Adsorption of Nickel in a Continuous System Using Biochar Obtained from Pyrolysis of Rice Husk at Low Temperature

Abstract

This work evaluates the properties of the biochar obtained through the pyrolysis of rice husk at low temperature and its use as adsorbent of nickel in a continuous system. The particle size and the pyrolysis time of the biomass were varied. Yield, the percentage of carbon, functional groups, surface area and calorific value was determined. The yield of the biochar was obtained between 30.85 and 41.78%, obtaining the best results for the particle size of 0.5 mm and the pyrolysis time of 12 h, while the highest percentage of carbon was of 26. 66%, an adsorption column was designed for the removal of nickel from pollution water using biochar derived from rice husk as an adsorbent material for its subsequent scaling to pilot scale dimensions. For this study, experiments were performed in the built adsorption column, where water samples were taken at the exit of the commune every 15 minutes until arriving at 2 hours, for further analysis, calculation of removal percentages, construction of rupture curves and determination of scaling parameters of the column. Removal percentages between 19% and 86%, break times between 12 and 46 minutes were found, obtaining the best percentages with a height of 20 cm and 25 ppm of nickel. Unused bed heights that be determined were 12.11 cm and 7.23 cm. Finally, was analysed how was the development of the adsorption process in each case and the behaviour of the breakthrough curve biochar respect to activated carbon, which showed that this technology can be a moderately viable alternative since the functional groups and the high surface area activated carbon has make it better adsorbent biochar.