This paper aims to fabricate over centimeter size of porous silica monolith having meso-pores with large surface area. A precursor of porous silica monolith was obtained by sintering a monolithic SiO2-poly (vinyl alco...This paper aims to fabricate over centimeter size of porous silica monolith having meso-pores with large surface area. A precursor of porous silica monolith was obtained by sintering a monolithic SiO2-poly (vinyl alcohol) (PVA) nanocomposite at 600oC-1100oC. The sintering behavior was examined by means of Raman spectroscopy and a porosimetry. The PVA of the SiO2-PVA nanocomposite was combusted below 600oC, subsequently the silica nanoparticles of the nanocomposite were sintered above 900oC. The Raman spectroscopy suggested that amorphous structure of the porous silica monolith obtained above 1000oC was similar to that of a silica glass. The BET surface area and pore radius of the porous silica monolith decreased with increasing sintering temperature. These values were tailored in the range of ca. 0-291 m2.g-1 and 5-25 nm, respectively, by controlling the sintering temperature and time. The fabricated porous-silica monolith was translucent or opaque porous-silica depending on the pore size.展开更多
3-Aminopropyltriethoxysilane functionalized worm-like mesoporous silica monolithic（WMSM-NH2） was prepared and used as a new regenerable adsorbent for the removal of Cu2＋ ions. The analysis results show that the WMS...3-Aminopropyltriethoxysilane functionalized worm-like mesoporous silica monolithic（WMSM-NH2） was prepared and used as a new regenerable adsorbent for the removal of Cu2＋ ions. The analysis results show that the WMSM-NH2 monolithic had a high efficiency value of 99.3% for Cu2＋ remediation when the Cu2＋ solution was at an initial concentration of 10.32 mg/L. The regeneration study of the WMSM-NH2 monolithic presented that the adsorp- tion efficiency of 89.0% was remained and a mass of 92.0% was left after seven adsorption-desorption cycles were executed. The monolithic material with high resistance to the acid and good mechanical stability can facilitate the operations of adsorption and regeneration of the adsorbent.展开更多
Mesoporous carbon monolith was synthesized by the direct carbonization of compressed sucrose/silica composite, which was prepared by using sol-gel method. The structural and textural properties of the materials were i...Mesoporous carbon monolith was synthesized by the direct carbonization of compressed sucrose/silica composite, which was prepared by using sol-gel method. The structural and textural properties of the materials were investigated by XRD, DRIFT, N2-adsorption and SEM. The characterization study shows that the resultant carbon monolith possesses a relatively high surface area, large pore volume and well interconnected pore system. Addition of a certain amount of citric acid or aluminum nitrate into the sol-gel precursor of sucrose/silica composite could considerably change the structure parameters of the carbon monolith.展开更多
Monolithic silica spin column extraction （MonoSpin-SPE） was developed as a simple, sensitive, and eco-friendly pretreatment method which combined with ultra-fast liquid chromatography-mass spectrometry （UFLC-MS） t...Monolithic silica spin column extraction （MonoSpin-SPE） was developed as a simple, sensitive, and eco-friendly pretreatment method which combined with ultra-fast liquid chromatography-mass spectrometry （UFLC-MS） to determine the levels of six phthalate esters, dimethyl- （DMP）, diethyl- （DEP）, dipropyl- [ DPrP], butyl-benzyl- （BBP）, dicyclohexyl- （DcHP）, and di-n-octyl-（DOP） phthalate in physiological saline samples. Under optimized experimental conditions, the method was linear in the following ranges： 0.2- 50 μg/L for DMP, DEP, DPrP, DcHP and DOP; 5- 100 μg/L for BBP. The correlation coefficients （R2 ） were in the range of 0. 9951 - 0. 9995 for all the analytes and the limits of detection （LODs） and limits of quantification （LOQs） were in the ranges of 0.02 - 0.9 μg/L and 0.08 - 2.7μg/L, respectively. The pretreatment process showed good reproducibility with inter-day and intra-day relative standard deviations （RSDs） below 8.5% and 11.2%, respectively. This method was used to determine the levels of six phthalate esters in physiological saline samples and the recoveries ranged from 71.2% to 107.3%. DMP and DEP were found in actual physical saline samples （brand A and brand B）.展开更多
Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva,the monol...Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva,the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.展开更多
