Reaction Rate Constant Research Articles

Distinguishable photorecycling of PVDF nanocomposites membrane for reactive yellow 145 dye and real industrial wastewater treatment by different photocatalytic processes

This paper investigates the photocatalytic performance and recyclability of PVDF-MWCNTs-TiO2 nanocomposite membranes for the treatment of textile wastewater under sunlight irradiation. The nanocomposites were fabricated by incorporating varying weight ratios of MWCNTs-TiO2 (1 %, 3 %, 6 %, and 9 %) into PVDF matrices using a solvent casting method. Optimal loading of MWCNTs-TiO2 at 9 wt% resulted in nanocomposites with enhanced surface area (94.15 m2/g), reduced band gap (2.38 eV), uniform dispersion of nanoparticles, and abundant surface hydroxyl groups. Under Xenon lamp irradiation, the optimized PVDF-9 %(MWCNTs-9 %TiO2) nanocomposite achieved a high apparent reaction rate constant (kapp) of 9.92 × 10−3 s−1 for photocatalytic degradation of the model dye Reactive Yellow 145. Significantly, when tested on-site at a Saudi Arabian textile facility over 6 months, this nanocomposite effectively reduced the chemical oxygen demand (COD) of real wastewater samples to regulatory limits of 1000 ppm under natural sunlight irradiation. The COD values were lowered from an initial 5050–6200 ppm to a final range of 785–945 ppm using the PVDF-9 %(MWCNTs-9 %TiO2) membrane. Furthermore, the optimized nanocomposite exhibited good recyclability, retaining around 87 % of its initial activity after 8 reuse cycles for industrial wastewater treatment. The excellent photocatalytic efficiency and reusability of the MWCNTs-TiO2 modified PVDF nanocomposite under solar irradiation highlight its promise as a sustainable membrane technology for environmental remediation.

Enhanced photocatalytic reduction of Cr (VI) using Ag@AgCl/RGO/CuO nanocomposite under visible light

This study investigated the photocatalytic activity of three nanocomposites, namely Ag@AgCl, Ag@AgCl/RGO, and Ag@AgCl/RGO/CuO, by examining their ability to reduce Cr (VI) using visible light irradiation. The photocatalytic samples were characterized using various methods, including X-ray diffraction, Fourier transform infrared spectroscopy, field emission-scanning electron microscopy, Raman spectroscopy, UV–Vis diffuse reflectance spectra, and photoluminescence spectroscopy. Our findings showed that the incorporation of CuO and RGO co-catalysts significantly improved the photocatalytic reduction of Cr (VI) in the plasmonic Ag-AgCl sample. Among the three samples, the Ag@AgCl/RGO/CuO nanocomposite demonstrated the highest efficiency in reducing Cr (VI) to Cr (III) using visible light with a 98 % reduction of Cr(VI) within 45 min. The improved efficiency of the Ag@AgCl/RGO/CuO photocatalyst could be attributed to its superior ability to absorb visible light and reduce the rate of electron-hole recombination. The Ag@AgCl/RGO/CuO also showed a reaction rate constant of 0.086 min−1, which was approximately 17 times faster than that of Ag@AgCl.

Persulfate-Based Advanced Oxidation Process for Chlorpyrifos Degradation: Mechanism, Kinetics, and Toxicity Assessment.

Persulfate-based advanced oxidation process has been proven to be a promising method for the toxic pesticide chlorpyrifos (CPY) degradation in wastewater treatment. However, due to the limitation for the short-lived intermediates detection, a comprehensive understanding for the degradation pathway remains unclear. To address this issue, density functional theory was used to analyze the degradation mechanism of CPY at the M06-2X/6-311++G(3df,3pd)//M06-2X/6-31+G(d,p) level, and computational toxicology methods were employed to explore the toxicity of CPY and its degradation products. Results show that hydroxyl radicals (·OH) and sulfate radicals (SO4•-) initiate the degradation reactions by adding to the P=S bond and abstracting the H atom on the ethyl group, rather than undergoing α-elimination of the pyridine ring in the persulfate oxidation process. Moreover, the addition products were attracted and degraded by breaking the P-O bond, while the abstraction products were degraded through dealkylation reactions. The transformation products, including 3,5,6-trichloro-2-pyridynol, O,O-diethyl phosphorothioate, chlorpyrifos oxon, and acetaldehyde, obtained through theoretical calculations have been detected in previous experimental studies. The reaction rate constants of CPY with ·OH and SO4•- were 6.32 × 108 and 9.14 × 108 M-1·s-1 at room temperature, respectively, which was consistent with the experimental values of 4.42 × 109 and 4.5 × 109 M-1 s-1. Toxicity evaluation results indicated that the acute and chronic toxicity to aquatic organisms gradually decreased during the degradation process. However, some products still possess toxic or highly toxic levels, which may pose risks to human health. These research findings contribute to understanding the transformation behavior and risk assessment of CPY in practical wastewater treatment.

