测试——聚乙烯亚胺改性磁性膨润土对Pb2+和Cu2+的吸附性能(测试稿件)

在磁性膨润土(MBent)表面接枝聚乙烯亚胺(PEI)制备了聚乙烯亚胺改性磁性膨润土(PEI/KH560/MBent),采用FTIR、VSM、XRD、TGA、EA、SEM和EDS对其进行了表征,考察了其对水溶液中Pb_²⁺和Cu_²⁺的吸附性能。结果表明,聚乙烯亚胺已成功接枝于磁性膨润土表面,并有效提高其对Pb_²⁺和Cu_²⁺吸附量；溶液初始pH对吸附量影响较大,随着pH的增大,吸附量增加。在pH=5,溶液初始质量浓度为300 mg/L,PEI/KH560/MBent对Pb_²⁺和Cu_²⁺吸附量分别为96.21和61.08 mg/g；吸附过程符合准二级动力学模型,吸附行为符合Langmuir吸附等温模型。热力学研究表明,吸附为自发吸热过程。经过5次循环利用后,其吸附容量仍保持初始的60%以上,表明PEI/KH560/MBent具有一定的重复利用性。

Adsorption properties of polyethyleneimine modified magnetic bentonite for Pb2+ and Cu2+

Polyethyleneimine-modified magnetic bentonite (PEI/KH560/MBent) was prepared by grafting polyethyleneimine (PEI) on the surface of magnetic bentonite (MBent) and characterized by FTIR, VSM, XRD, TGA, EA, SEM and EDS. The adsorption performance of PEI/KH560/MBent for Pb_²⁺ and Cu_²⁺ in aqueous solution was studied. The results showed that polyethyleneimine was successfully grafted onto the surface of magnetic bentonite and effectively increased the adsorption capacity for Pb_^2??+ and Cu_²⁺. The initial pH of solution had a great influence on the adsorption capacity. When the pH increased, the adsorption capacity increased. Under the conditions of pH=5 and the initial concentration of the solution of 300 mg/L, the actual adsorption capacities of PEI/KH560/MBent for Pb_{^{2 ??+}} and Cu_²⁺ were 96.21 and 61.08 mg/g, respectively. The adsorption process was more in line with the quasi-second-order kinetic model, and the adsorption behavior was more consistent with the Langmuir adsorption isotherm model. The results of thermodynamic studies indicated that the adsorption was a spontaneous endothermic process. After 5 cycles of recycling, the adsorption capacity remained above 60% of the original, indicating that PEI/KH560/MBent had certain reusability.