Fe_3O_4@SiO_2@CS/PAA的制备及其对Cr(Ⅵ)吸附性能的研究

Preparation of Fe_3O_4@SiO_2@CS/PAA and Its Application in Absorbing Cr(Ⅵ)from Wastewater

针对含Cr(Ⅵ)废水来源广、危害大、易蓄积、难去除等特点,基于壳聚糖对Cr(Ⅵ)良好的吸附性能,合成了具有以Fe_3O_4为内核、SiO_2为夹心层、CS/PAA为外壳的类"三明治"结构,富含氨基、羟基、羧基等功能基团的新型吸附剂Fe_3O_4@SiO_2@CS/PAA.在最优工艺条件t=75℃,pH=2下,吸附剂投量仅为1.0g·L-1时,对质量浓度为100mg·L-1的Cr(Ⅵ)模拟废水Cr(Ⅵ)的去除率高达64.69%,这表明该吸附剂具有较高的吸附量,该吸附剂对Cr(Ⅵ)的吸附机理服从准二级动力学过程,该吸附过程以化学作用为主。Fe_3O_4@SiO_2@CS/PAA是一种优良的Cr(Ⅵ)吸附剂,将有效解决Cr(Ⅵ)难处理的问题,为吸附剂的无毒无害化的研究提供一定的理论和现实指导意义。

According to the fact that Cr（Ⅵ）-containing wastewater has widespread sources,great toxicity,ease to accumulate but difficulty to remove,on the basis of the excellent adsorption performance of chitosan（CS）,a novel＂sandwich＂structure adsorbent Fe_3O_4@SiO_2@CS/PAA,of which Fe_3O_4 is the core,SiO_2 is the sandwich layer,and CS/PAA is the shell,was synthesized.The as-prepared adsorbents were rich in amino,carboxyl,and hydroxyl groups.The absorbents for treatment of Cr（Ⅵ）（100mg/L）simulation wastewater exhibited high adsorption for Cr（Ⅵ）under the optimum condition t=75 ℃,pH=2,ρm=1.0g/L,and the Cr（Ⅵ）removal rate reached64.69%.The adsorption process follows a pseudo-second-order kinetic model and is dominated by chemical action.The Fe_3O_4@SiO_2@CS/PAA particles are excellent adsorbent for Cr（Ⅵ）,which solves the difficult removing problem of Cr（Ⅵ）and provides theoretical and practical significance for non-toxic and harmless adsorbents.