Refinement of kinetic model and understanding the role of dichloride radical (Cl2•−) in radical transformation in the UV/NH2Cl process

The ultraviolet/monochloramine (UV/NH2Cl) process is an emerging advanced oxidation process with promising prospects in water treatment. Previous studies developed kinetic models of UV/NH2Cl for simulating radical concentrations and pollutant degradation. However, the reaction rate constants of Cl2•− with bicarbonate and carbonate (kCl2•−, HCO3− and kCl2•−, CO32−) were overestimated in literature. Consequently, when dosing 1 mM chloride and 1 mM bicarbonate, the current models of UV/NH2Cl severely under-predicted the experimental concentrations of three important radicals (i.e., hydroxyl radical (HO•), chlorine radical (Cl•), and dichloride radical (Cl2•−)) with great deviations (> 90 %). To investigate this issue, the transformation reactions among these three radicals in UV/NH2Cl were systematically studied. For the first time, it was found that in addition to Cl•, Cl2•− was also an important parent radical of HO• in the presence of chloride, and chloride could effectively compensate the inhibitory effect of bicarbonate on HO• generation in the system. Moreover, reactions and rate constants in current models were scrutinized from corresponding literature, and the reaction rate constants of Cl2•− with bicarbonate and carbonate (kCl2•−, HCO3− and kCl2•−, CO32−) were reevaluated to be 1.47 × 105 and 3.78 × 106 M−1s−1, respectively, by laser flash photolysis. With the newly obtained rate constants, the refined model could accurately simulate concentrations of all three radicals under different chloride and bicarbonate dosages with satisfactory deviations (< 30 %). Meanwhile, the refined model performed much better in predicting pollutant degradation and radical contribution compared with the unrefined model (with the previously estimated kCl2•−, HCO3− and kCl2•−, CO32−). The results of this study enhanced the accuracy and applicability of the kinetic model of UV/NH2Cl, and deepened the understanding of radical transformation in the process.

A novel ZnCo2O4/BiOBr p-n/Z-scheme heterojunction photocatalyst for enhancing photocatalytic activity.

In this study, we developed a novel p-n/Z-scheme heterojunction photocatalyst, ZnCo2O4/BiOBr (ZCo/BB), through a straightforward and safe hydrothermal-calcination-solvent thermal method. The composite photocatalyst demonstrated exceptional photocatalytic efficacy, particularly when the mass ratio of ZnCo2O4 was 25% (referred to as 25% ZCo/BB). Structural characterization and electrochemical analysis revealed that 25% ZCo/BB exhibited a larger specific surface area and a faster electron transfer rate. Under visible light exposure for 30min, methylene blue (MB) degradation reached 92%, and the reaction rate constants were 8.2 and 3.7 times higher than those observed for individual ZnCo2O4 and BiOBr, respectively. Furthermore, the 25% ZCo/BB demonstrated exceptional photocatalytic stability over four cycles, maintaining over 80% MB degradation after each cycle. The outstanding photocatalytic activity was attributed to the p-n/Z-scheme heterojunction construction, which promoted charge separation and inhibited carrier recombination. In addition, ·OH and h+ were the major active species in photocatalysis, and · was identified as a secondary active species. This work presents an efficient heterojunction photocatalyst for the degradation of organic wastewater.

Theoretical Study on Ethylamine Dissociation Reactions Using VRC-VTST and SS-QRRK Methods.

Barrierless bond dissociation reactions play an important role in fuel combustion. In this work, the pressure-dependent dissociation rate constants of ethylamine (EA) are accurately determined using variable-reaction-coordinate variational transition-state theory combined with the system-specific quantum Rice-Ramsperger-Kassel method. Before the kinetics calculations, the performances of four density functional theory methods in describing the bond dissociation of EA are evaluated against the benchmark method, FIC-MRCISD(T)+Q/cc-pVTZ, and the MN15-L/cc-pVTZ method is the best choice. By comparison of the Gibbs free energies and the rate constants for the bond dissociation reactions of EA, ethanol, and propane, the influence of functional groups on the reaction kinetics is discussed. The kinetics calculations show that the dissociation rate constants of EA are sensitive to pressure at low pressures and high temperatures, and the dominant channel is the reaction that yields C2H5 and NH2 radicals. A literature combustion model of EA is updated with our calculations, and the satisfactory agreement between the model predictions and reported ignition delay times of EA suggests the reliability of our calculations.

