A pioneering study on EDOT recovery from the PEDOT wastewater: Integration of COSMO-SAC prediction, experiment, and process simulation

3,4-ethylenedioxythiophene (EDOT) is a significant material in the electronics industry for synthesizing Poly (3,4-ethylenedioxythiophene) (PEDOT). However, a significant amount of EDOT (>50%) is discarded in wastewater during the electrochemical polymerization of PEDOT owing to the low conversion of EDOT. To address this issue, a process for recovering EDOT through extraction and subsequent distillation was presented. Toluene was chosen as the extractant through a combination of COSMO-SAC and experiments, and the extraction mechanism was analyzed by quantum chemistry calculation. Next, the liquid-liquid equilibrium (LLE) data for the quaternary system of water, ethanol, toluene, and EDOT were obtained and fitted with the NRTL model. Furthermore, the recovery process was simulated and optimized. The results indicate that the recovery ratio of EDOT is higher than 99.8%, and the profit of per ton wastewater is 5756.97 CNY. The proposed process shows great potential for industrial application and cleaner production.