Adsorption of Copper (II) Ions from Aqueous Solution onto Synthetic Goethite and Two Naturally Available Red Soils from Yaoundé –Cameroon

Abstract

The present investigation deals with the utilization of synthetic goethite and two red soils obtained from AHALA-NSAM and NKOLOFANE as adsorbent for the removal of copper from waste water. The synthetic goethite was characterized by IR, XRD and BET where the red soils were characterized by XRD, Chemical Analysis and BET. A series of experiments were conducted in a batch system to evaluate the effect of system variables. The effect of contact time, pH and the initial concentration of copper (II) solution were considered. The results show that the contact time of 180 minutes, 20 minutes and 15 minutes are sufficient to fit the equilibrium for GEO, E1-B1 and NSAM-B2 respectively. The optimal adsorption pH for the adsorption of copper (II) ions is 4.6±1. The maximal quantities adsorbed by every adsorbent were 78 .2 mg/g for GEO, 41.2mg/g for E1-B1 and 32.2mg/g for NSAM-B2. The experimental results obtained have been correlated to four kinetic models including the first order, the second order, Elovich and intra particle diffusion models. The kinetic model that gave the value of the linear correlation coefficient which best fits is that of second order. Three isotherms models amongst which are Langmuir, Freundlich and Tempkin’s have been applied to the experimental data. The Langmuir model best described the adsorption of copper (II) ions in aqueous solution by the three adsorbents.