Search

This study aims the improvement of antibacterial and biocompatibility properties of electrospray ternary blends of chitosan/poly(ethylene glycol)/hyaluronic acid. It conserves microscale particle structure even after incorporating zinc oxide (ZnO), the zeolite Mobil Composition of Matter No. 41 (MCM41) and penicillin G during this technique. Three different electrospray (ESP) blend compositions (ESPI, ESPII and ESPIII) have been produced in order to improve both antibacterial activity against to both gram-positive and gram-negative bacteria and biocompatibility. Results of FTIR spectroscopy and microscopy verified with SEM, EDS and AFM analyses. Hyaluronic acid surface has been specified definitely through ZnO-based ESPI surface composed of heterogeneously dispersed microparticles. Surface structures of ESPII and ESPIII have more homogenously dispersed microparticles as hill–valley surface by the aid of MCM 41-PEN. Antibacterial activity has been performed by Kirby–Bauer method. ESPI has good antibacterial activity against both gram-positive (S. aureus and S. epidermidis) and gram-negative bacteria (E. cloacea). Each electrospray film displayed good biocompatibility against to mouse fibroblast cell line L929 (ATTC number CCL-1). The highest amount of cell proliferation has been detected on ESPIII surface. [ABSTRACT FROM AUTHOR]

Effluents from numerous Industries like textile, paint, pharmaceutical, steel and electroplating industries liberate both Zinc [Zn (II)] and Chromium [Cr (VI)] heavy metals. In this work, adsorptive interaction of toxic Zn (II) heavy metal in aqueous solution with synthesized mesoporous silica based MCM‐41 was investigated. Further, the effects of presence of Cr (VI) heavy metal on the adsorption of Zn (II) and vice versa were investigated by simultaneous competitive binary adsorption from Cr (VI) and Zn (II) aqueous binary solution. Batch experiments were executed to see the effects of parameters like pH, adsorbent dose (m), adsorbate concentration and adsorption time (t). Optimum conditions for Zn (II) treatment were obtained as: initial pH (pHi) =7, m=0.1 g/L and t=2 h. Competitive adsorption of both Cr (VI) and Zn (II) from their binary solution was studied at 288− 308 K temperatures. Obtained equilibrium data were then fitted to different competitive multicomponent isotherm models like Langmuir (extended), Freundlich isotherm (extended), Sheindrof‐Rebuhn‐Sheintuch (SRS) isotherm and Redlich‐Peterson isotherm (modified) models, and various isotherm interaction parameters were calculated. Effluents from numerous Industries like textile, paint, pharmaceutical, steel and electroplating industries liberate both Zinc [Zn (II)] and Chromium [Cr (VI)] heavy metals. Adsorption of Zn (II) and Cr (VI) heavy metal from their binary aqueous solution on synthesized mesoporous silica based MCM‐41 was investigated. The Zn (II) and Cr (IV) adsorption was found antagonistic type. The modified R−P isotherm model suits best to the experimental data obtained from binary adsorption followed by extended‐Freundlich isotherm model and Sheindrof‐Rebuhn‐Sheintuch model. [ABSTRACT FROM AUTHOR]

Adsorption experiment of carbon dioxide was performed on MCM41 silica impregnated with 10~50 wt% EDA (ethylenediamine) and MEA (monoethanolamine) using GC-TCD with U type packed column at 313K isothermal temperature. The prepared adsorbents were characterized by BET surface area, X-ray diffraction and FT-IR. The results showed the best adsorption capacity was shown with MCM-41 impregnated by 30 wt% EDA and more amine impregnation would bring impregnations on surfaces of absorbent. Also, NH transformed to NH since silanol groups on surfaces of absorbent and amine were interacted, so that CO absorption capacities were reduced. Further researches on CO desorption after adsorption should be followed. Also impregnation efficiency as well as relationships between carbon dioxide concentration and temperature during actual combustion should be investigated. [ABSTRACT FROM AUTHOR]

