Production of Tetramethyl Ammonium Hydroxide Using Bipolar Membrane Electrodialysis

To produce tetramethyl ammonium hydroxide (TMAH) at lower energy consumption and with less environmental pollution, a bipolar membrane electrodialysis (BMED) of A-BP configuration (A, anion exchange membrane; BP, bipolar membrane) was adopted to electro-alkalize tetramethyl ammonium chloride. The results for one-unit BMED stack indicate that current efficiency increases and energy consumption decreases as feed concentration increases or current density decreases. The highest current efficiency can reach 99.9%, and the lowest energy consumption is 1.43 kWh kg−1. On the basis of a 3-unit BMED, the process cost is estimated to be 0.33 $ kg−1 of TMAH. This method is not only environmentally friendly but also cost-effective.