In Vitro Bioadsorption of Cd2+ Ions: Adsorption Isotherms, Mechanism, and an Insight to Mycoremediation

Abstract

The objective of this paper is to establish the significance of the mycoremediation of contaminants such as Cd2+ to achieve sustainable and eco-friendly remediation methods. Industries such as electroplating, paint, leather tanning, etc. release an enormous amount of Cd2+ in wastewater, which can drastically affect our flora and fauna. Herein, we report on the in vitro bioadsorption of Cd2+ ions using fungal isolates obtained from different contaminated industrial sites. The detailed studies revealed that two fungal species, i.e., Trichoderma fasciculatum and Trichoderma longibrachiatum, were found to be most effective against the removal of Cd2+ when screened for Cd2+ tolerance on potato dextrose agar (PDA) in different concentrations. Detailed adsorption studies were conducted by exploring various experimental factors such as incubation time, temperature, pH, inoculum size, and Cd2+ salt concentrations. Based on optimum experimental conditions, T. fasciculatum exhibited approximately 67.10% removal, while T. longibrachiatum shows 76.25% removal of Cd2+ ions at pH 5.0, 120 h incubation time, at 30°C. The inoculum sizes for T. fasciculatum and T. longibrachiatum were 2.5% and 2.0%, respectively. Finally, the morphological changes due to Cd2+ accumulation were examined using scanning electron microscopy (SEM). Further, Fourier transform infrared spectroscopy (FTIR) spectroscopy reveals the presence of various functional groups (-CH, –C=O, NH and –OH), which seem to be responsible for the efficient binding of Cd2+ ions over the fungal surfaces.