Novel catalytic degradation of Diazinon with ozonation/mg-Al layered double hydroxides: optimization, modeling, and dispersive liquid-liquid microextraction.

Abstract

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. 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. The highest removal efficiency of 92% was observed in optimum conditions as follow; initial diazinon concentration: 120mg/L, pH: 8.25, LDH dose: 750mg/L, and reaction time: 70min. The quadratic model was obtained with a good fit. The removal of COD and TOC were 80% and 74%, respectively. This process can be suggested and used in the treatment of various industrial wastewaters. The online version contains supplementary material available at 10.1007/s40201-021-00687-w.