Inorganic Supports Research Articles

Preparation and characterization of magnetic featured supported heterogeneous catalysts

Magnesium ferrite nanoparticles containing organic or inorganic support materials were preparated as heterogeneous catalysts. The characterization of the catalysts was performed by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), emission scanning electronic microscope/energy dispersive spectroscopy (SEM/EDS). Magnetic properties of the catalysts were determined by a vibrating sample magnetometer (VSM). Specific surface area and pore size distribution of the catalysts were obtained from nitrogen adsorption-desorption data at 77K by Brunauer-Emmett-Teller (BET) method.

Supported permethylindenyl titanium catalysts for the synthesis of disentangled ultra-high molecular weight polyethylene (disUHMWPE).

Novel permethylindenyl-phenoxide (PHENI*) ansa-metallocene titanium complexes have been synthesised and immobilised on inorganic solid supports to afford highly effective catalysts for slurry-phase ethylene polymerisation. When supported on solid polymethylaluminoxane these complexes were both extremely active (up to 3.7 × 106 gPE molTi-1 h-1 bar-1) and produced substantially disentangled polyethylene with a weight-average molecular weight (Mw) of 3.4 MDa (disUHMWPE).

Рекомбинантные штаммы-продуценты термостабильной липазы из Thermomyces lanuginosus и их применение в гетерогенном биокатализе, в том числе, в процессах низкотемпературного синтеза сложных эфиров

Abstract-This work was devoted to the construction of recombinant strains Escherichia coli BL21 (DE3) and Pichia pastoris X33, producing a 1,3-specific thermostable lipase from Thermomyces lanuginosus. The sequences of two lipase genes were optimized for expression in bacteria and methylotrophic yeasts, then synthesized and cloned into the corresponding expression vectors. As a result of genetic engineering manipulations, E. coli and P. pastoris strains were constructed that efficiently produced recombinant lipase from T. lanuginosus, which accumulated in the cytoplasm in an amount of 30-40% of the total cellular protein. Recombinant P. pastoris clones secreted lipase into the nutrient medium at a concentration of at least 1 g/L. Lipases produced by the recombinant clones, designated as rE.coli/lip and rPichia/lip, respectively, contained a six-histidine sequence (-His6) in the C-terminal region. The resulting lipases were immobilized on/in solid inorganic supports in order to develop heterogeneous biocatalysts (HB) for the enzymatic conversion of triglycerides and fatty acids. The rPichia/lip enzyme was adsorbed on mesoporous silica and macroporous carbon aerogel. The properties of the prepared HB, their enzymatic activity, substrate specificity and operational stability were studied in the reaction of esterification of fatty acids with aliphatic alcohols in organic solvents at 20 ± 2°C. It was found that immobilized lipases had a relatively wide substrate specificity, as well as high operational stability, and the prepared HB almost completely retained their high esterifying activity for several tens of reaction cycles. Key words: Escherichia coli, Pichia pastoris, recombinant strains-producers, Thermomyces lanuginosus lipase gene, immobilization, biocatalysts, esterification The authors are grateful to V. L. Kuznetsov for the provided samples of carbon aerogel and A. V. Ryabchenko for gene-engineering manipulation aimed at obtaining the recombinant rE. coli strain, a producer of the rE.coli/lip enzyme. The work was carried out under the Project on Fundamental Research within the framework of a state assignment to the Institute for Catalysis "Catalysts and Processes of Renewable Raw Material Conversion" (no. 0239-2021-0005).

On the geometric trajectories of pores during the thermal sintering of relevant catalyst supports

The thermal events typically encountered during the reactivation of inorganic catalytic supports have been investigated. For this, two relevant inorganic materials were studied; an amorphous silica and a gamma (γ) alumina. The materials were thermally treated in air at temperatures ranging 700 up to 1100 °C and the structural and textural changes were assessed. The crystallinity was enhanced and the textural parameters decreased, but the most remarkable effect was the pore trajectory. This varies depending on the sintering mechanism, contractive sintering (silica) or coarsening (alumina), which was detected by high-resolution physisorption. The reduction in the surface area is not a good indicator of the pore changes; in addition to pore changes, the material can also suffer densification, and both effects determine the surface area. Finally, the study shows that thermal treatment is an easy way to modify the pore size of the studied materials; the γ-alumina showing more controllability.

