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负载型分子筛催化臭氧氧化深度处理煤气化废水效果研究

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

  • 摘要: 针对难降解煤气化废水的深度处理,选择6种不同硅铝比的分子筛作为载体,对应制备了6种Cu/Co负载型催化剂,对其开展了催化臭氧氧化深度处理煤气化废水的效果研究,并对催化剂反应机制进行了深入探讨。试验结果表明,负载后催化剂的臭氧催化氧化效率皆有提高,最高可提升14倍左右,其中ZSM-5和SAPO-34负载的COD去除率可达70%以上;进一步研究证明,负载后催化剂的催化氧化反应点位主要存在其颗粒表面,但ZSM-5负载后有相当部分点位存在本体溶液,促进了与溶液有机物的接触概率,从而提高了传质;β型分子筛具有最高的表面吸附性能,对COD的吸附可达24%;臭氧催化反应点位分布和硅铝比对催化剂的臭氧催化性能具有较大影响,催化剂表面吸附性能对有机物去除贡献较大,但对臭氧催化活性的提升较弱。

     

    Abstract: 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.

     

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