Optimization of chloride ion removal from drinking water using graphene oxide modified with AgNO3 via CCD-based RSM method

Abstract

Chloride (Cl−) is one of the pollutants that can cause significant health risks when its concentration is high in drinking water. Utilizing adsorption has a superiority in removing pollutants from water due to their large active surface area, small volume, and high adsorption capacity. Herin, graphene oxide (GO) modified with AgNO3 was used for Cl− removal. FESEM, EDAX, FTIR, zeta potential (ζ), and XRD analysis were employed for the characterization of synthesized adsorbent. The maximum Cl− removal (99.24 %) was achieved under optimized conditions by RSM based on CCD method (adsorbent dosage: 2 g/L, Cl− concentration: 30 mg/L, and reaction time: 17 min). The models of Langmuir and Freundlich isotherms were employed to determine the adsorption process. It was found that the Langmuir isotherm model with an R2 value of 0.9987 described the Cl−removal process appropriately. Finally, a comparison between the adsorbent's performance before and after modification with AgNO3 was made, demonstrating that the modified absorbent provided 87 % better efficiency than the unmodified adsorbent in the case of Cl−removal.