CuSO4/[Cu(NH3)4]SO4-Composite Thermochemical Energy Storage Materials.

The thermochemical energy-storage material couple CuSO4/[Cu(NH3)4]SO4 combines full reversibility, application in a medium temperature interval (<350 °C), and fast liberation of stored heat. During reaction with ammonia, a large change in the sulfate solid-state structure occurs, resulting in a 2.6-fold expansion of the bulk material due to NH3 uptake. In order to limit this volume work, as well as enhance the thermal conductivity of the solid material, several composites of anhydrous CuSO4 with inorganic inert support materials were prepared and characterized with regard to their energy storage density, reversibility of the storage reaction, thermal conductivity, and particle morphology. The best thermochemical energy storage properties were obtained for a 10:1 CuSO4-sepiolite composite, combining an attractive energy storage density with slightly improved thermal conductivity and decreased bulk volume work compared to the pure salt.

Photodegradation of Phenolic Compounds from Water in the Presence of a Pd-Containing Exhausted Adsorbent

A closed-cycle technology regarding the use of an exhausted Pd-based adsorbent as a photocatalyst in the degradation process of phenol is presented. Pd (II) represents a precious metal of great economic importance. Its obtained from natural sources become more difficult to achieve. Therefore, also considering the regulations of the “circular economy,” its recovery from secondary sources turn out to be a stringent issue in the last years. Pd(II) ions are removed from aqueous solution through adsorption onto Florisil (an inorganic solid support—magnesium silicate) impregnated with Cyphos IL 101 (trihexyl tetradecyl phosphonium chloride). It was observed that the presence of the ionic liquid (IL) in the adsorbent structure doubles the adsorption efficiency of the studied materials. The newly obtained Pd-based photocatalyst was exhaustively characterized and was used in the degradation process of phenol from aqueous solutions. The phenol degradation process was studied in terms of the nature of the photocatalyst used, time of photodegradation and solid: liquid ratio. It was observed that both the presence of IL and Pd lead to an increase in the efficiency of the phenol degradation process. The new Pd-based photocatalyst could be efficiently used in more cycles of phenol photodegradation processes. When is used as a photocatalyst the Florisil impregnated with IL and loaded with 2 mg/g of Pd, a degree of mineralization of 93.75% is obtained after 180 min of irradiation of a phenol solution having a concentration of 20 mg/L and using a solid:liquid ratio = 1:1.

PH-Sensitive Drug Delivery System Based on Mesoporous Silica Modified with Poly-L-Lysine (PLL) as a Gatekeeper.

In this work, we synthesized a novel pH-triggered drug delivery system to enhance the bioavailability of the anticancer drug doxorubicin (DOX) through the gatekeeper poly-L-lysine (PLL) on the pore entrances of mesoporous silica nanoparticles (MSNs). Firstly, mesoporous silica was selected as the inorganic support for drug loading. Secondly, PLL was employed as the gatekeeper to control the cargo transport. In a neutral environment, the PLL brushes became shrunken and formed a dense barrier on the pore entrances of PLL/MSNs, which closed the pores and thus prevented the release of cargo. In an acidic environment, the cargo was released from the carrier PLL/MSNs because the pore entrances were opened by the swollen PLL brushes. The DOX-loaded PLL/MSNs (PLL/MSNs-DOX) showed 1.5 times higher drug release under acidic condition (pH = 4) than under neutral condition (pH = 7). During the drug release experiment for 48 h under acidic condition, PLL/MSN-DOX released about 50% of the drug after 9 h and approximately 85% after 24 h, whereas pristine MSNs loaded with DOX (MSNs-DOX) released about 50% of the drug after 30 min and reached equilibrium after 24 h. The MSNs also demonstrated their effectiveness in storing anticancer drugs until the desired environmental trigger is present. Therefore, the pH-responsive MSNs have great potential as a targeting cancer therapy.

