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Kinetic approach for investigating the “Microwave Effect” / Basak Temur Ergan in Industrial & engineering chemistry research, Vol. 50 N° 11 (Juin 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp 6629–6637 Titre : Kinetic approach for investigating the “Microwave Effect” : decomposition of aqueous potassium persulfate Type de document : texte imprimé Auteurs : Basak Temur Ergan, Auteur ; Mahmut Bayramoglu, Auteur Année de publication : 2011 Article en page(s) : pp 6629–6637 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic  Potassium  persulfate Résumé : In this work, the specific effect of microwave (MW) energy on chemical reactions was investigated by online monitoring of the decomposition kinetics of potassium persulfate (K2S2O8). Experiments conducted at constant temperature and constant MW power revealed that the rate constant was about 1.1–1.8 times higher than the rate constant of the thermally heated system at the same temperature, depending on the MW power. To model the dependence of the rate constant on the MW power as k = f(P) exp(−g(P)/T), various functional forms of MW power were envisaged for g(P) (activation energy Ea) and for f(P) (preexponential factor ko). Linear, quadratic, and cubic polynomial models were tried for both functions. Nonlinear regression analysis was performed and detailed statistical analysis was applied, and the best results were obtained with quadratic f(P) and cubic g(P) functions, with the highest R2adj (0.9975) and the lowest standard deviation (0.94 × 10–5). The mathematical model revealed that both the activation energy and preexponential factor were higher than their thermal counterparts (for P = 0.75 kW dm–3, ko,mw/ko,th = 120, Ea,mw/Ea,th = 1.12). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200095y [article] Kinetic approach for investigating the “Microwave Effect” : decomposition of aqueous potassium persulfate [texte imprimé] / Basak Temur Ergan, Auteur ; Mahmut Bayramoglu, Auteur . - 2011 . - pp 6629–6637. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp 6629–6637 Mots-clés : Kinetic  Potassium  persulfate Résumé : In this work, the specific effect of microwave (MW) energy on chemical reactions was investigated by online monitoring of the decomposition kinetics of potassium persulfate (K2S2O8). Experiments conducted at constant temperature and constant MW power revealed that the rate constant was about 1.1–1.8 times higher than the rate constant of the thermally heated system at the same temperature, depending on the MW power. To model the dependence of the rate constant on the MW power as k = f(P) exp(−g(P)/T), various functional forms of MW power were envisaged for g(P) (activation energy Ea) and for f(P) (preexponential factor ko). Linear, quadratic, and cubic polynomial models were tried for both functions. Nonlinear regression analysis was performed and detailed statistical analysis was applied, and the best results were obtained with quadratic f(P) and cubic g(P) functions, with the highest R2adj (0.9975) and the lowest standard deviation (0.94 × 10–5). The mathematical model revealed that both the activation energy and preexponential factor were higher than their thermal counterparts (for P = 0.75 kW dm–3, ko,mw/ko,th = 120, Ea,mw/Ea,th = 1.12). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200095y

Nickel removal from waters using a surfactant-enhanced hybrid powdered activated carbon/microfiltration process. II. the influence of process variables / Coskun Aydiner 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. 903–913 Titre : Nickel removal from waters using a surfactant-enhanced hybrid powdered activated carbon/microfiltration process. II. the influence of process variables Type de document : texte imprimé Auteurs : Coskun Aydiner, Auteur ; Mahmut Bayramoglu, Auteur ; Bulent Keskinler, Auteur ; Orhan Ince, Auteur Année de publication : 2009 Article en page(s) : p. 903–913 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Carbon/Microfiltration  --  ProcessProcess  Variables  --  Influence Résumé : This study focused on the removal of nickel ions from aqueous solution using a surfactant-enhanced (SE) powdered activated carbon (PAC)/microfiltration (MF) hybrid membrane process. The main objective of the research is to investigate the technical performance of the process under the influences of all relevant process variables namely process time, recycling time, pH, temperature, PAC concentration, surfactant concentration, nickel concentration, cross-flow velocity, and transmembrane pressure, thus to reveal its applicability to water problems involved in heavy metal pollution. The concentrations of PAC, surfactant, metal, and H+ ion were determined as significant process stream variables, while transmembrane pressure and temperature came into prominence as significant operating variables. ANOVA calculations indicated that the total influences of these six variables on process performance realized in a range of about 93−98%. Nickel concentration and PAC amount in the feed were established as the most influential variables for nickel rejection, and surfactant rejection and permeate flux, respectively. The increase of PAC from 0.1 to 4 g/L led to a flux decline of about 60%. The most critical parameter for process performance was the mass ratio of PAC to surfactant (PAC/surfactant) per unit mass of metal removed. The process which may be effectively operated in continuous cross-flow filtration mode within a short filtration time of 30 min has crucial advantages compared to high pressure driven membrane processes and offers a promising alternative to remove heavy metal pollutants from drinking waters and metal bearing wastewaters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8004308 [article] Nickel removal from waters using a surfactant-enhanced hybrid powdered activated carbon/microfiltration process. II. the influence of process variables [texte imprimé] / Coskun Aydiner, Auteur ; Mahmut Bayramoglu, Auteur ; Bulent Keskinler, Auteur ; Orhan Ince, Auteur . - 2009 . - p. 903–913. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 903–913 Mots-clés : Carbon/Microfiltration  --  ProcessProcess  Variables  --  Influence Résumé : This study focused on the removal of nickel ions from aqueous solution using a surfactant-enhanced (SE) powdered activated carbon (PAC)/microfiltration (MF) hybrid membrane process. The main objective of the research is to investigate the technical performance of the process under the influences of all relevant process variables namely process time, recycling time, pH, temperature, PAC concentration, surfactant concentration, nickel concentration, cross-flow velocity, and transmembrane pressure, thus to reveal its applicability to water problems involved in heavy metal pollution. The concentrations of PAC, surfactant, metal, and H+ ion were determined as significant process stream variables, while transmembrane pressure and temperature came into prominence as significant operating variables. ANOVA calculations indicated that the total influences of these six variables on process performance realized in a range of about 93−98%. Nickel concentration and PAC amount in the feed were established as the most influential variables for nickel rejection, and surfactant rejection and permeate flux, respectively. The increase of PAC from 0.1 to 4 g/L led to a flux decline of about 60%. The most critical parameter for process performance was the mass ratio of PAC to surfactant (PAC/surfactant) per unit mass of metal removed. The process which may be effectively operated in continuous cross-flow filtration mode within a short filtration time of 30 min has crucial advantages compared to high pressure driven membrane processes and offers a promising alternative to remove heavy metal pollutants from drinking waters and metal bearing wastewaters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8004308