nfluence of functional groups on the adsorption behaviour of substituted-benjoic acids at the alpha-alumina / water interface
IR@NEIST: CSIR-North East Institute of Science and Technology, Jorhat
View Archive Info| Field | Value | |
| Title |
nfluence of functional groups on the adsorption behaviour of substituted-benjoic acids at the alpha-alumina / water interface
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| Creator |
Borah, J M
Sarma, J Mahiuddin, S |
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| Subject |
Material Science
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| Description |
Adsorption kinetics of hemimellitic and trimellitic acids at a fixed initial concentration of 0.30mM
onto �-alumina surfaces were carried out in batch method in the presence of 0.05mM NaCl(aq) at
pH 5 and 288.15, 298.15, 303.15, and 313.15 K. The experimental data were significantly better fitted
to pseudo-second-order kinetic equation of non-linear form in the entire time duration. The state
of equilibration time of benzenetricarboxylic acids at 298.15K follows the sequence: hemimellitic
acid < trimellitic acid < trimesic acid. Adsorption isotherms of hemimellitic and trimellitic acids were carried
out at 298.15 K, pH 5–10, and 0.05mM NaCl(aq) by varying acid concentration. The adsorption data
were fitted to Langmuir adsorption model. Adsorption density of benzenetricarboxylic acids follows the
sequence: trimesic acid < trimellitic acid < hemimellitic acid. Comparison of the adsorption densities of
benzenetricarboxylic acids with dihydroxybenzoic and monohydroxybenzoic acids indicates that (i) in
benzenetricarboxylic acids the position and equally the number of –COOH groups, (ii) the two phenolic
–OH groups at any two position in the benzene ring of dihydroxybenzoic acids, and (iii) the phenolic –OH
groups at ortho position in the benzene ring of monohydroxybenzoic acids are the governing parameters
for yielding higher adsorption density onto �-alumina surface. Exception is the 2,4-dihydroxybenzoic
acid amongst dihydroxybenzoic acids series, which yields highest adsorption density due to ortho and
para position of the phenolic –OH groups. The thermodynamic data indicate that the adsorption process
is spontaneous for both the systems. The magnitude of shifting of �s(–COO−) and �as(–COO−) after
adsorption of trimellitic and hemimellitic acids onto �-alumina surface indicate that both acids form
outer-sphere surface complexes.
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| Publisher |
Elsevier
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| Date |
2011
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://neist.csircentral.net/13/1/2887%2DAlumina_substitued_benzoic_acis_Colloids_Surf_2011%2C_375%2C_42%2D49.pdf
Borah, J M and Sarma, J and Mahiuddin, S (2011) nfluence of functional groups on the adsorption behaviour of substituted-benjoic acids at the alpha-alumina / water interface. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 375. pp. 42-49. ISSN 0927-7757 |
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| Relation |
http://neist.csircentral.net/13/
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