Studies on surface characterisation and isotherm modelling: Biosorption of arsenic(III) onto low cost biosorbent derived from orange peel

Abstract

The paper described the removal of As(III) from contaminated water by orange peel (OP) by a low cost biosorbent. The effects of various parameters such as mesh size, pH, temperature, adsorbent dosage and contact time were studied in batch experimental setup. Physiochemical analysis of OP biomass was carried out through scanning electron microscopy (SEM) and fourier transmission infrared spectroscopy (FTIR). It was observed that the pH had a strong effect on biosorption capacity. At the optimum treatment conditions of pH (7), temperature (30^oC), contact time (90 min) and adsorbent dosage (4 g), OP biomass was found to be effective for the removal of As(III) with 82.45% sorption efficiency at a concentration of 50 mg/l As(III), and thus uptake capacity was 1.18 mg As(III)/gm of biomass. To establish the most appropriate correlation for the equilibrium curves, isotherm studies were performed for As(III) ion using Freundlich and Langmuir adsorption isotherms. Langmuir isotherm was

found to be best fitted to equilibrium sorption data with higher linear correlation coefficient (R² = 0.992). A low cost OP biosorbent shows a potential and promising simple method for the removal of As(III) ion.