Moment Analysis Method for Measurement of Reaction Equilibrium and Rate Constants by Using High-Performance Liquid Chromatography.

The moment analysis method was developed for the determination of association equilibrium constant (KA) and association (ka) and dissociation (kd) rate constants of intermolecular interactions between solute and ligand molecules. They are accurately determined by using moment equations from elution peak profiles because they are measured by using high-performance liquid chromatography (HPLC) under preferable conditions that neither immobilization nor chemical modification (i.e., fluorescence labeling) of solute and ligand molecules is required. To demonstrate the effectiveness of the method, it was applied to the inclusion complex formation system between dibenzo-18-crown-6 (DB18C6) and alkaline earth metal cations, i.e., Mg2+, Ca2+, and Sr2+, as a concrete example. Because the diameter of the three metal cations is smaller than that of the inner cavity of DB18C6, the values of KA, ka, and kd were analytically determined by assuming the stoichiometry of 1:1 between DB18C6 and the metal cation. They reflected the influence of the difference in the size between the inner cavity of DB18C6 and the metal cations on the inclusion complex formation. It seems that the moment analysis method based on HPLC separation is effective for the multifaceted analysis of chemical reactions because some characteristics of the method are different from those of other conventional methods. It must contribute to the dissemination of an opportunity for the study of chemical reactions to many researchers because of the versatility of HPLC.

The Importance of Anharmonicity and Solvent Effects on the OH Radical Attack on Nucleobases.

Previous theoretical investigations of the reactions between an OH radical and a nucleobase have stated the most important pathways to be the C5-C6 addition for pyrimidines and the C8 addition for purines. Furthermore, the abstraction of a methyl hydrogen from thymine has also been proven an important pathway. The conclusions were based solely on gas-phase calculations and harmonic vibrational frequencies. In this paper, we supplement the calculations by applying solvent corrections through the polarizable continuum model (PCM) solvent model and applying anharmonicity in order to determine the importance of anharmonicity and solvent effects. Density functional theory (DFT) at the ωB97-D/6-311++G(2df,2pd) level with the Eckart tunneling correction is used. The total reaction rate constants are found to be 1.48 ×10-13 cm3 molecules-1s-1 for adenine, 1.02 ×10-11 cm3 molecules-1s-1 for guanine, 5.52 ×10-13 cm3 molecules-1s-1 for thymine, 1.47 ×10-13 cm3 molecules-1s-1 for cytosine and 7.59 ×10-14 cm3 molecules-1s-1 for uracil. These rates are found to be approximately two orders of magnitude larger than experimental values. We find that the tendencies observed for preferred pathways for reactions calculated in a solvent are comparable to the preferred pathways for reactions calculated in gas phase. We conclude that applying a solvent has a larger impact on more parameters compared to the inclusion of anharmonicity. For some reactions the inclusion of anharmonicity has no effect, whereas for others it does impact the energetics.

The investigation of initial decomposition paths of methyltrichlorosilane on (0001) and (000[formula omitted]) surfaces of 4H-SiC: A DFT study

Methyltrichlorosilane (CH3SiCl3, MTS), a favored precursor for chemical vapor deposition (CVD) process of silicon carbide (SiC) epitaxial layer fabrication in a wide variety of temperatures, has been investigated prevalently. In this work, the investigation focused on the initial decomposition paths of MTS with active surface sites on 4H-SiC surfaces. The surfaces employed in this study include both (0001) face and (0001¯) face, which represent Si face and C face, respectively. The decomposition pathways of MTS decomposed with the active surface sites of 4H-SiC surfaces were researched theoretically with employment of transition state theory (TST). The barriers of Gibbs free energies and the estimated reaction rate constants were acquired to discuss the decomposition reactivity of MTS with the active sites on 4H-SiC surfaces. This work shows that MTS has tendency to decompose on both (0001) face and (0001¯) face of 4H-SiC, the H and Cl atoms can be abstracted by active surface sites on (0001) face and (0001¯) face, and impingement of MTS to active surface sites on (0001) and (0001¯) surfaces can yield C-containing and Si-containing surface species.

