Naphthalene adsorption on activated carbons using solvents of different polarity |
| |
Authors: | C O Ania B Cabal J B Parra A Arenillas B Arias J J Pis |
| |
Institution: | (1) Instituto Nacional del Carbón (CSIC), Apdo 73, 33080 Oviedo, Spain |
| |
Abstract: | The hydrophobic-hydrophilic character of a series of microporous activated carbons was explored as a key factor in competitive
adsorption of a non-polar compound from liquid phase. The selectivity of the carbon surface towards naphthalene was explored
by performing the adsorption isotherms in water, cyclohexane and heptane. Solvent polarity and adsorbent hydrophobic character
were found to strongly influence the adsorption capacity of naphthalene. In aqueous media, despite the non-polar character
of the adsorbate, surface acidity lowered adsorption capacity. This is attributed to the competition of water from the adsorption
sites, via H-bonding with surface functionalities and the formation of hydration clusters that reduce the accessibility and
affinity of naphthalene to the inner pore structure. In organic media the uptake decreased due to competition of the hydrophobic
solvent for the active sites of the carbon and to solvation effects. This competitive effect of the solvent is minimized in
oxidized carbons as opposed to the trend obtained in aqueous solutions. The results confirmed that although adsorption of
naphthalene strongly depends on the narrow microporosity of the adsorbent, competitive adsorption of the solvent for the active
sites becomes important. |
| |
Keywords: | Hydrophobicity Surface polarity Organic solvents Naphthalene Adsorption |
本文献已被 SpringerLink 等数据库收录! |