Adsorption of cadmium from aqueous solution by biomass: comparison of solid pineapple waste, sugarcane bagasse and activated carbon

Abstract

The use of low-cost adsorbent derived from agricultural waste has been investigated for the removal of Cd(II) from aqueous solution. This research reports the feasibility of using solid pineapple waste (SPW), sugarcane bagasse (SCB) and activated carbon (AC) derived from palm kernel for the removal of Cd(II) under different experimental conditions. Batch experiments were carried out at various pH (3-12), adsorbent dosage (0.01-2 g) and contact time (15-150 min). The maximum Cd(II) removal was shown by SPW (90%) followed by SCB (55%) and AC (30%) at pH 7 with a contact time of 120 min, adsorbent dosage of 1.0 g and at 1.0 ppm of the initial concentration of Cd(II) solution. The kinetics study shows that the adsorption process fitted the pseudo-second-order-model. The experimental data was analysed by both Freundlich and Langmuir isotherm models. It was found that the Langmuir model appears to well fit the isotherm. The Langmuir maximum adsorption capacity calculated from Langmuir for SPW, SBC and AC were 0.3332 mg/g, 0.1865 mg/g and 0.1576 mg/g respectively. The order of Cd(II) removal by the adsorbents was SPW>SCB>AC. Thus, SPW may be an alternative adsorbent for the removal of Cd(II) ions form aqueous solution. The characterization of the SPW, SCB and AC were also carried out by using Scanning Electron Microscopy (SEM) and Nitrogen Gas Adsorption - Single Point Surface Area Analyzer (BET)