In this study, high-performance FAU (NaY type) zeolite membranes were successfully synthesized using small-sized seeds of 50 nm, and their gas separation performance was systematically evaluated. Employing nano-sized NaY seeds and an ultra-dilute reaction solution with a molar composition of 80 Na2O: 1Al2O3: 19 SiO2: 5000H2O, the effects of synthesis temperature, crystallization time, and porous support (α-Al2O3 or mullite) on the formation of FAU membranes were investigated. The results illustrated that further extending the crystallization time or increasing the synthesis temperature led to the formation of a NaP impurity phase on the FAU membrane layer. The most promising FAU membrane with a thickness of 2.7 µm was synthesized on an α-Al2O3 support at 368 K for 8 h, and had good reproducibility. The H2 permeance of the membrane was as high as 5.34×10-7 mol/(m2 s Pa), and the H2/C3H8 and H2/i-C4H10 selectivities were 183 and 315, respectively. The C3H6/C3H8 selectivity of the membrane was as high as 46 with a remarkably high C3H6 permeance of 1.35× 10-7 mol/(m2 s Pa). The excellent separation performance of the membrane is mainly attributed to the thin, defect-free membrane layer and relatively wide pore size (0.74 nm).

A series of Zn-modified Hβ (Zn/Hβ) catalysts were prepared by using the different zinc precursors such as ZnSO4·7H2O, ZnCl2, C4H6O4Zn·2H2O and Zn(NO3)2·6H2O, and their catalytic performance in the ethanol conversion to propylene reaction was evaluated. Results indicate the amount and strength distribution of acid sites of the Zn/Hβ catalysts were easily tuned by employing different type of zinc precursors. More importantly, when the Zn species were introduced to the Hβ, the propylene yield was significantly enhanced, whereas the yields of the byproducts such as ethylene and C2-C4 alkanes were remarkably suppressed. For the catalyst prepared by using the ZnCl2 precursor (Zn/Hβ-C), a higher propylene yield up to 43.4% was achieved as a result of the moderate amount and distribution of acid sites. The average coking rate of the used Zn/Hβ catalysts strongly depended on the amount of total acid sites, especially the strong acid sites, i.e., the higher the amount of total acid sites of the catalyst, the greater the average coking rate. For the catalyst prepared by using the ZnSO4·7H2O precursor, Zn/Hβ-S exhibited a better stability even after depositing more coke, which is due to the higher amount of strong acid sites.

This study aimed to evaluate if the change of vehicle for CTZ (chloramphenicol, tetracycline, zinc oxide, and eugenol) paste improves the inhibition of Enterococcus faecalis in vitro. The vehicles evaluated alone and mixed with CTZ were eugenol, propylene glycol (PG), chitosan, su-per-oxidized solution (SOS), grapefruit-seed extract (GSE), and as a negative control, 0.9% saline solution. A clinical isolated of E. faecalis was morphological and biochemical characterized, in-cluding antimicrobial susceptibility was tested using 20 antimicrobial agents. Once character-ized, the clinical isolated was cultivated to performed Kirby–Bauer disc diffusion method with paper discs embedded with the different vehicles mixed or used alone, incubating at 37 ºC for 24 h. Data were analyzed by One-way ANOVA and the means were compared using Tukey test with a significance level of p<0.05. For vehicles used alone, GSE presented the greatest inhibition showing a statistically significant difference with the rest of the vehicles. When vehicles were mixed with the CTZ paste, PG showed a greater inhibition with a statistically significant differ-ence from the rest of the vehicles. In conclusion, the vehicle used to mix the CTZ paste plays an im-portant role in the inhibition of E. faecalis in vitro, therefore we consider that this can be an im-portant factor to achieve success in the use of this technique.

L-glutamate is one the most important excitatory neurotransmitter at central nervous system level and it is implicated in several pathologies. So, it is very important to monitor its variations, in real time in animal models’ brain. Amperometric biosensors have been used because of their very high temporal and spatial resolution, and because suitable for a short to mid-term implantation. The present study aimed to develop and characterize a new glutamate biosensor design that exploits the selectivity of Glutamate Oxidase (GluOx) for l-glutamate, and the capability of a small molecule as propylene glycol (PG) to influence and extend the stability and the activity of enzyme. Different designs were evaluated by modifying the main components in their concentrations to find the most suitable design. Moreover, enzyme concentrations from 100 U/ml up to 200 U/ml were verified and different PG concentrations (1%, 0.1% and 0.05%) were tested. The most suitable selected design was Pt_c/PPD/PEI(1%)₂/GlutOx₅/PG(0.1%) and it was compared to the same already described design loading PEDGE, instead of PG, in terms of over-time performances. PG has proved to be capable of determining an over-time stability of the glutamate biosensor in particular in terms of linear region slope (LRS) up to 21 days.

The processing of alkanes (the main components of natural gas) for obtaining of industrially important chemical products is one of the most urgent environmental problems, because the major share of raw materials are burned in torches. Therefore, the main goal of the work is the development of catalysts and conditions for obtaining of important petrochemical products from light alkanes. For the preparation of catalysts, Mo, Cr and Ga oxide catalysts as well as catalysts based on heteropoly compounds, supported on natural materials were used. The catalysts were prepared by the capillary impregnation method and used in oxidative conversion in a flowing unit while varying the process conditions. It has been determined that 5 and 10% MoCrGa catalysts are optimal for obtaining of liquid and gaseous products, and 1% catalyst is more favorable for the synthesis of gaseous products. Supported catalysts from heteropoly acid Н₃PW₁₂O₄₀ are highly active in oxidative dehydrogenation and cracking processes, which are concurrent. High activity is caused by dispersity of catalysts, formation of crystal hydrates and amorphous phase of heteropoly acid in a condition of interaction with carrier. Maximum yield of C₂H₄ - 35.2% at 973 K, C₃H₆ – 20.0% and C₄H₈ – 14.3% at 773 К were observed.

The esterification of propylene glycol methanol (PM) and acetic acid (AA) is an important reaction for the production of propylene glycol methyl ether acetate (PMA). Herein, we used macroporous ion exchange resin Amberlyst-35 as a catalyst to explore the effects of reaction conditions on the reaction rate and equilibrium yield of PMA. Under the optimized conditions of reaction temperature of 353 K, initial reactant PM/AA molar ratio of 1:3, and catalyst loading of 10 wt%, PMA equilibrium yield reached 78%, which is the highest equilibrium yield so far. The reaction equilibrium constants and activity coefficients were estimated to obtain reaction thermodynamic properties, indicating the exothermicity of the reaction. Furthermore, Pseudo-homogeneous (PH), Eley-Rideal (ER), and Langmuir-Hinshelwood-Hogen-Watson (LHHW) kinetic models were fitted based on experimental reaction kinetic data. The results demonstrate that the LHHW model is the most consistent with experimental data, indicating surface reaction controlled process and exhibiting an apparent activation energy of 62.0 kJ/mol. This work represents a valuable example of calculating the reaction thermodynamic and kinetics, which are particularly essential for promising industrial reactor design.