聚多巴胺包覆磁性纳米材料吸附去除模拟废水中的铅离子

Adsorption and removal of lead from simulated waste water using polydopamine modified magnetic nanoparticles

采用共沉淀法制备聚多巴胺包覆的磁性纳米材料(Fe_3O_4@PDA NPs),并利用透射电子显微镜(TEM)、X光电子能谱(XPS)、振动磁强计(VSM)等手段表征了磁性纳米材料的化学组成和物理形貌.考察了溶液p H值、吸附平衡时间、纳米材料投加量、共存离子及离子强度等对铅吸附的影响,确定最佳实验条件为吸附平衡时间1 h、pH 5.5、吸附剂投加量1.5 g·L^(-1).常见共存离子均不干扰铅的吸附去除.通过直线方程拟合,证实Fe_3O_4@PDA NPs对铅离子的吸附等温线符合Langmuir方程,为单分子层吸附,饱和吸附量约为20.68 mg·g^(-1).1.5 h内,Fe_3O_4@PDA NPs对自来水、模拟废水中铅的吸附去除效率可以达到97.2%以上,此结果表明Fe_3O_4@PDA NPs可以用于铅污染环境水样的净化处理中.

A coprecipitation method was employed for the synthesis of polydopamine coated magnetic nanoparticles（ Fe3O4@ PDA NPs）. Transmission electron microscopy（ TEM）,X-ray photoelectron spectroscopy（ XPS）,vibrating sample magnetometer（ VSM） were used to characterize the structure of the magnetic nanoparticles, and all the results indicate the successful synthesis of Fe3O4@ PDA NPs. The effects of solution p H, adsorption equilibrium time, dosage of Fe3O4@ PDA NPs and coexisting anions on the adsorption of lead were investigated. And results showed that the adsorption isotherms of lead in our experiments could be well described by Langmuir equation,while the maximum adsorption capacity of lead reached 20. 68 mg·g^-1 under the optimal conditions of equilibrium time 1 h,p H 5. 5,and Fe3O4@ PDA NPs 1. 5 g·L^-1. Furthermore,Fe3O4@ PDA NPs could remove at least 97. 2% of lead from tap water or simulated waste water within 1.5 h,which demonstrates the potential application of Fe3O4@ PDA NPs in the treatment of lead polluted environmental water.