Facile synthesis of ZnO/halloysite nanotube composite with greatly enhanced photocatalytic performance

ZnO/halloysite nanotube composites (ZH-X, X = 10, 30, 40, 50, 70), with different mass ratio of ZnO to halloysite nanotubes (HNTs), were fabricated successfully via a facile wet chemical technique in anhydrous ethanol under a mild reaction condition. ZnO nanoparticles about 9 nm in size were inhibited from agglomeration and loaded homogeneously on the surface of HNTs. The microstructure, specific surface area, light absorption ability, photocatalytic performance, etc. of the ZH-X composites varied with the mass ratio of ZnO to HNTs. All ZH-X composites displayed better photocatalytic performance than pure ZnO sample did. With the increasing of ZnO content, the photocatalytic activity of ZH-X composite toward degrading methylene blue (MB) solution strengthened gradually and reached the maximum by ZH-40 composite (with ZnO content of 28.57 wt%), then decreased step by step. ZH-40 (0.05 g) removed 99.88% of MB (100 mL, 15 mg/L) after adsorption in dark and then photocatalytic degradation for 60 min, and whose photocatalytic reaction rate constant was 5.73 times that of pure ZnO. The enhanced photocatalytic efficiency of ZH-40 composite was attributed to the interfacial effect of ZnO and HNTs as well as the dispersed ZnO nanoparticles, which maintained the adsorption ability of HNTs and improved the separation and migration of photo-generated electron and hole pairs. This work provides a feasible method for loading photocatalyst on clay mineral to realize efficient photocatalysis.

N-octyltrimethylammonium bromide-assisted self-assembly of CoMo precursors to prepare CoMoS/Al2O3 catalysts for highly selective hydrodesulfurization of thiophene

A novel (C11H26N)2Co(MoS4)2 complex was prepared via the n-octyltrimethylammonium bromide-assisted self-assembly of CoMo precursors for the selective hydrodesulfurization (HDS) of thiophene. The complex was generated by the interaction between the negatively charged CoMo compound and the positively charged n-octyltrimethylammonium ions. Then positively charged bimolecular layers were formed owing to van der Waals forces between the C11H26N+ and the complex, and they were anchored on the negatively charged γ-Al2O3. Compared with CoMoS/γ-Al2O3 catalysts prepared by impregnation, the optimal CoMoN-0.3/γ-Al2O3 catalyst exhibited better performance for selective HDS due to the enhanced Mo dispersion, the close contact between Co and Mo, and the increased amount of CoMoS phases on γ-Al2O3. Among these catalysts, the optimal CoMoN-0.3/γ-Al2O3 catalyst with the highest concentration of CoMoS phases exhibited the highest HDS reaction rate constant of 6.95 × 10-6 mol·g−1·s−1 and the best selective factor of 26.1 for the selective HDS of thiophene with 1-hexene.

Activation of peroxydisulfate via BiCoFe-layered double hydroxide for effective degradation of aniline.

The sulfate radical-based advanced oxidation processes (SR-AOPs) is a promising method for the degradation of pollutants, with the development of highly efficient catalysts for persulfate activation has been widely concerned. The novel BiCoFe-LDH (BCF-x) was synthesized successfully by coprecipitation method, which can activate peroxydisulfate (PDS) efficiently to degrade aniline. Comparative analysis with pure CoFe-LDH revealed a remarkable increase in reaction rate constant by approximately 14.66 times; the degradation rate of aniline (10mg/L) was 100% in 60min with the condition of 0.5g/L BCF-1.5 and 0.5g/L PDS, due to BCF-1.5 which was characterized as a complex of CoFe-LDH and Bi2O2CO3, promoting electron transport to improve the efficiency of activated PDS. In the reaction system, SO4•-, ·OH, and 1O2 were responsible for the aniline degradation and ·OH was the primary one. Furthermore, this work proposes a reaction electron transfer catalytic mechanism, which provided a new insight and good application prospect for efficient activation of PDS for pollutant degradation.

Study on the Mechanism of Lipid Peroxidation Induced by Carbonate Radicals.

