Characterization of banana peel by scanning electron microscopy and FT-IR spectroscopy and its use for cadmium removal

This study describes the use of banana peel, a commonly produced fruit waste, for the removal of Cd(II) from environmental and industrial wastewater. The banana peel was characterized by FT-IR and scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) analysis. The parameters pH, contact time, initial metal ion concentration and temperature were investigated and found to be rapid (∼97% within 10 min). The Langmuir adsorption isotherm was used to describe partitioning behavior for the system at room temperature. The value of QL was found to be (35.52 mg g−1) higher than the previously reported materials. The binding of metal ions was found to be pH-dependent with the optimal sorption occurring at pH 8. The retained species were eluted with 5 mL of 5 × 10−3 M HNO3 with the detection limit of 1.7 × 10−3 mg L−1. Kinetics of sorption followed the pseudo-first-order rate equation with the rate constant k, equal to 0.13 ± 0.01 min−1. Thermodynamic parameters such as Gibbs free energy at 303 K (−7.41 ± 0.13 kJ mol−1) and enthalpy (40.56 ± 2.34 kJ mol−1) indicated the spontaneous and endothermic nature of the sorption process. The developed method was utilized for the removal of Cd(II) ions from environmental and industrial wastewater samples using flame atomic absorption spectrophotometer (FAAS).