Chen D H, Leu J C, Huang T C
Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.
J Chem Technol Biotechnol. 1994 Dec;61(4):351-7. doi: 10.1002/jctb.280610411.
A membrane reactor-separator, in which an anion-exchange membrane and a urease-immobilized poly(vinyl alcohol) (PVA) membrane were clamped together to separate the feed solution and the stripping solution of a dialysis cell, was constructed. The urea in the feed solution passed through the anion-exchange membrane, water film, and then was hydrolyzed to ammonium carbamate in the urease-immobilized PVA membrane. The experimental results showed that no ammonium ion was found in the feed solution under either phosphate or citrate buffer systems at 0.05-0.2 mol dm-3 and pH 6-9, and various initial concentrations of urea in the feed solution (20-200 mmol dm-3). This indicates that the water film between two membranes allows the carbamate ions to decompose into ammonium and carbonate ions completely before entering the anion-exchange membrane. The device therefore can be used for the removal of urea from feed solution, while preventing the backflow of ammonium ions from the stripping solution or water film into feed solution. It has significant potential in the development of a wearable or portable artificial kidney. The properties of the urease-immobilized PVA membrane were examined. A kinetic model describing the transport-reaction behavior of urea in the membrane reactor-separator was developed, and the optimum values of the reactor parameters were obtained.
构建了一种膜反应器-分离器，其中将阴离子交换膜和固定有脲酶的聚乙烯醇（PVA）膜夹在一起，以分离透析池的进料溶液和汽提溶液。进料溶液中的尿素穿过阴离子交换膜、水膜，然后在固定有脲酶的PVA膜中水解为氨基甲酸铵。实验结果表明，在0.05 - 0.2 mol dm⁻³且pH为6 - 9的磷酸盐或柠檬酸盐缓冲体系下，进料溶液中未检测到铵离子，进料溶液中尿素的初始浓度范围为20 - 200 mmol dm⁻³。这表明两层膜之间的水膜使氨基甲酸根离子在进入阴离子交换膜之前完全分解为铵离子和碳酸根离子。因此，该装置可用于从进料溶液中去除尿素，同时防止铵离子从汽提溶液或水膜回流到进料溶液中。它在可穿戴或便携式人工肾的开发中具有巨大潜力。研究了固定有脲酶的PVA膜的性能。建立了描述尿素在膜反应器-分离器中传输-反应行为的动力学模型，并获得了反应器参数的最佳值。
