Effectiveness of Musa balbisiana bract toward chromium removal from industrial tannery effluent: Optimization, kinetics, isotherms, regeneration, and cost estimation

Abstract

Eradicating chromium from industrial effluent is essential for environmental security and economic reasons. This study investigates the potency of activated Musa balbisiana bract biomass as a biosorbent to remove hexavalent chromium (Cr⁶⁺) from real industrial tannery effluent (ITE). The characterization study exemplifies the existence of irregular structures and excessive cavities, and the occurrence of functional groups (hydroxyl, carboxyl, esters, and alkynes) are benefitting the deposition of Cr⁶⁺ on the biosorbent. A maximum biosorption capacity of 42.75 ± 0.21 mg/g was observed at an optimum pH of 6.5, biosorbent dosage of 0.3 g, initial Cr⁶⁺ concentration of 50 mg/L, and contact time of 120 min. The validation experiment confirmed the removal efficiency of total chromium, trivalent chromium, and Cr⁶⁺ 92.56 ± 0.80 %, 98.63 ± 0.20 %, and 96.21 ± 0.50 %, respectively. Among the models, Langmuir isotherm (R²: 0.9992) and pseudo-second order (R²: 0.9999) kinetic models greatly correlate with the equilibrium data. A 2-tier membrane module was examined for continuous study and reached 88.23 ± 0.60 % Cr⁶⁺ removal. Statistical analysis was performed to confirm the significance of adsorption results. The likelihood of the desorption and regeneration of the treated biosorbent was investigated. The estimated cost per volume of ITE treated and unit of pollutant removal from ITE employing Musa balbisiana bract biosorbent is around $3.08/m³ and $3.75/kg.