Pillared anionic clays or layered double hydroxides were prepared by means of hydrothermal ion exchange reaction of [Zn 2Al(OH) 6]NO 3· x H 2O (ZnAl NO 3) with [GaW 11 O 39 M(H 2O)] 7- (abbr...Pillared anionic clays or layered double hydroxides were prepared by means of hydrothermal ion exchange reaction of [Zn 2Al(OH) 6]NO 3· x H 2O (ZnAl NO 3) with [GaW 11 O 39 M(H 2O)] 7- (abbreviated as GaW 11 M, M=Mn 2+ , Co +2 or Ni 2+ ). The layered compounds were characterized by means of XRD, IR, elemental analysis and DTA. The X ray diffraction and IR spectra show that the new anionic clays synthesized are layered compounds with the gallery heights of 0.99-1.00 nm and the Keggin structure tungstogallic heteropolyanions almost completely replace the interlayer NO - 3, entering the layer and retain their Keggin structure. The DTA gives a thermostability order of ZnAl GaW 11 Ni >ZnAl GaW 11 Co>ZnAl GaW 11 Mn>ZnAl NO 3. The ctalytic tests showed that the new pillared compounds have higher catalytic activities in the cyclooxidation reaction of maleic acid.展开更多
Because phenolic compounds are toxic for methanogenic bacteria many problems concerning the high toxicity and biodegradability of the olive oil mill wastewater (OMW) have been encountered during anaerobic treatments o...Because phenolic compounds are toxic for methanogenic bacteria many problems concerning the high toxicity and biodegradability of the olive oil mill wastewater (OMW) have been encountered during anaerobic treatments of this effluent. In this work, we try to develop a new catalytic process for the degradation of phenolic compounds, producing less toxic OMW for methanogenic bacteria, facilitating the anaerobic digestion. This process consists of an oxidative reaction using copper supported on alumina pillared clay in presence of a photocatalytic system (H2O2 with UV light). Preliminary results showed that the use of the copper supported catalyst in presence of 0.88% H2O2 (v/v) allows after 2 h colour reduction (25%), significant abatement of total organic carbon (40%), and important removal of polyphenolic compounds (63%) especially those of high molecular mass and subsequently decreases the OMW toxicity from 100% to 70%. This catalytic pre-treatment process of OMW was efficient for anaerobic digestion.展开更多
Pillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of thymol by alumi...Pillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of thymol by aluminum pillared clay (PILC). The PILCs displayed a total surface area of 270 m2/g, a total pore volume of 0.246 cm3/g and an average pore diameter of 8.9 A, which corresponds to the size of Al13 forming the pillars between the clay layers. The adsorption capacity shown by the PILCs for thymol from water is close to 319 mg?g-1 for low solid/liquid ratio (0.2%). This result suggests that the PILCs have both hydrophobic and hydrophilic characteristics, as a result of the presence of silanol and siloxane groups formed during the pillaring and calcination of the PILCs. The experimental data were analyzed by the Freundlich and the Langmuir isotherm types for low values of equilibrium concentration. The rise of the isotherm in this range of concentrations was related to the affinity of thymol for clay sites, and the equilibrium data fitted well with the Freundlich model with maximum adsorption capacity of 319.51 mg/g for a ratio RS/L = 0.2%. Pseudo-first and pseudo-second-order kinetic models were tested with the experimental data and pseudo-first order kinetics was the best for the adsorption of thymol with coefficients of correlation R2 ≥0.986, and the adsorption was rapid with 90% of the thymol adsorbed within the first 20 min.展开更多
Mono-substituted Keggin ions PW11O39Cr(H2O)4 , PW11TiO403 and PW11VO404 were intercalated between the layers of the clay of anions of Zn-Al type using the ion exchange method to obtain a new type of pillared layered m...Mono-substituted Keggin ions PW11O39Cr(H2O)4 , PW11TiO403 and PW11VO404 were intercalated between the layers of the clay of anions of Zn-Al type using the ion exchange method to obtain a new type of pillared layered microporous materials ZnAl-PW11Cr, ZnAl-PW11Ti and ZnAl-PW11V with basal spacing (1.48±0.02) run. On the basis of the MAS NMR results of 27A1 and 31P, a steric pillared layered structure model of orientation localization of PW11VO40,4- in the orientation in which the C2 axis of PW11VO404-is perpendicular to the host layer. It has been found that this kind of pillared layered microporous materials possess a higher catalytic activity for the esterification of acetic acid with n-butanol than H-type molecular sieves.展开更多
