Dye Wastewater Treatment By Catalytic Ozonation Using Ti-Ce Composite As Catalyst

Recently, development of dyeing and printing industries make water quality of dyeing wastewater more complicated. So it is important to develop more efficient treatment methods for dyeing wastewater treatment. Dyeing wastewater is characterized by large amount of discharge, high colourity, complicated component, high organic content and poor biodegradability and has potential carcinogenicity to human and aquatic creatures. Compared with other traditional processes, catalytic ozonation has been concerned recently due to its strong oxidation and mineralization ability on dyeing wastewater. In this paper, Ti-Ce composite catalysts were prepared by sol-gel method. The catalysts were evaluated by treatment of acid orange II and rhodamine B in water to study their catalytic activities on decoloration and mineralization of dyes wastewater.The Ti-Ce composite catalysts were synthesized by sol-gel method. Different kinds of catalyst by means of changing the Ti-Ce ratio and sintered temperature were prepared.The structures and morphology characteristics of Ti-Ce composite catalyst were characterized with transmission electron microscopy (TEM), X-Ray diffraction (XRD), BET surface areas measurement and zeta potential analysis. The catalyst compositions were different with different Ti-Ce ratios and sintered temperature from analyzing XRD patterns of catalysts, Transmission electron microscope (TEM) image showed that catalyst particle sizes were variety and no consistent morphology, BET surface areas demonstrated the specific surface areas decreased with increased temperature.The catalytic ozonation of acid orange II and rhodamine B were studied in ozone reactor with Ti-Ce composite catalysts under different reaction conditions. A shortened time on decoloration and a high improvement in mineralization efficiency were gained when Ti-Ce composite catalysts employed comparing with single ozonation. The order of catalytic activities in catalytic ozonation of acid orange Ⅱ followed: Ti-Ce1/0.8>Ti-Ce1/0.6>Ti-Cel/0.2>single ozonation. The optimal atomic ratio of Ti and Ce was1to0.8, the highest decoloring efficiency and TOC removal rate were97.0%and96.3%respectively after10minutes and2hours catalytic ozonation reaction. When catalytic ozonation of rhodamine B, the catalyst had a highest TOC removal rate after1hour’s reaction when the ratio of Ti to Ce was1to0.6and sintered temperature was550℃. The mineralization rate of orange Ⅱ and rhodamine B were remarkablely inhibited by the TBA addition. Therefore, it can be concluded that the Ti-Ce composite catalyst addition promoted ozone decomposing to hydroxyl radicals.After catalytic ozonation, the metallic ion leaching concentration was rather low indicated that Ti-Ce composite catalyst had a good stability.