Abstract

The biosorption of Cu(II) from dilute aqueous solution using Erythrodontium barteri as a biosorbent has been studied as a function of pH, contact time and initial Cu(II) ion concentration at the temperature of  27^o­­­C. The residual Cu(II) in solution was determined using atomic absorption spectrophotometer. The pH study shows that pH dependence of biosorption and optimum pH was 5. The study on contact time shows that the biosorption is time dependent and maximum biosorption was obtained after 150 min. The adsorption isotherms obtained fitted well into the Freundlich and Langmuir isotherms. The Freundlichequation obtained is log Γ = 0.8549log C_e + 1.5566 while the Langmuir equation is:      = 0.0254/Ce + 0.0026 with correlation factors of 0.9917 and 0.9907, respectively. The standard deviations are 0.0159 and 0.0006, respectively. The free energy change (ΔGËš) obtained for the biosorption of Cu(II) at the temperature of 297K, initial Cu(II) concentration of 100 mgL^-1 and pH 5 is -11.108 kJmol^-1. This result indicates that the biosorption process is highly spontaneous and therefore shows that Erythrodontium barteri biomass could be successfully used for the biosorption of Cu(II) from waste streams.

Key words: Biosorption, Erythrodontium barteri, copper (II), isotherm.