磁性壳聚糖改性硅藻土吸附去除水中的铅离子

Adsorptive removal of Pb^(2+) using magnetic chitosan modified diatomite

采用壳聚糖与Fe_3O_4对硅藻土进行混合改性,制备出一种吸附效果好、且能从液相中磁分离的新型复合吸附剂。通过SEM、XRD、VSM和FTIR等手段对其进行表征,并探究溶液pH、吸附剂投加量以及吸附温度等条件对水溶液中Pb^(2+)吸附效果的影响。结果表明:壳聚糖和Fe_3O_4都能够负载到硅藻土上面。当溶液pH为5、吸附剂投加量为10 g·L^(-1)、初始浓度为10 mg·L^(-1)时,Pb^(2+)去除率可以达到96.4%。吸附过程较好地符合假二级动力学模型和Langmuir吸附等温模型,热力学数据说明该吸附是吸热、自发的过程。

Diatomite was modified with chitosan and Fe_3O_4 to obtain a new composite that could not only serve as an effective adsorbent but could also be magnetically separated from an aqueous phase. The new composite was characterized by SEM,XRD,SEM,and FTIR,and its adsorption of Pb^2＋was investigated under various initial pH values,adsorbent dosages,and temperatures. The results indicated that both chitosan and Fe_3O_4 were coated on the diatomite. When the solution pH,initial concentration,and adsorbent dosage were 5,10 mg ·L^-1,and 10 g·L^-1,respectively,the adsorption efficiency could reach 96. 4%. The adsorption was well described by the pseudo-second-order kinetic model and Langmuir adsorption isotherm model. The thermodynamic data showed that the adsorption process was endothermic and spontaneous.