Chloramphenicol removal from water by various precursors to enhance graphene oxide-iron nanocomposites

Idham, M. F.*; Falyouna, O.*; Eljamal, R.*; Maamoun, I.; Eljamal, O.*

Due to synthesis variation affecting various graphene oxide (GO) physicochemical parameters and cost efficiency aspects, the present study investigated the influence of GO precursor components for GO precipitated nZVI nanocomposite (nZVI/GO) and optimized removal conditions to remove chloramphenicol (CAP) from water. In order to synthesize nZVI/GO nanocomposites, four methods of GO precursor synthesis were used, denoted GO1, GO2, GO3, and GO4. A novel synthesis process is introduced based on economic and time-less-consuming protocols to produce GO precursor. A series of desorption experiments were also implemented in various eluents to clarify the CAP removal mechanism. Interestingly, this study demonstrated the substantial impact of GO precursor on the nanocomposite performance in eliminating CAP. The introduced novel GO successfully served as an excellent nZVI precipitation medium and enhanced CAP removal efficiency. Empirical optimization demonstrated that nZVI/GO4-1:1 could eliminate up to 91% of 100 mg/L CAP by dosage as low as 0.25 g/L at pH 5. nZVI/GO4 displayed CAP removal stability throughout a more comprehensive pH range, and remarkable recyclability, making it more promising and practical than bare nZVI and other analyzed nanocomposites. Kinetics data demonstrated a high degree of compatibility with the pseudo-first-order (PFO) and pseudo-second-order (PSO). Through kinetics and statistical analyses, desorption experiments, FTIR spectroscopy, and EDX analysis, nZVI/GO4 removed some of the CAP through the adsorption mechanism controlled by physisorption and chemisorption. In contrast, the oxidation mechanism eliminated the remaining CAP.