Adsorptive removal of arsenate from aqueous solution by iron oxide coated calcined freshwater snail shell

Abstract

The primary goal of this research is to compare the efficacy of raw freshwater snail shell (Viviparus Contectus) (FSS) and iron oxide coated calcined snail shell (IOCCSS) in removing As(V) ions from aqueous solution medium via adsorption. FTIR, XRD, EDX, BET surface area analysis and SEM image methods were used to characterise the structures of the obtained solid sorbents. The effects of solution's initial pH, initial As(V) concentration, contact time, adsorbent dose, and ambient temperature parameters on the removal of As(V) ions from aqueous solution medium with FSS and IOCCSS solid sorbents were analysed, and optimum conditions were determined. The maximum efficiency of As(V) ions adsorption was measured 94.27% at a pH value of 7.0, contact time of 60 min, initial ion concentration of 2.0 mg/L, the adsorbent dose of 2.0 g/L, and the ambient temperature of 50°C. Thermodynamic parameters ΔH, ΔG and ΔS were calculated for the removal of As(V) ions with IOCCSS solid sorbent, and the adsorption process was determined to be endothermic. The best fit was obtained by Langmuir isotherm model with maximum monolayer sorption capacity of 3.42 mg/g for arsenate. According to the obtained results, the low-cost IOCCSS solid sorbent has been proposed as a viable alternative material for the removal and preconcentration of As(V) from aqueous solutions.