Advanced treatment of coal gasification wastewater by catalytic ozonation with supported molecular sieves

For advanced treatment of the refractory coal gasification wastewater,six kinds of molecular sieves with different Si and Al ratios were selected as the carriers,on which basis,six kinds of Cu/Co supported catalysts were prepared correspondingly.The treatment effect of catalytic ozonation on coal gasification wastewater (prepared solution) was carried out,and the reaction mechanism was deeply discussed.The results of real-wastewater treatment show that the catalytic oxidation efficiency of the catalyst after loading can be improved,the max increment can be about 14 times,and the COD removals of the ZSM-5 and SAPO-34 loads are both up to 70%.Further studies have shown that the main catalytic oxidation reaction sites of the catalyst after loading mainly exist on its particle surface,while there are many reaction sites remaining in the bulk solution after the load of ZSM-5,which promotes the interactive probability with the organic matter of the solution,thus improves the mass transfer efficiency.The β catalyst possesses the best surface adsorption ability,which can be as high as 24% of COD sorption rate.Overall,the experimental results show that the distribution of the ozone catalytic reaction sites and the ratio of silicon and aluminum content have important effects on the catalytic performance of the catalyst，however，although the surface adsorption performance contributes a lot to the pollutants removal,it enhances little to the catalytic abilities.