Arsenic removal from wastewater using the bio-based graphene oxide and magnetite nanocomposites: reaction kinetic study

Abstract

Water contamination with arsenic (As) is a global issue challenging the environment, ecosystem, and human health. Among arsenic decontamination techniques, sorption is highly acknowledged, efficienct, low cost and simple technique and gaining much interest in recent decades. Efficacy of newly synthesizd biobased graphene oxide magnetite (bGO/FeNPs) nanocomposites from biomass of Triticum aestivum L. for As removal fromcontaminated water was estimated in present study. The biobased graphene oxides (bGO) via pyrolysis (bGO-P) and chemical exfoliation (bGO-C) processes were synthesized and fabricated with magnetite nanoparticles (FeNPs) in order to synthesize functionalized bGO-P/FeNPs and bGO-C/FeNPs nanocomposites, respectively. Theses green synthesized nanomaterials/nanocomposites were characterized using UV–Visible spectrophotometry, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM–EDX) techniques. Presence of different functional groups such as COOH, O-H, C = C, C-O-C, C-O and C-OH depicted by FTIR spectra evidencing the modification and fabrication of synthesized nanomaterials and nanocomposites. The elemental composition of bGO-C (57.53% C and 31.74% O), bGO-P (23.14% C and 46.56% O), bGO-C/FeNPs (56.64% C, 24.10% O, and 18.17 Fe), and bGO-P/FeNPs (35.22% C, 38.22% O and 21.28% Fe) confirming the presence of carbon, oxygen, and doping of iron in synthesized nanocomposites. Sorption studies were conducted by applying different doses (10, 25 and 75 mg) of synthesized nanocomposites to 100, 250 and 500 ppm of As. To estimate sorption behaviour, data was fitted to Langmuir and Freundlich isotherms. The Langmuir model exhibited a strong correlation (R²), suggesting favorable monolayer adsorption. Both bGO-C/FeNPs and bGO-P/FeNPs nanocomposites demonstrated high removal efficiencies (> 90%), with bGO-C/FeNPs showing better performance. Nevertheless, bGO-P/FeNPs also proved to be an effective and promising solution for As remediation indicating successful incorporation of Fe into the graphene-based matrices. These findings advance sustainable arsenic remediation strategies and provide a strong foundation for future research and policy decisions for the remedation of contaminated water.