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Intermolecular interactions between surfactants and cationic dyes and effect on antimicrobial properties / Nastaran Hashemi in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8347–8352 Titre : Intermolecular interactions between surfactants and cationic dyes and effect on antimicrobial properties Type de document : texte imprimé Auteurs : Nastaran Hashemi, Auteur ; Gang Sun, Auteur Année de publication : 2010 Article en page(s) : pp. 8347–8352 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Cationic  molecules Résumé : Cationic molecules can interact with anionic and other cationic species in solutions. Electrostatic and hydrophobic interactions between two series of cationic antimicrobial dyes and several surfactants were studied using a UV−vis spectrophotometer. The dye containing more cationic charges with a short alkyl chain showed stronger binding power with surfactants than the one with less positive charge, while the ones with longer chains exhibited lower binding energy. These dyes could form complex structures with anionic surfactant species in solutions at very low concentrations of the surfactant (far below critical-micelle-forming concentrations of the surfactants), which was revealed from the changes in absorbance and wavelength of the maximum absorbance (λmax) of photospectrometry. However, when the concentrations of surfactants were above their critical micelle concentrations, the dyes could redissolve and dissociate into molecular or ionic forms. Such results were confirmed by conductivity and antimicrobial functions of the solutions. These findings are useful in understanding the impact of anionic surfactants on cationic antimicrobial agents. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101001d [article] Intermolecular interactions between surfactants and cationic dyes and effect on antimicrobial properties [texte imprimé] / Nastaran Hashemi, Auteur ; Gang Sun, Auteur . - 2010 . - pp. 8347–8352. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8347–8352 Mots-clés : Cationic  molecules Résumé : Cationic molecules can interact with anionic and other cationic species in solutions. Electrostatic and hydrophobic interactions between two series of cationic antimicrobial dyes and several surfactants were studied using a UV−vis spectrophotometer. The dye containing more cationic charges with a short alkyl chain showed stronger binding power with surfactants than the one with less positive charge, while the ones with longer chains exhibited lower binding energy. These dyes could form complex structures with anionic surfactant species in solutions at very low concentrations of the surfactant (far below critical-micelle-forming concentrations of the surfactants), which was revealed from the changes in absorbance and wavelength of the maximum absorbance (λmax) of photospectrometry. However, when the concentrations of surfactants were above their critical micelle concentrations, the dyes could redissolve and dissociate into molecular or ionic forms. Such results were confirmed by conductivity and antimicrobial functions of the solutions. These findings are useful in understanding the impact of anionic surfactants on cationic antimicrobial agents. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101001d

New refreshable n-halamine polymeric biocides: n-chlorination of acyclic amide grafted cellulose / Song Liu in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 613–618 Titre : New refreshable n-halamine polymeric biocides: n-chlorination of acyclic amide grafted cellulose Type de document : texte imprimé Auteurs : Song Liu, Auteur ; Gang Sun, Auteur Année de publication : 2009 Article en page(s) : p. 613–618 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : antibacterial--  functions  polymerization--processes Résumé : Acyclic N-halamine structures have demonstrated antibacterial functions similar to cyclic N-halamine. Precursors of acyclic halamine such as acrylamide and methacrylamide can be easily grafted onto surfaces of substrates via radical polymerization processes. However, due to easy hydrolysis of primary amides during chlorination and steric hindrance of secondary amide to conversion to acyclic halamine structures, the acyclic halamines still have limitations to many applications in preparation of antimicrobial materials. To reduce hydrolysis of amide during chlorination, particularly under alkaline conditions, addition of electrolytes such as NaCl was able to improve chlorination of polyacrylamide grafted cotton (chlorine content 458 ppm) with less than 10% hydrolysis under slightly basic (pH = 8) conditions. Both acidic conditions and the addition of salt can increase the chlorination of secondary amides and provide effective antibacterial functions on the treated cellulose (5 log reduction of E. coli in contact time of 120 min). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007902 [article] New refreshable n-halamine polymeric biocides: n-chlorination of acyclic amide grafted cellulose [texte imprimé] / Song Liu, Auteur ; Gang Sun, Auteur . - 2009 . - p. 613–618. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 613–618 Mots-clés : antibacterial--  functions  polymerization--processes Résumé : Acyclic N-halamine structures have demonstrated antibacterial functions similar to cyclic N-halamine. Precursors of acyclic halamine such as acrylamide and methacrylamide can be easily grafted onto surfaces of substrates via radical polymerization processes. However, due to easy hydrolysis of primary amides during chlorination and steric hindrance of secondary amide to conversion to acyclic halamine structures, the acyclic halamines still have limitations to many applications in preparation of antimicrobial materials. To reduce hydrolysis of amide during chlorination, particularly under alkaline conditions, addition of electrolytes such as NaCl was able to improve chlorination of polyacrylamide grafted cotton (chlorine content 458 ppm) with less than 10% hydrolysis under slightly basic (pH = 8) conditions. Both acidic conditions and the addition of salt can increase the chlorination of secondary amides and provide effective antibacterial functions on the treated cellulose (5 log reduction of E. coli in contact time of 120 min). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007902

