小分子有机醇强化过硫酸盐氧化水中二苯甲酮⁃3的研究

Anhydrous alcohols enhanced peroxydisulfate oxidation of Benzophenone⁃3 in aqueous solution

探究了小分子有机醇对过二硫酸盐(Peroxydisulfate,PDS)氧化降解二苯甲酮⁃3(Benzophenone⁃3,BP⁃3)的强化作用及反应机制.研究结果表明,4种有机醇(甲醇、丙醇、乙二醇和丙三醇)均在一定浓度范围内能有效促进过硫酸盐氧化降解BP⁃3,BP⁃3的降解速率随醇类分子碳链长度和羟基数目的增加而增加,增强效果依次为丙三醇>乙二醇>丙醇>甲醇.在低添加量时(21.9~350μmol·L^(-1)),有机醇的添加增加了BP⁃3降解速率,但随着醇量的增加呈现出先增大后减小的趋势,例如丙三醇添加量从21.9μmol·L^(-1)增加到87.6μmol·L^(-1),BP⁃3降解动力学常数从2.91×10^(-4) s^(-1)提高到3.58×10^(-4) s^(-1),增加了0.23倍;但加入过多的醇却抑制了BP⁃3的降解,例如丙三醇添加量从87.6μmol·L^(-1)进一步增加到350μmol·L^(-1),BP⁃3降解速率降低29.0%(2.54×10^(-4) s^(-1)).反应温度也能有效促进醇的强化作用,温度从40℃升至60℃,添加丙三醇87.6μmol·L^(-1),BP⁃3的降解速率常数从6.84×10^(-6) s^(-1)提高至6.69×10^(-4) s^(-1),提高了96.8倍.小分子有机醇主要是通过与·OH反应产生醇自由基,进一步激活过硫酸盐产生SO·_(4)^(-),显著增加了SO·_(4)^(-)的产率,从而加速过硫酸盐降解BP⁃3的效率.

This paper explored the machanism of peroxydisulfate(PDS)oxidation of benzophenone⁃3(BP⁃3)promoted by small molecule organic alcohols.The results indicated that all four organic alcohols(methanol,propanol,ethylene glycol and glycerol),within a certain concentration range,effectively promoted PDS degradation of BP⁃3.The enhanced degradation rate of BP⁃3 varied with the chain length and the number of hydroxyl groups in the alcohols molecules,in the order of glycerol>ethylene glycol>propanol>methanol.At low dosages(21.9~350μmol·L^(-1)),the addition of organic alcohols increased the degradation rate of BP⁃3.But further increase of alcohol dosage resulted in a decrease of the degradation rate.Specifically,with the addition of glycerol increased from 21.9μmol·L^(-1) to 87.6μmol·L^(-1),the degradation kinetic constant of BP⁃3 increased 0.23 times from 2.91×10^(-4) s^(-1) to 3.58×10^(-4) s^(-1).However,too much addition of alcohol inhibited the degradation of BP⁃3.For example,further increased glycerol from 87.6μmol·L^(-1) to 350μmol·L^(-1),the degradation rate of BP⁃3 was reduced by 29.0%(2.54×10^(-4) s^(-1)).The reaction temperature also influenced reaction rate,and when temperature was increased from 40℃to 60℃,with 87.6μmol·L^(-1) glycerol addition,the degradation rate constant of BP⁃3 was increased by 96.8 times from 6.84×10^(-6) s^(-1) to 6.69×10^(-4) s^(-1).Small molecular organic alcohols mainly generated alcohol free radicals by reacting with·OH,which further activated persulfate to produce SO·_(4)^(-),and significantly increased the yield of SO·_(4)^(-),thereby accelerating the efficiency of the PDS degradation of BP⁃3.