Biosorption potential and kinetic studies of vegetable waste mixture for the removal of Nickel(II)

Biosorption potential of new low cost biosorbent prepared from vegetable waste, composed of 1:1 mixture of potato and carrot peels for the removal of Ni(II) from aqueous solution was determined. The residual metallic ion concentrations were determined using an atomic absorption spectrophotometric technique (AAS). Batch experiments were conducted to optimize parameters such as initial pH, temperature, contact time, initial metal ion concentration and biosorbent dose and the results showed that maximum adsorption of Nickel (79.32 %) occurs when the contents were stirred for 75 min with 3.0 g of biosorbent at 35 °C and pH 4. Kinetic studies of the reaction revealed that it follows a pseudo-second order reaction. The experimental results were analyzed in terms of Langmuir and Freundlich isotherms. The Langmuir isotherm model fits well to data of Ni(II) biosorption by the prepared biomass as compared to the model of Freundlich. Both neat and Ni loaded biosorbent samples were analyzed by AAS using a dry ashing process in a furnace and also by use of a FT-IR spectrophotometer and an X-Ray florescence spectrometer in order to confirm the biosorption of Ni(II) and the results have revealed that a significant amount of Ni is present in the spent biosorbent.