Studies on the adsorption of arsenic on Cali[6]arene.

Chennakesavulu, K and Bhaskar Raju, G and Prabhakar, S (2010) Studies on the adsorption of arsenic on Cali[6]arene. Journal of Physical Organic Chemistry, 23 . pp. 723-729.



p-tert-butyl calix[6]arene (PTC6) was synthesized and characterized by solid- and liquid-state NMR and LC-MS techniques. The adsorption of arsenite and arsenate on calix[6]arene under different pH conditions and adsorbate doses was studied. The maximum adsorption of arsenic species on calix[6]arene was observed around neutral pH and the adsorption density of As (III) was higher than that of As (V). The adsorption of neutral H3AsO3 and negatively charged H2AsOS4 molecules on calix[6]arene was attributed to the condensation reaction between hydroxyl groups of PTC6 and arsenic species. The complexation of arsenite with phenolic oxygen was confirmed by solid-state 13C NMR CP-MAS. Exo attack mechanism was proposed to describe the interaction of arsenous and arsenic acid molecules with PTC6. The specific interaction between calix[6]arene and arsenic species was further substantiated by zeta-potential (z-potential) measurements and free energy of adsorption. The free energy of adsorption (Gads) estimated from Stern–Grahame equation was found to be 25 kJ/mole for As (III) and 19 kJ/mole for As (V).

Item Type:Article
Official URL/DOI:http://DOI 10.1002/poc.1641
Uncontrolled Keywords:free energy of adsorption, Arsenic, arsenate, adsorption, calix(6)arene, removal
Divisions:NML Chennai > Mineral Processing
ID Code:4023
Deposited By:Dr. G Bhaskar Raju
Deposited On:26 Sep 2011 14:51
Last Modified:14 Dec 2011 12:40
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