Adsorption of heavy metals by exhausted coffee grounds as a potential treatment method for waste waters

Abstract

The adsorption of the heavy metal ions Cu2+, Zn2+, Cd2+ and Pb2+ from aqueous solution by used coffee grounds has been investigated as a potential low-cost treatment method for heavy metal-containing waste waters that is based on a readily available natural by-product. The results show that metal ion adsorption is efficient over a fairly wide pH range and adsorbed metals are reversibly leached from the exhausted coffee by dilute acid without significant loss of the adsorptive capacity for subsequent re-use. © 2006 The Surface Science Society of Japan.