Removal of phenol, phenoxide and chlorophenols from waste-waters by adsorption and electrosorption at high-area carbon felt electrodes
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, vol.513, no.2, pp.100-110, 2001 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 513 Issue: 2
- Publication Date: 2001
- Doi Number: 10.1016/s0022-0728(01)00529-0
- Journal Name: JOURNAL OF ELECTROANALYTICAL CHEMISTRY
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Page Numbers: pp.100-110
- Keywords: adsorption, electrosorption, phenol, chlorophenols, carbon-felt, waste-water purification, DOUBLE-LAYER
- Akdeniz University Affiliated: Yes
Abstract
The adsorption and electrosorption behavior of phenol, sodium phenoxide, 1-, 2- and 3-chlorophenol and 2,6-dichlorophenol were studied at high-area carbon-felt (C-felt) electrodes by in situ UV spectroscopy in relation to development of procedures for purification of industrial waste-waters. Spectral characteristics and calibration parameters were evaluated for the phenolic species studied. It was demonstrated that the initial concentrations (about 1 mM) of these compounds can be reduced by a factor of 3 or more from waste-waters by adsorption at the C-felt already at a level of small percentage coverage on the surface ( < 10%). It was also found that the rate of adsorption of these compounds can be enhanced by polarizing the C-felt electrode, especially in the presence of an inert supporting electrolyte such as Na2SO4. Suppression of hydrolysis of phenoxide in the presence of NaOH, associated with ionization of phenol, diminishes the adsorption of phenoxide probably due to its hydration, causing it to be more hydrophilic than phenol. However, in situ analysis of aqueous phenoxide solution, without NaOH, as a mixture of phenoxide anion and phenol, the hydrolysis product, is made possible by the experimental setup and the software used, and shows that both species were adsorbed and electrosorbed at the C-felt. Among the three monochlorophenols, 4-chlorophenol exhibited the lowest rate of adsorption with 2-chlorophenol having the highest according to a kinetically first-order treatment of the adsorption data, while 2,6-dichlorophenol was adsorbed at an intermediate rate. (C) 2001 Elsevier Science B.V. All rights reserved.