Oxidative degradation of organophosphorous pesticides by -nhalamine fabrics / Xin Fei in Industrial & engineering chemistry research, Vol. 48 N° 12 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5604–5609 Titre : Oxidative degradation of organophosphorous pesticides by -nhalamine fabrics Type de document : texte imprimé Auteurs : Xin Fei, Auteur ; Gang Sun, Auteur Année de publication : 2009 Article en page(s) : pp. 5604–5609 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cotton  Cotton/polyester  fabrics  Halamine  structures  Organophosphorus  pesticides Résumé : Cotton and cotton/polyester fabrics containing halamine structures were able to react with certain organophosphorus pesticides upon contact. The reaction occurred at thione group in methyl parathion and malathion, and reaction products were oxon compounds. The fabric containing imide and amide halamine structures were able to oxidize 90% of methyl parathion in less than 2 h of contact time under room temperature, while the amine halamine structure needed longer time to reach the same level of oxidation. The reaction was endothermic, and the oxidation rate was in first order to the concentrations of the pesticides. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801254u [article] Oxidative degradation of organophosphorous pesticides by -nhalamine fabrics [texte imprimé] / Xin Fei, Auteur ; Gang Sun, Auteur . - 2009 . - pp. 5604–5609. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5604–5609 Mots-clés : Cotton  Cotton/polyester  fabrics  Halamine  structures  Organophosphorus  pesticides Résumé : Cotton and cotton/polyester fabrics containing halamine structures were able to react with certain organophosphorus pesticides upon contact. The reaction occurred at thione group in methyl parathion and malathion, and reaction products were oxon compounds. The fabric containing imide and amide halamine structures were able to oxidize 90% of methyl parathion in less than 2 h of contact time under room temperature, while the amine halamine structure needed longer time to reach the same level of oxidation. The reaction was endothermic, and the oxidation rate was in first order to the concentrations of the pesticides. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801254u

Production of reactive oxygen species by photoactive anthraquinone compounds and their applications in wastewater treatment / Ning Liu in Industrial & engineering chemistry research, Vol. 50 N° 9 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5326-5333 Titre : Production of reactive oxygen species by photoactive anthraquinone compounds and their applications in wastewater treatment Type de document : texte imprimé Auteurs : Ning Liu, Auteur ; Gang Sun, Auteur Année de publication : 2011 Article en page(s) : pp. 5326-5333 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Waste  water  purification  Production Résumé : 2-Anthraquinone sulfonate (2-AQS) was found to exhibit an abnormally high singlet-oxygen quantum yield in aqueous solution after UVA irradiation based on a widely used testing method for singlet oxygen. To discover the cause of the abnormal results, several possible reactive oxygen species were also measured in the system. Results revealed that 2-AQS and two other similar compounds produced singlet oxygen, hydroxyl radicals, and superoxide, so-called reactive oxygen species (ROS), under UVA exposure. The production of hydroxyl radical contributed to the abnormally high quantum yield. Quantifications of the ROS produced by these compounds were conducted by oxidation ofp-nitrosodimethylaninline in the presence and absence of either L-histidine or superoxide dismutase. EPR results also confirmed the formation of singlet oxygen by these compounds under UVA irradiation. The influence of different exposure times on the formation of ROS was measured for all three photosensitive compounds. The effects of different additives on the production of ROS were also investigated. The results showed that some compounds traditionally known as "hydroxyl radical scavengers" instead served as hydroxyl radical "generation promoters" under UVA exposure in the system. Moreover, for the first time, these photosensitive compounds were used to degrade a textile colorant, namely, Reactive Black 5, achieving the total decoloration of this compound within 10 min. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128654 [article] Production of reactive oxygen species by photoactive anthraquinone compounds and their applications in wastewater treatment [texte imprimé] / Ning Liu, Auteur ; Gang Sun, Auteur . - 2011 . - pp. 5326-5333. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5326-5333 Mots-clés : Waste  water  purification  Production Résumé : 2-Anthraquinone sulfonate (2-AQS) was found to exhibit an abnormally high singlet-oxygen quantum yield in aqueous solution after UVA irradiation based on a widely used testing method for singlet oxygen. To discover the cause of the abnormal results, several possible reactive oxygen species were also measured in the system. Results revealed that 2-AQS and two other similar compounds produced singlet oxygen, hydroxyl radicals, and superoxide, so-called reactive oxygen species (ROS), under UVA exposure. The production of hydroxyl radical contributed to the abnormally high quantum yield. Quantifications of the ROS produced by these compounds were conducted by oxidation ofp-nitrosodimethylaninline in the presence and absence of either L-histidine or superoxide dismutase. EPR results also confirmed the formation of singlet oxygen by these compounds under UVA irradiation. The influence of different exposure times on the formation of ROS was measured for all three photosensitive compounds. The effects of different additives on the production of ROS were also investigated. The results showed that some compounds traditionally known as "hydroxyl radical scavengers" instead served as hydroxyl radical "generation promoters" under UVA exposure in the system. Moreover, for the first time, these photosensitive compounds were used to degrade a textile colorant, namely, Reactive Black 5, achieving the total decoloration of this compound within 10 min. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128654