UV/H_2O_2降解水中痕量NDMA的效能研究

采用UV/H2O2降解水中的痕量NDMA,考察了水中NDMA初始浓度、H2O2投量、pH、天然有机物及常见阴离子等因素的影响,并分析了NDMA的降解产物。结果表明,在UV辐照度为1 000μW/cm2、NDMA初始浓度为0.1 mmol/L、H2O2投量为20 mg/L、pH值为4的条件下,UV/H2O2对NDMA的降解效果较好(反应5 min后对NDMA的去除率接近100%);水中的天然有机物和Cl-、SO42-、NO3-、HCO3-等阴离子对NDMA的降解均有抑制作用,腐殖酸浓度越大其抑制作用越强,阴离子的抑制作用由大到小依次为HCO3-、NO3-、SO24-、Cl-;NDMA的主要降解产物为二甲胺和硝酸盐,此外还有少量亚硝酸盐、甲酸盐和甲胺生成。

Study on Photodegradation of NDMA Using UV/H_2O_2 Process

The photodegradation of nitrosodimethylamine (NDMA) by UV/H_2O_2 was investigated by analyzing the effect of initial concentration of NDMA, concentration of H_2O_2, solution pH, NOM and some anions in natural water on both NDMA photolysis and photodegradation products.The results show that the photodegradation efficiency is optimal when the radiant intensity of UV is 1 000 μW/cm~2, the in-itial concentration of NDMA is 0.1 mmol/L, the concentration of H_2O_2 is 20 mg/L, and the initial pH of reaction solution is 4.Under these conditions, the removal rate of NDMA is near 100% within 5 mi-nutes.The photodegradation reaction of NDMA is suppressed by NOM and some anions such as Cl~-, SO_4~2- , NO_3~- and HCO_3~-.While the concentration of humie acid is higher, the influence is greater.The influence of anions is HCO_3~- > NO_3~- > SO_4~(2-)> Cl~-.The primary products of NDMA degradation are ni-trate and dimethylamine (DMA), and the minor products are nitrite, formate and methylamine (MA).