Adsorption of divalent copper ions from aqueous solution by sphagnum moss peat

Abstract

The adsorption of copper from aqueous solution was studied using Irish sphagnum moss peat. The process was found to be pH dependent, the optimum range being 4.0 to 5.0. Langmuir and Freundlich isotherms were found at different initial copper concentrations and pH values. Based on these data, an expression has been derived which enables the removal to be calculated for any initial concentration and pH value. The maximum adsorption capacity for sphagnum moss peat was found to be 16.4 mg/g of peat. This occurred (at 25 °C) when the peat dose was 4 g/l and the initial adjusted pH was 5.0. The kinetics of the adsorption were also examined and, using a peat dose of 20 g/l and a pH of 5.0, were found to confirm a model which has been used previously to describe metal adsorptions by peat. An expression relating the removal efficiency to the dosage of peat, at pH 5, is also described.