COPPER (II) BIOREMOVAL FROM SIMULATED INDUSTRIAL WASTEWATER BY ACID-TREATED PLANTAIN (MUSA PARADISIACA) PEEL AND PLANTAIN PEEL-CHITOSAN COMPOSITE: KINETIC, MASS TRANSFER AND ISOTHERM MODELLING STUDIES

Abstract

The study investigated and evaluated the feasibility of using a cost-effective biosorbent developed from the mixture of ripe and unripe plantain peel for copper (II) bioremoval from simulated industrial wastewater. The mixture of ripe and unripe plantain peel was modified with phosphoric acid and chitosan to produce acid-treated plantain peel (APP) and plantain peel-chitosan composite (PP-CH) biosorbents. The effects of experimental conditions: initial copper (II) concentration, agitation time, agitation speed and biosorbent concentration on the biosorption process were evaluated. The results showed that copper (II) biosorption was dependent on the experimental conditions. Pseudo-second-order kinetic model best fitted the kinetics data of copper (II) biosorption to suggest chemisorption mechanism while the biosorption mechanism was film diffusion-controlled. Freundlich and Dubinin-Radushkevich (D-R) isotherm models provided the best correlation (  > 0.99) of the equilibrium biosorption data. The maximum monolayer biosorption capacity ( ) was found to be 27.40 and 23.81 mg/g for PP-CH composite and APP, respectively. The D-R mean free energy ( ) values of 10.4 and 10 kJ/mol for PP-CH composite and APP respectively confirmed that the mechanism of copper (II) biosorption was of chemisorption. Quantitative recovery of copper (II) (78-95%) was evident with the use of inorganic acids (H₂SO₄ and HNO₃) as eluents. Therefore, modified plantain peel has the potential for application as an effective biosorbent for copper removal from wastewaters.