Comprehensive analysis of the thermal properties of capric-myristic, lauric-myristic and palmitic-stearic acids and their shape-stabilization in an inorganic support

Complete thermal characterization was performed to the binary eutectics capric-myristic (CA:MA), lauric-myristic (LA:MA) and palmitic-stearic (PA:SA). The obtained thermophysical properties included theoretical calculus along with experimental measurements as phase change temperatures, latent heats, specific heat capacities and degradation temperatures, through modulated differential scanning calorimetry (MDSC) and thermogravimetry analysis (TGA). Likewise, vacuum-assisted method was successfully employed to produce novel shape-stabilized phase change materials (SS-PCMs), with a porous clay mineral as a support, using different impregnation percentages (25%, 35% and 40%) of CA:MA, LA:MA and PA:SA. Thermal properties were obtained in the same manner as for the binary eutectic mixtures, besides, scanning electron microscope (SEM) was used to study the SS-PCMs morphologies and leakage test performed. From the MDSC measurements, empirical equations of specific heat capacity as a function of temperature were proposed for the binary eutectics and SS-PCMs. The results of this work revealed that the optimal percentage of CA:MA, LA:MA and PA:SA was 35%, in terms of low leakage (<2%), latent heats around 45 kJ kg−1 and average heat capacities of 1.4 J g−1°C−1. As the new composites presented a wide range of phase change temperatures then SS-CAMA (23°C), SS-LAMA (36°C) and SS-PASA (55°C) can be used for diverse applications as in construction, food industry and domestic hot water tanks.

Extraction Chromatography Materials Prepared with HDEHP on Different Inorganic Supports for the Separation of Gadolinium and Terbium

Bis(2-ethylhexyl)phosphoric acid (HDEHP) is frequently used as an extractant in the separation and recovery of lanthanides by solvent extraction and extraction chromatography, where HDEHP (stationary phase) is fixed on an inert support and the mobile phase is an aqueous solution. Because the results of extraction chromatography strongly depend on the support material, in this study, we aim to prepare solid extractants (extraction chromatography materials) with different inorganic supports impregnated with HDEHP for the adsorption of Gd and Tb from HCl solutions, putting emphasis on the effect of the supports on the solid extractant behavior. Gd and Tb partition data were determined in HCl solutions from the prepared extraction chromatography materials using elution analysis. Solid extractants were characterized by X-Ray diffraction, electron microscopy, and infrared spectroscopy in order to determine their properties and to explain their extraction behavior. The characterization of the solid extractants showed a heterogeneous distribution of the HDEHP on the surfaces of the different supports studied. The irregular shape of the support particles produces discontinuous and heterogenous silanization and HDEHP coatings on the support surface, affecting the retention performance of the solid extractant and the chromatographic resolution.

Nontraditional Catalyst Supports in Surface Organometallic Chemistry

Surface organometallic chemistry (SOMC) as a field aims to blend the positive attributes of homogeneous and heterogeneous catalysis. Significant insight into heterogeneous systems has been gained over the years through the synthesis, characterization, and application of well-defined surface organometallic catalysts, predominantly supported on silica and alumina. Considerable research efforts have focused on the application of homogeneous methods to the synthesis and characterization of these systems. Homogeneous catalysis has thrived on its ability to electronically and sterically tune ligands to yield desired reactivity and selectivity. Efforts in SOMC, however, have only recently turned to harnessing the stereoelectronic diversity of potential inorganic support materials beyond silica and alumina in order to exert similar control on the reactivity of the organometallic active site. The support material is intrinsically linked to electronic structure and reactivity of heterogeneous organometallic systems in the same way that ligands exert control over homogeneous catalyst systems. The ability to tune the reactivity of heterogeneous catalysts by changing the support is of great value, and it is anticipated that this will represent an area of significant growth in the field. In this perspective, the use and future of non-traditional catalyst supports, such as sulfated metal oxides, modified silicas, and redox active supports is dis-cussed.

