“三明治”双极膜的制备及其在降解含酚废水中的应用

纳米TiO₂上负载纳米Pt以制备纳米Pt/TiO₂半导体光催化剂, 壳聚糖(CS)经纳米Pt/TiO₂改性后作为阴膜层材料, 以羧甲基纤维素(CMC)作为阳膜层材料, 分别用戊二醛与FeCl₃对阴、阳膜层进行交联改性, 制备了CMC-Pt/TiO₂-CS双极膜, 并将该复合膜作为降解高浓度含酚废水电解槽的隔膜。结果表明: Pt/TiO₂光催化剂可促进双极膜中间层水的解离, 大大降低双极膜的膜阻抗和电阻电压降(IR降); 同时, Pt/TiO₂光催化剂表面生成的羟基自由基(·OH)可直接作用于苯酚, 使其彻底降解成无机小分子; 紫外光照下在16.7 mA·cm^-2的电流密度下电解高浓度含酚废水80 min后, CMC-Pt/TiO₂-CS 双极膜的苯酚降解率比CMC-TiO₂-CS 双极膜的苯酚降解率高12.7%; 整个电解过程CMC-Pt/TiO₂-CS 双极膜的膜电阻电压降保持在0.9 V。

Preparation of sandwich-type bipolar membrane and its application in the degradation of phenol

Chitosan (CS) was modified with nano-Pt/TiO 2 semiconductor photocatalyst which was prepared by doping Pt on TiO 2 in advance, and marked as CS-Pt/TiO 2 . CMC-Pt/TiO 2 -CS bipolar membrane was then prepared using carboxymethyl cellulose(CMC) and CS-Pt/TiO 2 which were cross-linked by FeCl 3 and glutaraldehyde, respectively. Sandwich-typed CMC-Pt/TiO 2 -CS bipolar membrane, the composite membrane with fine protons and hydroxyl ion-permeability, was then applied as the septum of the electrolytic cell in the degradation of phenol. Nano-Pt/TiO 2 semiconductor photocatalyst can not only generate hydroxyl radicals ( OH) which could directly degrade phenol into the small inorganic molecules, but also promote water splitting at the intermediate layer of CMC-Pt/TiO 2 -CS bipolar membrane and consequently reduce the impedance and resistance of bipolar membrane greatly. Compare CMC-Pt/TiO 2 -CS bipolar membrane with CMC-TiO 2 -CS bipolar membrane under UV irradiation, after 80 min electrolysis at the current density of 16.7 mA·cm -2 , the degradation rate of the former is 12.7 % higher than that of the latter, while IR drop of the former is as low as 0.9 V.