Removal of Zinc in an Aqueous Solution by Kaolin Kinetic and Thermodynamic Studies

kaolin, zinc, adsorption, kinetics, water treatment

Authors

  • Toufik CHOUCHANE Research Center in Industrial Technologies CRTI, P.O.Box 64, Cheraga 16014 Algiers Algeria
  • A. BOUKARI Research Center in Industrial Technologies CRTI, P.O.Box 64, Cheraga 16014 Algiers Algeria
March 25, 2020

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In this work, the physico-chemical characterization showed that the adsorbent consists mainly of silica and alumina and its structure is disordered. The specific surface area measured is more considerable for purifying and activated kaolin. The point of zero load is measured at pH 6.6.The  envisaged process is in batch systems. The results of the tests carried out indicate that the equilibrium is reached after 30 minutes. This sorption is maximum at 20°C, for stirring speed of 150 rpm, particle size between 150 and 200 µm and a pH 4.3. The maximum adsorption capacity is 39.9 mg/g. The kinetic study shows that the adsorption of zinc by kaolin follows the pseudo-first order kinetics and the Langmuir model is the most appropriate. In the same context, the results indicate a highly favorable adsorption of zinc on the kaolin(0 < RL< 1). Thus, application of the diffusion model informed that the external transport seems to be a step controlling the overall speed of the process while the intra-particle diffusion is involved in the overall rate of sorption process but this is not the only step that controls the speed.The thermodynamic parameters show that the adsorption of Zn on kaolin is spontaneous, exothermic and that randomness decreases at the interface during adsorption.