Removal of Fe2+, Zn2+ and Mn2+ from the mining wastewater by lemon peel waste

Abstract

This study is aimed to evaluate the possibility of lemon peel, as an agro-industrial waste, to remove Fe2+, Zn2+ and Mn2+ from single aqueous solutions and mining wastewater. For this purpose, the influence of various parameters: sorption time, initial pH solution, initial metal ion concentration and a dose of sorbent on the sorption process were studied in batch experiments. The experimental equilibrium data have been analysed utilizing linearized forms of Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms. The Langmuir isotherm provided the best theoretical correlation of the experimental equilibrium data for Fe2+, Zn2+ and Mn2+, with the maximum sorption capacities of 4.40, 5.03 and 4.52 mg g(-1), respectively. The percentage of targeted ions removal from single aqueous solutions was 92.9 % (Zn2+), 84.5 % (Fe2+) and 78.2 % (Mn2+). Regarding the sorption capability of lemon peel in mining wastewater, the maximum removal of Fe2+, Zn2+ and Mn2+ from mining wastewater was 49.62, 33.97 and 9.11 %, respectively. In addition, the potential reusability of the lemon peel as sorbent was investigated through desorption study in 0.1M of CH3COO4, HCl and HNO3 solution. The highest rate of desorption was achieved in 0.1 M HCl solution, reached a value of 55.19 % for Mn2+ and 37.24 % for Zn2+, while for Fe2+ the highest value of 25.82 % was achieved in 0.1M HNO3 solution.