Degradation of acetamiprid using graphene-oxide-based metal (Mn and Ni) ferrites as Fenton-like photocatalysts Asma Tabasum, Ijaz Ahmad Bhatti, Nimra Nadeem, Muhammad Zahid, Zulfiqar Ahmad Rehan, Tajamal Hussain and Asim Jilani ABSTRACT This study aims to explore the photocatalytic potential of graphene-oxide-based metal ferrites for the degradation of acetamiprid (an odorless neonicotinoid pesticide). Metal (Mn and Ni) ferrites (along with their graphene oxide composites) were prepared by the hydrothermal method while graphene oxide (GO) was synthesized using a modified Hummer’s method. The composites were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The photocatalysts were studied for their Fenton-like advanced oxidation process to degrade acetamiprid. The composites showed excellent activity against acetamiprid degradation (>90%) in 60 min under UV irradiation. The detailed optimization study was carried out to investigate the influential variables (such as pH, catalyst dose, pollutant concentration, irradiation time, oxidant dose, etc.) to achieve enhanced degradation efficiency. Moreover, the findings were endorsed by central composite design (CCD). It was concluded that degradation was enhanced in an appropriate combination of photocatalyst and hydrogen peroxide. The magnetic character of the metal ferrites and their composites played an important role in the easy separation and reusability of these materials. The present findings result in highly effective, easy to handle and stable heterogeneous photo-Fenton materials for wastewater remediation. Asma Tabasum Ijaz Ahmad Bhatti Nimra Nadeem Muhammad Zahid (corresponding author) Department of Chemistry, University of Agriculture, Faisalabad 38040, Pakistan E-mail: rmzahid@uaf.edu.pk; zahid595@gmail.com Zulfiqar Ahmad Rehan Department of Polymer Engineering, National Textile University, Faisalabad, Pakistan Tajamal Hussain Institute of Chemistry, University of the Punjab, Lahore Pakistan Asim Jilani Center of Nanotechnology, King Abdul-Aziz University, Jeddah 21589, Saudi Arabia Key words | central composite design (CCD), magnetic graphene oxide, MnFe 2 O 4 , NiFe 2 O 4 , pesticide, wastewater treatment INTRODUCTION Keeping in view the easy accessibility of clean water comply- ing with WHO-standards, there is a strong need for developing effective water treatment technologies. Various physico-chemical and biological pre-treatments are cur- rently used. Such treated water normally meets the legal requirements for discharge into water streams. Pesticides and drugs are among the major micro-pollutants found in urban secondary effluents (Al Aukidy et al. ; Bueno et al. ; Cabeza et al. ). Their low concentrations in aqueous streams threaten their inhabitants, owing to bio- accumulation in the muscular tissues of living creatures. Consequently, an effective, economical and eco-friendly treatment is now vital to cope with the recalcitrant chemicals. Pesticides are among the priority pollutants, specifically in countries that are developing agriculturally. Farmers usually spray pesticide formulations in excess onto the crops to raise the product quality and minimize the insect damage. The adsorbed pesticides become part of wastewater when fruits and vegetables are washed in the industry’s food processing unit. Acetamiprid (ACTM) is a commonly used neonicotinoid insecticide, being sprayed on citrus fruit (Garcia-Reyes et al. ). ACTM is chroni- cally as well as an acutely toxic and may cause cancer (Li et al. ). The wastewater treatment processes such as adsorption, membrane filtration, biodegradation are usually inefficient for the complete removal/degradation of aquatic pollutants. Advanced oxidation processes (AOPs) have been proved as successful substitutes for these inefficient and costly tech- niques (Tabasum et al. ). In-situ generated highly reactive hydroxyl radicals (oxidation potential of 2.8 V), are non-selective oxidative species (Konstantinou et al. ). The photo-Fenton process is among the most effective pollutant-remediation AOPs (Klamerth et al. ). 178 © IWA Publishing 2020 Water Science & Technology | 81.1 | 2020 doi: 10.2166/wst.2020.098 Downloaded from https://iwaponline.com/wst/article-pdf/81/1/178/676935/wst081010178.pdf by guest on 22 July 2020