纳米Fe^(3+)-TiO_2改性双极膜的制备、表征及其在海水中一、二价阳离子分离的应用  

Preparation and Characterization of Bipolar Membranes Modified by Nano-Fe^(3+)-TiO_2 and Their Application in Mono- and Divalent Cation Separation from Seawater

作　　者：刘宪[1] 陈晓[1] 陈日耀[1] 郑曦[1] 陈震[1] 

机构地区：[1]福建师范大学环境科学与工程学院,福建福州350007

出　　处：《高校化学工程学报》2014年第4期731-737,共7页Journal of Chemical Engineering of Chinese Universities

基　　金：福建省科技厅重点项目(2012H0019);福州市科技局项目(2012-G-116)

摘　　要：采用溶胶-凝胶法制备了Fe3+掺杂TiO2光催化剂。分析表明,制备的Fe3+-TiO2为锐钛矿型,其禁带宽度低于TiO2。将Fe3+-TiO2添加到聚乙烯醇-壳聚糖(PVA-CS)阴离子交换膜中,制备了PVA-CMC/Fe3+-TiO2-PVA-CS双极膜(BPM),(CMC:羧甲基纤维素钠)。研究结果表明,Fe3+-TiO2较TiO2具有更强的光催化双极膜中间界面层水解离能力,在太阳光照射下能大大提高水解离效率,降低双极膜膜阻抗和跨膜电压降。当电流密度为60 mA·cm-2时,PVA-CMC/Fe3+-TiO2-PVA-CS双极膜槽电压下降了0.8 V。此外,通过Fe3+-TiO2改性,CS膜亲水性和双极膜机械性能均获得提高。将改性后的双极膜用于分离模拟海水中一、二价阳离子,在太阳光照射下,K+离子和Na+离子双极膜透过率较无光照时有明显提高,电渗析2 h,K+离子和Na+离子的透过率分别为90.31%和82.93%,而二价阳离子的透过率均小于1.0%。A Fe^3＋-doped TiO2photocatalyst was prepared through a sol-gel method. X-ray diffraction （XRD） analysis indicates that the prepared Fe^3＋-TiO2 is in anatase phase and the band gap of Fe^3＋-TiO2 is smaller than that of TiO2. Moreover, the prepared Fe^3＋-TiO2 was added into polyvinyl alcohol-chitosan （PVA-CS） anion exchange membrane to prepare PVA-CMC/Fe^3＋-TiOz-PVA-CS bipolar membrane （BPM）, （here, CMC： carboxymethyl cellulose）. Experimental results show that Fe^3＋-TiO2 exhibits better photocatalytic performance for water splitting at the interlayer than that of TiO2. The water splitting efficiency of PVA-CMC/Fe^3＋-TiOz-PVA-CS BPM is improved under sunlight irradiation, and the membrane impedance and trans-membrane voltage drop are obviously decreased. At current density of 60 mA.cm^-2, the cell voltage of a PVA-CMC/Fe^3＋-TiOz-PVA-CS BPM-equipped cell decreases by 0.8 V. Moreover, the hydrophilicity of the CS membrane and the mechanical properties of the BPM are increased after Fe^3＋-TiO2 modification. The PVA-CMC/Fe^3＋-TiOz-PVA-CS BPM was applied to separate monovalent and divalent cations in simulation seawater. The penetration rates of K^＋ and Na^＋ ions through BPM are increased under sunlight irradiation. When electrodialysis time is 2 h, the penetration rates of K^＋ and Na^＋ ions are 90.31% and 82.93% respectively, and the penetration rates of the divalent cations are all smaller than 1%.

关 键 词：双极膜 光催化 水解离 一价 二价阳离子分离 

分 类 号：O646[理学—物理化学]