A photocatalytic degradation of Crystal Violet (CV) in aqueous solution was investigated in batch reactor. Box–Behnken experimental design was using to establish a quadratic model showing the functional relationship between degradation rate and four operational parameters: pollutant concentration, irradiation time, zinc oxide (ZnO) dose, and stirring speed, at free pH (~ 7), lamp irradiance (45 W m⁻²) and ambient temperature (~25°C). The results show that the most influential factor on the process was the CV concentration, with an effect of 48.27%, followed by the ZnO dose with an effect of 15.16%, at the third position comes the irradiation time with an effect of 11.81%, and the forth influencing parameter was the stirring speed with an effect of 1.04%. A total CV degradation (100%) was reached for ultraviolet (UV) irradiation time equal to 90 min, ZnO dose of 0.7 g L⁻¹, and stirring speed of 558 rpm for CV initial concentration of 55 mgL⁻¹. For CV concentration equal to 100 mg L⁻¹solar irradiation seems to be better up to 96% of degradation against 62% for UV lamp after 120 min of irradiation time. The O^•−₂ radicals were the main active species responsible for the degradation of CV. The degradation kinetic was well described by the pseudο first-οrder mοdel.

中文翻译：

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水溶液中结晶紫的光催化处理：Box-Behnken 优化和降解机制

在间歇反应器中研究了水溶液中结晶紫 (CV) 的光催化降解。Box-Behnken 实验设计用于建立二次模型，显示降解率与四个操作参数之间的函数关系：污染物浓度、辐照时间、氧化锌 (ZnO) 剂量和搅拌速度、游离 pH 值 (~7)、灯辐照度 (45 W m ^-2) 和环境温度 (~25°C)。结果表明，对该过程影响最大的因素是 CV 浓度，影响为 48.27%，其次是 ZnO 剂量，影响为 15.16%，排在第三位的是辐照时间，影响为 11.81%，第四个影响参数是搅拌速度，影响为1.04%。对于等于 90 分钟的紫外线 (UV) 照射时间、0.7 g L ^{-1 的}ZnO 剂量和 558 rpm 的搅拌速度，对于 55 mgL ^{-1 的}CV 初始浓度，达到了总 CV 降解（100%）。对于等于 100 mg L ^{-1 的}CV 浓度，在 120 分钟的辐照时间后，太阳辐射的降解率似乎高达 96%，而紫外线灯的降解率为 62%。O ^•− ₂自由基是导致 CV 降解的主要活性物质。伪一阶模型很好地描述了降解动力学。