Adsorption of Iron with Biosorbents derived from Longan Peel, Pomelo Peel and Jackfruit Peel

High iron (Fe2+) concentration in groundwater is a severe issue in many regions of the world. This study attempts to investigate the effectiveness of biosorbents derived from longan peel (LP), pomelo peel (PP) and jackfruit peel (JP) for the adsorption of Fe2+ from aqueous solution in various forms. A batch adsorption study was carried out with an initial Fe2+ concentration of 10 mg/L for 2 h. The results showed that the highest removal efficiency was achieved for PP and its biochar at 97.38% and 99.45%, respectively. High removal efficiency implied that PP contained favourable characteristics for the adsorption of Fe2+. Under the scanning electron microscope (SEM), the surface structure of PP displayed visible dimensions with a relatively large pore size compared with LP and JP. Characterisation study using Fourier-transform infrared spectroscopy (FTIR) reveals that the carboxylate groups and ester carbonyl band participated in the adsorption process. At higher initial pH of 5.83, adsorption of Fe2+ using PP gives higher removal efficiency due to lower competition on electrostatic interaction between positive ions in the solution and the surface of biosorbents. Furthermore, adsorption uptake of 83.0 mg/g was attainable with an initial concentration of 100 mg/L. This study has proven the feasibility of PP as a low cost biosorbents for removing Fe2+ in an aqueous solution.