Studying the effects of Aspergillus niger (MF431834) dead biomass on water defluoridation in batch and bed column: Adsorption kinetics, characterization, genotoxicity studies

Abstract

Fluoride pollution in water caused by biological and anthropogenic activities has been recorded as a significant global issue, posing severe risks to the ecosystem. The present study focuses on the isolated fungus Aspergillus niger (MF431834)-dead biomass served as novel adsorbents for defluorination. The dead fungal mycelium of A. niger was used to study the biosorption of fluoride from an aqueous medium while varying the pH, fluoride concentrations, bio-sorbent concentrations, temperatures, contact periods, and coexisting ions. After the batch experimentation, the maximum fluoride adsorption capacity of 93.85 % was achieved by 0.2 g dosage, a 50-min equilibrium time was predicted as a contact time, considerable fluoride adsorption was observed at 15 mg/L of initial fluoride concentration, the maximum fluoride adsorption of 92 % was achieved by pH 2.0, and NaOH was the best desorption agent. The biosorption of fluoride ion well pseudo-second-order (R20.99) compared to pseudo-first-order and the biosorption equilibrium data were more suited by the Langmuir isotherm than the Freund isotherm model. Thermodynamic parameters such as ΔG°, ΔS°, and ΔH° the biosorption of fluoride ions by endothermic nature. Energy Dispersive Spectroscopy (SEM-EDX) and Fourier transform infrared (FTIR) spectroscopy examine the biosorption of fluoride by fungal bio-sorbent. Fluoride removal was also significantly attained in the column study with bio-sorbent. The findings demonstrated that A. cepa subjected to untreated polluted fluoride water exhibited chromosome abnormalities, including disorganized, disturbed metaphase, chromosomal displacement in anaphase, aberrant telophase, spindle disturbances, and binucleate cells. The highest chromosomal aberrations and mitotic inhibition were found in roots exposed to contaminated fluoride water. The novelty of this research can be used as a biomarker to identify the genotoxic effects of fluoride water contamination on biota. Hence, the native fungus A. niger exhibits as an effective adsorbent for fluoride elimination, being valuable in the theory and practical management of environmental pollution.