Removal of Co by carbonaceous material obtained through solution combustion of tamarind shell.

New carbonaceous materials were obtained through solution combustion process of tamarind shell in the presence of urea and ammonium nitrate, and all of them were tested for Co removal. The effect of temperature (from 600 to 1000°C) and water volume on surface texture of carbonaceous material and its adsorptive capacity was evaluated. Scanning electron microscope, Fourier transform infrared spectroscopy, X-ray powder diffraction, and Brunauer-Emmett-Teller (BET) model were used to characterize the obtained carbonaceous material before applying for the removal of cobalt. The point of zero charge was also determined. The results indicate that BET-specific surface areas ranged from 6.40 to 216.72 m2g-1 for the carbonaceous materials obtained at 600, 700, 800, 900, and 1000°C. The one obtained at 900°C (CombTSF900) was found to be the most effective adsorbent for the removal of Co(II) ions from aqueous solutions, with a maximum sorption capacity (Qmax) of 43.56 mg/g. Carbonaceous material obtained through the solution combustion process improves morphological characteristics of adsorbent in a short time, and could be used as an alternative method for the removal of cobalt.

Carbonaceous material obtained from exhausted coffee by an aqueous solution combustion process and used for cobalt (II) and cadmium (II) sorption.

New carbonaceous materials were obtained using a fast aqueous solution combustion process from mixtures of exhausted coffee, ammonium nitrate (oxidizer) and urea (fuel) heated at 600, 700, 800 or 900 °C. The resulting powders were effective adsorbents for removing Co(II) and Cd(II) from aqueous solutions. Exhausted coffee was also calcined at different temperatures and compared. The products were characterized, and the obtained carbons had BET specific surface areas of 114.27-390.85 m(2)/g and pore diameters of 4.19 to 2.44 nm when the temperature was increased from 600 to 800 °C. Cobalt and cadmium adsorption by the carbonaceous materials was correlated with the maximum adsorption capacities and specific surface areas of the materials. The method reported here is advantageous because it only required 5 min of reaction to improve the textural properties of carbon obtained from exhausted coffee, which play an important role in the material's cobalt and cadmium adsorption capacities.