[Spectral Analysis of Trace Fluorine Phase in Phosphogypsum].

Phosphogypsum, which contains more than 90% of the calcium sulfate dehydrate (CaSO4 · 2H2O), is a kind of important renewable gypsum resources. Unlike the natural gypsum, however, phosphorus, fluorine, organic matter and other harmful impurities in phosphogypsum limit its practical use. To ascertain the existence form, content and phase distribution of trace fluoride in phosphogypsum has important theoretical values in removing trace fluoride effectively.

Fabricating a sustained releaser of heparin using SBA-15 mesoporous silica.

The sustained release of heparin in sufficient amounts and over long time is a challenge to drive the development of functional materials. In this paper SBA-15 mesoporous silica is selected in the search for a favorable morphology and optimized surface state for the sustained release of heparin. In situ carbonization of the template in the as-synthesized sample enables SBA-15 to possess narrowed channels with rougher surfaces, while modification with (aminopropyl)triethoxysilane (APTES) through a one-pot synthesis offers SBA-15 with positive charges to attract heparin through electro-static interactions.

One-pot synthesis of a hierarchical PMO monolith with superior performance in enzyme immobilization.

A novel hierarchical periodic mesoporous organosilica (PMO) monolith is synthesized by using N,S-bis[3-(triethoxysilyl)propyl]-carbamothioic acid for the first time, in order to fabricate a highly efficient enzyme immobilizer. The hierarchical monolith is spontaneously formed with mild shearing force without further additives, in which the primary particles can be selectively prepared to be inter-connected with each other end to end to form a net-like framework throughout the whole monolith, and the inorganic/organic composition is finely controlled by adjusting the initial composition of the silica precursors. As the result, an ordered net framework with micrometer sized macropores and large mesopores is simultaneously obtained together with a high organic content, favoring high enzyme immobilization, in which they demonstrate an enhanced adsorption capacity, superior immobilization stability and good reusability.

Sustained release of heparin on enlarged-pore and functionalized MCM-41.

Mesoporous silica MCM-41 and SBA-15 were chosen to study the adsorption and release of bulky biomolecule heparin, in order to develop new heparin controlled delivery system and expand the application of mesoporous materials in life science. To explore how the structure of support such as pore size and surface state affects the accommodation and release of heparin, we used decane as swelling agent to enlarge pores of MCM-41, introduced amino groups for improving the biocompatibility of support, and controllably retained templates in the as-synthesized sample. The influence of modification on the structure of samples was investigated by XRD and N(2) adsorption-desorption, whereas their performance of adsorbing and releasing heparin was assessed with that of toluidine blue method.

Promoting immobilization and catalytic activity of horseradish peroxidase on mesoporous silica through template micelles.

New concept on the promotion of immobilization and catalytic activity of enzyme on mesoporous silica through template micelles is proposed and realized in this paper. Proper P123 templates are controllable retained in the as-synthesized SBA-15, not only to anchor the horseradish peroxidase (HRP) guest, but also to establish the crowding-like microenvironment around the enzyme. The influence of retaining templates on the pore structure of SBA-15, immobilization, and catalytic activity of HRP is studied, and the possible process of template removal is proposed.

Controlling the primary particle evolution process towards silica monoliths with tunable hierarchical structure.

In order to establish the hierarchical structure in multiple levels on mesoporous silica, this article reports a new strategy to prepare the monolith with the pore configuration in nanometer scale, micro-morphology in micrometer level and macroscopic shape in millimeter or larger grade. These hierarchical monoliths are synthesized in a weak acidic condition by using triblock copolymer P123, hydroxyl carboxylic acid and tetramethyl orthosilicate (TMOS), and the textural properties of the mesostructure can be facilely adjusted by simply controlling the synthesis condition without any additive. During the synthesis, the primary particles can be selectively synthesized as monodispersed sphere, noodle, prism, straight rods with different size or irregular bars, and their connection plus arrangement in 3D directions can be also regulated.

Low-cost and effective phenol and basic dyes trapper derived from the porous silica coated with hydrotalcite gel.

