Adsorption of cadmium from aqueous solution using Rooibos shoots as adsorbent

Abstract

The use of Rooibos shoots, a natural adsorbent, for cadmium removal from wastewater is proposed. The effects of initial pH, adsorbent dosage, contact time, and initial concentration were investigated in the batch adsorption mode. The optimum pH was found to be 5.5. Isotherm and kinetic data were modeled; the data fitted best to the Freundlich model, and, kinetically, the adsorption was of pseudo-second order as shown by the high R2 value of 0.9928 along with close agreement between the experimental qe (13.9 mg g−1) and calculated qe (14.24 mg g−1) values. The studied biomass material was found to be effectively used for removal of cadmium from contaminated mine wastewater.