Modern porous monoliths have been conceived as a new class of stationary phases for high performance liquid chromatography(HPLC) in classical columns in the early 1990s and later extended to the capillary format.These...Modern porous monoliths have been conceived as a new class of stationary phases for high performance liquid chromatography(HPLC) in classical columns in the early 1990s and later extended to the capillary format.These monolithic materials are prepared using simple processes carried out in an external mold(inorganic monoliths) or within the confines of the column(organic monoliths and all capillary columns).These methods afford macroporous materials with large through-pores that enable applications in a rapid flow-through mode.Since all the mobile phase must flow through the monolith,the convection considerably accelerates mass transport within the monolithic separation medium and improves the separations.As a result,the monolithic columns perform well even at very high flow rates.The applications of monolithic capillary columns are demonstrated on numerous separations in the HPLC mode.展开更多
Surfactant template synthesis of mesoporous silica monolith was carried out via modified fast sol gel process. It was easy to obtain crack free silica monolith due to low volume shrinkage during the gelation. The morp...Surfactant template synthesis of mesoporous silica monolith was carried out via modified fast sol gel process. It was easy to obtain crack free silica monolith due to low volume shrinkage during the gelation. The morphology of the titled silica was characterized by transmission electron microscopy and X ray diffraction. The results showed that the pores were worm like and the pore size was about 4 nm. Further nitrogen isothermal absorption experiment indicated that the specific area of the titled material was 391 m 2/g, which was comparable with the reported value 306 m 2/g in literature.展开更多
An improved bulk sol-gel process was found to prepare transparent, non-cracking, highly pure and mono-component monolithic silica gels with a low volume shrinkage. HSi（OC2H5）3 was used as a gel acceleration to short...An improved bulk sol-gel process was found to prepare transparent, non-cracking, highly pure and mono-component monolithic silica gels with a low volume shrinkage. HSi（OC2H5）3 was used as a gel acceleration to shorten the whole sol-gel processing time in the place of the carbonate powders in bulk sol-gel process. The mono-component silica gel monoliths prepared via the improved bulk sol-gel process possess a microporous structure and a good transmittance in the UV-Vis region, and the mass fraction of silica is 89%, the mass fraction of small molecules is 11%.展开更多
文摘This paper aims to fabricate over centimeter size of porous silica monolith having meso-pores with large surface area. A precursor of porous silica monolith was obtained by sintering a monolithic SiO2-poly (vinyl alcohol) (PVA) nanocomposite at 600oC-1100oC. The sintering behavior was examined by means of Raman spectroscopy and a porosimetry. The PVA of the SiO2-PVA nanocomposite was combusted below 600oC, subsequently the silica nanoparticles of the nanocomposite were sintered above 900oC. The Raman spectroscopy suggested that amorphous structure of the porous silica monolith obtained above 1000oC was similar to that of a silica glass. The BET surface area and pore radius of the porous silica monolith decreased with increasing sintering temperature. These values were tailored in the range of ca. 0-291 m2.g-1 and 5-25 nm, respectively, by controlling the sintering temperature and time. The fabricated porous-silica monolith was translucent or opaque porous-silica depending on the pore size.
基金Supported by the National Natural Science Foundation of China（Nos. 50573030 and 21171065）.
文摘3-Aminopropyltriethoxysilane functionalized worm-like mesoporous silica monolithic（WMSM-NH2） was prepared and used as a new regenerable adsorbent for the removal of Cu2＋ ions. The analysis results show that the WMSM-NH2 monolithic had a high efficiency value of 99.3% for Cu2＋ remediation when the Cu2＋ solution was at an initial concentration of 10.32 mg/L. The regeneration study of the WMSM-NH2 monolithic presented that the adsorp- tion efficiency of 89.0% was remained and a mass of 92.0% was left after seven adsorption-desorption cycles were executed. The monolithic material with high resistance to the acid and good mechanical stability can facilitate the operations of adsorption and regeneration of the adsorbent.
