Coffee grounds as an adsorbent for copper and lead removal form aqueous solutions

Abstract

Water contamination is an actual problem around the world. The main source of contaminated water is the industry. Industrial wastewater is contaminated with hazardous substances such as heavy metals (Cu, Pb, Zn, Cd, Cr and etc.) and petroleum products. Wastewater technology is various, one of them – the biological sorption. In this study, removal of copper (Cu) and lead (Pb) from contaminated aqueous solutions has been investigated by using coffee grounds as a natural adsorbent. The research is a bench scale experiment type and analysis have performed by using different fractions (>200 µm and <200 µm particle size) of adsorbent in solutions with four (0.5, 1.0, 1.5 and 3.0 mg/L) different concentrations of both metal. Studies showed that coffee grounds are great adsorbent for heavy metal removal from aqueous solutions. Using the >200 µm fraction of coffee grounds for copper removal the treatment efficiency is 85.9% when the metal concentration is 0.5 mg/L, while the lead is 87.2%. Increasing metal concentration in the solution of the adsorbent treatment efficiency decreases to 71.76% for Cu and 86.76 % for Pb. When the smaller fractions (>200 µm) are used in coffee grounds treatment efficiency increases by 6–1 1% for copper, and 8–9% for lead.