Evaluation of some agricultural by product/wastes for adsorption of nitrite ions from water

Abstract

Adsorption technology is one of the most widely used techniques to remove pollutants from water using adsorbents derived from agricultural residues. This technology is characterized by high efficiency and low cost. In this study, olive waste cake and coffee granulate were treated with NaOH and then used to remove nitrite ions (NO₃^- ) from aqueous solutions. The characterization study of the adsorbents was carried out using infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA). The effect of important factors on the adsorption process, such as shaking time, initial concentration of NO₃^- and the amount of adsorbents were investigated. The remaining concentration in the treated solutions were analyzed by a UV spectrophotometer. Results indicated that the best adsorption conditions were pH 3, NO₃^- initial concentration 70 mg/l, adsorption time 90 min, and 0.3 g of adsorbent amount. The maximum adsorption capacity of coffee waste and olive cake was found to be 12.7 and 12.66 mg/g, respectively