【摘要】 在平推流光化学反应器中采用纳米TiO2光催化乙酰甲胺磷溶液,考察了多种因素对矿化效果的影响。研究结果表明:随着催化剂浓度的增加,乙酰甲胺磷矿化率逐渐升高,当催化剂质量浓度在0.4 g/L时,其矿化率达到最大值为91.36%,然而当催化剂浓度继续增加时,由于TiO2的屏蔽效应,矿化效率反而降低;由于催化剂表面吸附位点的限制,乙酰甲胺磷矿化率随其初始浓度的增加而降低,乙酰甲胺磷光催化矿化过程符合准一级反应动力学模型以及Langmuir-Hinshelwood模型,其相关参数k=1.05×10-5mol/(L·min)和K=7 638 L/mol。随着反应液pH值的增大,乙酰甲胺磷矿化率也随之升高,其原因是在反应液pH值升高,溶液中OH-浓度增加,OH-可以充当光致空穴的俘获剂,加强氧化效果;在较低流速时,光催化矿化率随着流速的增加而升高,然而流速进一步增加时,矿化率反而下降。流速增加既能够增加乙酰甲胺磷与催化剂之间的碰撞,也能增加催化剂微粒的聚集。更多还原

【Abstract】 The nanosized TiO2photocatalysis was used to mineralize acephate solution in a plug flow simulation reactor and the influence of the different factors on the mineralization efficiency were investigated. The results showed that the mineralization efficiency of acephate increases with elevated concentration of TiO2suspension. When the concentration of TiO2was up to 0.4 g/L, the mineralization rate reached the maximum(91.36%). When the concentration of TiO2was above0.4 g/L, the efficiency reduced slightly due to the shielding effect; the kinetic rate of acephate mineralization decreased with increasing initial concentration of acephate, which could be described using the first-order model. The Langmuir-Hinshelwood model was used to rationalize the mechanisms of reactions occurring on TiO2surfaces and the value of k and K of L-H model constants were: k = 1.05 × 10-5mol/(L·min) and K = 7 638 L/mol; the OH-concentration increased with the pH, which was considered as a acceptor to trap, which could inhibit the recombination of photogenerated hole and charges,thereby improving the acephate photocatalytic mineralization efficiency; inorganic ions was considered as a acceptor to trap photogenerated electrons, which could inhibit the recombination of photogenerated hole and electrons, thereby improving the glyphosate photocatalytic mineralization efficiency.更多还原