Aluminosilicate Research Articles

EFFECT OF BOVINE SERUM ALBUMIN ON THE LUMINESCENT PROPERTIES OF FLAVONOIDS

Flavonoids, as representatives of the class of aromatic phenols, in the structure of which have several cyclic groups and form chelates with many metal ions. Quercetin, morin and rutin belong to the group of polyphenolic compounds that actively absorb ultraviolet light and have wide absorption bands with high values of molar absorption coefficients. Quercetin and morin in ethanolic solutions show their own intense luminescence. The luminescence intensity (Ilum) of rutin, in the 3-oxy group of which the hydrogen atom is replaced by rhamnose, is of little importance.
 In the presence of bovine serum albumin (BSA) Ilum sorbates of morin and rutin complexes increase 2-3 times. This work studied the effect of BSA on Ilum sorbates of flavonoid complexes under the conditions of obtaining the optimal analytical signal.
 BSA has a slight intrinsic luminescence due to the presence of the amino acid tryptophan in its molecule. The possibility of intermolecular energy transfer in the BSA-rutin (morin) system is due to the overlap of the BSA luminescence spectra with the rutin and morin absorption bands. The study of the luminescent properties of BSA in the presence of flavonoids of different concentrations upon excitation of one component - serum albumin, showed that in the spectrum of its luminescence appear new, characteristic of flavonoids bands of sensitized luminescence. As the concentration of flavonoids grows, the Ilum of the acceptor increases with a simultaneous decrease in the luminescence of the BSA donor, which indicates the intermolecular transfer of excitation energy from the BSA donor to the flavonoid acceptor.
 The use of sorbents as a solid matrix causes a significant increase in Ilum complexes Y(III) and Sc(III) with flavonoids (up to 100 times). The highest value of Ilum complex Y(III) with quercetin is found on aluminum phosphate and silica gel 100/160, for complexes Y(III) with rutin on dextran-type sorbent Sephadex G-75 and G-150. Similar results were obtained for the Sc(III) complex with morin.
 It was found that in the presence of albumin in the excitation spectrum of the complex Y(III) – rutin hyper and batochromic shift of the band is observed, which indicates the interaction with BSA with the formation of the complex Y(III) – rutin – BSA. The effect of BSA on the Sc(III) complex with morin has a different character, as the interaction takes place at a low pH value, at which the BSA is not negatively charged and a complex compound with Sc(III) is not formed.
 The introduction of BSA into the system Ln(III) – flavonoid leads to an increase in Ilum. of sorbates of complexes due to intermolecular transfer of excitation energy from BSA energy donor to flavonoid acceptor. The linear region of dependence of luminescence intensity sorbates of complexes on the concentration of morin is observed in the range of concentrations (0.005-0.02)·10-3 mol/l, for rutin (0.005-0.01)·10-3mol/l, for quercetin – (0.005- 0.015)·10-3 mol/l. The range of determined concentrations is sufficient to determine the content and amount of flavonoids in vegetable raw materials.
 Keywords: flavonoids; luminescence; yttrium; scandium; quercetin; morin; rutin; albumin.

Studies on phase evolution, microstructure and crystallization kinetics in Nd2O3 doped Li2O-Al2O3-SiO2 glass system

Nd2O3 doped Lithium Alumino Silicate (LAS) glass of composition (wt.%) 57SiO2–19Al2O3–3.5Li2O-7P2O5–11.5X–2Nd2O3 (X = B2O3, MgO, ZnO, TiO2, ZrO2) was synthesized and transformed into glass ceramic. X Ray Diffraction (XRD) showed formation of TiZrO4 nano crystalline phase at 948 K and major phase β-spodumene (β-LiAlSi2O6) along with some minor phases at temperatures >1073 K. In the intermediate temperature range, γ-spodumene /LixAlxSi3-xO6 (0<x<1)/Virgilite was identified as a major phase which was shown to get converted into stable β-spodumene phase at elevated temperature. Micrographs of heat treated samples revealed nanocrystals of size (<25 nm) of Titanium Zirconate phase at 948 K and shell type microstructure of β-spodumene phase at temperature >1073 K. Decrease in thermal expansion coefficient (α) from 5.5×10−6/K to 2.98×10−6/K (303–573 K) was observed for sample crystallized at around 1073 K. Non isothermal DTA data showed two exothermic peaks, indicating crystallization of two different phases in temperature range of 993 to 1223 K. Activation energy for crystallization (Ea) of first peak was found to be 168±20 kJmol−1 and 187±20 kJmol−1 using Kissinger and Marotta methods, respectively. Model free kinetics was used to find more accurate kinetic parameters such as Ea and predict isothermal reaction progress.

