Abstract: The combined UV/chlorine process, as a photochemistry process, was investigated to improve the removal efficiency of ammonia in drinking water. Based on a central composite design, the effects of Cl/N mass ratio, UV radiation time and pH value and their combination on the ammonia removal rate were evaluated. Based on a mathematical model established between them, and these technical parameters for the combined UV/chlorine process was optimized. The results showed that all of the three factors had significant impacts on ammonia removal and the combined influence of Cl/N mass ratio and UV radiation time was also outstanding. Furthermore, the prediction of a second-order regression model (R²=0.992) derived by response surface methodology was satisfactory. The conditions obtained by optimization to meet the standard of ammonia concentration in drinking water (0.5 mg·L^-1) were: Cl/N mass ratio 4.00,UV radiation time 6.00 min and pH value 7.5. The experimental value agreed with the predicted value with only 0.64% deviation. Finally, these results illustrated that combined UV/chlorine process was an effectively alternative method for ammonia-containing water treatments, with several advantages of low chemical consumption, high efficiency and easy operation.

Key words: photochemistry, optimization, mathematical modeling, combined UV/chlorine process, ammonia removal, central composite design

摘要： 基于响应面优化法，研究紫外/氯耦合处理饮用水中氨氮的效能。考察氯氮质量比、紫外辐射时间和pH值3个影响因素及其交互作用对氨氮去除的影响，采用二阶方程进行数学模拟，并优化工艺条件。结果表明，紫外/氯耦合技术能有效去除氨氮，三因素均对氨氮的去除影响显著，各因素的交互作用也显著存在。数学拟合模型的相关系数较高（R²=0.992），模型回归性好。满足饮用水氨氮出水要求（0.5 mg·L^-1）的最优工艺条件为：氯氮质量比4.00，紫外辐射时间6.00 min和pH值7.5。验证实验结果与预测值的偏差仅为0.64%，响应面拟合方程可用于氨氮去除率的预测和最优工艺条件的确定。紫外/氯耦合技术是一种新型的氨氮去除方法，具有投药量小、去除效率高、操作简单等优点。

关键词: 光化学, 优化, 数学模拟, 紫外/氯耦合, 氨氮去除, 中心复合设计