Robust Magnetic γ-Fe2O3/Al-ZnO Adsorbent for Chlorpyriphos Removal in Water

In this research, the removal of the pesticide chlorpyriphos (CPE) from water by adsorption using a novel adsorbent made of gamma-Fe2O3/Al-ZnO nanocomposite was studied. The adsorbent was characterized using Fourier-transformed infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area, and vibrating sample magnetometry (VSM). The main parameters affecting the adsorption process, including the initial pH (2-12), the concentration of pesticide (10-70 ppm), the %Fe2O3 of the adsorbent, and the adsorption time (<= 60 min), were studied. The results demonstrated that the adsorption of CPE depended on the pH, with a maximum removal of 92.3% achieved at around neutral pH. The adsorption isotherm was modelled and the results showed that the Freundlich model fitted the experimental data better than the Langmuir and Temkin models. The kinetics of adsorption were also studied and modelled using the pseudo-first-order and pseudo-second-order models, with the former being found more suitable. Energy dispersive X-ray (EDX) analysis confirmed the adsorption of CPE on gamma-Fe2O3/Al-ZnO, while FTIR analysis suggested that the hydroxyl, N-pyridine, and chloro functional groups governed the adsorption mechanism. Furthermore, VSM analysis revealed that the magnetization saturation of gamma-Fe2O3/Al-ZnO nanocomposite, after CPE adsorption, was slightly lower than that of fresh gamma-Fe2O3/Al-ZnO but remained adequate for the efficient separation of the adsorbent simply using a magnet. This study demonstrates that binary gamma-Fe2O3/Al-ZnO magnetic nanocomposites are effective for the removal of chlorpyriphos and could be highly promising materials for the removal of emerging pollutants in wastewater.

Automated summary

This research studied the adsorption removal of the pesticide chlorpyriphos (CPE) from water using a novel adsorbent made of gamma-Fe2O3/Al-ZnO nanocomposite. The adsorption process was influenced by parameters such as pH, pesticide concentration, %Fe2O3 of the adsorbent, and adsorption time. The study found that the maximum removal of CPE occurred at neutral pH and the Freundlich model best fit the adsorption isotherm. The results suggest that the gamma-Fe2O3/Al-ZnO nanocomposite is effective for the removal of chlorpyriphos and could be a promising material for the removal of emerging pollutants in wastewater.