Removal of Ni from aqueous solutions by activated carbon prepared from oily waste using physical activation method with steam

In this study, the carbonaceous adsorbents were prepared from the waste of crude oil storage tanks using with steam at various temperatures. The optimum adsorbent was selected for further experiments after characterization of specific surface area and textural properties. Batch experiments of nickel adsorption were performed with initial concentration of 25-200 mg/L, pH 2-8, contact time 5-240 min and absorbent dose of 1-5 g/L. The results showed that among the three synthesized absorbents, the obtained adsorbent at 900 ˚C showed the higher surface and best structural properties with a specific surface area of 422 m2/g and a total pore volume of 0.55 m3/g. The results of nickel adsorption showed that the removal efficiency increases with increasing the contact time and absorbent dose. Maximum nickel adsorption efficiency was obtained at pH 5, contact time of 60 min and absorbance dose of 2 g/L. In addition, it was observed that the adsorption data follow the Langmuir and Freundlich isotherms. The results of fitting the kinetic models for all adsorbents indicate that the adsorption process follow the pseudo second order kinetic model. Base on the results of this study, it can be stated that the activated carbon produced from oily sludge can be considered as an efficient and cost effective adsorbent for treatment of industrial wastewater.