Graphene Oxide–Polyaniline as a Water Dissociation Catalyst in the Interfacial Layer of Bipolar Membrane for Energy-Saving Production of Carboxylic Acids from Carboxylates by Electrodialysis

Abstract

Bipolar membrane (BPM) was prepared by layer-by-layer casting of the cation-exchange layer (CEL; sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO), interfacial layer (IL), and anion-exchange layer (AEL; quaternized PPO) in the same solvent to achieve good adhesion. Graphene oxide-polyaniline composite (GO-PANI) was introduced in the IL of BPM as water dissociation (WD) catalyst. Under applied reverse bias, water molecules in the IL zone dissociate and generate H+ and OH– useful electrosynthesis by BPM electrodialysis (BPMED). Prepared BPM was assessed by current–voltage (i–V) curves and performance of BPMED for converting homologues carboxylates into their corresponding acid and base. Under the operating conditions in BPMED, 71–63% recovery of the different carboxylic acids was recorded with 92–97% CE and 0.90–0.98 kWh kg–1 energy consumption. Negligible co-ion leakage across the BPM also revealed its efficient nature and product (carboxylic acid) purity. Additionally, low and stable Vdiss (0.77−1....