Based on the reported research, hydroxyl radicals can be rapidly transformed into carbonate radicals in the carbonate-bicarbonate buffering system in vivo. Many of the processes considered to be initiated by hydroxyl radicals may be caused by carbonate radicals, which indicates that lipid peroxidation initiated by hydroxyl radicals can also be caused by carbonate radicals. To date, theoretical research on reactions of hydrogen abstraction from and radical addition to polyunsaturated fatty acids (PUFAs) of carbonate radicals has not been carried out systematically. This paper employs (3Z,6Z)-nona-3,6-diene (NDE) as a model for polyunsaturated fatty acids (PUFAs). Density functional theory (DFT) with the CAM-B3LYP method at the 6-311+g(d,p) level was used to calculate the differences in reactivity of carbonate radicals abstracting hydrogen from different positions of NDE and their addition to the double bonds of NDE under lipid solvent conditions with a dielectric constant of 4.0 (CPCM model). Grimme's empirical dispersion correction was taken into account through the D3 scheme. The energy barrier, reaction rate constants, internal energy, enthalpy and Gibbs free energy changes in these reactions were calculated With zero-point vibrational energy (ZPVE) corrections. The results indicated that carbonate radicals initiate lipid peroxidation primarily through hydrogen abstraction from diallyl carbon atoms. The reaction of hydrogen abstraction from diallyl carbon atoms exhibits the highest reaction rate, with a reaction rate constant approximately 43-fold greater than the second-ranked hydrogen abstraction from allyl carbon atoms. This process has the lowest energy barrier, internal energy, enthalpy, and Gibbs free energy changes, indicating that it is also the most spontaneous process.

In-situ fabrication of MOF-derived MnO-C modified graphite felt for electro-activation of peroxymonosulfate toward degradation of tetracycline: Performance, mechanism and degradation pathway

Peroxymonosulfate (PMS) activation by synergy of electrochemistry and catalyst has emerged as a promising technique for the degradation of organic contaminants. Herein, manganese oxide-carbon modified graphite felt (MnO-C/GF) electrodes are successfully synthesized by pyrolyzing Mn-MOF/GF composite. MnO-C/GF is employed as an anode to remove tetracycline (TC) in a process of PMS activation with the assistance of electrochemistry (EC). Under optimal conditions (50 mg/L TC, 10 mA·cm−2, pH 7, 0.80 mM PMS,0.05 M Na2SO4, 25 °C), MnO-C800/GF electrode (pyrolysis at 800 °C) achieves remarkable degradation efficiency of 90.48 % for TC after 60 min in EC-PMS system. The reaction rate constant (k) of MnO-C800/GF increases by 4.54 and 2.38 times compared to bare GF and MnO/GF in EC-PMS system, respectively. In addition, quenching test and electron paramagnetic resonance test reveal that ·OH, SO4−, O2− and 1O2 are involved in the degradation process at MnO-C800/GF-EC-PMS system. According to the results of density functional theory and liquid chromatography-mass spectrometry, the degradation of TC mainly includes hydrogenation, demethylation, deamidation, dehydroxylation and ring-opening reactions. This work demonstrates that the combination of electrochemistry and metal oxide-activated PMS is a highly efficient approach for the degradation of antibiotic contaminant.

Synergistic impacts of radiative flow of Maxwell fluid past a rotating disk with reactive conditions: An Arrhenius model analysis

This study presents an analysis of the hydromagnetic radiative flow of a Maxwell fluid past a rotating disk around its own axis with an angular velocity Ω0 which has enormous applications in metal casting (help to optimize the solidification and cooling of molten metals), plastic molding and aerospace engineering (cooling system of aircraft engines). The flow is constrained by boundaries that induce convection and chemical reactions described by the Arrhenius model. By applying similarity transformations, the non-linear partial differential equations, which describe the flow phenomenon, are metamorphosed into the non-dimensional system of ordinary differential equations (ODEs). The obtained ODEs are then solved numerically using ‘Keller box method’, an efficient computational technique, by implementing the finite-difference approach. The influence of different parameters, namely magnetic field strength, radiation parameter, reaction rate constant, and convective heat transfer coefficient, on the flow and heat/mass transfer characteristics are investigated. The findings suggest that the higher activation energy leads to a slower rate of reaction. As the reaction rate decreases, the consumption of reactant molecules and the reduction in their concentration also slow down. The influence of the convective heat transfer coefficient is also examined in terms of its effect on the thermal and concentration boundary layers. As the stretching parameter increases, the Maxwell fluid undergoes greater deformation, leading to greater strain and a consequent slowing of the fluid's radial velocity. Heat transfer is enhanced by thermal radiation and convective condition at the surface of rotating disk. The findings of this study provide valuable insights into the industries dealing with Maxwell fluids, enabling them to enhance process efficiency, optimize resource utilization, and develop sustainable and environmentally friendly solutions.

