Biosorption of heavy metals on Citrus maxima peel, passion fruit shell, and sugarcane bagasse in a fixed-bed column

This study used three types of agricultural waste, Citrus maxima peel, passion fruit shell, and sugarcane bagasse, to produce biosorbents for copper(II), cadmium(II), nickel(II), and lead(II) metal ion removal in a fixed-bed column. The biosorbent properties were characterized using scanning electron microscopy, zeta potential analysis, Fourier transform infrared spectroscopy, and cation exchange capacity. The adsorption capacities were determined using the Thomas model for various pH values and flow rates. The results indicated that biosorbents possess carboxylic acid groups, which function as exchangeable cation and complexation sites for removing heavy metals. The biosorbents exhibited great adsorption capacity.