Adsorption of copper (II) ions from aqeuous solution on natural and modified agricultural waste

The use of agricultural waste as an adsorbent for industrial effluent remediation is economically feasible due to its low operating costs. Thus, this research has been undertaken to identify the potential of raw and modified corncob and pineapple waste to produce suitable adsorbent for scavenging divalent cations of copper (II) ions in aqueous solution. In this regard, powdered natural and hydrochloric acid-treated agricultural waste namely raw corncob (RCC), chemically modified corncob (CMCC), natural pineapple waste (NPW) and acid-treated pineapple waste (ATPW) were prepared to analyze and compare the adsorption performance by batch sorption system. The influence of basic physicochemical parameters such as pH of the solution (pH 2-5), contact time (30-120 min), adsorbent dosage (0.25-1.0 g), and initial copper ion concentration (10-50 ppm) were determined in this work. The optimum condition removal of Cu2+ ion by corncob and pineapple waste were at pH 5.02 and pH 4, respectively, 120 min, 0.25 gram of adsorbent and 40.8 mg/L of initial concentration of copper ions. Equilibrium data were further analyzed to evaluate the kinetics and isotherm behavior of the adsorbate - adsorbent system. Kinetic data analysis revealed that pseudo-second order kinetic model was best obeyed whilst equilibrium data showed a better fit of Langmuir than Freundlich isotherm models for both wastes. The maximum adsorption capacity (qmax) from Langmuir isotherm model was found to be 2.52, 2.36 1.97 and 1.72 mg/g for ATPW, CMCC, NPW and RCC. It can be concluded that the overall performance of the prepared acid treated adsorbents indicated better adsorption capacity than natural adsorbents with the depicted presence of statistical significant difference between both adsorbents.