Ce-MCM-41分子筛催化臭氧氧化水中腐殖酸

Mineralization of Humic Acid in Water by catalytic ozonation with Ce-MCM-41

  • 摘要: 采用水热法合成铈掺杂MCM-41(Ce-MCM-41)介孔分子筛,并将其用于臭氧氧化水中腐殖酸.本文研究了催化剂投加量、铈掺杂量、反应温度和初始pH对腐殖酸降解及矿化的影响. 结果表明,腐殖酸在Ce-MCM-41/O3体系内可实现有效降解. 与单独臭氧氧化相比,Ce-MCM-41催化剂的加入可提高臭氧氧化腐殖酸的矿化效果. 催化剂投加量为100 mg/L时,催化剂具有较好的催化活性,反应60min,DOC去除率为70.58%(Si/Ce=80);三种铈掺杂量催化剂的添加均能提高腐殖酸矿化效果. 在278 ~308 K实验范围内,腐殖酸溶液的DOC去除率和UV254去除率均随反应温度升高而提高.溶液初始pH为6.0~8.5时,DOC去除率随碱性增强而略微下降. 表明温度和溶液初始pH影响催化臭氧氧化去除腐殖酸的效果. 此外,还考察了添加Ce-MCM-41对含溴水臭氧氧化过程中溴酸盐生成的影响,与单独臭氧相比,1.00 g Ce-MCM-41分子筛的加入减少了46.94%溴酸盐生成. 结果表明添加Ce-MCM-41分子筛可抑制溴酸盐的生成. 因此Ce-MCM-41分子筛可用于提高臭氧氧化腐殖酸效果和减少含溴水臭氧氧化过程中溴酸盐的生成.

     

    Abstract: Ce-MCM-41 was directly synthesized by a hydrothermal method and applied as a heterogeneous catalyst for ozonation of humic acid (HA) in aqueous solution. The influences of different factors on removal and mineralization of humic acid were investigated , such as catalyst dosage, cerium doped content , temperature and initial pH. The results showed that humic acid could be efficiently degraded in Ce-MCM-41/O3 system. Compared with ozonation alone, Ce-MCM-41can enhance the mineralization of HA. As the catalyst dosage was 100 mg/L, the catalyst have good activity for ozonation of HA and DOC removal was 70.58%(Si/Ce=80) after 60min reaction. The addition of three cerium doped content of the catalysts were good for mineralization of HA. And DOC removal and reduction of UV254 were increased with reaction temperature in the range of 288 K308 K. As the range of initial pH was6.08.5, DOC removal was slightly decreased with the increase of initial pH of HA solution. It showed that temperature and initial pH of HA solution had an impact on the removal of HA. Additionally, the effects of Ce-MCM-41 on bromate formation in bromide-containing water were also investigated, compared with ozonation alone, and adding 1.00g Ce-MCM-41 contribute to reducing 46.94% bromate. The results implied that the bromate formation was effectively inhibited with Ce-MCM-41.Ce-MCM-41 was benefited to improve the efficiency of ozonation of HA and reduction of bromate formation during ozonation of bromide-containing water.

     

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