研究了邻苯二甲酸二甲酯(DMP)的光催化降解过程,探讨邻苯二甲酸酯类物质的光催化降解行为和降解机理。分别用高效液相(HPLC)和TOC测定仪检测不同降解时间段水样的邻苯二甲酸二甲酯浓度和矿化率。结果表明:当DMP初始浓度为20 mg/L,催化剂用量为70 mg/L,光催化反应140 min时DMP降解率和矿化率分别达到95.1%和62.5%,反应60 min内体系pH值不断减小,之后基本维持不变,同时通过液相色谱串联电喷雾质谱(LC/MS)检测到DMP光催化反应中产生了1,2-二甲氧羰基苯酚(1,2-dimetoxycarbonyl phenol)、7-甲酰基-2,4-庚二烯酸甲酯(7-formoxyl-2,4-hep-tadien acid methyl ester)和7-羟基-2,4-庚二烯酸甲酯(7-hydroxy-2,4-heptadien acid methyl ester)等中间产物,由此推测DMP的降解可能从苯环上的碳链断裂开始,中间生成酯类化合物,最后矿化成水和二氧化碳。
The photocatalytic process of dimethyl phthalate(DMP) was investigated to discuss the degradation behavior and mechanisms of DMP.The concentration and mineralization rate of DMP were detected by the HPLC and TOC analyzer,respectively.The result showed that the efficiency of degradation and mineralization within 140 minutes were 95.1% and 62.5%,respectively,under the conditions of DMP initial concentration 20 mg/L and catalyst dosage 70 mg/L.The pH value in aqueous solution declined gradually in incipient 60 minutes,and then remained stable.Additionally,according to liquid chromatography/mass spectrometry(LC/MS) identification,the major intermediates of DMP included 1,2-dimetoxycarbonyl phenol,7-formoxyl-2,4-heptadien acid methyl ester and 7-hydroxy-2,4-heptadien acid methyl ester,the degradation of DMP was mainly started from the chain scission of benzene ring,and then the intermediates transformed to esters molecules which were finally mineralized to water and carbon dioxide.