改性海藻酸钠/壳聚糖双极膜成对电解制备乙醛酸  

Electro-Generation of Glyoxylic Acid in Pairs by Modified Sodium Alginate/Chitosan Bipolar Membrane

作　　者：黄振霞[1] 郑曦[1] 陈日耀[1] 陈晓[1] 陈震[1] 

机构地区：[1]福建师范大学化学与材料学院实验中心,福建福州350007

出　　处：《高校化学工程学报》2008年第4期725-728,共4页Journal of Chemical Engineering of Chinese Universities

基　　金：福建省自然科学基金(D0710009);福建省高校基金项目(2007F5032)

摘　　要：以镍网电极-改性海藻酸钠/壳聚糖双极膜(Ni-mSA/mCS BM)作为阴阳两室间的隔膜,利用双极膜的中间界面层水解离特性成对电解制备乙醛酸。水解离特性分析结果表明,双极膜中水解离后生成的H+透过mSA阳离子膜进入阴极室中,可及时补充草酸电还原生成乙醛酸过程中的H+消耗;OH-透过mCS阴离子膜进入阳极室中,与乙二醛电氧化生成乙醛酸过程中产生的H+结合生成H2O,可促进正向反应的速度。以饱和草酸和盐酸的混合液作阴极液,以10%乙二醛和10%KBr的混合液作阳极液,镍网为阴极,二氧化铅为阳极,在电流密度为20mA-cm-2常温下电解,阴极电流效率达82.9%,阳极电流效率达75.7%,电解电压低于2.7V。The bipolar membrane （BM） consisted of nickel net modified with sodium alginate/chitosan （Ni-mSA/mCS） was used as a separating membrane in the electrolysis cell to electro-generation of glyoxylic acid in pair; the glyoxylic acid was produced by electro-reduction of oxalic acid in cathode chamber and by electro-oxygenation of glyoxal in anode chamber. The water dissociation peculiarity in the interface layer of the bipolar membrane （BM） was investigated. The results show that, through the mSA cation exchange membrane, the H^＋ dissociated in BM moves into the cathode chamber in time to supply the H^＋ consumed in electro-reduction of oxalic acid in the cathode chamber, and the OH^- dissociated in BM moves through the mCS anion exchange membrane into anode chamber to form H2O with the H^＋ produced by electro-oxygenation of glyoxal in anode chamber, which will promote the reaction rate of the positive direction. The experimental results show that, when using the mixture of saturate oxalic acid and HCl as cathode electrolyte, the mixture of 10% glyoxal and 10% KBr as anode electrolyte, Ni net as cathode and PbO2 as anode, with the current density of 20 mA·cm^-2 at room temperature, the current efficiencies can be up to 82.9% and 75.7% for cathode and anode chamber, respectively, and the electrolysis voltage is as low as 2.7 V.

关 键 词：双极膜 草酸 乙二醛 成对电解 乙醛酸 

分 类 号：TQ225.61[化学工程—有机化工] TQ151.52