Bipolar membrane electrodialysis for clean production of L‐10‐camphorsulfonic acid: From laboratory to industrialization

Abstract In this study, bipolar membrane electrodialysis (BMED) was implemented for cleaner production of L ‐10‐camphorsulfonic acid ( L ‐CSA) to lower the environmental impact. Under the current density of 300–400 A/m 2 and feed salt concentration of 6–10 wt.%, the energy consumption and current efficiency were 2.24–2.70 kWh/kg and 20.89–29.5%, respectively. Positron annihilation lifetime spectroscopy, x‐ray photoelectron spectroscopy with ion beam etching, and other characterizations were used to elucidate the transport behaviors of large‐sized anions across the membranes. It was speculated that the large‐sized camphor sulfonate ions were more likely to deposit on the surface of the anion‐exchange membrane to form a deposition layer under a direct current electric field. The appearance of water splitting at this deposition layer would offset the water dissociation in the bipolar membrane. Nevertheless, the successful commissioning of industrial‐scale stack proved the feasibility and sustainability of BMED technique for a closed loop L ‐CSA production.