Biosorption of Cu (II) ions on peanut shells and brewing waste. Incorporation of contaminated biomass in ceramics

Abstract

The presence of heavy metals in natural water has harmful effects on the health of many biological species and on the environment. Biosorbents are widely recognized as low-cost sorbents because they are abundant in nature, or because they are waste materials from agroindustry. In the present work, the removal of Cu (II) ions in aqueous solution is studied using peanut shells and brewing wastes as adsorbent materials. In addition, the possibility of immobilizing the metal together with the biomass in ceramic matrices is proposed, starting with the study of the optimal firing temperature. An exhaustive characterization of both biomasses was carried out, and numerous variables in the biosorption process were analyzed in search of conditions that maximize their adsorbent capacity. The results show that peanut shells achieve removals of the metal up to 40%, while barley residues cannot exceed 2.3% removal. Based on the results obtained and given that both biomasses are an abundant and low-cost industrial by-products, biosorption using peanut shells is suggested as an effective and economical process for the removal of copper ions in polluted waters. In turn, temperatures of 950°C-1000ºC are established as the optimum firing range for the ceramic matrices, to analyze the immobilization of the removed metals.