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Electro-membrane process for In situ Ion substitution and separation of salicylic acid from its sodium salt / Mahendra Kumar 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 923–930 Titre : Electro-membrane process for In situ Ion substitution and separation of salicylic acid from its sodium salt Type de document : texte imprimé Auteurs : Mahendra Kumar, Auteur ; Bijay P. Tripathi, Auteur ; Shahi, Vinod K., Auteur Année de publication : 2009 Article en page(s) : p 923–930 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Electro-Membrane  Process Résumé : An electrochemical membrane process (EMP) with three compartments (anolyte, catholyte, and central compartment) based on in-house-prepared cation-exchange membrane (CEM) was developed to achieve in situ ion substitution and recovery of salicylic acid (SAH) from its sodium salt. The physicochemical and electrochemical properties of the ion-exchange membrane (cation- and anion-exchange membrane) under standard operating conditions reveal its suitability for the proposed reactor. Experiments using sodium salicylate (SANa) solutions of different concentrations were carried out under varied applied current density to study the feasibility of the process. Overall electrochemical reaction for the in situ ion substitution and separation of SAH from SANa under operating conditions is also proposed. Results showed that developed EMP with CEMs proved promising for the in situ ion substitution and separation of SAH with recovery of SAH with current efficiency close to 90% and energy consumption around 10 kW h/kg of the SAH produced. This process was completely optimized in terms of operating conditions such as initial concentration of SANa in the central compartment, the applied current density, Na+ flux, recovery percentage, energy consumption, and current efficiency. Furthermore, the process efficiency and energy consumption of EMP for the production of SAH were compared with electrodialysis (ED) used for the separation of Na2SO4 and SAH, formed due to acidification of SANa by H2SO4. It was observed that EMP showed high current efficiency, recovery, and low energy consumption, in comparison with ED under similar experimental concentrations. It was concluded that the proposed EMP is an efficient alternate for producing SAH from SANa by economical and environmental friendly manner. Also the production of NaOH in the cathode stream is a spin off of the EMP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801317n [article] Electro-membrane process for In situ Ion substitution and separation of salicylic acid from its sodium salt [texte imprimé] / Mahendra Kumar, Auteur ; Bijay P. Tripathi, Auteur ; Shahi, Vinod K., Auteur . - 2009 . - p 923–930. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 923–930 Mots-clés : Electro-Membrane  Process Résumé : An electrochemical membrane process (EMP) with three compartments (anolyte, catholyte, and central compartment) based on in-house-prepared cation-exchange membrane (CEM) was developed to achieve in situ ion substitution and recovery of salicylic acid (SAH) from its sodium salt. The physicochemical and electrochemical properties of the ion-exchange membrane (cation- and anion-exchange membrane) under standard operating conditions reveal its suitability for the proposed reactor. Experiments using sodium salicylate (SANa) solutions of different concentrations were carried out under varied applied current density to study the feasibility of the process. Overall electrochemical reaction for the in situ ion substitution and separation of SAH from SANa under operating conditions is also proposed. Results showed that developed EMP with CEMs proved promising for the in situ ion substitution and separation of SAH with recovery of SAH with current efficiency close to 90% and energy consumption around 10 kW h/kg of the SAH produced. This process was completely optimized in terms of operating conditions such as initial concentration of SANa in the central compartment, the applied current density, Na+ flux, recovery percentage, energy consumption, and current efficiency. Furthermore, the process efficiency and energy consumption of EMP for the production of SAH were compared with electrodialysis (ED) used for the separation of Na2SO4 and SAH, formed due to acidification of SANa by H2SO4. It was observed that EMP showed high current efficiency, recovery, and low energy consumption, in comparison with ED under similar experimental concentrations. It was concluded that the proposed EMP is an efficient alternate for producing SAH from SANa by economical and environmental friendly manner. Also the production of NaOH in the cathode stream is a spin off of the EMP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801317n

