rss_2.0Polish Journal of Chemical Technology FeedSciendo RSS Feed for Polish Journal of Chemical Technology Journal of Chemical Technology 's Cover of elevated pressure on gas-solid flow properties in a powder feeding system<abstract> <title style='display:none'>Abstract</title> <p>In view of the powder feeding system, a multi-physical coupling model of the gas-powder-piston was established based on the Euler-Euler two-fluid model. The numerical simulation method was applied to explore the effects of dense gas-solid flow characteristics under different operating pressures. The results show that gas-solid pulsations at different operating pressures are mainly concentrated in the upper part of the powder tank. An elevated operating pressure efficiently decreases the powder layer area (ε<sub>p</sub> = 0.1) fluctuation. As the operating pressure increases from 0.5 MPa to 3.0 MPa, the rising time and fluctuation rate of pressure are reduced by 71.4% and 62.3%, respectively, and the pressure in the tank has a long stabilization period. Meanwhile, the variation of the instantaneous powder flow rate is more stable and its average value is closer to the theoretical. A high-pressure environment is more conducive to the stable transportation of powder.</p> </abstract>ARTICLE2022-10-16T00:00:00.000+00:00Starch plasticization with choline dihydrogencitrate-based deep eutectic system<abstract> <title style='display:none'>Abstract</title> <p>Two-component deep eutectic solvents (DES) based on choline dihydrogencitrate and glycerol or urea were tested as starch plasticizers. Thermal analysis techniques were applied to characterize the properties of starch/DES systems. The X-ray diffractometry measurements revealed a significant decrease in crystallinity indicating that used DES exhibited the ability to penetrate the ordered regions of potato starch, which is a necessary feature of a true plasticizer. However, the differential scanning calorimetry and dynamic thermal analysis results surprisingly showed an increase of T<sub>g</sub> of starch materials indicating chemical crosslinking at elevated temperature. The eutectic solvents based on choline dihydrogencitrate could act as a plasticizer and a simultaneously crosslinking agent.</p> </abstract>ARTICLE2022-10-16T00:00:00.000+00:00Synthesis, physicochemical studies, fluorescence behavior, and anticancer properties of transition metal complexes with the pyridyl ligand<abstract> <title style='display:none'>Abstract</title> <p>A novel series of complexes with the formula [MLCl] [M = Co(II) (1), Ni(II) (2), Cu(II) (3), Zn(II) (4)] arising from Pyridyl ligand, N,N′-bis(1-(2-pyridyl)ethylidene)-2,2-dimethylpropane-1,3-diamine), ligand, L, was synthesized and investigated by elemental analyses, FT-IR, <sup>1</sup>H and <sup>13</sup>C NMR, Powder XRD, and thermal analyses. TGA analysis indicated that all complexes degraded in three different steps, while the PXRD examination showed well-defined sharp crystalline peaks for the complexes, indicating significant crystallinity. The antiproliferative activity of the ligand and its complexes were also evaluated <italic>in vitro</italic> against the HeLa (Human Cervical Cancer Cells) and HCT116 (Colon Cancer Cells) cell lines. The findings suggested complex <bold>4</bold> to be potential anticancer agent against these cell lines. In addition, ligand and its complexes also exhibited considerable emission properties.</p> </abstract>ARTICLE2022-10-16T00:00:00.000+00:00Innovative NPK Fertilizers based on Polyacrylamide and Polyvinyl Alcohol with Controlled Release of Nutrients<abstract> <title style='display:none'>Abstract</title> <p>The aim of the present work was the preparation and properties evaluation of two innovative fertilizers based on multicomponent polymers characterized by a controlled release of nutrients. One method was based on a multi-component liquid containing different amounts of microelements NPK 12-5-6 fertilizers with polyacrylamide hydrogel beads. The second method concerned the cross-linking of biodegradable polyvinyl alcohol with multi-component NPK fertilizers. Polyacrylamide-based compositions with the highest amount of NPK salts as well as polyvinyl alcohol-based fertilizers in dense gel form, based on 60 phr crosslinking concentrate have shown optimal properties. Regardless of the type of fertilizers used, their components were released slowly. The obtained fertilizers were classified according to the kinetics of nutrient release. Fertilizers made from polyacrylamide based fertilizers have been classified into a group of controlled release fertilizers (CRF), while those made from biodegradable environmentally friendly polyvinyl alcohol have been defined as slow released fertilizers (SRF).