Microstructure investigation of the Na/Ca aluminosilicate hydrate gels and its thermal compatibility in fly ash–GGBS cementitious binder

The synthesis of geopolymers (Na/Ca alumino silicate hydrate gels) was carried out in different proportions of fly ash and GGBS: 0/100 (A), 50/50 (B) and 100/0 (C). The gel composition at elevated temperature was characterised by studying the microstructure through X-ray diffraction (XRD). In addition, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were also employed for structural characterisation. Thermal expansion and thermal conductivity experiments were conducted through thermal gravimetric analysis/differential thermal analysis (TGA/DTA). The compressive strength gain in the composites after exposure to a temperature of 800 °C was compared and found to be higher in CpT than ApT samples, which is attributed to thermal transformation enabled by dehydration and dehydroxylation of the N-A-S-H gel. The thermal stress–induced microcracks were observed to be higher in ApT and BpT samples but lower in CpT samples as evidenced by SEM. The lines representing binding energy (BE) in XPS showed marked changes in their position, intensity and % composition related to crystal field of the elements and it is reflected in the compressive strength. It was found that the addition of slag in Bp decreases the binding energies of Si, Ca, Al, Na and O by changing the local environment in the network by charge delocalisation and reducing the intensity of Ca peaks to a greater extent at 800 °C. The O1s peak of all heated samples correspond to the non-bridging oxygen atoms. These research findings open up the possibility for the fabrication of thermally insulated ceramic type geopolymers.

Efficient Etherification of 2,5-Bis(hydroxymethyl)furan to 2,5-Bis(propoxymethyl)furan by an Amorphous Silica-Alumina Catalyst in a Fixed-Bed Reactor.

The efficient etherification of 2,5-bis(hydroxymethyl)furan (BHMF) to 2,5-bis(propoxymethyl)furan (BPMF) was achieved by using low-cost amorphous silica-aluminas (ASA) catalysts in a fixed-bed reactor. A considerable yield of BPMF up to 85.1 % was obtained over ASA-30 catalyst under the reaction conditions of 140 °C, 2.0 MPa of N2 , and 0.015 h-1 of WHSV. The excellent performance of ASA-30 catalyst could be attributed to the relatively stronger acidity (>375 °C) and larger mesoporous size (6 nm), thereby facilitating the conversion of BHMF to BPMF. In addition, the lower ratio of Brønsted/Lewis acid sites for ASA catalyst was found to efficiently suppress the occurrence of side reactions.

Single vs. dual-binder surface design of spray-dried Si–Al-sol-bound kaolin-matrixed SAPO-34 nanocatalyst for conversion of methanol to light-olefins in fluidized bed reactor

This study investigates shaping and characterization of fluidizable methanol to olefins catalysts using single-binder or dual-binder. Physicochemical and mechanical properties were investigated with different methods likewise FESEM, XRD, TGA, FTIR, TPD-NH3 and BET-BJH. Furthermore, MTO process tests were accomplished to investigate the catalytic activity in the fluidized bed and fixed bed reactor and revealed that the sample shaped using dual-binder has larger surface area than the shaped one using single-binder (alumina sol or silica sol). Catalysts with silica sol and alumina-silica sol binder show relatively lower attrition resistance than the catalysts with alumina sol binder. Furthermore, implementation of alumina-silica sol provides increased acidity of the MTO catalyst which led to the increased selectivity and life time in fluidized bed reactor compared to alumina sol and silica sol binder. In addition, the MTO catalyst shaped with alumina-silica sol exhibited slightly lower coke deposition compared to the one made with single binder.

