二氧化钛平推流反应器光催化矿化草甘膦研究

PHOTOCATALYTIC MINERALIZATION OF GLYPHOSATE IN A PLUG FLOW SIMULATION REACTOR BY NANOSIZED TiO_2

在平推流光化学反应器中采用纳米TiO2光催化矿化N-(膦酰基甲基)甘氨酸(草甘膦)溶液,考察了多种因素对矿化效果的影响。结果表明,在碱性溶液中,OH-可以充当光致空穴的俘获剂,从而提高了草甘膦的光催化矿化效率;外加氧化剂可以作为电子的接受体,通过接受光生电子来抑制光生电子与光生空穴的复合,提高光催化反应的量子产率,从而促进草甘膦的光催化矿化;升高温度可促进具有强氧化性自由基的生成,同时也可抑制光生电子和光生空穴的复合,促进草甘膦在催化剂表面的矿化;外加有机物可与草甘膦共同竞争催化剂表面的活性位点,从而阻碍了草甘膦在催化剂表面的矿化;在一定范围内,光催化矿化率随无机离子浓度的增加而升高,但当无机离子的质量浓度>4 mg/L时,矿化率下降。

The nanosized TiO2photocatalysis was used to mineralize glyphosate solution in a plug flow simulation reactor and the influence of the different factors on the mineralization efficiency were investigated.The results show that in alkaline solution,OH-was considered as an acceptor to trap,which could improve the glyphosate photocatalytic mineralization efficiency.Adscititious oxidants were considered as an acceptor to trap photogenerated electrons,which could inhibit the recombination of photogenerated holes and charges,thereby improves the glyphosate photocatalytic mineralization efficiency.Rising the temperature can promote the generation of strong oxidizing free radical,which also could enhance the glyphosate mineralization efficiency by inhibiting the recombination of photoproduced holes and electrons.The presence of adscititious organic compounds can inhibit photocatalytic reaction due to its competition with glyphosate for the reactive sites.At some extend,the photocatalytic mineralization rate of glyphosate increased with raising the inorganic ions concentrations.However,the mineralization rate reduces slightly when the inorganic ions concentrations above 4 mg/L.