Winemaking using immobilized kefir cells on natural zeolites

The present study investigated the use of natural zeolites, an inorganic support with multiple technological advantages, for kefir culture immobilization and subsequent evaluation in winemaking at various temperatures (5–45 °C). Cell immobilization was confirmed by Scanning Electron Microscopy and immobilized kefir cells biodiversity was studied by Next Generation Sequencing. Simultaneous alcoholic and malolactic wine fermentations were monitored in repeated batch fermentations for a period >3 months, indicating a high operational stability, even at 5 °C. Alcohol content up to 12.5% vol, malic acid conversion up to 69.2% and ethanol productivity values several fold higher than those observed in traditional practice were reported in fermentations with immobilized cells on natural zeolites. PCA applied to minor volatiles detected by HS-SPME GC/MS showed that mostly the fermentation temperature affected the profile of the aroma-related compounds, while the high total ester concentrations detected at 20 οC ascertained the high quality of the products. Importantly, all new wines were accepted by the tasting panel. The results indicated the high potential of immobilized kefir culture on natural zeolites in scale-up industrial applications and suggested their exploitation in the development of low alcohol wines and wines with a semi-sweet character.

Recent advances in preparation and application of sulfonic acid derivatives bonded to inorganic supports

Heterogeneous acid-catalyzed organic transformations can be classified as one of the most important aspects of catalysis mostly due to its ability in recycling. This review deals with general discussion on the preparation of sulfonic acid derivatives immobilized on inorganic supports such as silica, periodic mesoporous silica, magnetic nanoparticles, metal organic frameworks, KIT-6, ZSM-5, MCM-41, bentonite, boehmite, clay, and other inorganic supports via organic linker. In addition, application of these inorganic supports in the acceleration of organic transformation is discussed one by one. This review aims to provide an overview of the recent developments in the field of heterogenizing homogeneous catalysts with a particular emphasis on the reaction scope and advantages of heterogeneous solid acid catalysts.

Zinc(II)‐poly(urea‐formaldehyde) supported on magnetic nanoparticles: A hybrid nanocatalyst for green synthesis of spiropyrans, spiroxanthenes, and spiropyrimidines

Immobilization of metal ions onto inorganic supports has very interesting biological, industrial, and catalysis applications. In this study, CoFe2O4@SiO2@PUF@Zn(OAc)2 nanostructure was successfully fabricated by immobilization of zinc acetate on the surface of poly(urea‐formaldehyde) supported on magnetic CoFe2O4@SiO2 nanoparticles through a layer‐by‐layer assembly. The structure of hybrid nanoparticles was characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, energy‐dispersive X‐ray spectroscopy, inductively coupled plasma atomic emission spectroscopy, vibrating sample magnetometry, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy, and transmission electron microscopy. Zinc‐poly(urea‐formaldehyde) supported on magnetic nanoparticles (MNPs@SiO2@PUF@Zn) was successfully used for the synthesis of spirooxindolopyran and spirooxindoloxanthene derivatives in aqueous medium as an environmentally benign condition. High yields, short reaction times, green solvent, reusability without significant reduction in catalytic activity, and simple separation of the catalyst using an external magnet along with environmental compatibility are some benefits of this procedure.

Silica -magnetic inorganic hybrid nanomaterials as versatile sensing platform

Several hybrid sensing materials, which are organized by interaction of organic molecules onto inorganic supports, have been developed as a novel and hopeful class of hybrid sensing probes. The hybrid silica-magnetic based sensors provide perfect properties for production of various devices in sensing technology. The hybridization of silica and magnetic NPs as biocompatible, biodegradable and superparamagnetic structures provides the opportunity to produce capable sensing materials. The fluorescence, electrochemical and calorimetric sensors based on silica-magnetic materials can be applied in quantitative detection of various analytes. This review touches upon a subject of the design and synthesis of different sensors based on magnetic-silica hybrid nanomaterials and discusses their applications for improved detection of analytes in environmental and biological fields.

Immobilization of Acidithiobacillus ferrooxidans-1333 on the Waste Ore Particles for the Continuous Oxidation of Ferrous Iron.

