Unveiling the potential of Aspergillus terreus SJP02 for zinc remediation and its driving mechanism

In present study, 15 morphologically different fungi isolated from rhizopheric soils of an industrial area were screened for their Zn²⁺ removal efficiency from aqueous solution. Isolate depicting highest potential was molecularly identified as Aspergillus terreus SJP02. Effect of various process parameters viz. biosorbent dose, contact time, temperature, agitation rate, pH and initial Zn²⁺ concentration on the fungal sorption capacity were studied. The biosorbent exhibited maximum Zn²⁺ sorption capacity of 10.7 ± 0.2 mg g^{- 1} in 60 min. Desorption studies showed 71.46% Zn²⁺ recovery rate in 120 min with 0.01 N HNO₃, indicating efficient metal recovery for reuse and subsequent reutilization of spent mycosorbents. Acid digestion study suggested adsorption being the primary mechanism accounting for 87% Zn²⁺removal. It was further confirmed by the FE-SEM and EDX analysis. FTIR analysis suggested involvement of amino, hydroxyl, carbonyl, and phosphate functional groups of fungal cell wall in adsorption. The experimental results were in accordance with the tested isotherm and kinetic models, and suggested the role of physical adsorption for Zn²⁺ removal. Noteworthy, the present study showed better sorption capacity in considerably shorter equilibration time compared to previous reports and advocate potential utilization of A. terreus SJP02 for bioremediation of Zn²⁺ contaminated wastewater at industrial scale.