
王学松
陈光
冯洪燕
汤帅
ZHENG Xiao;WANG Xue-song;CHEN Guang;FENG Hong-yan;TANG Shuai(School of Chemical Engineering,Huaihai Insistute of Technology,Lianyungang 222003,China;Co-innovation Center of Jiangsu Marine Bio-industry Technology,Huaihai Institute of Technology,Lianyungang 222000,China;Jiangsu Key Laboratory of Bioresources and Eco-environment,Huaihai Institute of Technology,Lianyungang 222003,China)
出处
《环境工程》
CAS
CSCD
北大核心
2019年第7期119-123,208,共6页
Environmental Engineering
基金
江苏省优势学科建设工程资助项目(CXKT20180324)
