Production of Aldonic Acids by Bipolar Membrane Electrodialysis

Abstract

Conventional methods for the synthesis of aldonic acids are typically expensive and complex, generate contaminated water, and generally yield a low purity of the products. In this work, the bipolar membrane electrodialysis (BMED) process was used as an environmentally friendly and efficient method to produce aldonic acids (lactobionic acid and gluconic acid as examples). The influence of cell configuration and current efficiency was investigated. The BMED process was further evaluated on the basis of energy consumption and current efficiency. The experimental results show that the two studied cell configurations (two compartment cell configuration and multichamber cell configuration) were viable to increase the concentration of aldonic acids to a satisfactory level. The multichamber cell configuration stack, consisting of two cation exchange membranes in conjunction with a bipolar membrane, was found more suitable to produce gluconic acid due to lower energy consumption, higher current efficiency, and higher conversion rate. The process with a multichamber cell configuration could increase product conversion rate by about 3.5% and current efficiency by about 4.1% by comparing with the two compartment cell configuration at the same operation conditions, with a minor increase in the energy consumption of below 0.5%.