EQUILIBRIUM ISOTHERM STUDIES ON BATCH BIOSORPTION OF TOXIC NICKEL THROUGH FILAMENTOUS FUNGI

Sorption Equilibrium

Abstract

The release of metal-loaded wastewater is one of the most debatable environmental and health challenges faced by our community. Among different metals, nickel (Ni) is a commonly occurring potentially toxic element present in the environment due to various natural and industrial activities. Filamentous fungi are among the most economical biofriendly biosorbents, while adsorption through solid–liquid systems is well explained by the variety of isotherm models including Redlich-Peterson and Temkin isotherms. In the current study, all seven members of phylum Ascomycota including Aspergillus niger, A. terreus, A. flavus, Rhizopus arrhizus, Alternaria alternata, and Trichoderma harzianum showed considerable Ni removal efficiency over the concentration range of 25-100 ppm. The experimental accuracy of the equilibrium data relating to the influence of the initial metal concentration on the fungal biosorption capacity was more suitably explained by the three-dimension Redlich-Peterson isotherm due to the best fit of data (R² = 0.93-0.99) than the two-dimension Temkin isotherm (R² = 0.88-0.95). The results acquired represent the effectiveness of fungal species as a low-cost adsorbent for Ni(II) ions.