纳米磁性磷酸二氢钙对Cd的吸附、回收与再生  

Adsorption,Reclaim,and Regeneration of Cd by Magnetic Calcium Dihydrogen Phosphate Nanoparticles

作　　者：李玉娇 杨志敏[1] 陈玉成[1] 黄磊[1] 唐海燕 LI Yu-jiao;YANG Zhi-min;CHEN Yu-cheng;HUANG Lei;TANG Hai-yan(Chongqing Engineering Research Center of Rural Cleaning, College of Resources and Environment, Southwest University, Chongqing 400716, China)

机构地区：[1]西南大学资源环境学院农村清洁工程重庆市工程研究中心,重庆400716

出　　处：《环境科学》2019年第4期1849-1856,共8页Environmental Science

基　　金：国家重点研发计划项目(2017YFD0801004)

摘　　要：以Ca(H_2PO_4)_2、铁盐与亚铁盐为原料,采用共沉淀法制备成纳米磁性材料Ca(H_2PO_4)_2@Fe3O_4(NMCDP),研究其对Cd^(2+)的吸附、回收与再生效果.透射电镜(TEM)、红外光谱(FTIR)、X射线衍射(XRD)显示,NMCDP粒径约60 nm,稳定性良好,饱和磁化强度为30. 9 emu·g^(-1).吸附动力学表明,NMCDP对Cd^(2+)的吸附1 h之内即可达到平衡,符合准二级动力学模型.吸附热力学表明,NMCDP对Cd^(2+)的吸附符合Langmuir与Freundlich等温吸附模型,最大吸附量为142. 50 mg·g^(-1).在pH值由2增加到3时,吸附量随溶液初始pH值的升高而增加,当pH值大于3后,逐渐保持稳定;溶液中共存离子Na+、Mg^(2+)、Cu^(2+)对材料吸附Cd^(2+)均有一定的影响,影响程度Cu^(2+)> Mg^(2+)> Na+.采用0. 01 mol·L^(-1)HCl与EDTA-Na_2均可解吸出部分吸附的Cd^(2+),以EDTA-Na_2解吸率较高,达到68%,从而实现NMCDP的再生.In order to improve the adsorption-separation of Cd^2+ in water treatment, magnetic Fe3O4 coated Ca(H2PO4)2 nanoparticles (NMCDP) were developed by coprecipitation. The properties of these nanoparticles were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and magnetization curves. Experiments were carried out to investigate the effect of adsorption, reclaiming, and regeneration. The results showed that NMCDP was a stable material with a particle size of 60 nm and a saturation magnetization of 30.9 emu·g^-1. The adsorption rate of Cd^2+ by NMCDP was fast, and adsorption equilibrium could be achieved within 1 hour. The kinetic data were well fitted by a pseudo-second-order model, and the isotherm adsorption data agreed with the Langmuir and Freundlich model, with a maximum adsorption capacity of 142.50 mg·g^-1. The adsorption capacity of Cd^2+ was affected by the pH and increased when the pH was increased from 2 to 3, while with continued increase of the pH of the solution, the adsorption capacity gradually became stable. The coexisting ions in the solution had an effect on the adsorption of Cd^2+, especially the divalent cation Cu^2+. The NMCDP could be regenerated by using 0.01 mol·L-1 HCl and EDTA-Na2, and the results indicated that it could be recycled with a desorption rate of 68% by EDTA-Na2 solution.

关 键 词：磁性 磷酸二氢钙 纳米 Cd2+ 吸附 

分 类 号：X131[环境科学与工程—环境科学]