An Evaluation of the Removal of Progesterone in Wastewater by Adsorption onto Waste Tea Leaves

Abstract

The removal of endocrine disrupting chemical progesterone by adsorption onto waste black tea leaves was investigated in laboratory-scale experiments. The removal efficiency was compared with the widely used granular activated carbon (GAC). The performance of waste black tea leaves for the adsorption of progesterone was found to be comparable to conventional GAC. The maximum adsorption capacities for tea leaves and GAC were 1.8 mg/g and 1.4 mg/g respectively. The values for the thermodynamic parameters associated with sorption of progesterone onto tea leaves were Gibb's free energy (-6.0 KJ/mol), enthalpy (-3.7 KJ/ mol) and entropy (8.0 J/mol K), indicating that the sorption process was favorable, spontaneous and involved physical adsorption held by Van der Waal forces. The adsorption was guided by diffusion within the pores of the tea leaves.