A mesoporous titanium/silicon -containing montmorillonite-based catalytic materials has been synthesized by novel gallery-templated techniques. XRD, SEM, framework IR, and N2 adsorptiondesorption isotherms provided e...A mesoporous titanium/silicon -containing montmorillonite-based catalytic materials has been synthesized by novel gallery-templated techniques. XRD, SEM, framework IR, and N2 adsorptiondesorption isotherms provided evidence of the formation of Si/Ti pillars. The synthetic materials show potential catalytic application for hydroxylation of phenol with peroxide.展开更多
Compared with water-based well treatment fluid systems,hydrocarbon-based fluids possess advantages such as better fluid compatibility and lower formation damage,especially in water-sensitive formations.Hydrocarbonbase...Compared with water-based well treatment fluid systems,hydrocarbon-based fluids possess advantages such as better fluid compatibility and lower formation damage,especially in water-sensitive formations.Hydrocarbonbased fluids are therefore often used in oilfield operations including hydraulic fracturing,sand control,and coiled tubing cleanout.The metal-crosslinked,phosphate ester-based gelled hydrocarbon(or gelled oil)fluids have been the preferred choice among hydrocarbon-based fluids since they are cost effective,robust at elevated temperatures,and operationally simple as only a couple of fluid additives are involved.Functioning as the gelling agent in gelled oil fluids,phosphate ester could cause fouling in refinery equipment.It is therefore desirable to lower the dosage of the phosphate ester-based gelling agent as much as possible,but without adversely affecting the fluid performance.A number of materials have been identified that could enhance the gelled oil viscosity and stability,which in turn translates into the reduction of the phosphate ester needed in the gelled oil.Among these enhancing materials,a type of aluminum pillared montmorillonite clay(the additive)was found to enhance the gelled oil viscosity to the largest extent.In laboratory tests,30 ppt(30 pounds per thousand gallons)of the additive increased the gelled oil viscosity by 84%(±5%)at 250°F when compared with the baseline gelled oil without the additive.With the additive dosage at 30 ppt,the amount of the phosphate ester in the gelled oil could be reduced by 25%without decreasing the fluid viscosity.The additive was successfully applied to the crude oil-based gelled fluid,resulting in multiple times of viscosity increase in the study.In addition to the gelled oil viscosity enhancement,the additive also increased the regained permeability in the coreflow tests to near 3 times.展开更多
文摘Pillared anionic clays or layered double hydroxides were prepared by means of hydrothermal ion exchange reaction of [Zn 2Al(OH) 6]NO 3· x H 2O (ZnAl NO 3) with [GaW 11 O 39 M(H 2O)] 7- (abbreviated as GaW 11 M, M=Mn 2+ , Co +2 or Ni 2+ ). The layered compounds were characterized by means of XRD, IR, elemental analysis and DTA. The X ray diffraction and IR spectra show that the new anionic clays synthesized are layered compounds with the gallery heights of 0.99-1.00 nm and the Keggin structure tungstogallic heteropolyanions almost completely replace the interlayer NO - 3, entering the layer and retain their Keggin structure. The DTA gives a thermostability order of ZnAl GaW 11 Ni >ZnAl GaW 11 Co>ZnAl GaW 11 Mn>ZnAl NO 3. The ctalytic tests showed that the new pillared compounds have higher catalytic activities in the cyclooxidation reaction of maleic acid.
文摘Because phenolic compounds are toxic for methanogenic bacteria many problems concerning the high toxicity and biodegradability of the olive oil mill wastewater (OMW) have been encountered during anaerobic treatments of this effluent. In this work, we try to develop a new catalytic process for the degradation of phenolic compounds, producing less toxic OMW for methanogenic bacteria, facilitating the anaerobic digestion. This process consists of an oxidative reaction using copper supported on alumina pillared clay in presence of a photocatalytic system (H2O2 with UV light). Preliminary results showed that the use of the copper supported catalyst in presence of 0.88% H2O2 (v/v) allows after 2 h colour reduction (25%), significant abatement of total organic carbon (40%), and important removal of polyphenolic compounds (63%) especially those of high molecular mass and subsequently decreases the OMW toxicity from 100% to 70%. This catalytic pre-treatment process of OMW was efficient for anaerobic digestion.
