Adsorption characteristics of Copper (II), Zinc (II) and Mercury (II) by four kinds of immobilized fungi residues

This study investigated the adsorption characteristics of Copper (II), Zinc (II) and Mercury (II) by immobilized Flammulina velutipes, Auricularia polytricha, Pleurotus eryngii and Pleurotus swear:us residues. Lagergren model, elovich and intraparticle diffusion model were used to present the adsorption kinetics, and it was proved that Langmuir isotherm model and pseudo-second order kinetics are the best suitable model with high correlation coefficient to characterize the adsorption process of Copper (II), Zinc (II) and Mercury (II). The results showed that adsorption process finished in 120 min at pH 6.0. The adsorption rate of Cu2+, Zn2+ and Hg2+ were reached to 53.8-84.1% of total in the initial 60 min, and finished in 120 min. Ion exchange and complexation of F. velutipes were the main mechanisms for adsorption of metal ions by characterizations of Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). In addition the functional group of cell walls such as hydroxyl, amide, carbonyl, phosphoric played a critical role in ions adsorption of edible mushroom residues. Cu2+, Zn2+ and Hg2+ in wastewater could be efficiently removed by F. velutipes residue with removal ratio of 73.11%, 66.67% and 69.35%, respectively.