铁、铝催化过氧化氢氧化有机物特征

Characteristics of organic matters during hydrogen peroxide oxidation catalyzed by iron or aluminum

氧化作为水处理常用的方法,对水质和水处理过程影响深远,因而备受关注.运用三维荧光光谱和紫外差异分析等技术研究过氧化氢单独氧化、铝催化过氧化氢氧化、铁催化过氧化氢氧化对水体有机物的作用;并分析其对溶解性有机物(DOM)的结构和形成消毒副产物潜能的影响.结果表明,铁、铝明显催化过氧化氢对有机物的氧化过程,且铁催化能力明显强于铝.当催化剂投量均为0.018 mmol·L^(-1),过氧化氢投加量3.5 mg·L^(-1)时,UV254和TOC值的去除率分别是铁催化35.5%、36.4%和铝催化5.0%、29.3%,而单独氧化仅为14.0%、16.7%.利用三维荧光光谱和紫外差异吸收值去卷积分可以明显检测出上述3种氧化对有机物结构影响的差异.催化氧化不改变荧光峰位置,但不同程度地削弱了各荧光峰强度和区域荧光积分值.其中,铁催化对于类蛋白区、可见光区类富里酸和紫外区类富里酸降解程度较高.由紫外差异去卷积分得到,3种体系对水体有机物紫外结构破坏位点在272 nm处是一致的,但破坏程度不同.如3.5 mg·L^(-1)H2O2、0.018 mmol·L^(-1)催化剂投量时,紫外吸收差异值ΔA272/A272分别为单独氧化7.0%,铝催化8.3%,铁催化18.9%.催化氧化对有机物紫外结构铝催化特征位点为λ339 nm、λ364 nm;铁催化特征位点为λ319 nm、λ425 nm.铝、铁离子催化氧化均提高了三卤甲烷的去除率,铝催化去除率优于铁催化.

Oxidation,as a commonly used water treatment method,has a profound impact on water quality and water treatment,and it draws close attention. Effects of oxidation by hydrogen peroxide,hydrogen peroxide oxidation catalyzed by iron and oxidation catalyzed by aluminum on aquatic organic matter（ AOM） were studied by using three-dimensional fluorescence and ultraviolet differential absorbance methods. Influence of the above oxidation reactions on the structure and disinfection by-products formation potential of dissolved organic matter（ DOM） was analyzed.Results showed that iron and aluminum significantly catalyzed the oxidation of organic matter by hydrogen peroxide,and the catalytic ability of iron was stronger than that of aluminum. When the dosages of catalyst and H2 O2 were 0.018 mmol·L-1 and 3.5 mg·L-1 respectively,the removal rates of UV254 and TOC were 35.5%,36.4% respectively for iron catalysis and 5.0%,29.3% for aluminum catalysis,while only 14. 0%, 16. 7% for oxidation by hydrogen peroxide. Three-dimensional fluorescence spectroscopy and UV differential absorbance deconvolution integral were used to detect the differences of the three oxidation rveactions for the structure of organic matter. Catalytic oxidation had no effect on the position of the fluorescence peak,while the intensity of fluorescence peak and the integral value of regional fluorescence were weakened to some extent. Among them,iron catalysis had higher degree of degradation for the protein-like region,fulvic-like acid of visible region and fulvic-like acid of ultraviolet region. According to the UV differential deconvolution,it can be obtained that sites damaged by three systems were consistent for organic matter in water at 272 nm,but the degree of damage was different. For example,while the doses of catalyst and H2 O2 were0.018 mmol·L-1,and 3.5 mg·L-1 respectively,the difference in UV absorbance ΔA272/A272 was7.0% for oxidation by hydrogen peroxide,8.3% for aluminum catalysis and 18.9% for iron catalysis,respectively. In addition,aluminum catalytic characteristic locations were 339 nm and 364 nm. Iron catalytic characteristic locations were 319 nm and 425 nm. The removal rate of trihalomethane was increased by iron and aluminum catalysis oxidation,and the removal rate of aluminum catalysis was better than that of iron catalysis.