Background: The biooxidation of ferrous iron has a great potential for the regeneration of ferric iron, in operations such as bioleaching, bioremediation. Many natural inorganic materials were investigated for use as supports immobilizing Acidithiobacillus ferrooxidans. The waste chalcopyrite is another natural inorganic material of which particles are easy to prepare from the leached out ore heaps and the source is abundant.Objectives: The aim of this work is to investigate several characteristics of the particles of waste ore that determines possibility of use as supports for immobilization of Acidithiobacillus ferrooxidans in the packed-bed bioreactor.Materials and Methods: Acidithiobacillus ferrooxidans-1333 stored in Korean Centre for Culture Collection was used. The supports were prepared by sieving the particles of 5~30 mm in size out from the waste chalcopyrite ore heap. The cells were immobilized by the successive batch culture method and oxidation rate of the bioreactor was investigated in the continuous flow mode.Results: The cell density of Acidithiobacillus ferrooxidans-1333 immobilized on the particles of waste chalcopyrite was 2.71×108 cells g-1 and the highest oxidation rate of the packed-bed bioreactor was 3.65g.L-1.h-1. Oxidation rate of the bioreactor was less influenced by the concentration of ferrous and ferric iron in the input solution as well as by the aeration rate and dilution rate than other materials mentioned in other previous works.Conclusion: The waste chalcopyrite particle is efficient support material for immobilization of Acidithiobacillus ferrooxidans with comparable or superior characteristics to natural inorganic support materials reported before.

Decontamination of contaminated water by palladium catalyst: a short review

The release of different organic and inorganic water contaminants like halogenated organics, oxyanions, and nitrosamines in the form of solvents, pesticides and even metals that exceed their concentration in the water bodies has destroyed the water ecosystem to a greater extent. These contaminants originate from different point and non-point sources that are inorganic and organic in nature depending on the anthropogenic or natural activity. Although several methods have been utilised and modified to avert the problem, catalysis is among the promising techniques to address the issue. The catalytic reduction method using palladium has been studied extensively. These catalysts are generated using organic and inorganic supports. The use of organic supports is quite useful as they possess a number of functional groups to hold the palladium through different modes of interaction. Based on literature obtained from the different search engines 92 articles have been selected to report the various approaches for the treatment of contaminated water by catalysis. These articles also highlight the methods and characterisation techniques used to decontaminate the polluted water. Thus, we have summarised and interpreted the recent relevant literature related to palladium on suitable support as a potential catalyst for treatment of contaminated water via reduction method.

A Novel Hybrid Organic-Inorganic Nanomaterial: preparation, Characterization and Application in Synthesis of Diverse Heterocycles

Immobilization of metal ions on the inorganic supports has found many interesting biological, industrial, and catalysis applications. In this work, a novel organic–inorganic hybrid nanomaterial (nano-Fe3O4@TiO2-Pr-2AB@Cu) using simple chemical co-precipitation method, functionalization and subsequent incorporation of copper ion was prepared. The structure of hybrid nanomaterial was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), the field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET) surface area analysis, and inductively coupled plasma-optical emission spectrometry (ICP/OES). Subsequently, the catalytic properties of the prepared hybrid nanostructure were investigated in green synthesis of dihydropyridines, amidoalkylnaphthols, and chromene derivatives. The desired products were identified by FT-IR and nuclear magnetic resonance (NMR) spectroscopies. The catalyst could be recycled for seven reaction runs with slight loss of the catalytic activity and negligible copper (Cu) leaching. Some other advantages of this method are the short reaction time, high yield, easy separation of the catalyst by the external magnetic field, and easy workup procedure.