An Investigation into the Effect of Backup Coat Sands on Investment Casting Products

Investment casting is a well-known method for producing precise and finished products. The shell-making process takes a long time and consumes a large amount of coating sands. On the wax pattern tree, the ceramic coating sands are used as a primary coat and several backup coats. Zirconia sand is used for primary coating on a shell in this work. Backup coat sands are made up of fused silica and alumina silica. Colloidal silica is used as a binding material in the formation of all shells. In the work, the effect of fused silica and alumina-silica sand as a backup coat on casting properties was determined. The experimental work evaluated casing properties such as microstructures, grain size measurement, gas porosity, and shrinkages. On the dried, de-waxed, and fired shell, the porosity of the shell mold was determined for the permeability level. Alumina-silica sand has a porosity of 27 to 31 percent, whereas fused silica has a porosity of 22 to 25 percent. It produces better casting properties in alumina–silica casting products than fused silica. Casting grain sizes range from 22 to 38 microns. The grain size of alumina-silica casting is finer than that of fused silica shell casting. Gas porosity and shrinkage in the casting were found to be moderate in all castings.

Use of TLC-Densitometric Method for Determination of Valproic Acid in Capsules.

Determination of valproic acid in the drug was carried out on the aluminum silica gel 60F254 plates and using acetone–water–chloroform–ethanol–ammonia at a volume ratio of 30:1:8:5:11 as the mobile phase, respectively. Two methods of detection of valproic acid were used. The first was a 2% aqueous CuSO4×5H2O solution, and the second was a 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system. The applied TLC-densitometric method is selective, linear, accurate, precise, and robust, regardless of the visualizing reagent used for the determination of valproic acid in Convulex capsules. It has low limits of detection (LOD) and limits of quantification (LOQ), which are equal to 5.8 μg/spot and 17.4 μg/spot using a 2% aqueous CuSO4×5H2O solution as visualizing agent and also 0.32 μg/spot and 0.97 μg/spot using a 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system as visualizing reagent, respectively. The described analytical method can additionally be used to study the identity of valproic acid in a pharmaceutical preparation. The linearity range was found to be 20.00–80.00 μg/spot and 1.00–2.00 μg/spot for valproic acid detected on chromatographic plates using a 2% aqueous CuSO4×5H2O solution and the 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system, respectively. A coefficient of variation that was less than 3% confirms the satisfactory accuracy and precision of the proposed method. The results of the assay of valproic acid equal 96.2% and 97.0% in relation to the label claim that valproic acid fulfill pharmacopoeial requirements. The developed TLC-densitometric method can be suitable for the routine analysis of valproic acid in pharmaceutical formulations. The proposed TLC-densitometry may be an alternative method to the modern high-performance liquid chromatography and square wave voltammetry in the control of above-mentioned substances, and it can be applied when other analytical techniques is not affordable in the laboratory.

Promoting Aromatic C-H Activation through Reactive Brønsted Acid-Base Pairs on Penta-Coordinated Al-Enriched Amorphous Silica-Alumina.

The surface acidity and local coordination environment of zeolites and amorphous silica-aluminas (ASAs) can promote acid-catalyzed C-H activation in many important hydrocarbon conversion reactions. Acid sites generated by penta-coordinated Al species (AlV) can lead to enhanced acidity and changes in the surface coordination. We evaluated the potential of flame-derived ASAs with enriched AlV for C-H activation using hydrogen/deuterium (H/D) exchange with benzene-d6. With increasing Al content of ASAs, the exchange rate increased, whereas the activation energy (Ea) slightly decreased due to the enhanced Brønsted acidity. The ASAs exhibited significantly higher exchange rates and lower Ea values than the sol-gel-derived ASAs and zeolite H-ZSM-5. The superior activity is attributed to the fact that more oxygen coordinated with AlV species on flame-made ASAs, which can act as acceptors for D+, enhancing the deuterium displacement. These findings could offer a valuable alternative strategy for tailoring high-performance solid acids to promote hydrocarbon conversion reactions.