基金Supported by the National Natural Science Foundation of China(Nos.20403006 and 20773050)the State Basic Research Project of China(No.2005CB221405)
文摘Mesoporous carbon monolith was synthesized by the direct carbonization of compressed sucrose/silica composite, which was prepared by using sol-gel method. The structural and textural properties of the materials were investigated by XRD, DRIFT, N2-adsorption and SEM. The characterization study shows that the resultant carbon monolith possesses a relatively high surface area, large pore volume and well interconnected pore system. Addition of a certain amount of citric acid or aluminum nitrate into the sol-gel precursor of sucrose/silica composite could considerably change the structure parameters of the carbon monolith.
基金supported by the National Natural Science Foundation of China(Nos.90813015,20935002)
文摘Monolithic silica spin column extraction （MonoSpin-SPE） was developed as a simple, sensitive, and eco-friendly pretreatment method which combined with ultra-fast liquid chromatography-mass spectrometry （UFLC-MS） to determine the levels of six phthalate esters, dimethyl- （DMP）, diethyl- （DEP）, dipropyl- [ DPrP], butyl-benzyl- （BBP）, dicyclohexyl- （DcHP）, and di-n-octyl-（DOP） phthalate in physiological saline samples. Under optimized experimental conditions, the method was linear in the following ranges： 0.2- 50 μg/L for DMP, DEP, DPrP, DcHP and DOP; 5- 100 μg/L for BBP. The correlation coefficients （R2 ） were in the range of 0. 9951 - 0. 9995 for all the analytes and the limits of detection （LODs） and limits of quantification （LOQs） were in the ranges of 0.02 - 0.9 μg/L and 0.08 - 2.7μg/L, respectively. The pretreatment process showed good reproducibility with inter-day and intra-day relative standard deviations （RSDs） below 8.5% and 11.2%, respectively. This method was used to determine the levels of six phthalate esters in physiological saline samples and the recoveries ranged from 71.2% to 107.3%. DMP and DEP were found in actual physical saline samples （brand A and brand B）.
基金supported by the Fundamental Research Foundation of Xi’an Polytechnic University ( XGJ07001)
文摘Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva,the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.
基金Supported by grants of the National Institute of General Medical Sciences,National Institutes of Health(GM-48364),and the Materials Sciences and Engineering Division of the U.S.Department of Energy(DE-AC02-05CH11231).
文摘Modern porous monoliths have been conceived as a new class of stationary phases for high performance liquid chromatography(HPLC) in classical columns in the early 1990s and later extended to the capillary format.These monolithic materials are prepared using simple processes carried out in an external mold(inorganic monoliths) or within the confines of the column(organic monoliths and all capillary columns).These methods afford macroporous materials with large through-pores that enable applications in a rapid flow-through mode.Since all the mobile phase must flow through the monolith,the convection considerably accelerates mass transport within the monolithic separation medium and improves the separations.As a result,the monolithic columns perform well even at very high flow rates.The applications of monolithic capillary columns are demonstrated on numerous separations in the HPLC mode.
文摘Surfactant template synthesis of mesoporous silica monolith was carried out via modified fast sol gel process. It was easy to obtain crack free silica monolith due to low volume shrinkage during the gelation. The morphology of the titled silica was characterized by transmission electron microscopy and X ray diffraction. The results showed that the pores were worm like and the pore size was about 4 nm. Further nitrogen isothermal absorption experiment indicated that the specific area of the titled material was 391 m 2/g, which was comparable with the reported value 306 m 2/g in literature.
文摘An improved bulk sol-gel process was found to prepare transparent, non-cracking, highly pure and mono-component monolithic silica gels with a low volume shrinkage. HSi（OC2H5）3 was used as a gel acceleration to shorten the whole sol-gel processing time in the place of the carbonate powders in bulk sol-gel process. The mono-component silica gel monoliths prepared via the improved bulk sol-gel process possess a microporous structure and a good transmittance in the UV-Vis region, and the mass fraction of silica is 89%, the mass fraction of small molecules is 11%.