文摘Pillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of thymol by aluminum pillared clay (PILC). The PILCs displayed a total surface area of 270 m2/g, a total pore volume of 0.246 cm3/g and an average pore diameter of 8.9 A, which corresponds to the size of Al13 forming the pillars between the clay layers. The adsorption capacity shown by the PILCs for thymol from water is close to 319 mg?g-1 for low solid/liquid ratio (0.2%). This result suggests that the PILCs have both hydrophobic and hydrophilic characteristics, as a result of the presence of silanol and siloxane groups formed during the pillaring and calcination of the PILCs. The experimental data were analyzed by the Freundlich and the Langmuir isotherm types for low values of equilibrium concentration. The rise of the isotherm in this range of concentrations was related to the affinity of thymol for clay sites, and the equilibrium data fitted well with the Freundlich model with maximum adsorption capacity of 319.51 mg/g for a ratio RS/L = 0.2%. Pseudo-first and pseudo-second-order kinetic models were tested with the experimental data and pseudo-first order kinetics was the best for the adsorption of thymol with coefficients of correlation R2 ≥0.986, and the adsorption was rapid with 90% of the thymol adsorbed within the first 20 min.
基金Project supported by the National Natural Science Foundation of China
文摘Mono-substituted Keggin ions PW11O39Cr(H2O)4 , PW11TiO403 and PW11VO404 were intercalated between the layers of the clay of anions of Zn-Al type using the ion exchange method to obtain a new type of pillared layered microporous materials ZnAl-PW11Cr, ZnAl-PW11Ti and ZnAl-PW11V with basal spacing (1.48±0.02) run. On the basis of the MAS NMR results of 27A1 and 31P, a steric pillared layered structure model of orientation localization of PW11VO40,4- in the orientation in which the C2 axis of PW11VO404-is perpendicular to the host layer. It has been found that this kind of pillared layered microporous materials possess a higher catalytic activity for the esterification of acetic acid with n-butanol than H-type molecular sieves.
基金supported by the National Natural Science Foundation of China(29706011)Zhejiang Provincial Natural Science Foundation NSF(201057)is acknowledged
文摘A mesoporous titanium/silicon -containing montmorillonite-based catalytic materials has been synthesized by novel gallery-templated techniques. XRD, SEM, framework IR, and N2 adsorptiondesorption isotherms provided evidence of the formation of Si/Ti pillars. The synthetic materials show potential catalytic application for hydroxylation of phenol with peroxide.
基金The authors would like to thank Dr.Ghaithan A.Al-Muntasheri for his advice to the paper and the related project。
文摘Compared with water-based well treatment fluid systems,hydrocarbon-based fluids possess advantages such as better fluid compatibility and lower formation damage,especially in water-sensitive formations.Hydrocarbonbased fluids are therefore often used in oilfield operations including hydraulic fracturing,sand control,and coiled tubing cleanout.The metal-crosslinked,phosphate ester-based gelled hydrocarbon(or gelled oil)fluids have been the preferred choice among hydrocarbon-based fluids since they are cost effective,robust at elevated temperatures,and operationally simple as only a couple of fluid additives are involved.Functioning as the gelling agent in gelled oil fluids,phosphate ester could cause fouling in refinery equipment.It is therefore desirable to lower the dosage of the phosphate ester-based gelling agent as much as possible,but without adversely affecting the fluid performance.A number of materials have been identified that could enhance the gelled oil viscosity and stability,which in turn translates into the reduction of the phosphate ester needed in the gelled oil.Among these enhancing materials,a type of aluminum pillared montmorillonite clay(the additive)was found to enhance the gelled oil viscosity to the largest extent.In laboratory tests,30 ppt(30 pounds per thousand gallons)of the additive increased the gelled oil viscosity by 84%(±5%)at 250°F when compared with the baseline gelled oil without the additive.With the additive dosage at 30 ppt,the amount of the phosphate ester in the gelled oil could be reduced by 25%without decreasing the fluid viscosity.The additive was successfully applied to the crude oil-based gelled fluid,resulting in multiple times of viscosity increase in the study.In addition to the gelled oil viscosity enhancement,the additive also increased the regained permeability in the coreflow tests to near 3 times.