Isoelectric separation of proteins using charged ultrafilter membranes with different functionality under coupled driving forces / Saxena, Arunima in Industrial & engineering chemistry research, Vol. 49 N° 2 (Janvier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 780–789 Titre : Isoelectric separation of proteins using charged ultrafilter membranes with different functionality under coupled driving forces Type de document : texte imprimé Auteurs : Saxena, Arunima, Auteur ; Shahi, Vinod K., Auteur Année de publication : 2010 Article en page(s) : pp 780–789 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Membrane  process  Isoelectric  separation  proteins. Résumé : A simple membrane process for the protein fractionation under coupled driving forces (pressure and potential difference) has been developed using acidic functionalized (sulphonated, carboxyleted, and phosphorylated) ultrafilter membranes, based on the interpolymer of poly(vinyl chloride) (PVC) and styrene-divinyl benzene (DVB) copolymer. Introduction of the different functional groups was confirmed by Fourier transform infrared (FTIR), CHNS analysis, and ion-exchange capacity measurements. Molecular weight cut off (MWCO) determination of these membranes suggested their ultrafilter nature, while their contact angle values showed hydrophilic characteristics. The apparent pore radius of these membranes was estimated by water permeation studies, while electro-osmotic permeation data was used for the determination of zeta potential under the operating environment. Systematic studies on the effects of pH, or nature of the charge on the casein (CAS) and lysozyme (LYS), on their adsorption characteristic using these charged ultrafilter membranes were carried out. Protein transmission (selectivity) and membrane throughput across both membranes were studied using binary mixture of protein under different gradients at pH points: 2.0, 5.0, 10.7, and 13.0. It was concluded that separation from the binary mixture of CAS−LYS of LYS at pH 5.0 (pI of CAS) using charged ultrafilter membranes was possible with high selectivity and throughput. It was observed that transmission of protein can be governed by varying the nature and extent of charge on the protein (pH) and membrane matrix, polarity of applied potential gradient with an ultrafilter membrane of given pore dimensions. In these novel processes, charge on the protein, nature and extent of the charge on the membrane interfaces, and polarity of the potential gradient all are governing the transport of a given protein across the membrane, which resulted high selectivity and membrane throughput under coupled driving forces. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900258d [article] Isoelectric separation of proteins using charged ultrafilter membranes with different functionality under coupled driving forces [texte imprimé] / Saxena, Arunima, Auteur ; Shahi, Vinod K., Auteur . - 2010 . - pp 780–789. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 780–789 Mots-clés : Membrane  process  Isoelectric  separation  proteins. Résumé : A simple membrane process for the protein fractionation under coupled driving forces (pressure and potential difference) has been developed using acidic functionalized (sulphonated, carboxyleted, and phosphorylated) ultrafilter membranes, based on the interpolymer of poly(vinyl chloride) (PVC) and styrene-divinyl benzene (DVB) copolymer. Introduction of the different functional groups was confirmed by Fourier transform infrared (FTIR), CHNS analysis, and ion-exchange capacity measurements. Molecular weight cut off (MWCO) determination of these membranes suggested their ultrafilter nature, while their contact angle values showed hydrophilic characteristics. The apparent pore radius of these membranes was estimated by water permeation studies, while electro-osmotic permeation data was used for the determination of zeta potential under the operating environment. Systematic studies on the effects of pH, or nature of the charge on the casein (CAS) and lysozyme (LYS), on their adsorption characteristic using these charged ultrafilter membranes were carried out. Protein transmission (selectivity) and membrane throughput across both membranes were studied using binary mixture of protein under different gradients at pH points: 2.0, 5.0, 10.7, and 13.0. It was concluded that separation from the binary mixture of CAS−LYS of LYS at pH 5.0 (pI of CAS) using charged ultrafilter membranes was possible with high selectivity and throughput. It was observed that transmission of protein can be governed by varying the nature and extent of charge on the protein (pH) and membrane matrix, polarity of applied potential gradient with an ultrafilter membrane of given pore dimensions. In these novel processes, charge on the protein, nature and extent of the charge on the membrane interfaces, and polarity of the potential gradient all are governing the transport of a given protein across the membrane, which resulted high selectivity and membrane throughput under coupled driving forces. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900258d