Novel low-cost and effective adsorbents of phenol and basic dyes were made by coating amorphous silica with hydrotalcite (HT) gel followed by soaking in alkaline solution, and the surface basic-acidic properties of resulting composites were evaluated by CO(2)-TPD, Hammett indicator method and NH(3)-TPD, respectively. Both BET surface area and microporous surface area of the composites were increased after they were soaked with alkaline solution; meanwhile the center of pore size distribution was changed from 9 to 3-4 nm. These composites efficiently captured phenol in gaseous and liquid phases, superior to mesoporous silica such as MCM-48 or SBA-15 and zeolite NaY, and the equilibrium data of gaseous adsorption could be well fitted to Freundlich model.

Novel phenol capturer derived from the as-synthesized MCM-41.

Novel phenol-capturer was prepared by modifying the as-synthesized mesoporous silica MCM-41 with tetraethylenepentamine (TEPA), not only saving the energy and time for removal of template, but also opening the way to utilize the micelles for adsorption. Once the organic modifier was distributed in the template micelle of MCM-41 to form a web within the mesoporous channel, the composite could adsorb more phenols in gas stream than activated carbon for the first time. With an unwanted high adsorption capacity, this mesoporous silica-amine composite represented potential application for trapping phenols, especially in tobacco smoke to protect environment.

[FTIR analysis of oil shales from Huadian Jilin and their pyrolysates].

Thermochemical conversion is the key technology for the comprehensive utilization of Chinese oil shale resources. Oil shales from three mining areas of Huadian Jilin were pyrolyzed at 500 degrees C in a quartz tube reactor and their pyrolyzed cokes and shale oil were derived. One oil shale was also pyrolyzed at 600 degrees C and 700 degrees C to assess the influence of temperature on pyrolysates.

Adsorption of nitrosamines by mesoporous zeolite.

On the basis of a study of the adsorption of zeolite and mesoporous silica, we attempted to create a hierarchical structure in the new nitrosamines trapper. Thus, mesoporous HZSM-5 zeolite was fabricated through impregnating a structure-directing agent into the as-synthesized MCM-41 followed by dry-gel conversion to transform amorphous silica to zeolite crystal. The texture of mesoporous ZSM-5 was tailored by adjusting the Si/Al ratio in the MCM-41 source and the thermal treatment time.

Hierarchical functionalized MCM-22 zeolite for trapping tobacco specific nitrosamines (TSNAs) in solution.

To enable zeolite to trap bulky environment pollutants such as tobacco specific nitrosamines (TSNAs), we tailored the porous structure of MCM-22 zeolite by desilication to obtain a sample with mesopores centered 3.5 nm, in order to promote the mass transport. The meso-MCM-22 was further functionalized with -SO(3)H group to enhance the efficiency in adsorption of TSNAs.

Effective nitrosamines trap derived from the in situ carbonized mesoporous silica MCM-41.

A new route to modify the mesoporous silica MCM-41 with carbon, using the inherent surfactant template in the as-synthesized sample as the carbon precursor, is reported in this article. Apart from the advantage of omitting energy and time required for removal of template, the resulting silica-carbon composites exhibit a high efficiency in adsorption and catalytic decomposition of N-nitrosopyrrolidine (NPYR), the typical carcinogenic pollutant in environment. The influence of carbonization temperature on the structure and performance of the resulting carbon-silica composite was investigated by use of XRD, N(2) adsorption-desorption, FTIR and TG-DSC techniques, and the instantaneous adsorption and the temperature-programmed surface reaction (TPSR) of NPYR as well as the reduction of nitrosamines level of cigarette smoke were also utilized to assess the actual function of these composites.

Emissions of SO2, NO and N2O in a circulating fluidized bed combustor during co-firing coal and biomass.

This paper presents the experimental investigations of the emissions of SO2, NO and N20 in a bench scale circulating fluidized bed combustor for coal combustion and co-firing coal and biomass. The thermal capacity of the combustor is 30 kW. The setup is electrically heated during startup.