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Natural stilbite (Ca-stilbite) zeolites have been collected from the queries near Pashan area, Pune, Maharashtra, India. The calcium ions in the Ca-stilbite structure are partially exchanged by magnesium ions using ion exchange process. The Ca-stilbite and Mg- stilbite samples are characterized by XRD, EDS, FTIR and TG/DTA techniques and are used as the functional materials for the preparation of thick films using screen printing technique. The screen printed films, deposited on glass substrates, are then sintered at 650 °C for proper adhesion to take place. These thick films are used as sensors to test ethanol. The XRD profiles and FTIR spectra reveal that the sensor material is a stilbite zeolite. EDS data shows that the magnesium ions are exchanged in the stilbite structure. TG/DTA study shows the thermal behavior of the samples wherein the structural breakdown occurs at 520 °C and weight loss due to desorption of water molecules can be revealed by exo & endo peaks. Ethanol sensing studies show that both the Ca-stilbite and Mg-stilbite films are sensitive to ethanol. In case of Mg-stilbite films, the operating temperature and ethanol response are found to be dependent on magnesium concentration. Lower the magnesium concentration lower is the operating temperature and higher is the ethanol sensitivity. Mg-stilbite films with specific concentration (0.05 M) shows the consistent ethanol sensing performance in comparison to Ca-stilbite film wherein response to ethanol decreases after repetitive use. The study reveals that Mg-stilbite thick film (0.05 M) is stable ethanol sensor which can be operated at 65 °C with reproducible characteristics.

Kỹ thuật trùng hợp phân tán đã được sử dụng để tổng hợp polymer polystyrene xốp có liên kết chéo với divinylbenzene. Các ảnh hưởng của các tham số tổng hợp khác nhau (lượng tác nhân khởi đầu, chất liên kết chéo và dung môi, loại dung môi và tốc độ khuấy) đã được đánh giá đối với kích thước hạt trung bình, phân bố kích thước hạt và hình thái bề mặt. Kết quả phân tích bằng SEM, TEM, EDX, FTIR và sàng cho thấy kích thước hạt trung bình giảm khi lượng tác nhân khởi đầu tăng. Độ đồng nhất tối ưu đạt được ở lượng tác nhân khởi đầu thấp và lượng chất liên kết chéo cao. Các kết quả cũng cho thấy rằng loại dung môi không ảnh hưởng đến kích thước hạt trung bình, trong khi phân bố hạt và hình thái bề mặt bị ảnh hưởng bởi tốc độ khuấy.

Three-dimensional ordered macroporous (3DOM) rare earth oxide—CeO2 was prepared by colloid crystal template. Cerous nitrate in the presence of citric acid was used as precursor and polystyrene (PS) beads as template. The effect and mechanism between citric acid and cerous nitrate was studied. The introduction of citric acid as chelator could overcome the disadvantage from the low melting point of single cerous nitrate and played an important role to the formation of 3DOM structure. The resulted CeO2 had three-dimensional ordered structure, uniform pore distribution, and interconnected macropores through small holes, which makes CeO2 probably become a new-type catalyst or catalyst support in future.

A serial of mesoporous silica materials (including highly ordered and worm-like mesoporous structure) have been successfully prepared using ionic liquids as templates in alkaline conditions. The combined characterizations of XRD, N2 isotherms, and TEM techniques exhibit that samples templated by ionic liquids produced from long-chain alkyl bromide (I-16 and I-14) show highly ordered mesoporous structure with uniform pore size and high surface area in the presence of NaOH or ammonia. Additionally, worm-like mesoporous silica materials have been also prepared using ionic liquids produced from short-chain alkyl bromide (I-12, I-10 and I-8) as templates in the presence of NaOH, tetramethylammonium hydroxide or ammonia. Our present work is of importance because it provides a new methodology to synthesize mesoporous materials for various applications.

