A novel platform of self-immobilized Aspergillus flavus with selenium nanoparticles biomixture for enhanced Cr removal: economic production, characterization, optimization, kinetic study, cytotoxicity evaluation and application in wastewater treatment

Abstract With continuous exacerbation of industrialization, the environment is prone to dramatic imbalance, which eventually menaces the public health. Therefore, the current study quested for remediating Cr(III) using self-immobilized fungal pellets hybridized with indigenously-fabricated SeNPs. Firstly, the effluent from potato chips processing was utilized as economic nutriment for the production of fungal-SeNPs hybrid system. This novel composites promoted the removal of Cr(III) by 58 ± 3.31% comparing to 41.2 ± 2.17% implemented by fungal-pellets. Characterization analysis by SEM, EDX, and FTIR emphasized the porous architecture and functional groups that all contributed chiefly to the biosorption process. The statistical optimization approach deduced that 2.15 g L -1 of fungal-SeNPs-composites eliminated 92.7 ± 1.8% of Cr(III) (270 mg L -1 ) at an initial pH of 4.8 within 1 h, resulting 1.57-fold enhancement. Thereafter, the microtoxicity of remediated solution declared the marginal prohibition in the growth patterns of Escherichia coli , Bacillus cereus and Candida albicans ranging from 0.9% to 5.57%. However, the cytotoxicity underscored the viability of Wi-38 and Vero cells by 92.17 ± 0.78 and 97.08 ± 0.24%, respectively. Meanwhile, the adsorption process was well-fitted with Fractional Power model followed by the Intra-Particle Diffusion and Elovich models, which denoted that the adsorption process was predominantly governed by chemisorption. Strikingly, fungal-SeNPs-composites succeeded in significantly remediating 90.3 ± 3.5, 80.4 ± 2.7, 77.5 ± 2.3 and 71.6 ± 1.8% of Cr(III) from fresh water, municipal discharge, industrial effluent and seawater-artificially inoculated with Cr(III), respectively; reflecting the leverage of water type and quality (i.e., physicochemical/biological contents) on the remediation potency. Accordingly, this study unveiled the promising performance of self-immobilized-SeNPs biomixture as an eco-friendly, sustainable, frugal and proficient adsorptive material.