Efficient Removal of Florasulam, Metalaxyl, and Thiamethoxam Pesticides from Water Using Carboxymethyl Cellulose-Functionalized Magnetic Graphene Oxide Nanoparticles

Abstract

Magnetic Graphene Oxide Nanoparticles (MGO-NPs) and a series of Carboxymethyl Cellulose-functionalized Magnetic Graphene Oxide Nanoparticles (CMC-MGO-NPs) were prepared for application as adsorbents in pesticide removal. Three distinct CMC-MGO-NPs were prepared by varying the weight ratios of CMC to MGO-NPs (1 : 1, 3 : 1, and 5 : 1, w/w). The nanocomposites were characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and zeta potential analysis, which confirmed their successful preparation. In addition, specific surface area and porosity were determined. These products were then evaluated for their efficiency in removing florasulam, metalaxyl, and thiamethoxam pesticides from aqueous solutions. Key operational parameters were optimized using a Plackett-Burman factorial design, which identified pesticide concentration, adsorbent dosage, temperature, pH, agitation time, and ionic strength as the most statistically significant factors affecting removal efficiency. Significantly, the CMC-MGO-NPs-2 demonstrated high maximum removal efficiencies of 93.82% for florasulam and 88.10% for metalaxyl, highlighting their strong affinity for these pesticides. However, a lower efficiency of 28.46% was observed for thiamethoxam, indicating selectivity in the adsorption process. In addition, the adsorption of pesticides onto CMC-MGO-NPs-2 was evaluated using various kinetic and isotherm models. These results underscore the potential of CMC-MGO-NPs-2 as a highly effective, low-cost, and magnetically separable adsorbent for the remediation of specific pesticides from wastewater.