</p> </abstract>ARTICLE2022-10-16T00:00:00.000+00:00Adsorption of CO by surface modified coal-based activated carbons: kinetic and thermodynamic analysis<abstract> <title style='display:none'>Abstract</title> <p>The effects of different surface modifiers on the CO<sub>2</sub> adsorption capacity of coal-based activated carbons were studied, and the diffusion behavior, adsorption kinetics and thermodynamic parameters of CO<sub>2</sub> in activated carbons were analyzed. The results show that compared with ethylene glycol, 1,2-propylenediamine and zinc chloride, potassium hydroxide and sodium hydroxide can greatly improve CO<sub>2</sub> adsorption capacity. The adsorption rate is faster, and the adsorption capacity is larger, with the maximum CO<sub>2</sub> adsorption capacity being 33.54 mL/g. Fick's law can well describe the diffusion behavior of CO<sub>2</sub> in activated carbon. The addition of a surface modifier can increase the diffusion coefficient. The diffusion of CO<sub>2</sub> in activated carbon falls into the category of crystal diffusion. The adsorption kinetics of CO<sub>2</sub> before and after surface modification follow the Bangham equation. During the adsorption process, δ H &lt; 0, δ G &lt; 0, δ S &lt; 0. Surface modification can reduce adsorption heat and promote adsorption, and the adsorption process is dominated by physisorption.</p> </abstract>ARTICLE2022-10-16T00:00:00.000+00:00The Oxygen Reduction Activity of Nitrogen-doped Graphene<abstract> <title style='display:none'>Abstract</title> <p>Graphite nitrogen, pyridine nitrogen and pyrrole nitrogen are the main nitrogen types in nitrogen-doped graphene materials. In order to investigate the mechanism of the oxygen reduction activity of nitrogen-doped graphene, several models of nitrogen-doped graphene with different nitrogen contents and different nitrogen types are developed. The nitrogen content is varied from 1.3 at% to 7.8 at%, and the adsorption energy is calculated according to the established models, then the band gaps are analyzed through the optimization results, so as to compare the magnitude of the conductivity. Finally, the oxygen reduction activity of graphite nitrogen-doped graphene (GNG) is found to be better than pyridine nitrogen-doped graphene (PDNG) and pyrrole nitrogen-doped graphene (PLNG) when the nitrogen content is lower than 2.6 at%, and the oxygen reduction activity of PDNG is the best when the nitrogen content was higher than 2.6 at%.</p> </abstract>ARTICLE2022-10-16T00:00:00.000+00:00Determination of twist drill bits wear: the effect of the composition and structure of the steels<abstract> <title style='display:none'>Abstract</title> <p>The aim of the study was to relate the influence of the chemical composition, structure, and basic properties as hardness of the tested drill bits on resistance to their wear. The chemical composition of the drill bit was investigated using the electric excitation emission spectrometry method and EDS microanalysis. Metallographic specimens were prepared and observed to determine the structure of each tool. Hardness tests were carried out on the shank and the working part of the tools. Material wear tests were carried out on the basis of measuring the wear of the drill bit flank. It has been shown that the appropriate selection of the chemical composition and heat treatment has a significant impact on the wear resistance of cutting tools, which directly translates into their quality.</p> </abstract>ARTICLE2022-10-16T00:00:00.000+00:00Application of foam separation in production of β-glucanase in Pichia<abstract> <title style='display:none'>Abstract</title> <p>β-glucanase is widely used in many fields and has great economic value and development space, but it faces the difficulties of separation and nutrient destruction in the process of industrial production. Foam separation is a simple, mild and efficient adsorption separation technique that enables efficient separation and extraction of β-glucanase. In this study, five single factors (loading volume, pH, separation gas velocity, fermentation loading concentration, surfactant concentration) of foam separation and harvest of β-glucanase produced by Pichia pastoris were studied. The best univariate condition was: 600 mL/min separation gas velocity, loading volume of 200 mL, initial enzyme concentration of 100 g/mL, surfactant concentration of 0.3 mg/mL and pH of 5. Based on the best univariate condition, the optimal separation conditions of β-glucanase were further explored, and the five-factor four-level orthogonal test was designed. From the experimental results, the best separation condition was: 600 mL/min, loading volume of 200 mL, initial enzyme concentration of 100 μg/mL, surfactant concentration of 0.5 mg/mL and pH of 5. Under this separation condition, the enrichment ratio (E) was 0.56 and the recovery rate (R) was 96.01%.