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|Title: ||Kinetics, Equilibrium and Thermodynamic|
|Authors: ||M. Alandis, N.|
A. Aldayel, O.
K. Mekhemer, W.
A. Hefne, J.
|Keywords: ||Thermodynamic; Chromium ; Natural Bentonite; kinetics;|
|Issue Date: ||2008 |
|Publisher: ||Research India Publications|
|Abstract: ||The possible use of commercial Natural Bentonite (untreated) (NB), as an
adsorbent for the removal of chromium ions [Cr (III)] from aqueous solution,was investigated. The sorption of Cr (III) from aqueous solutions on NB has been studied by a batch technique. We have investigated how solution pH, temperature, adsorbent amount, contacts time and bentonite treatment (washing and heat treatment) affect this process. The calcinations at 700oC and washed bentonite samples termed by CB and WB respectively. The adsorbed amount of chromium ions on NB has increased with increasing pH, adsorbent mass and temperature. The sorption of Cr (III) on NB isendothermic process in nature. Sorption data have been interpreted in terms of Freundlich and Langmuir equations. The experimental data were correlated reasonably well by the adsorption isotherm of the Langmuir, and the isotherm parameters (qm and K) have been calculated as well. Batch adsorption models,
based on the assumption of the pseudo first-order and pseudo second-order
mechanism were applied to examine the kinetics of the adsorption. The results showed that kinetic data were followed fitting the pseudo second-order. Thermodynamic parameters such as ΔH°, ΔS° and ΔG° were calculated. The adsorption process was found to be endothermic and spontaneous. The enthalpy change for chromium adsorption has been estimated as 27 kJ mol−1, indicating that the adsorption of Cr(II) by NB corresponds to a physical reaction The adsorption capacity of calcined bentonite (CB) was very high compared to Natural bentonite (NB) and washed bentonite WB. was observed.|
|ISSN: ||ISSN 0973-1792|
|Appears in Collections:||College of Science|
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