紫外/过—硫酸盐工艺对水中除草剂Isoproturon的降解特性

Degradation Characteristics of Aqueous Herbicide—Isoproturon by Ultraviolet/Peroxymonosulfate Process

探究了典型苯脲类除草剂异丙隆(Isoproturon,ISO)在紫外/过一硫酸盐(Ultraviolet/Peroxymonosulfate,UV/PMS)组合工艺下的降解特性。系统研究了在不同PMS浓度、UV强度、pH及不同常见水体背景离子(Cl^(-)、HCO_(3)^(-)、NH_(4)^(+)和SO_(4)^(2-))浓度下对该过程中ISO降解效果的影响并探讨了相关内在作用机制。结果表明,ISO的去除效率为:UV/PMS>>UV>PMS。PMS是一种不对称的氧化剂,可被UV激活产生强氧化性自由基(SO_(4)^(·-)和HO^(·))从而可显著提高ISO的去除速率至80.09%,其降解符合拟一级动力学模型。PMS投加量和pH(5~9)的增加,大大加快了ISO的去除。背景离子实验表明,SO_(4)^(2-)对UV/PMS中的ISO降解无显著影响,而Cl^(-)和NH_(4)^(+)则均会产生抑制效应;HCO_(3)^(-)的存在则促进了ISO的降解。基于电力和化学品的总成本,通过单位电能消耗量(EE/O)来估计整个UV/PMS组合工艺的成本效益,从而为水处理中ISO去除时本工艺的相关成本效益及实际应用提供理论依据和数据参考。

For the degradation characteristics of Isoproturon(ISO),a typical phenylurea herbicide was investigated under the Ultraviolet/Peroxymonosulfate(UV/PMS)process.The effects of different PMS concentrations,UV intensity,solution pH,and common water background ions(Cl-,HCO_(3)-,NH_(4)^(+),and SO_(4)^(2-))on the degradation of ISO were systematically studied,and the relevant internal mechanisms were discussed in this process.The results showed the removal efficiency of ISO in the process in the order of UV/PMS>>UV>PMS.The PMS is an asymmetric oxidant,which can be activated to produce strong oxidizing free radicals(SO_(4)^(·-)and HO^(·))to improve the removal rate of ISO to 80.09%,and its degradation conforms to the pseudo first-order kinetic model.The increase in PMS dosage and pH value(5~9)significantly accelerated the removal of ISO.The inorganic anion experiments showed that the SO_(4)^(·-)had no significant effect on the degradation of ISO in the UV/PMS system,while Cl^(−)and NH_(4)^(+)can produce an inhibitory effect.The presence of HCO_(3)^(-)promoted the degradation of ISO.Based on the total cost of electricity and chemicals,the costeffectiveness of the UV/PMS process was estimated through the unit electric energy consumption(EE/O).It provides a theoretical basis and data reference for the relevant cost-effectiveness and practical application of the water treatment process.