Treatment of local scrubber wastewater for semiconductor by using photo-catalytic ozonation

Abstract

This study investigates the oxidation of local scrubber wastewater (LSW) from semiconductor manufacture by using ozonation, catalytic ozonation (ozone/Al2O3 and ozone/TiO2–Al2O3), and photo-catalytic ozonation (UV/TiO2–Al2O3, ozone/UV and ozone/UV/TiO2–Al2O3). The results show that catalyst Al2O3 and TiO2–Al2O3 promotes the TOC removal under the condition of neutral or alkaline buffer solution during catalytic ozonation of LSW. The Al2O3 induces highest promotion in TOC removal efficiency, which is higher than ozone alone by 26% TOC removal under alkaline buffer solution. However, TiO2–Al2O3 and Al2O3 cannot display the promotion in TOC removal under acidic condition. In addition, a pre-treatment of anion ion-exchange is employed and the result indicates that decreasing the anion ions concentration before AOPs can imply higher TOC removal during AOPs of LSW. In this study, ozone/UV under raw LSW acidic condition and ozone/Al2O3 under alkaline buffer solution present 95% and 88% TOC removal rate respectively and show the higher TOC removal efficiency than other AOPs. Therefore, these two kinds of AOP can serve as the very viable AOP methods in the LSW reclamation for semiconductor.