A duplex process was proposed with which a titania containing calcium and phosphate on the surface of titanium alloy was formed by microarc oxidation in aqueous electrolytes, and finally converted to bioactive layer containing hydroxyapatite by subsequent hydrothermal synthesis. The layer is porous in micro scale and composed of crystals in nanometer size. There was no distinct interface between the hydroxyapatite layer and the substrate.

In the present paper, highly transparent, monolithic and hydrophobic silica aerogel monoliths were prepared by using tetraethoxysilane (TEOS) as precursor and methyltriethoxysilane (MTES) as co-precursor with different MTES/TEOS molar ratios (M) by two-step acid–base catalyzed sol–gel process followed by supercritical alcohol drying. The molar ratio of TEOS, ethanol (EtOH), water (0.001 M oxalic acid catalyst) and ammonium hydroxide (1 M NH4OH) was kept constant at 1:5:3.5:3.5 respectively, while the molar ratio of MTES/TEOS (M) was varied from 0 to 0.75. It has been observed that as the M value increases, the gelation time increases. It has been found that lower (0.25) M values resulted in highly transparent (optical transmission >90 % for a 10 mm thick sample at 700 nm wavelength) and negligible volume shrinkage (<10 %) but less hydrophobic aerogels, whereas higher (0.75) M values resulted in semitransparent (<25 % optical transmission at 700 nm for a 10 mm thick sample) aerogels with >10 % volume shrinkage but excellent hydrophobicity. A good compromise of acceptable optical transmittance (~87 % optical transmission at 700 nm wavelength for a 10 mm thick sample) with negligible volume shrinkage (6 %) were obtained at M = 0.50. The hydrophobicity of the aerogels was tested by measuring the contact angle between a water droplet and silica aerogel surface. The hydrophobicity was confirmed by Fourier transform infra-red spectroscopy and contact angle measurements. the aerogels have been characterized by percentage of volume shrinkage, optical transmittance, scanning electron microscopy, thermal conductivity measurements and thermogravimetric analysis and differential thermal analysis.

An efficient catalyst for selective oxidation of alcohols was prepared by grafting the Cu(II) Schiff base complex onto the channels of mesoporous silica material SBA-15. The characterizations illustrated that the functionalized SBA-15 maintained the primary hexagonally ordered mesoporous structure, and the Cu(II) Schiff base complexes were bonded inside the mesoporous channels of SBA-15. The selective oxidation of benzyl alcohol was carried out in water phase with hydrogen peroxide. The C6H5CH2OH conversion could reach 98.5 % with 100 % of the selectivity to C6H5CHO under the optimum conditions. The catalyst could also react well on the selective oxidation of other primary alcohols.

To enhance the adsorption selectivity of pillared clays an attempt is made to modify the initial pore size by a controlled deposition of carbon. Cracking of hydrocarbons in the pores of the pillared clay results in coke deposits which can alter the pore size. Based on the evaluation of the amount of coke, the coke density, the decrease in micropore volume, changes in the micropore size distribution and the acidity it was possible to distinguish between pore-blocking, pore-filling and pore-narrowing effects. The modification mechanisms strongly depend on the initial porous structure, the acidity (Brönsted/Lewis), the cracking conditions (static or flow) and the hydrocarbons used. The carbon deposition results in a decrease in pore volume due to pore-filling (Ti-PILC) and pore-blocking (Al-PILC) without achieving a controlled pore-narrowing but some indications for pore-entrance narrowing were found.

Benzene adsorption on four synthesized metal–organic frameworks (MOFs): MOF-520(Al), MOF-5(Zn), ZIF-8(ZnO–Zn), MOF-74(Mg) and three commercial MOFs: Basolite C300, Basolite F300 and Basolite Z377 at 20 °C is investigated. The materials studied feature high surface areas ranging from 950 to 3760 m2/g and large micropore volumes varying from 0.37 to 1.79 cm3/g. Nevertheless, the volume of supermicropores is one of the main factors that determines C6H6 adsorption performance of MOFs. Additionally, in the case of some MOFs, open metal sites enhance interactions between gas molecules and the surrounding framework.