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 HNO3solution. 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 HNO3solution.