Use of tea or coffee lees as adsorbent for removal of benzene from wastewater

Abstract

The object of this work was to investigate several adsorbents to determine their effective removal of benzene from wastewater. Tea and coffee lees were found to effectively adsorb benzene. Equilibrium adsorption isotherms conformed to the Freundlich isotherm (log-log linear). Adsorption of benzene by tea or coffee lees was observed in the pH range of 1 to 11. At equilibrium, the adsorption efficiency of tea or coffee lees for benzene was lower than that of activated carbon. The removal of benzene by tea or coffee lees was attributed to the uptake by intracellular particles called spherosomes. Ninety minutes after application of lees to wastewater (pH 10) containing 0.1 g/l of benzene, 75 to 82% of the benzene had been removed.