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Adding microsized silica particles to the catalysis/ultrafiltration system / Zhaoxiang Zhong in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4933–4938 Titre : Adding microsized silica particles to the catalysis/ultrafiltration system : catalyst dissolution inhibition and flux enhancement Type de document : texte imprimé Auteurs : Zhaoxiang Zhong, Auteur ; Xin Liu, Auteur ; Rizhi Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 4933–4938 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic  reactionCrossflow  ultrafiltration  Microsized  silica  particles Résumé : A system combining catalytic reaction with crossflow ultrafiltration (UF) was used to catalytic ammoximation of cyclohexanone to the oxime over titanium silicalite-1 (TS-1) catalysts. The effect of microsized silica particles on the performance of the catalysis/UF system was investigated in terms of catalytic activity and membrane filterability through dissolution and ultrafiltration experiments. Adding silica particles in the system inhibits the dissolution of TS-1 catalysts and increases both the reaction conversion and the selectivity significantly. Further characterizations (XRF, XRD, FTIR, etc.) indicated that the presence of silica particles remarkably limits the ammonia damage to the microstructure frame of TS-1 catalyst. In addition, silica particles play an important role in substantially removing the deposited TS-1 cake from the membrane surface, benefiting from the scouring effect. According to the results of visual observation to the tested membranes and the estimation of hydrodynamic forces acting on particles, microsized particles are hard to deposit on the membrane surface at the studied conditions and therefore a flux improvement has been achieved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801774a [article] Adding microsized silica particles to the catalysis/ultrafiltration system : catalyst dissolution inhibition and flux enhancement [texte imprimé] / Zhaoxiang Zhong, Auteur ; Xin Liu, Auteur ; Rizhi Chen, Auteur . - 2009 . - pp. 4933–4938. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4933–4938 Mots-clés : Catalytic  reactionCrossflow  ultrafiltration  Microsized  silica  particles Résumé : A system combining catalytic reaction with crossflow ultrafiltration (UF) was used to catalytic ammoximation of cyclohexanone to the oxime over titanium silicalite-1 (TS-1) catalysts. The effect of microsized silica particles on the performance of the catalysis/UF system was investigated in terms of catalytic activity and membrane filterability through dissolution and ultrafiltration experiments. Adding silica particles in the system inhibits the dissolution of TS-1 catalysts and increases both the reaction conversion and the selectivity significantly. Further characterizations (XRF, XRD, FTIR, etc.) indicated that the presence of silica particles remarkably limits the ammonia damage to the microstructure frame of TS-1 catalyst. In addition, silica particles play an important role in substantially removing the deposited TS-1 cake from the membrane surface, benefiting from the scouring effect. According to the results of visual observation to the tested membranes and the estimation of hydrodynamic forces acting on particles, microsized particles are hard to deposit on the membrane surface at the studied conditions and therefore a flux improvement has been achieved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801774a

Conditions optimization and kinetics for the cleaning of ceramic membranes fouled by BaSO4 crystals in brine purification using a DTPA complex solution / Junjie Gu in Industrial & engineering chemistry research, Vol. 50 N° 19 (Octobre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 19 (Octobre 2011) . - pp. 11245-11251 Titre : Conditions optimization and kinetics for the cleaning of ceramic membranes fouled by BaSO4 crystals in brine purification using a DTPA complex solution Type de document : texte imprimé Auteurs : Junjie Gu, Auteur ; Huiqin Zhang, Auteur ; Zhaoxiang Zhong, Auteur Année de publication : 2011 Article en page(s) : pp. 11245-11251 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization  Kinetics  Ceramic  membranes Résumé : We investigated the cleaning efficiency and kinetics of multichannel ceramic membranes fouled during brine purification. The foulants were first characterized by means of SEM, EDX, and XRD analyses, and we found that mainly BaSO4 crystals were deposited on the membrane surface. A cleaning solution composed of diethylenetrinitrilopentaacetic acid (DTPA), oxalic acid, and NaOH was developed to regenerate the fouled ceramic membranes. The membranes could be completely recovered with the cleaning solution. The cleaning rate increased with the concentration of DTPA (C DTPA) and temperature (T) but was not sensitive to the crossflow velocity (CFV) or transmembrane pressure (TMP). The optimized cleaning condition was C DTPA = 1.0 × 10–3 mol/L, T = 50 °C, CFV = 3.0 m/s, and TMP = 0.10 MPa. A dissolution kinetics model associated with both the concentration factor and temperature factor was developed, which fitted well the experimental results. This model was used to determine the reaction rate constants during the cleaning process at different temperatures. Based on this model, we found that the activation energy of BaSO4 dissolution using the cleaning solution consisted of DTPA, oxalic acid, and NaOH was lower than that of using pure DTPA solution. The results support the conclusion that the compound solution provided a better cleaning performance than pure DTPA solution. DEWEY : 660 ISSN : 0888-5885 En ligne : http://journals1.scholarsportal.info/details.xqy?uri=/08885885/v50i0019/11245_co [...] [article] Conditions optimization and kinetics for the cleaning of ceramic membranes fouled by BaSO4 crystals in brine purification using a DTPA complex solution [texte imprimé] / Junjie Gu, Auteur ; Huiqin Zhang, Auteur ; Zhaoxiang Zhong, Auteur . - 2011 . - pp. 11245-11251. