PVDF/PDA/Ag催化膜对亚甲基蓝的催化降解

Degradation of methylene blue with PVDF/PDA/Ag catalytic membrane

为制备可降解染料抗污染的催化膜材料,首先用多巴胺(DA)对聚偏氟乙烯(PVDF)粉末进行改性,然后用改性的PVDF粉末制备了多孔平板膜,随后利用聚多巴胺的还原性原位在膜中负载和固定了银纳米颗粒,得到了PVDF/PDA/Ag催化膜;采用傅里叶变换红外光谱仪、场发射扫描电镜、X射线光电子能谱仪、电感耦合等离子体发射光谱仪等对膜进行表征,并用亚甲基蓝溶液对膜的催化性能进行测试.结果表明:PDA改性的PVDF膜表面和膜孔中成功引入了Ag纳米粒子;随着催化反应温度由20℃增加到40℃,催化膜对亚甲基蓝的催化反应速率常数由0.088 min^(-1)增加到0.394 min^(-1);实验中对亚甲基蓝的催化降解呈一级反应动力学,表观反应速率常数为0.066 15 min^(-1),活化能Ea值为56.13 k J/mol,而且催化膜表现出很好的重复利用性,在重复使用8次后,降解率仍保持在80.8%以上.

In order to prepare catalytic membrane materials for degrading dyes,the PVDF powders were modified with do-pamine firstly,and then the porous PVDF/PDA/Ag membrane was prepared by modified PVDF powders.Then,the silver nanoparticles were loaded and fixed in the membrane by the reduction of dopamine,and the catalytic membrane was obtained.Fourier transform infrared spectroscopy spectra,field-emission scanning electron microscope,X-ray photoelectron spectroscopy,inductively coupled plasma atomic emission spectroscopy were used to characterize the prepared film.Results indicated that silver nanoparticles were introduced into the surface and pores of the modified membrane.With the catalytic reaction temperature increased from 20℃to 40℃,the reaction rate constant of the catalytic membrane increased from 0.088 min-1 to 0.394 min-1.The catalytic degradation of methylene blue by catalytic membrane belongs to the first-order reaction kinetics.And the apparent reaction rate constant was 0.066 15 min-1,the activation energy Ea was 56.13 kJ/mol.Moreover,the highly reusable of catalytic membrane has been also prepared,the degradation percent remained above 80.8%after eight cycles.