Abstract
In this work, the removal of cobalt ions from aqueous solutions by carbon soot which is a very cheap industrial by-product has been studied. Its objective was to investigate the possibility of using carbon soot instead of high cost commercial adsorbent materials for the removal of cobalt from aqueous solution. Different adsorption isotherms (Langmuir, Freundlich, and Brauner-Emmett-Teller) were applied. The adsorption rate constant (Kad), rate constant for intraparticle diffusion (Kp), pore diffusion coefficient (D), overall reaction rate (K), equilibrium constant (Kc), activation energy (E) and the thermodynamic functions ΔG°, ΔH° and ΔS° were estimated. Also the effect of time, sorbent dose, initial concentration and the pH at different temperatures were studied. The results were interesting, indicating that carbon soot is capable of removing cobalt(II) from an aqueous solution. The equilibrium time for cobalt(II) adsorption on soot is larger than that on powdered activated carbon. Cobalt adsorption is pH dependent. The kinetics of adsorption was investigated as first order diffusion controlled and spontaneous process.