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 19 (Octobre 2011) . - pp. 11245-11251 Mots-clés : Optimization  Kinetics  Ceramic  membranes Résumé : We investigated the cleaning efficiency and kinetics of multichannel ceramic membranes fouled during brine purification. The foulants were first characterized by means of SEM, EDX, and XRD analyses, and we found that mainly BaSO4 crystals were deposited on the membrane surface. A cleaning solution composed of diethylenetrinitrilopentaacetic acid (DTPA), oxalic acid, and NaOH was developed to regenerate the fouled ceramic membranes. The membranes could be completely recovered with the cleaning solution. The cleaning rate increased with the concentration of DTPA (C DTPA) and temperature (T) but was not sensitive to the crossflow velocity (CFV) or transmembrane pressure (TMP). The optimized cleaning condition was C DTPA = 1.0 × 10–3 mol/L, T = 50 °C, CFV = 3.0 m/s, and TMP = 0.10 MPa. A dissolution kinetics model associated with both the concentration factor and temperature factor was developed, which fitted well the experimental results. This model was used to determine the reaction rate constants during the cleaning process at different temperatures. Based on this model, we found that the activation energy of BaSO4 dissolution using the cleaning solution consisted of DTPA, oxalic acid, and NaOH was lower than that of using pure DTPA solution. The results support the conclusion that the compound solution provided a better cleaning performance than pure DTPA solution. DEWEY : 660 ISSN : 0888-5885 En ligne : http://journals1.scholarsportal.info/details.xqy?uri=/08885885/v50i0019/11245_co [...]

Integrated membrane process for the treatment of desulfurization wastewate / Na Yin in Industrial & engineering chemistry research, Vol. 49 N° 7 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3337–3341 Titre : Integrated membrane process for the treatment of desulfurization wastewate Type de document : texte imprimé Auteurs : Na Yin, Auteur ; Fei Liu, Auteur ; Zhaoxiang Zhong, Auteur Année de publication : 2010 Article en page(s) : pp. 3337–3341 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Integrated  Membrane  Desulfurization  Wastewate Résumé : In the desulfurization process for purification of coking gas, a huge amount of wastewater is generated. In order to recover the usable substances such as suspended sulfur (SS) and ammonium salts, e.g., (NH4)2S2O3 and NH4SCN, in the wastewater and also to avoid severe environmental problems in the case of improper disposal, an integrated membrane process mainly consisting of ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) was proposed to treat the wastewater. In the UF process, a ceramic membrane was employed to remove SS and an efficiency of 99.9% and a steady flux of about 500 L·m−2·h−1 were achieved. In the NF step, (NH4)2S2O3 was separated from NH4SCN with a retention ratio of 95.0%, and finally 83.0% of (NH4)2S2O3 was recovered in the retentate, whereas 99.2% of NH4SCN was recovered in the permeate via dialysis with deionized water. In the RO process, NH4SCN can be recovered with an efficiency of 99.0% through a four-pass filtration process. Meanwhile, the RO permeate can be reused in the salt diafiltration process. The results show that the proposed integrated membrane process is technically feasible and economically efficient for the treatment of desulfurization wastewater generated in the coking industry. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901267q [article] Integrated membrane process for the treatment of desulfurization wastewate [texte imprimé] / Na Yin, Auteur ; Fei Liu, Auteur ; Zhaoxiang Zhong, Auteur . - 2010 . - pp. 3337–3341. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3337–3341 Mots-clés : Integrated  Membrane  Desulfurization  Wastewate Résumé : In the desulfurization process for purification of coking gas, a huge amount of wastewater is generated. In order to recover the usable substances such as suspended sulfur (SS) and ammonium salts, e.g., (NH4)2S2O3 and NH4SCN, in the wastewater and also to avoid severe environmental problems in the case of improper disposal, an integrated membrane process mainly consisting of ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) was proposed to treat the wastewater. In the UF process, a ceramic membrane was employed to remove SS and an efficiency of 99.9% and a steady flux of about 500 L·m−2·h−1 were achieved. In the NF step, (NH4)2S2O3 was separated from NH4SCN with a retention ratio of 95.0%, and finally 83.0% of (NH4)2S2O3 was recovered in the retentate, whereas 99.2% of NH4SCN was recovered in the permeate via dialysis with deionized water. In the RO process, NH4SCN can be recovered with an efficiency of 99.0% through a four-pass filtration process. Meanwhile, the RO permeate can be reused in the salt diafiltration process. The results show that the proposed integrated membrane process is technically feasible and economically efficient for the treatment of desulfurization wastewater generated in the coking industry. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901267q