</p> </abstract>ARTICLE2022-10-16T00:00:00.000+00:00(-)-Menthol-β-cyclodextrin inclusion complex production and characterization<abstract> <title style='display:none'>Abstract</title> <p>(-)-Menthol has been widely used in clinical medicine, flavor, and fragrance. However, high volatility, short retention time, low solubility in water, and whisker growth of menthol are crucial problems for its application. In this paper, (-)-menthol-β-cyclodextrin inclusion complex was fabricated to solve these problems. The product was characterized by X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. The results showed that menthol was successfully encapsulated in the cavity of β-cyclodextrin. Menthol itself vaporized almost completely at around 120 <sup>o</sup>C, while the maximum menthol release rate occurred at 267.5 <sup>o</sup>C after the formation of the inclusion complex. The stability and retention time were improved. The menthol release reaction order, apparent activation energy and the pre-exponential factor were obtained and their values were 0, 142.9 kJ/mol and 1.6 × 10<sup>13</sup> respectively. The structure of menthol-β-cyclodextrin inclusion complex was investigated by molecular simulation and the minimum energy, –116.7 kJ/mol, was obtained at –0.8 × 10<sup>–10</sup> m.</p> </abstract>ARTICLE2022-07-20T00:00:00.000+00:00Study on synthesis and photoelectric properties of AgInS quantum dots<abstract> <title style='display:none'>Abstract</title> <p>AgInS<sub>2</sub> Quantum dots (AIS QDs) have high quantum yield and catalytic performance, which is promising materials in photo-catalytic and optoelectronic fields. In the paper, it adopted a simple and non-toxic method to synthesize AIS QDs. The effect of reaction temperature on the growth mechanism, optical and physical properties of AIS had been extensively investigated by using L-cysteine as the sulfur source, and their application in catalytic hydrogen production was also studied. The results demonstrated that the fluorescence properties will be quenched with the increase of temperature, indicating that the separation speed of electron hole pairs of samples obtained at higher temperature was faster. Meantime, the electron transport capacity and the photocurrent had also improved with the increase of reaction temperature. Finally, the sample obtained at 100 <sup>o</sup>C had higher hydrogen production rate.</p> </abstract>ARTICLE2022-07-20T00:00:00.000+00:00High performance fluidized bed photoreactor for ethylene decomposition<abstract> <title style='display:none'>Abstract</title> <p>Removal of C<sub>2</sub>H<sub>4</sub> in the air was carried out in the continuous flow reactor with the photocatalytic bed (expanded polystyrene spheres coated by TiO<sub>2</sub> or SiO<sub>2</sub>/TiO<sub>2</sub>) under irradiation of UV light. Continuous flow of a gas stream through the reactor was realised at the static bed and under bed fluidization. The required flow of a gas stream through the reactor for bed fluidisation was 500–700 ml/min, whereas for the static bed the flow rate of 20 ml/min was used. Fluidized bed reactor appeared to be much more efficient in ethylene removal than that with the stationary bed. It was caused by the increased speed of C<sub>2</sub>H<sub>4</sub> mass transfer to the photocatalyst surface and better utilization of the incident UV light. In the fluidized bed reactor calculated rate of C<sub>2</sub>H<sub>4</sub> degradation was around 10 μg/min whereas in the stationary state 1.2 μg/min only.</p> </abstract>ARTICLE2022-07-20T00:00:00.000+00:00The analysis of pressure drop, spray angle, and sprinkling intensity distribution in the spray stream produced by the water-foam nozzle<abstract> <title style='display:none'>Abstract</title> <p>This paper summarises a series of large-scale fire suppression tests conducted to simulate a fire in the big surface and/or surface sprinkling. The subject of this paper is the research on water spraying with the use of the Turbo Jet 2011 water-foam nozzle manufactured by Supon Białystok. The results discuss the pressure losses caused by the flow through the discharge hose, spray angle, and the intensity of surface sprinkling. The greatest stream ranges and the highest maximum values of the sprinkling intensity were obtained at the capacity of 400 l/min, and a solid spray angle. The smallest values were obtained at 200 l/min, a pressure of 5 bar, and a solid spray angle. The actual pressures taking into account the losses in the hose section were calculated. As for the highest firefighting effectiveness of the stream, the authors recommended the following parameters: semi spray angle, 200 l/min, and 2.5 bar.