Purpose

In this study MgAl- layered double hydroxides (MgAl-LDH) nanoparticles were prepared by a simple and fast co-precipitation method and used as a catalyst in the ozonation process to degrade diazinon from aqueous solutions.

Methods

The structure of the synthesized MgAl-LDH was investigated by X-ray diffraction pattern (XRD) and field emission scanning electron microscope-energy dispersive spectroscopy (FESEM-EDX). The response surface methodology (RSM) was used to investigate the effects of different parameters including of reaction time, initial diazinon concentration, pH, and LDH dose on the removal of diazinon by MgAl-LDH catalytic ozonation process. Central Composite Design (CCD) was employed for the optimization and modeling of the process. Dispersive liquid–liquid microextraction (DLLME) method was used to extract diazinon from aqueous samples. The GC-Mass analysis was performed to determine intermediate compounds during diazinon degradation reactions. To evaluate the process performance, TOC and COD removal were measured under optimum conditions.

Results

The highest removal efficiency of 92% was observed in optimum conditions as follow; initial diazinon concentration: 120 mg/L, pH: 8.25, LDH dose: 750 mg/L, and reaction time: 70 min. The quadratic model was obtained with a good fit. The removal of COD and TOC were 80% and 74%, respectively.

Conclusion

This process can be suggested and used in the treatment of various industrial wastewaters.

中文翻译：

---

臭氧化/mg-Al层状双氢氧化物新型催化降解二嗪农：优化、建模和分散液液微萃取

 目的

在本研究中，通过简单快速的共沉淀方法制备了 MgAl 层状双氢氧化物 (MgAl-LDH) 纳米粒子，并将其用作臭氧化过程中的催化剂，以降解水溶液中的二嗪农。

 方法

通过X射线衍射图(XRD)和场发射扫描电子显微镜-能谱仪(FESEM-EDX)研究了合成的MgAl-LDH的结构。采用响应面法(RSM)研究了反应时间、二嗪农初始浓度、pH和LDH剂量等不同参数对MgAl-LDH催化臭氧氧化工艺去除二嗪农的影响。采用中央复合设计（CCD）对过程进行优化和建模。采用分散液-液微萃取（DLLME）方法从水样中提取二嗪农。进行GC-质谱分析以确定二嗪农降解反应期间的中间化合物。为了评估工艺性能，在最佳条件下测量了 TOC 和 COD 去除率。

 结果

在如下最佳条件下观察到最高去除效率为 92%；二嗪磷初始浓度：120mg/L，pH：8.25，LDH剂量：750mg/L，反应时间：70分钟。获得了拟合良好的二次模型。 COD和TOC的去除率分别为80%和74%。

 结论

该工艺可建议用于各种工业废水的处理。