Isotherm and kinetic modeling of Cd(II) uptake from aqueous solutions using an agri-waste biosorbent jute stick powder

Abstract

The removal of cadmium(II) from aqueous solutions in a batch system was conducted by using an agri-waste biomass Jute Stick Powder (JSP). To optimize parameters like metal concentration, solution pH, adsorbent amount, contact time and agitation speed, batch experiments were conducted. Further experiments were performed, using optimized conditions at pH 4.5, adsorbent dosages of 0.5 g/100 mL, a contact time of 60 min and shaking speed of 180 rpm. Favorable adsorption occurred at around pH 4.5, with a maximum adsorption capacity of 10.003 mg g-1. Detailed analysis has been conducted by testing kinetic models such as pseudo-first-order and pseudo-second-order models to determine the sorption rate and mechanism. The adsorption process was confirmed by various isotherm models and experimental data for Cd(II) biosorption fitted well to the Freundlich isotherm model at room temperature and under optimum conditions. Positive values of the thermodynamic parameter ΔG assumed that the metal adsorption process was spontaneous. JSP can be used repeatedly more than three times with a small efficiency loss. Experimental data plotted to the isotherm and kinetic models confirms that JSP can be used as a potential biosorbent for the successful removal of Cd(II) ions from waste water.