Investigation on Titanium Silicalite ETS‐4 Catalyzed Ozonation for Chemicals in Wastewater, Exemplified With 4‐Chlorophenol. Issue 12 (27th September 2016) - Chen, Chunmao
Abstract : The parent titanium silicalite ETS‐4 (pETS‐4) and alkali‐modified ETS‐4 (BETS‐4) catalysts were utilized for catalytic ozonation of chemicals in wastewater as exemplified with 4‐chlorophenol (4‐CP). NaOH treatment resulted in more TiO and TiOTi structure exposures and Ti surface enrichment on ETS‐4. The ozonation catalyzed by BETS‐4 catalysts showed better catalytic performance compared with pETS‐4 and single ozonation, which is probably due to increased Ti distribution on the surface of the catalysts. NaOH (0.3 mol/L) modified ETS‐4 (B0.3 ETS‐4) offered the highest chemical oxygen demand (COD) removal rate (89.2%) in catalyzed ozonation of 4‐CP solution. A negligible change of COD removal rate, surface morphology, and elemental composition were observed for five repeated cycles of B0.3 ETS‐4, indicating good reusability, and stability of B0.3 ETS‐4 in catalytic ozonation. B0.3 ETS‐4 catalyzed ozonation followed a molecular ozone oxidation mechanism rather than OH mediated oxidation. B0.3 ETS‐4 provided a platform to adsorb and activate 4‐CP and/or ozone molecules to accelerate reactions between them. This study demonstrated that ETS‐4 is a potentially efficient catalyst for ozonation of recalcitrant organic contaminants in wastewater. Abstract : There is great interest in developing an efficient catalytic ozonation process (COP) for wastewater treatment. Here, titanium silicalite ETS‐4 catalysts are utilized for catalytic ozonation of 4‐chlorophenol in water. The COP catalyzed by alkali‐modified ETS‐4 (BETS‐4) catalysts shows better catalytic performance in comparison with the single ozonation process. BETS‐4 is a potentially efficient catalyst for ozonation of recalcitrant organic contaminants in wastewater.