Coffee pulp characterization and treatment as adsorbent material for heavy metal removal from landfill leachates

Abstract

To add value to wastes from the coffee crop, this research physically and chemically characterized the coffee pulp waste from an organic farm crop located in Santa Bárbara (Antioquia-Colombia), specifically analyzing whether or not this material has promise for heavy metal removal from wastewater, such as landfill leachate. The coffee pulp was chemically and thermally modified to improve its physical and chemical condition and improve the sorption capacities. Sorption was characterized before and after modification thus point of zero charge, surface area, functional groups, elemental and morphological analysis, and its lignin, cellulose, and hemicellulose content. Sorption tests Cu and Pb for the coffee pulp removal capacity were also carried out in batches for determining chemical kinetics using leachates from Neal Road Landfill, in Butte County, Northern California, USA. Results showed that this material has a high potential for liquid-effluent treatment because the removal rate achieved was around 70% and 90% for the copper and lead, especially when there are simultaneously in the solution (leachate). Also, it can be concluded that in these experimental conditions, the biosorption by coffee pulp will allow the legally established permissible limits for landfill leachates to be satisfactorily fulfilled.