单偶氮染料AY17的光催化降解动力学及机制  

Photocatalytic Degradation Kinetics and Mechanism of Monoazo Dye Acid Yellow 17 by UV/TiO_2 in Aqueous Solution

作　　者：阳海[1,2] 魏宏庆[1] 胡乐天[1] 胡倩[1] 阳立平 刘华杰[1,2] 易翔[1] 易兵[1] 

机构地区：[1]湖南工程学院化学化工学院,生态纺织材料及染整新技术湖南省高校重点实验室,湘潭411104 [2]湘潭大学化工学院,湘潭411105 [3]深圳市环境科学研究院,深圳518001

出　　处：《环境科学》2016年第8期3086-3093,共8页Environmental Science

基　　金：湖南省自然科学基金项目(2015JJ3056);湖南省教育厅创新平台项目(14K030);国家自然科学基金项目(21207034)

摘　　要：为了研究水体环境中单偶氮染料酸性黄17(AY17)有效地去除方式及其可能的降解途径、转化和归趋等,实验首先探索了AY17在不同深度氧化体系中降解的可行性,研究发现其去除效率的大小按照UV/H_2O_2<UV/Na_2S_2O_8≈UV/FeSO_4·7H_2O<UV/KHSO_5<UV/TiO_2排列.然后选取UV/TiO_2体系,研究了催化剂用量,反应温度,底物浓度以及溶液初始p H值等因素对其光催化降解动力学的影响,结果表明AY17的光催化降解遵循假一级动力学,其降解速率常数为0.011 2 min^(-1);当催化剂TiO_2用量为3 g·L^(-1)时其降解效果最好;高温有利于AY17的光催化降解,而随着底物浓度和溶液初始p H值的升高,其降解速率常数显著下降.最后利用GC/MS对AY17光催化降解中间产物进行了初步鉴定,研究发现在·OH等活性氧物种的作用下偶氮键的断裂、羟基自由基对芳香环上基团的取代以及吡唑环的裂解是其主要降解途径.In order to explore the removal methods, transformation, environmental fate, effect and potential risk of dyes in environmental water,monoazo dye acid yellow 17（ AY17） was selected as model compound to investigate the degradation possibility in different advance oxidation processes（ AOPs）,and the degradation efficiencies followed the order of UV / H_2O_2 UV / Na_2S_2O_8≈UV/FeSO_4·7H_2O UV / KHSO_5 UV / TiO_2. Subsequently,the different parameters such as catalyst amounts,reaction temperature,substrate concentration and initial p H values affected the degradation rate significantly in the system of UV / TiO_2. The results indicated that the degradation of AY17 followed the pseudo-first-order kinetics,and the rate constant was 0. 011 2 min^（-1）. Additionally,the highest degradation rate constant was obtained when the catalyst dosage was 3 g·L^（-1）,higher reaction temperature was more beneficial to the degradation of AY17,and the degradation rate constants decreased with increasing substrate concentration and initial p H values.Lastly,the degradation intermediates were also identified by GC / MS,and the degradation pathways were also proposed at the initial stage of photocatalytic process,including the breakage of azo bonds,groups substitution of ·OH on aromatic ring and cleavage of pyrazol ring.

关 键 词：酸性黄17(AY17) 光催化 活性氧物种 动力学 降解机制 

分 类 号：X131[环境科学与工程—环境科学]