TY - JOUR
T1 - Kinetic and thermodynamics of chromium ions adsorption onto low-cost dolomite adsorbent
AU - Albadarin, Ahmad B.
AU - Mangwandi, Chirangano
AU - Al-Muhtaseb, Ala'a H.
AU - Walker, Gavin M.
AU - Allen, Stephen J.
AU - Ahmad, Mohammad N.M.
PY - 2012/1/1
Y1 - 2012/1/1
N2 - The chromium bearing wastewater in this study was used to simulate the low concentration discharge from a major aerospace manufacturing facility in the UK. Removal of chromium ions from aqueous solutions using raw dolomite was achieved using batch adsorption experiments. The effect of; initial Cr(VI) concentration, amount of adsorbent, solution temperature, dolomite particle size and shaking speed was studied. Maximum chromium removal was found at pH 2.0. A kinetic study yielded an optimum equilibrium time of 96h with an adsorbent dose of 1g/L. Sorption studies were conducted over a concentration range of 5-50mg/L. Cr(VI) removal decreased with an increase in temperature (q max: 20°C=10.01mg/g; 30°C=8.385mg/g; 40°C=6.654mg/g; and 60°C=5.669mg/g). Results suggest that the equilibrium adsorption was described by the Freundlich model. The kinetic processes of Cr(VI) adsorption onto dolomite were described in order to provide a more clear interpretation of the adsorption rate and uptake mechanism. The overall kinetic data was acceptably explained by a pseudo first-order rate model. Evaluated ΔG o and ΔH o specify the spontaneous and exothermic nature of the reaction. The adsorption takes place with a decrease in entropy (ΔS o is negative).
AB - The chromium bearing wastewater in this study was used to simulate the low concentration discharge from a major aerospace manufacturing facility in the UK. Removal of chromium ions from aqueous solutions using raw dolomite was achieved using batch adsorption experiments. The effect of; initial Cr(VI) concentration, amount of adsorbent, solution temperature, dolomite particle size and shaking speed was studied. Maximum chromium removal was found at pH 2.0. A kinetic study yielded an optimum equilibrium time of 96h with an adsorbent dose of 1g/L. Sorption studies were conducted over a concentration range of 5-50mg/L. Cr(VI) removal decreased with an increase in temperature (q max: 20°C=10.01mg/g; 30°C=8.385mg/g; 40°C=6.654mg/g; and 60°C=5.669mg/g). Results suggest that the equilibrium adsorption was described by the Freundlich model. The kinetic processes of Cr(VI) adsorption onto dolomite were described in order to provide a more clear interpretation of the adsorption rate and uptake mechanism. The overall kinetic data was acceptably explained by a pseudo first-order rate model. Evaluated ΔG o and ΔH o specify the spontaneous and exothermic nature of the reaction. The adsorption takes place with a decrease in entropy (ΔS o is negative).
KW - Adsorption
KW - Dolomite
KW - Hexavalent chromium
KW - Kinetic study
KW - Thermodynamic parameters
UR - http://www.scopus.com/inward/record.url?scp=84155195032&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2011.10.080
DO - 10.1016/j.cej.2011.10.080
M3 - Article
AN - SCOPUS:84155195032
SN - 1385-8947
VL - 179
SP - 193
EP - 202
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
ER -