Reduction of organic wastewater by isopropyl alcohol/water separation technology using zeolite membrane

BackgroundIn the single-wafer wet cleaning process, a large amount of IPA mixed wastewater is discharged as organic wastewater. As semiconductor layer structures become more complex, organic wastewater is expected to increase further. The treatment of organic wastewater emits large amounts of CO2, placing a burden on the environment.AimWe are aiming to develop a system that separates IPA from IPA mixed wastewater and reuses it in the original cleaning process.ApproachWe examined the approach of separating IPA and water using a zeolite membrane. We prepared the IPA/water separation tool on a small scale and constructed a simulation model to match the experimental tool.ResultsUsing this experimental tool, we were able to concentrate IPA mixed water with an IPA concentration of 20 wt% to 99.6 wt%. Furthermore, simulation results could match the experimental results within a 3 wt% variation range.ConclusionsBy utilizing separation technology with zeolite membranes, water was removed from the IPA mixture and concentrated to a reclaimable level of IPA concentration. The simulation results also suggested the possibility of scaling up the results of this experiment.