Evaluation of the adsorption of aquatic humic substances in batch and column experiments by thermally modified activated carbons / Unai Iriarte-Velasco in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5445–5453 Titre : Evaluation of the adsorption of aquatic humic substances in batch and column experiments by thermally modified activated carbons Type de document : texte imprimé Auteurs : Unai Iriarte-Velasco, Auteur ; Jon I. Álvarez-Uriarte, Auteur ; Noemí Chimeno-Alanís, Auteur Année de publication : 2009 Article en page(s) : pp. 5445–5453 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Granular activated carbons Batch Column mode experiments Aquatic humic substances Résumé : Two commercially available granular activated carbons (GACs) were thermally modified and evaluated for their adsorption properties in batch and column mode experiments. The widely used and well characterized aquatic humic substances were used as adsorbate. The aim was to relate the adsorption properties of GAC with their physicochemical properties and also evaluate the impact of heat treatment under nitrogen atmosphere on the performance of the adsorbent in both batch and column operation modes. Heat treatment had a qualitatively similar effect on surface basicity and pore volume of both adsorbents. However, in quantitative terms, significant differences were reported. Heat-treatment enhanced batch adsorption capacity only for GAC-A. Surface available in pores within 12−15 Å width was strongly correlated to the NOM adsorption capacity. Benefits of thermal treatment were more evident at high initial solute concentrations. Results from batch adsorption did not have a straightforward relationship with column adsorption performance. Column adsorption capacities at complete breakthrough reached 26% and 79% of batch mode capacities. The highest difference was observed for carbon GAC-A, which corresponds to the more mass transfer limited system. During column operation smaller fractions of NOM were more readily adsorbed compared to batch mode. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900053p [article] Evaluation of the adsorption of aquatic humic substances in batch and column experiments by thermally modified activated carbons [texte imprimé] / Unai Iriarte-Velasco, Auteur ; Jon I. Álvarez-Uriarte, Auteur ; Noemí Chimeno-Alanís, Auteur . - 2009 . - pp. 5445–5453. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5445–5453 Mots-clés : Granular activated carbons Batch Column mode experiments Aquatic humic substances Résumé : Two commercially available granular activated carbons (GACs) were thermally modified and evaluated for their adsorption properties in batch and column mode experiments. The widely used and well characterized aquatic humic substances were used as adsorbate. The aim was to relate the adsorption properties of GAC with their physicochemical properties and also evaluate the impact of heat treatment under nitrogen atmosphere on the performance of the adsorbent in both batch and column operation modes. Heat treatment had a qualitatively similar effect on surface basicity and pore volume of both adsorbents. However, in quantitative terms, significant differences were reported. Heat-treatment enhanced batch adsorption capacity only for GAC-A. Surface available in pores within 12−15 Å width was strongly correlated to the NOM adsorption capacity. Benefits of thermal treatment were more evident at high initial solute concentrations. Results from batch adsorption did not have a straightforward relationship with column adsorption performance. Column adsorption capacities at complete breakthrough reached 26% and 79% of batch mode capacities. The highest difference was observed for carbon GAC-A, which corresponds to the more mass transfer limited system. During column operation smaller fractions of NOM were more readily adsorbed compared to batch mode. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900053p

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Natural organic matter adsorption onto granular activated carbons / Unai Iriarte-Velasco in Industrial & engineering chemistry research, Vol. 47 N°20 (Octobre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7868-7876 Titre : Natural organic matter adsorption onto granular activated carbons : implications in the molecular weight and disinfection byproducts formation Type de document : texte imprimé Auteurs : Unai Iriarte-Velasco, Auteur ; Jon I. Álvarez-Uriarte, Auteur ; Noemí Chimeno-Alanís, Auteur ; Juan R. Gonzalez-Velasco, Auteur Année de publication : 2008 Article en page(s) : P. 7868-7876 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbon Granular activated carbon (GAC) Thermogravimetric analysis (TGA) Résumé : Adsorption of natural organic matter (NOM) by granular activated carbon (GAC) was studied. Three different carbons of different origin were initially used. The physical properties were studied by means of N2 adsorption. Chemical properties were studied by means of thermogravimetric analysis (TGA), acid−base titrations, and FTIR. Only one of the carbons showed a broad adsorption band in the 1300−1000 cm−1 region in FTIR spectra, which can be assigned to C−O stretching and O−H bending modes of alcoholic, phenolic, and carboxylic groups. Adsorption of NOM was studied by batch adsorption experiments. Uptake of NOM by the different carbons was evaluated by UV absorbance, disinfection byproduct formation potential tests, and HPLC-SEC chromatography. Freundlich equation was used to fit equilibrium data. pHPZC and overall surface basicity were shown to improve the removal of THM precursors. Differences in the molecular weight distribution of the adsorbed material by different carbons were reported. A clear correlation was found between the reduction in the THM formation capacity of sample and the reduction in intensity of a specific peak in SEC chromatograms. Furthermore, THMFP tests showed the existence of some fractions of NOM not adsorbable with activated carbons and undetected by measurement of DOC. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800912y [article] Natural organic matter adsorption onto granular activated carbons : implications in the molecular weight and disinfection byproducts formation [texte imprimé] / Unai Iriarte-Velasco, Auteur ; Jon I. Álvarez-Uriarte, Auteur ; Noemí Chimeno-Alanís, Auteur ; Juan R. Gonzalez-Velasco, Auteur . - 2008 . - P. 7868-7876. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7868-7876 Mots-clés : Carbon Granular activated carbon (GAC) Thermogravimetric analysis (TGA) Résumé : Adsorption of natural organic matter (NOM) by granular activated carbon (GAC) was studied. Three different carbons of different origin were initially used. The physical properties were studied by means of N2 adsorption. Chemical properties were studied by means of thermogravimetric analysis (TGA), acid−base titrations, and FTIR. Only one of the carbons showed a broad adsorption band in the 1300−1000 cm−1 region in FTIR spectra, which can be assigned to C−O stretching and O−H bending modes of alcoholic, phenolic, and carboxylic groups. Adsorption of NOM was studied by batch adsorption experiments. Uptake of NOM by the different carbons was evaluated by UV absorbance, disinfection byproduct formation potential tests, and HPLC-SEC chromatography. Freundlich equation was used to fit equilibrium data. pHPZC and overall surface basicity were shown to improve the removal of THM precursors. Differences in the molecular weight distribution of the adsorbed material by different carbons were reported. A clear correlation was found between the reduction in the THM formation capacity of sample and the reduction in intensity of a specific peak in SEC chromatograms. Furthermore, THMFP tests showed the existence of some fractions of NOM not adsorbable with activated carbons and undetected by measurement of DOC. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800912y

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