Effect of Sealing Treatment of Modified Aluminum Phosphate Sealing Agent on Corrosion Resistance of Fe-Based Amorphous Coating

A modified aluminum phosphate sealing agent was prepared by using aluminum dihydrogen phosphate and silica sol as raw materials, and was used for sealing treatment of iron-based amorphous coating. The phase of sealing agent was analyzed by XRD. SEM and TG-DSC were used to characterize the surface morphology of the coating before and after sealing and the heat resistance of the sealing agent. The corrosion resistance of the sealing coating was evaluated by electrochemical measurements. The results show that the modified aluminum phosphate sealing agent has good heat resistance, and fine and close sealing layer was obtained, thus the corrosion resistance is significantly improved.

Techno-Economic Evaluation of Thermal and Catalytic Pyrolysis Plants for the Conversion of Heterogeneous Waste Plastics to Liquid Fuels in Nigeria

Techno-economic potentials of thermal and catalytic pyrolysis plants for the conversion of waste plastics to liquid fuels have been widely studied, but it is not obvious which of the two plants is more profitable, as the existing studies used different assumptions and cost bases in their analyses, thereby making it difficult to compare the economic potentials of the two plants. In this study, industrial-scale thermal and catalytic waste plastics pyrolysis plants were designed and economically analyzed using ASPEN PLUS. Amorphous silica-alumina was considered the optimum catalyst, with 3:1 feed to catalyst ratio. Based on 20,000 tons/year of feed and 20% interest rate, the catalytic plant, having a net present value (NPV) of &#83582208 million, was found to be economically less attractive than the thermal plant, having the NPV of &#83582426.4 million. On the contrary, sensitivity analyses of the two plants at a feed rate of 50,000 tons/year gave rise to a slightly higher NPV for the catalytic plant (&#83589861 million) than the thermal plant having NPV of &#83589838 million, thereby making the former more economically attractive for processing large amounts of waste plastics into liquid fuels. Consequently, as the catalytic plant showed a better scale economy and would produce higher quality liquid fuels than the thermal plant, it is recommended for commercialization in Nigeria.

Characterization of the Clay Collected in the Locality of Dolisie in Congo-Brazzaville

This work aims at the characterization of the clay of the locality of Dolisie for its valorization. The mineralogical analysis was determined by the following techniques (DRX, IR, ATG and ATD), chemical analysis was determined by ICP-AES, CEC was assessed by the Metson method. The geothermal properties were determined by the granulometric analysis of the clay soil and allowed us to position the Dolisie clay in the texture triangle, the landings limits obtained allowed to place the Dolisie clay in the abacus of Casagrande and on the workability map of Bain and Highy. Chemical analysis showed that silica alumina as well as iron oxides are the major constituents in Dolisie clay The mineralogical balance showed that kaolinite and illite have similar percentages which are (20.51%) kaolinite, (28.08) illites. This leads us to believe that kaolinite is not the dominant mineral and the IR spectrum shows that kaolinite is poorly crystallized.

Effect of two-component amorphous silica-alumina (ASA) with different Si/Al molar ratios on hydrocracking reactions for increasing naphtha over NiW/USY-ASA

The combination of ASA-0.4 and ASA-2 produces new acidic OH groups by increasing the contact points between silicon and aluminum. These OH groups improve the density of acid sites and increases the area of the active adsorption area of the support.

Manipulation of amorphous precursors to enhance zeolite nucleation.

