异丙草胺光解体系中溶液酸度及电导率变化与降解的协同效应

采用自制光降解反应器研究了异丙草胺光解体系中溶液酸度及电导率的变化及与降解率的关系。结果表明,伴随光解进行,溶液的电导率和pH值同时产生有规律的变化。随着光照时间的延长,溶液电导率呈指数增加,到光解反应终了时,电导率增大近10倍,同时溶液电导率与溶液中异丙草胺的降解率亦呈指数对应关系。光解还造成溶液酸度增加,50mg·L-1异丙草胺溶液光照前后pH值由5.96降至3.35。根据对光解产物的分析,推测这两种数值的变化主要原因是异丙草胺的光解羟化脱氯。光解体系初始酸度的改变,对异丙草胺光解速率也有影响,酸度增大,明显抑制了异丙草胺的光解,而碱性环境加速了异丙草胺的光解。溶液酸度与光解进程具有良好的协同性。

Synergism Between Changes of Conductance and Acidity in Aqueous Solution and Process of Photodegradation of Herbicide Propisochlor

Photodegradation of new herbicide- propisochlor under UV irradiation was investigated in the present study. In process of photodegradation, both conductance and pH of solution changed regularly and simultaneously. During the photolysis, the conductance increased exponentially by nearly ten times at the end of the reaction. The acidity of propisochlor solution was gradually increased during the photolysis, and the pH of the solution varied from 5.96 to 3.35 in the whole reaction. The results indicated that the change of both pH and conductance was due to the photodechlorination of propisochlor. In acidic condition, the photolysis decreased, and in alkaline circumstance, it just reversed, according to the present study.