OZONE DECOMPOSITION OVER ACTIVE COAL ANCHORED Cu(II), Co(II), OR Mn(II) CHLORIDES

The known catalyst based on the inorganic support, MnCl2/SiО2, and used in personal respiratory protective devices showed its lack of prospects because of the very heavy load per a protective device and the short time of its protective action. As opposed to it, metal complex compositions based on activated carbons (AC) hold much promise. Since we intended to use activated carbons or compositions based on them in respirators protection against ozone, such an important parameter as the time of protective action was determined for activated carbons of different ranks and for the best one among MCl 2 /AC compositions (M is Cu, Co, or Mn, AC is activated carbon of KAD-iodnii rank) at initial ozone concentrations, СinО 3 , of 1,5 mg/m 3 and 10 mg/m 3 . For selection of the most effective MCl 2 /KAD-iodnii AC composition, the kinetics of ozone decomposition was investigated at СinО 3 = 500 mg/m3. The results of the latter testing showed that activity of the MCl2/KAD-iodnii AC compositions depended not only on the metal and anion nature but also on a degree of the activated carbon surface filling with metal ions. The maximum degree of ozone decomposition in a steady-state mode was demonstrated by MnCl 2 /KAD-iodnii AC. This fact can be explained by MnO 2 formation as a result of MnCl 2 oxidation with ozone. MnO 2 can be a secondary catalyst and stabilize the process of ozone decomposition. The time of protective action for activated carbons significantly depends on their chemical nature and specific micropore and mesopore volumes and increases in the order SKN-K < ART < KAD-iodnii < AG-3 < SKN-2M. MnCl2 anchoring on activated carbon of KAD-iodnii rank resulted in an essential increase in the time of protective action: an ozone outlet concentration was lower than MPCO 3 even in 48 hours. The protective properties of the catalyst for ozone microconcentration decomposition obtained by activated carbon of KADiodnii rank impregnation with MnCl2 are much better than those of the known domestic and foreign analogues and this composition can be used in the devices for protecting environment and human beings against ozone.

Synthesis and characterization of novel compounds and determining their antifungal properties against rainbow trout pathogen, Saprolegnia sp. in vitro

Saprolegnia growth on trout eggs is a problem frequently encountered in fish hatcheries worldwide. In the present study silver nanoparticles (Ag NPs) were effectively grafted on the zeolite and bentonite framework using the chemical reduction method. Zeolite and bentonite, silver nitrate (AgNO3), and sodium borohydride (NaBH4) were used as inorganic solid supports, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite through an ion-exchange path, in the external and interlamellar space of bentonite at room temperature. AgNO3 and NaBH4 were used as a silver precursor and reducing agent, respectively. The Ag/zeolite and Ag/bentonite nano compounds were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared (FTIR), X-ray powder diffraction (XRD), Energy-dispersive X-Ray spectroscopy (EDX) analysis. The results showed that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antifungal activity of Ag NPs in zeolites and bentonite were investigated against Saprolegnia sp. with different loads of nano composites and exposure time. All Ag/zeolite NCs and Ag/bentonite NCs were found to have antifungal activities. These results revealed that Ag NPs could be used as effective growth inhibitors in different biological systems, for instance in aquatic animal hatchery facilities.

Preparation and characterization of a novel organic–inorganic hybrid nanostructure: application in synthesis of spirocompounds

Immobilization and heterogenization of acidic/basic groups or organic tags on inorganic supports have found many important applications in recent years. In this investigation, a new hybrid organic–inorganic nanostructure was prepared. The structure of novel nanomaterial was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, vibrating sample magnetometer, scanning electron microscopy and the energy-dispersive X-ray spectroscopy techniques. The spirocompounds, especially spiroperimidines and pyranopyrazoles, are important structures with diverse biological activities and many applications in industries. So, the prepared hybrid nanomaterial was used as an efficient catalyst in the one-pot, green and simple protocol for the synthesis of pyranopyrazole, spiropyranopyrazole and spiroperimidine derivatives. The structure of some compounds is characterized by FT-IR, 1H-NMR and 13C-NMR analyses. In addition, the proposed intermediates were synthesized and identified to prove the presented mechanism of the reaction. This hybrid nanomaterial is a recyclable and highly efficient heterogeneous catalyst and easily separated by an external magnet from the reaction media. The short reaction time, high efficiency, operational safety and use of environmentally benign solvent are some benefits of this procedure.