Crystallization in media comprised of amorphous precursors is becoming a more common phenomenon for numerous synthetic, biological, and natural materials that grow by a combination of classical and nonclassical pathways. Amorphous phases can exhibit a wide range of physicochemical properties that may evolve during the course of nucleation and crystal growth. This creates challenges for establishing causal relationships between amorphous precursor properties and their effect(s) on the selection of mechanistic pathways of crystallization and ultimately the properties of the crystalline product. In this study, we examine ways to manipulate the composition and colloidal stability of amorphous (alumino)silicate precursors that are prevalent in nanoporous zeolite syntheses. Changes in the amorphous precursor properties are evaluated on the basis of their ability to enhance rates of crystal formation. Here, we use fumed silica as the primary silicon source and examine the effects of infusing the source or growth medium with additional alkali metal, which serves as an inorganic structure-directing agent to facilitate the formation of porous crystal structures. We also assess the impact of adding a polymer additive, which reduces the colloidal stability of precursors, wherein we posit that the confined pockets of solution within the interstitial spaces of the precursor aggregates play an important role in regulating the rate of zeolite crystallization. Three commercially relevant zeolites (mordenite, SSZ-13, and ZSM-5) were selected for this study based on their diverse frameworks and methods of preparation. Our findings reveal that alkali infusion significantly reduces the crystallization times for mordenite and SSZ-13, but has little impact on ZSM-5 synthesis. Conversely, we find that polymer addition markedly enhanced the rates of crystallization among all three zeolites, suggesting that this method may be a general approach to reduce zeolite synthesis times. Given the relatively high costs associated with commercial zeolite production, identifying new methods to improve the efficiency of hydrothermal syntheses can have significant practical implications beyond the fundamental benefits of developing new routes to tailor nonclassical crystallization.

Strategy for the synthesis of zeolite Y by artificial-fish-reef breeding negative crystals

Cationic polyacrylamide (CPAM) provides a breeding ground on which the initial (alumino)silicate species attach and accelerate zeolite nucleation and crystallization. A nano-plate-like small-crystal-sized NaY zeolite is synthesized.

ИССЛЕДОВАНИЕ ВЛИЯНИЯ ОСАДКА СТОЧНЫХ ВОД И ЦЕОЛИТА, ПРЕДПОСЕВНОЙ ОБРАБОТКИ СЕМЯН ЯРОВОГО ЯЧМЕНЯ НА ЕГО УРОЖАЙНОСТЬ

Purpose: to study the chemical composition of sewage sludge and zeolite, the sludge structure and also to evaluate the spring barley yield against the background of the ameliorant application and pre-sowing seed treatment with bischofite. Materials and methods. The object of research is the sewage sludge from the treatment facilities of Volzhsky and natural limestone zeolite. The chemical composition of sewage sludge and zeolite was studied under laboratory conditions. The study of sewage sludge structure was carried out by scanning electron microscopy. The field experiment was set up in accordance with generally accepted methods. Results. The chemical composition of the sewage sludge and the quality indicators of zeolite were determined. During the study, the increased content of nitrogen (6.7 %), phosphorus (2.8 %), potassium (0.21 %) was found in the sediment, the organic matter content was 80.0 %. Zeolite analysis data showed that it is based on silica SiO₂ (60.49 %) and alumina Al₂O₃ (12.1 %). When studying the structure of sewage sludge, it was found that the sample has a porous structure, particles of various sizes are found in it, meso- and macropores are present. Data on spring barley yield indicate that when treated with worked out sewage sludge, it increases to 3.15 and 3.25 t/ha against the background of control without seed treatment and with seed treatment with bischofite, respectively. In the variant without pre-sowing seed treatment and with the ameliorant introduction (sewage sludge + zeolite), the yield was 3.88 t/ha, in the variant with seed treatment with bischofite – 4.05 t/ha. Conclusions. To increase the productivity and yield of spring barley in the arid zone of the Volgograd region, it is advisable to use non-traditional ameliorant fertilizers with an optimal chemical composition. Pre-sowing seed treatment with bischofite had a positive effect on field germination and spring barley yield, however, additional studies of its effectiveness in pre-sowing seed treatment are needed.

