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Study of visible-light photocatalytic degradation of 2,4-dichlorophenoxy acetic acid in batch and circulated-mode photoreactors.
Journal of Environmental Health Science and Engineering ( IF 3.4 ) Pub Date : 2019-03-13 , DOI: 10.1007/s40201-019-00343-4
Sorur Safa 1 , Majid Mirzaei 2 , Foad Kazemi 3 , Mohammad Taghi Ghaneian 4 , Babak Kaboudin 3
Affiliation  

Purpose

The consumption of pesticides and chemical fertilizers is one of the major environmental and health problems. In this report, 2,4-dichlorophenoxyacetic acid (2,4-D) was chosen to evaluate the impact of photodegradation using LED (Light-emitting diode) (400 and 365 nm) sources in batch and programmable circulated-mode photoreactors respectively.

Methods

A β-cyclodextrin (β-CD) grafted titanium dioxide P25 (P25/β-CD) and complexation of 2,4-D and β-CD were synthesized via photoinduced and spray-drying methods, respectively. The structures were characterized. Moreover, we investigated the effects of the amount of catalyst, the β-CD amount on bed catalyst, irradiation time, kind of photoreactor on the photocatalytic degradation efficiency.

Results

Based on the results of experiments in batch reactor, the optimum amount of TiO2, β-CD grafted by catalyst were 1 and 0.1 g/L, respectively. In batch-mode the photodegradation efficiency of 2,4-D after 5 h with P25, P25/β-CD as a photocatalyst and 2,4-D/β-CD complex with P25 photocatalyst were approximately 81, 85 and 95% respectively. After 8 h of irradiation in circulated-mode reactor, degradation yields with P25, P25/β-CD and 2,4-D/β-CD complex along with P25 were 89, 91 and 96% respectively. On the other hand, the circulated-mode photoreactor with high efficiency was appropriate to degradation of the high concentration of 2,4-D solution (200 mg/L). After 5 successive cycles with 25 h of irradiation, P25 and P25/β-CD maintained as high 2,4-D removal efficiency as 82.6, 84% respectively, with excellent stability and reusability.

Conclusion

The photodegradation method can be used as an effective and environmental friendly process in the degradation of organic compound.


中文翻译:

2,4-二氯苯氧基乙酸间歇式和循环式光反应器的可见光光催化降解研究。

目的

农药和化肥的消耗是主要的环境和健康问题之一。在本报告中,选择 2,4-二氯苯氧乙酸 (2,4-D) 来分别评估使用 LED(发光二极管)(400 和 365 nm)光源在批处理和可编程循环模式光反应器中的光降解影响。

方法

分别通过光诱导和喷雾干燥方法合成了 β-环糊精 (β-CD) 接枝二氧化钛 P25 (P25/β-CD) 和 2,4-D 和 β-CD 的络合。对结构进行了表征。此外,我们还研究了催化剂用量、床催化剂上β-CD用量、辐照时间、光反应器种类对光催化降解效率的影响。

结果

根据间歇式反应器的实验结果,确定了 TiO 2的最佳用量, 催化剂接枝的β-CD分别为1和0.1 g/L。在间歇模式下,使用 P25、P25/β-CD 作为光催化剂以及 2,4-D/β-CD 与 P25 光催化剂配合物 5 小时后 2,4-D 的光降解效率分别约为 81、85 和 95% . 在循环模式反应器中辐照 8 小时后,P25、P25/β-CD 和 2,4-D/β-CD 复合物与 P25 的降解产率分别为 89%、91% 和 96%。另一方面,高效的循环模式光反应器适用于高浓度2,4-D溶液(200 mg/L)的降解。经过 5 个连续照射 25 h 的循环后,P25 和 P25/β-CD 的 2,4-D 去除效率分别保持在 82.6% 和 84%,具有优异的稳定性和可重复使用性。

结论

光降解法可作为一种有效且环境友好的有机化合物降解工艺。
更新日期:2019-03-13
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