</p> </abstract>ARTICLE2022-07-20T00:00:00.000+00:00Retrofitting Heat Exchanger Network of Industrial Ethylene Glycol Plant using Heat Integration based on Pinch Analysis<abstract> <title style='display:none'>Abstract</title> <p>Heat integration by pinch method is used to modify the heat exchanger network of an industrial ethylene glycol plant. The aim is to reduce the energy cost by operating the plant close to the maximum energy recovery. Pinch analysis identified a pinch temperature of 483 K, a minimum heating utility of 13,490.9 MJ/ton EO, and a minimum cooling utility of 25,697 MJ/ton EO. Using the pinch decomposition diagram and the standard procedure for matching hot and cold streams, a retrofit of the heat exchangers network is developed. The modified heat exchanger network reduces the external cooling duty by 45.5% and the external heating duty by 93.3%. This promising cost savings provide enough justification for restructuring the existing ethylene glycol plant. Moreover, an additional 6% reduction in the external cooling duty can be achieved by integrating the steam turbine below the pinch point.</p> </abstract>ARTICLE2022-07-20T00:00:00.000+00:00Enhancement of Thermal Stability, Conductivity and Smoke Suppression of Polyethylene Composites with Exfoliated MoS Functionalized with Magnetite<abstract> <title style='display:none'>Abstract</title> <p>This work reports a facile fabrication method to modify exfoliated molybdenum disulfide (e-MoS2) nanosheets with magnetite nanoparticles with various size distribution. The obtained materials have been utilized as nanofillers of polyethylene to enhance its thermal properties and flame retardance. The incorporation of magnetite modified MoS<sub>2</sub> nanosheets leads to the reduction of the peak heat release rate. The best thermal conductivity has been noticed for composites with e-MoS<sub>2</sub>/Fe<sub>3</sub>O<sub>4</sub> with 2 wt. % of nanofillers. The lowest CO emission was observed for the PE/e-MoS<sub>2</sub> composite containing also 2 wt. % of Fe<sub>3</sub>O<sub>4</sub>. All composites with exfoliated MoS<sub>2</sub> exhibited greater thermal properties in respect to the pristine polyethylene.</p> </abstract>ARTICLE2022-07-20T00:00:00.000+00:00Estimation of the upper flammability limits for alkanes in air at increased pressures<abstract> <title style='display:none'>Abstract</title> <p>A method is proposed to predict the upper flammability limits for alkanes in air at increased pressures. The upper flammability limits for methane, ethane, propane and n-butane/air mixtures at ambient temperature and initial pressure of 0.3 MPa–2.0 MPa are identified through the adiabatic flame temperature calculation model. The association of calculated adiabatic flame temperature with pressure is presented to determine the upper flammability limit. Research shows the good agreement between the forecast upper flammability limits with pressure dependence and the experimental upper flammability limit values. The average relative error of the estimated upper flammability limits for alkanes in air at high pressures reaches 2.52%.</p> </abstract>ARTICLE2022-07-20T00:00:00.000+00:00Molecular docking, theoretical calculations, synthesis of Ru(III), Pd(II) and VO(II) complexes and activity determination as antibacterial and antioxidant<abstract> <title style='display:none'>Abstract</title> <p>Molecular modeling calculations were used to validate 3D structures of new complexes of Ru(III), Pd(II) and VO(II) ions chelated with (E)-2-(phenylamino)-N-(pyridine-2-yl)methylene)acetohydrazide ligand. Furthermore, the calculations were used to estimate selected electronic chemical descriptors which are responsible for the biological activity. The first insight of the compound activity as antibacterial was evaluated by molecular docking analysis. The titled models showed stable binding towards lanosterol 14 alpha-demethylase (CYP51) enzyme of <italic>E. coli</italic>, indicating their inhibition effect toward bacterial growth. Structural study of the ligand and Ru(III), Pd(II) and VO(II) chelates was done using elemental analysis, FT-IR, <sup>1</sup>H-NMR techniques. Furthermore, complexes were physically investigated based on magnetic moment, molar conductance, electronic spectroscopic and thermal analysis techniques. The antibacterial study of the synthesized compounds screened against both Gram-positive and Gram-negative bacteria revealed that these compounds display remarkable antibacterial activity and can be used as therapeutic drugs for pathogenic bacterial diseases. All complexes and ligand showed good scavenging activities which indicate a promising result for their applications as antioxidants.