A feasibility study on the multistage process for the oxalic acid pretreatment of a lignocellulosic biomass using electrodialysis

The present study investigated the feasibility of the recovery and reuse oxalic acid in a multistage process for the pretreatment of a lignocellulosic biomass. Electrodialysis (ED), an electrochemical process using ion exchange membranes, was used to recover and reuse oxalic acid in the multistage process. The ED optimal condition for recover oxalic acid was potential of 10 V and pH 2.2 in synthetic solutions. The recovery efficiency of oxalic acid from hydrolysates reached 100% at potential of 10 V. The power consumption to treat 1 mol of oxalic acid was estimated to be 41.0 wh. At the same time, ethanol production increased up to 19 g/L in the ED-treated hydrolysate, corresponding to ethanol productivity of 0.27 g/L/h. It was clearly shown that bioethanol fermentation efficiency increased using the ED process, due to a small loss of fermentable sugar and a significantly high removal of inhibitory chemicals.