壬基酚聚氧乙烯醚在水溶液中的光降解行为研究

采用模拟日光灯和长波紫外灯（UVA-365nm）2种光源,对水溶液中壬基酚聚氧乙烯醚（NPEOs）的光降解动力学、降解过程中NPEO同系物成分的变化、以及氧化剂过氧化氢的加入对光降解的影响进行了研究,并采用LC-MS对光降解的产物进行了分析.研究表明,实验周期内NPEOs在模拟日光和长波紫外光下均发生不同程度的光降解,降解速率常数分别为6.20×10^-3　μmol/(L·h)和1.18×10^-2　μmol/(L·h).在模拟日光下,在NPEOs降解过程中观察到短链的NPEO_1,3分布比例的增加,而在长波紫外光下的降解过程中并没有发现NPEO成分分布的变化.过氧化氢的加入对NPEOs的光降解具有明显的促进作用,特别是在模拟日光下,0.01 mmol/L和1.00 mmol/L H₂O₂的加入使NPEOs的96h降解率由20.9%分别提高至44.4%和91.5%.通过LC-MS分析,初步认为壬基酚三乙氧基乙酸的烷基氧化产物(CA_3～9PEC₃)是溶液中NPEOs光降解的主要产物,并据此推断了可能的反应历程.

Photodegradation of Nonylphenol Polyethoxylates in Aqueous Solution

Two lamps, including simulated sunlight lamp and UVA-365 nm lamp, were used to study the kinetics and changes of component distribution of NPEOs mixture in solution during photodegradation, as well as the effect of H2O2 on the photodegradation. LC-MS was used to analyze the products of NPEOs photodegradation. It was found that photodegradation of NPEOs occurred under both simulated sunlight and UVA irradiation, with the degradation rate being 6.20 x 10(-3) micromol/(L x h) and 1.18 x 10(-2) micromol/(L x h), respectively. The component distribution of short chain NPEO(1,3) increased during the photodegradation process under simulated sunlight, while no obvious change was observed under UVA irradiation. The presence of the oxidant, H2O2, was found to be propitious to the photodegradation of NPEOs, especially under the irradiation of simulated sunlight. At different added concentrations of H2O2, the 96 h degradation percentage of NPEOs increased from 20.9% (non-H2O2) to 44.4% (0.01 mmol/L H2O2) and even 91.5% (1.00 mmol/L H2O2), respectively. The analysis for degradation products using LC-MS suggested that CA(3-9)PEC3 might he the major photodegradation products of NPEOs, based on which the reaction mechanism of NPEOs photodegradation was speculated.