Landfill leachate treatment using activated carbon obtained from coffee waste

Tratamento de lixiviado de aterro sanitário com carvão ativado obtido de resíduos de café

ABSTRACT

A set of experiments were carried out in order to establish and evaluate the potential of activated carbon, produced from coffee waste in adsorption process, in the depuration of landfill leachate. Different reagents were studied in the activation of carbon: HCl, HCl + H₂O₂, H₃PO₄, H₃PO₄ + H₂O₂, all with an impregnation rate of 1:1. The activated carbon that showed the best global results was activated with H₃PO₄, obtaining a 51.0, 32.8, 66.0, 81.0 and 97.1% elimination of chemical oxygen demand, ammonia, total chlorine, bromine and copper, respectively. This activated carbon has a total pore area of 4.85 m²/g and a median pore diameter of 65.32 micrometers. When different loads of this carbon were placed in a stirrer system in contact with landfill leachate, with the aim of evaluating the effect of the adsorption load and contact time, the concentration of ammonia decreased from the beginning of the adsorption process to the end of it, and the removal of ammonia increased with the increase in the adsorbent load. However, the trend of the amount adsorbed per unit mass decreased with increased dosage. The model Freundlich equilibrium isotherm fits experimental data adequately, giving R² values of 0.95, 1/n of 0.5183, and a K value of 7.08*10^-5 L/g, being favourable for adsorption process.

Keywords:
landfill leachate; adsorption; waste; by-product