Abstract: An interesting observation of achieving both MCM 41 and SBA-16 from rice husk ash, by varying the CTAB molar ratio is reported. The work furnishes the first report on achieving SBA-16 from rice husk ash derived silica using CTAB as the single surfactant. The meso phase has been characterized by low angle XRD, SEM, TEM, and N2 adsorption study. A reduction in CTAB to SiO2 molar ratio by 0.005 altered the mesoporous texture of silica from MCM 41 to SBA-16 under the prevailing conditions. MCM 41 possessed honeycomb like pores with thin walls, and exhibited surface area 807m2/g. SBA-16, with 226m2 /g surface area exhibited 3D cubic cage structured pores with thick microporous walls of size 8.9nm. The decisive role of surfactant concentration in fabricating the mesoporous texture of silica is demonstrated in this study. [Copyright &y& Elsevier]

The aim of this study is to determine the feasibility of loading biologically active molecules into templated mesoporous silica (MCM 41). This material shows an important mesoporosity associated to hexagonally organized channels, a narrow pore size distribution and a large surface area. Ibuprofen was selected as a model molecule since it is a well documented and much used anti-inflammatory drug. Furthermore, it has a lipophilic character and its molecular size is suitable for inclusion within the mesopores of the MCM 41 material.In order to load ibuprofen within the mesopores, adsorption experiments using various solvents or successive impregnations with solutions of ibuprofen in ethanol were performed. At each step of the loading process, the pore filling was characterized by nitrogen adsorption experiments and by X-ray diffraction. The impregnation procedure results in a significant improvement of the amount of ibuprofen loaded into MCM 41. The in vitro drug release was investigated with simulated biological fluids (gastric and intestinal). Hundred percent release is observed at the end of the in vitro experiment. [Copyright &y& Elsevier]

Two different possibilities for the preparation of immobilised ionic liquids are presented. Lewis acidic ionic liquids which have been shown to be highly active catalysts in alkylation reactions of the Friedel–Crafts type were supported on amorphous silica and MCM 41 materials. We describe the different methods used, as well as analytical data and some catalytical results achieved by these catalysts. [ABSTRACT FROM AUTHOR]

O alkylation of 2 naphthol has been investigated in the vapour phase over alkali loaded fumed silica and Cs MCM 41. Both SiO2 and MCM 41 had low C alkylation activities and no O alkylation activity. The introduction of alkali ions considerably increases 2 naphthol conversion with 2 methoxynaphthalene being the major product. The activity of the catalysts increases with alkali loading and the basicity of the metal (Cs > K > Na > Li). Very high conversion (∼99%) of 2 naphthol and selectivity (>95%) for 2 methoxynaphthalene are obtained over Cs loaded fumed silica and MCM 41. A small amount of 1 methyl 2 hydroxynaphthalene is also formed over the Li , Na and K loaded silica. [ABSTRACT FROM AUTHOR]

A series of chromium supported mesoporous MCM 41 silica catalysts (0.5–6 wt% Cr) were prepared and tested in the oxidative dehydrogenation of propane between 350 and 550°C. The catalytic activity, observed at temperatures as low as 350 °C, can be well explained on the basis of the existence of highly dispersed and reducible chromium species. [ABSTRACT FROM AUTHOR]

The new chiral salen complexes were synthesized and supported on mesoporous MCM 41 through the condensation of 3 aminopropyltrimethoxysilane and 2,6 diformyl 4 tert butylphenol by the multi grafting method. The immobilized optically active Co(II) salen complexes showed a very high enantioselectivity in the asymmetric borohydride reduction of aromatic ketones. The chiral salen Co(II) complexes immobilized over MCM 41 were stable during the reaction and exhibited a relatively high enantioselectivity for the reduction of ketones as compared with the homogeneous salen catalysts. [ABSTRACT FROM AUTHOR]

The vapor phase Beckmann rearrangement of cyclohexanone oxime to ɛ caprolactam catalyzed by mesoporous molecular sieves was studied. The proton form mesoporous molecular sieves, H MCM 41 and H FSM 16, exhibited extremely high activity, selectivity and stability for ɛ caprolactam formation when 1 hexanol was used as diluent. The weak acid sites and/or surface silanol groups of mesoporous molecular sieves play an important role in the selective ɛ caprolactam formation. [ABSTRACT FROM AUTHOR]