DIC analysis of nano concrete using functionalized and dispersed carbon nanotubes

Digital Image Correlation (DIC) method is considered as a powerful tool to capture material behavior for improved precision. This paper deals with effect of dispersion and functionalization of multiwall carbon nanotubes (MWCNTs) on fracture mechanics properties such as fracture energy and stress intensity factor. Fracture mechanics properties were found out using DIC technique and also by experimentally using a clip gauge and linear variable differential transformers (LVDT). The experiment was conducted under crack mouth opening displacement (CMOD) controlled manner and rate of loading was set as 0.0005 mm/s. MWCNTs were taken in a proportion of 0.1%, 0.2%, 0.3%, 0.4% and 0.5% by weight of cement and Nano silica and Nano alumina were considered as 3% and 2% by weight of cement respectively. The compressive strength is increased by 45.28% and tensile strength and flexural strength increased by108.26% and 53.249% respectively. It was seen that displacements measured by DIC and by experimentally were in the same line and also Load vs CMOD graphs plotted with both the methods are having similar behavior. Size effect was considered for preparation of all the specimens and by the results it can be seen that all specimens follow Bazant’s Size effect law.

Understanding the wetting discrepancy in calcium alumino silicate hydrate induced by Al/Si ratio.

The application of supplementary cementitious materials (SCMs) in concrete can improve its durability in the marine environment. Calcium alumino silicate hydrate (CASH) is the main hydration product of SCMs; however, to date, the mechanism of the wetting discrepancy in CASH with different Al/Si ratios has not been revealed at the molecular scale. Herein, the molecular dynamics simulation method was used to study the wettability of water nanodroplets on the surface of CASH substrates with different Al/Si ratios, aiming to reveal the influence of CASH gel with different Al contents on the wettability of water molecules. The simulation results suggested that the CASH interface with a high Al/Si ratio has better wettability for nanodroplets. The microcosmic analysis showed that the interaction between particles and the CASH substrate is affected by the Al content. The electronegativity of the CASH substrate increases due to the substitution of Al-O tetrahedrons, which makes it stronger to solidify Ca ions on its surface and easier to form hydrogen bonds with water molecules in a nanodroplet. The orientation distribution of water molecules further revealed the source of the force of the CASH substrate on nanodroplets at the atomic level. The analysis of the dynamic properties showed that the H-bonds between CASH substrate with a high Al/Si ratio and water molecules are more stable, and thus the nanodroplets have better stability on the surface of CASH.

Synthesis of Amorphous Silica-Alumina with Enhanced Specific Surface Area and Acidity by Ph-Swing Method and its Catalytic Activity in Cumene Cracking

Synthesis of Amorphous Silica-Alumina with Enhanced Specific Surface Area and Acidity by Ph-Swing Method and its Catalytic Activity in Cumene Cracking

Steam Catalytic Cracking of Crude Oil Over Novel Hierarchical Zeolite–Containing Mesoporous Silica–Alumina Core-Shell Catalysts

Steam Catalytic Cracking of Crude Oil Over Novel Hierarchical Zeolite–Containing Mesoporous Silica–Alumina Core-Shell Catalysts

Synthesis of hollow HZSM-5 zeolite-based catalysts and catalytic performance in MTA reaction

Although HZSM-5 zeolite is more and more widely used in petrochemical industry and other fields, its single narrow micropore system often leads to mass transfer issues during some types of catalytic reactions. In addition, dealumination in the presence of steam and coking due to the presence of strong acids sites are issues of aluminosilicate catalysts in general. In this work, a simple post-treatment method based on the traditional prepared HZSM-5 catalyst was proposed and an outlayer SiO2 encapsulated Gd/HZSM-5 catalyst with hollow and hierarchical porous systems ([email protected]/Z5-T) was obtained. This catalyst can overcome those defects for the traditional HZSM-5 mentioned above, such as, the outermost SiO2 layer can protect the aluminum species in the framework of Gd/HZSM-5 and cover part of strong acid sites, and the hollow and hierarchical porous systems can minimize the mass transfer resistance, etc. The [email protected]/Z5-T catalyst exhibited high selectivity of BTX (65.7%), especially xylene (39.7%), in the methanol to aromatics reaction (MTA) owing to the suitable acidity and optimized porous system. In addition, the [email protected]/Z5-T catalyst possessed much better hydrothermal stability and the excellent anticoking ability in the MTA reaction as expected. Thus, this should be a general method for the modification of silica alumina molecular sieve catalysts to obtain the novel catalyst with hollow and hierarchical porous systems, adjustable acidity and high hydrothermal stability.