Adsorption of Co (II) from aqueous solution by Natural clay mineral Beidellite

27807

In this study, removal of cobalt from wastewater using natural clay (beidellite) was investigated. The adsorption capacity of cobalt was studied at beidellite dosages (0.20-20 g/L), initial Co(II) concentrations (50-1000 mg/L), temperature (293-333 ^0K) and solution pH values (2-7). Maximum adsorption was observed at the pH range of 6-7.With an initial concentration of 50 and 400 mg/L of the adsorbate at pH 7.0 and contact time of 100 min, the percentage adsorptions were found to be 99.5% and 86.8%, respectively. The kinetic data obtained at different initial Co(II) concentrations (50- 1000 mg/L) indicated that adsorption rate was fast and most of the process was completed within 40 min, followed by slow attainment of equilibrium. Pseudo-second order model fitted the data well with very high correlation coefficients (r^2 0.985). Adsorption capacities was calculated from the Langmuir isotherm as 21.13 mg/g at an initial pH of 7 for the 50-1000 mg Co(II)/L solution. Thermodynamic parameters such as enthalpy (∆H^o ), free energy (∆G^o ) and entropy (∆S^o ) were calculated as - 2.01, 7.27-8.31, and 0.031 kJ/mol ^oK between 293-333 ^oK, respectively. These results show that adsorption of Co(II) on beidellite was an endothermic process and the process of adsorption was favoured at high temperatures. The present study revealed that such a natural clay material beidellite could be used as an efficient sorbent for the removal of cobalt from wastewater streams.

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Beidellite , cobalt , adsorption , isotherm , kinetic

Afyon Kocatepe University Journal Of Science an‎d Engineering

630

Afyon Kocatepe University Journal Of Science an‎d Engineering