Graphene oxide/goethite-chitosan composite to optimize adsorption of arsenic (III) from contaminated aquatic solution

Graphene oxide (GO) was cross-linked with goethite (α-Fe(OH)O)-chitosan to synthesize (GO/goethite-CS) composites with various morphologies, increased surface area, and significant adsorption efficiency of hazardous As (III) from contaminated aquatic solution. The composite was analyzed using SEM-EDAX, FESEM, TEM, TGA, FTIR, XRD, VSM, UV-visible, and BET methods. Anodic stripping voltammetry (ASV) allows the precise detection and estimation of trace arsenic metal in aquatic samples. Meanwhile, batch experiments were conducted to examine the effect of various factors, including pH, initial concentration, contact time, and temperature, on As (III) adsorption, as well as investigate thermodynamics, equilibrium isotherm, and adsorption kinetics. Thermodynamic studies evaluated the spontaneous and endothermic characteristics of the adsorption process. The maximum adsorption of As (III) onto GO/goethite-CS recorded 98.96 mg/g at pH 6 with a contact time of 200 min. The adsorption isotherm data showed that the Langmuir model effectively described the adsorption of As (III) onto the GO/goethite-CS sorbent. The maximum adsorption capacity (q_max) was 368.38 mg/g. The pseudo-second-order kinetic model was well fitted to the experimental data, indicating that the adsorption of As (III) onto GO/goethite-CS is a chemical method. Reusability studies indicated that the GO/goethite-CS composite could be recycled with minimum reduction in adsorption capacity. The results indicated that the GO/goethite-CS composite was efficient for the removal of As (III) from aquatic solutions, emphasizing a suitable sorbent for contaminated water remediation.