</p> </abstract>ARTICLE2022-04-13T00:00:00.000+00:00Synthesis, molecular modelling and antibacterial activity of 4-aryl-thiosemicarbazides<abstract> <title style='display:none'>Abstract</title> <p>N-Substituted phenyl/cyclohexyl-2-(pyridine-4-carbonyl) hydrazine-1-carbothioamides (2a–r) were synthesized, characterized by spectral and analytical data. The compounds were evaluated for antibacterial activity by the disc diffusion method. Most of the compounds showed activity against Gram-positive bacteria. Compound 2h with 4-Sulfapyrimidine phenyl substitution was found to be the most promising candidate, active against Gram-positive and methicillin-resistant <italic>Staphylococcus aureus</italic> (MRSA) strains with minimum inhibitory concentration (MIC) of (2–7 μg/mL). From the docking study, we predicted that compounds (2r, 2g, 2h, 2o, 2p and 2e) possess better antibacterial activity by having a good binding affinity with target protein and they could be used as potential drugs as antimicrobials. Amongst all the docked compounds, the compound 2h presented near binding affinity &amp; interaction docking score with DNA gyrase enzymes with reference to ciprofloxacin.</p> </abstract>ARTICLE2022-04-13T00:00:00.000+00:00An analytical model for wicking in porous media based on statistical geometry theory<abstract> <title style='display:none'>Abstract</title> <p>In this work, an analytical model describing liquid wicking phenomenon in porous media was constructed, based on the statistical geometry theory and the fractal theory. In the model, a new structure-property relationship, depicted by specific surface, porosity, tortuosity, pore fractal dimension, maximum pore size of the porous media, was introduced into the energy conservation equation. According to the theoretical model, the accumulated imbibition weight in porous media was achieved, and the predictions were verified by available experimental data published in different literatures. Besides, structure parameters influencing the imbibition process upon approaching equilibrium height were discussed. The model and results in this work are useful for the application of porous media in scientific research and industry.</p> </abstract>ARTICLE2022-04-13T00:00:00.000+00:00Preparation of hexamethylol melamine resin with low crystallization water and low viscosity for hexamethylol melamine/polyvinyl alcohol composite membrane<abstract> <title style='display:none'>Abstract</title> <p>Hexamethylol melamine resins (HMM) with low crystallization water content and low viscosity were prepared by inhibiting the condensation polymerization of low hexamethylol melamine. The effects of catalyst, pH, formalde-hyde/melamine ratio, reaction temperature and time on the synthesis parameters of HMM were investigated. The results showed that the sample (HMM8) synthesized with Na<sub>2</sub>CO<sub>3</sub>-NaHCO<sub>3</sub> as catalyst had the crystallization water content lower than 10%, being with a viscosity of about 0.26 Pa·s. The melting temperature of HMM8/polyvinyl alcohol (PVA) curing system was about 164.3 °C. It was found that the higher the amount of formaldehyde, the greater the hydroxyl methyl bounded to each triazine ring. Compared with the traditional melamine formaldehyde resin which had the crystallization water content of about 20–30%, the production of this resin was expected to reduce the energy consumption of industrial reaction, while the resin with 10% crystallization water content was more conducive to the development of alloying HMM/PVA composite membrane.</p> </abstract>ARTICLE2022-04-13T00:00:00.000+00:00Electrochemical synthesis of Zinc oxide/polymer/phosphotungstic acid composites for a UV detector<abstract> <title style='display:none'>Abstract</title> <p>ZnO is an ideal material for UV detection. However, due to the surface effect of ZnO, the photosensitivity of the ZnO based UV detector needs to be improved. In this study, we deposited a hydroxyl group functionalized (3,4-propylenethiophene) polymer (PProDOT-OH) film onto a hydrothermally grown ZnO nanoarray by electro-chemical deposition method to prevent the corrosion of ZnO by phosphotungsten acid (PWA), and then PWA was drip-coated on the composite film to prepare the ZnO/PProDOT-OH/PWA composite based UV detector. The structure and morphology of the composite were characterized by SEM, UV–vis, FT-IR, XRD, Raman, EDS, XPS analysis, illustrating the phosphotungstic acid was uniformly coated on ZnO/PProDOT-OH surface and confirming the composite was successfully synthesized. The UV detection performance was studied through preparing a UV detector with the composite material and results indicate that the introduction of PWA could enhance the responsivity of the ZnO/PProDOT-OH composite-based UV detector.</p> </abstract>ARTICLE2022-04-13T00:00:00.000+00:00en-us-1