Biosorption of Cu(II) From Water by Banana Peel Based Biosorbent: Experiments and Models of Adsorption and Desorption

Banana peel, a discarded agricultural waste was used to produce bioadsorbent through easy and environmental friendly processes. This banana peel based biosorbent was evaluated for adsorptive removal of copper from water and its desorption capability. The characterisation results showed this biosorbent had very high specific surface area, potential binding sites and functional groups. The optimal conditions for biosorption were found at pH 6.5, biosorbent size of less than 75μ, dose of 0.5g/100ml and 1-hour contact time. Thermodynamic analysis also indicated that its adsorption was spontaneous. Significant desorption of copper (94%) was obtained when using 0.1N H2SO4. Both adsorption and desorption equilibrium data were well described by Langmuir, SIPS and Koble-Corrigan models whilst kinetics data by pseudo-first order, Elovich and Intraparticle diffusion models. Models’ parameters were optimised by MATLAB’s non-linear modelling. All models had good fitness with the experimental data from high R (0.970-1.00), low non-linear errors RMSE (0.004-10.00) and low χ (0.0004-10.00). The maximum adsorption and desorption capacities were 20.37 and 32.40 mg/g, respectively. The adsorption processes were controlled by chemisorption. Both adsorption and desorption processes could be described by the pseudo-first order kinetic. The potential applicability of banana peel based bioadsorbent could be further examined in a large-scale.