Abstract
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.
Highlights
Landfilling is the most commonly used method for municipal solid waste (MSW) disposal around the world, though recycling, composting and incineration is currently being encouraged (XIE et al, 2014)
The aim of this study was to evaluate the potential of activated carbon (AC) obtained from coffee waste using different activation reagents, adsorbent loads, and adsorption treatment times to depurate Landfill leachate (LL), in order to reduce its concentration of iron, copper, ammonia, chemical oxygen demand (COD) and chloride in this kind of water
The AC that produced the best global results of elimination of ammonia, COD, copper, bromine and chlorine was the coffee waste that was activated using H3PO4, with an impregnation ratio of 1:1.The study carried out using this AC in order to evaluate the effect of adsorption time and the load of adsorbent reveals that the concentration of ammonia suffers a pronounced reduction from the beginning to minute 60 of the experiment
Summary
Landfilling is the most commonly used method for municipal solid waste (MSW) disposal around the world, though recycling, composting and incineration is currently being encouraged (XIE et al, 2014). Landfill leachate (LL) usually has high concentrations of organic pollutants, relatively high chemical oxygen demand (COD), toxic materials (xenobiotic organics), ammonia, heavy metals and inorganic salts, as well as refractory compounds such as humic substances and fulvic-like fractions, which are not degradable and cannot be effectively treated either by biological processes such as activated sludge, anaerobic filtration and anaerobic lagoons (MARTINS et al, 2012). It was observed that the concentration of ammonia, nitrate, electric conductivity, chloride and COD exceed permissive limits, evidencing groundwater contamination. If it is not properly collected and managed, it can potentially contaminate nearby surface and groundwater, affecting its quality and Chávez, R.P.; Pizarro, E.C.C.; Galiano, Y.L
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