Bio-sorption of a bi-solute system of copper and lead ions onto banana peels: characterization and optimization.

PURPOSE: Banana peel was used as a low-cost adsorbent for the removal of Cu and Pb ions from aqueous solution in a binary system.
METHODS: The interactive effects of the operating parameters such as initial concentration, pH, adsorbent dosage and particle size were studied in a batch mode using central composite design. The characterizations of banana peels were done using point of zero charge (pHpzc), Fourier infrared transform (FTIR), scanning electron microscopy (SEM) and elemental composition (EDS). RESULT: The point of zero charge of banana peels was determined to be 4.83. The FTIR, SEM and EDS showed the functional groups, surface morphology and elemental composition respectively before and after the adsorption process. The analysis of variance (ANOVA) showed a good fit of coefficient of determination (R2) for Cu and Pb being 0.998 and 0.988 respectively. The percentage removal of Cu and Pb increased with increasing adsorbent dosage, however, the bio-sorption capacity of Pb was greater than Cu. The optimized variable conditions for the bio-sorption of Cu and Pb using banana peel gave 99.79% and 88.94% removal for Pb and Cu respectively with initial concentration of 100 mg/L, pH 5, adsorbent dosage of 1 g and particle size of 75 μm. The above condition gave desirability of 0.959, which denotes that the optimum conditions are acceptable.
CONCLUSION: The regression model and the agreement between the experimental and predicted values confirmed the validity of second-order polynomial equation for the bio-sorption of Cu and Pb using banana peels. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40201-021-00632-x. © Springer Nature Switzerland AG 2021.