纳米二氧化钛-氧化锌改性双极膜制备与表征

Preparation and characterization of bipolar membrane modified by nano-sized TiO_2-ZnO

在壳聚糖(CS)阴离子交换膜层中添加纳米二氧化钛-氧化锌复合半导体材料,制备了PVA-SA/TiO2-ZnO-CS双极膜(其中:PVA为聚乙烯醇;SA为海藻酸钠),并用热重分析等对其进行了表征。研究结果表明,纳米二氧化钛-氧化锌复合半导体材料较纳米氧化锌或纳米二氧化钛单一半导体材料具有更强的光催化双极膜中间界面层水解离能力,能大大降低双极膜的膜阻抗和膜电阻压降(IR降)。当电流密度为60 mA/cm2时,在高压汞灯照射下,PVA-SA/TiO2-ZnO-CS双极膜的槽电压较没有高压汞灯照射时下降了1.0 V;而PVA-SA/TiO2-CS双极膜和PVA-SA/ZnO-CS双极膜仅分别下降了0.7 V和0.6 V。此外,添加纳米二氧化钛-氧化锌复合半导体材料可提高双极膜的亲水性、热稳定性和机械性能。

Nano-sized TiO2-ZnO compound semiconductor material was added into anion exchange membrane layers of chitosan（CS） to prepare PVA-SA/TiO2-ZnO-CS（wherein,PVA：polyvinyl alcohol;SA：sodium alginate） bipolar membrane（BPM）,and the prepared BPM was characterized by TG etc..Experimental results showed that nano-sized TiO2-ZnO had better photocatalytic property for water decomposition in the interlayer of BPM than that of any single nano-sized ZnO or nano-sized TiO2 semiconductor materials,and it could greatly reduce membrane impedance and IR drop of BPM.Under the irradiation of high-pressure mercury lamps,the cell voltage of PVA-SA/TiO2-ZnO-CS BPM decreased by 1.0 V than that without mercury lamp irradiation,when at current density of 60 mA/cm2;and the cell voltages of PVA-SA/TiO2-CS BPM and PVA-SA/ZnO-CS BPM were only reduced by 0.7 V and 0.6 V,respectively.Furthermore,the hydrophilicity,thermal stability,and mechanical properties of BPM all could be increased by the addition of nano-sized TiO2-ZnO compound semiconductor material.