Semiclassical reaction rate constant of non-adiabatic system by means of initial value representation

We applied the semiclassical initial value representation (SC-IVR) method with the classical electron analog to deal with electronically non-adiabatic reactive barriers and calculated the thermal reaction rate constant. The symmetric form of the flux–flux correlation function is used, and the matrix element of the Boltzmannized flux operator is derived using imaginary-time path integral techniques. This combined use of non-adiabatic SC-IVR and non-adiabatic path-integral sampling (NA-IVR&amp;PI) is beyond the treatment of mean-field, and we analyze its performance in comparison with some existing mean-field methods for different scenarios of potential energy surface. We found a systematically better performance. One exception is the deep tunneling regime, where the mean-field ring-polymer instanton is superior. In the golden rule limit, where all these mean-field methods break down, the significant advantage of NA-IVR&amp;PI is shown by using the electronic states for description of the dividing surface.

Gas-Phase Fabrication and Photocatalytic Activity of TiO2 and TiO2-CuO Nanoparticulate Thin Films.

CuO-loaded TiO2 nanomaterials have applications in pollutant degradation via photocatalysis. However, the existing methods of fabricating these nanomaterials involve liquid-phase processes, which require several steps and typically generate liquid waste. In this study, TiO2 and TiO2-CuO nanoparticulate thin films were successfully fabricated through a one-step gas-phase approach involving a combination of plasma-enhanced chemical vapor deposition and physical vapor deposition. The resulting films consisted of small, spherical TiO2 nanoparticles with observable CuO on the TiO2 surface. Upon annealing in air, the TiO2 nanoparticles were crystallized, and CuO was completely oxidized. The photocatalytic activity of TiO2-CuO/H2O2, when introduced into the rhodamine 6G degradation system, was substantially enhanced under both ultraviolet and visible light irradiation. Moreover, this study highlights the influence of pH on the photocatalytic activity; TiO2-CuO/H2O2 exhibited the highest photocatalytic activity at pH 13, with a reaction rate constant of 0.99 h-1 cm-2 after 180 min of visible light irradiation. These findings could facilitate the development of nanoparticulate thin films for enhanced pollutant degradation in wastewater treatment.

What Principle Governs the Chemical Dynamic/Kinetic Process (3)?

In this work we discussed the description of the chemical dynamic/kinetic process. It is noticed that the conventional one way description about the chemical dynamic/kinetic process is a mathematically correct but physically incorrect description, because the chemical reaction doesn’t follow the one way mechanism as scientist’ will. Instead, the forward chemical dynamic/kinetic processes are always accompanied by the backward chemical dynamic/kinetic processes. Based on this physical picture for the chemical reaction dynamic/kinetic process, it is concluded: 1.the forward and backward chemical reactions follow the same route, just the time direction is reversed and 2.the exponential factor of the rate constant of the chemical reaction is the same for forward and backward chemical reaction dynamic/kinetic processes.

Physical-chemical and biopharmaceutical research of ointments with cyminal

Local wound treatment remains one of the most pressing problems of modern medicine. The effectiveness of local drug therapy with the use of various medications depends on the differentiated use of drugs depending on the phase of the wound process.&#x0D; Taking into account modern wound treatment technologies, it is important to develop the composition and technology of an application drug (cream, ointment, gel) taking into account not only the phase of the wound process, but also the Time-concept component, in particular the ability of the drug to create an optimal moist environment and have antimicrobial properties, since the absence of infection in the wound is the basis for successful healing.&#x0D; The aim of our study was to develop an optimal composition of ointment for wound treatment based on technological and physicochemical studies.&#x0D; The rheological properties of the samples were studied using a Reotest-2 rotational viscometer (USA) with a water circulating heater. The structural viscosity was determined at a temperature of 20 ± 0,2 °C. Thermostatization was performed in the ITZH-0-03 thermostat.&#x0D; The temperature was determined by a laboratory thermometer with a division price of 0,1 °C. The acid-base balance was determined potentiometrically according to the State Standard Form I. The pharmacokinetic parameters of the drug were determined by dialysis through a semipermeable membrane.&#x0D; The experimental ointment is a non-Newtonian fluid. Its fluidity begins after a certain mechanical stress is applied, i.e., after the kinetic energy of the particles of the structural frame increases, which leads to the breakdown of bonds between its elements. The maximum destruction of the system occurs at a temperature of 40 °С. The experimental data showed that the pH of the ciminal ointment is in the range from 5,5 to 7.5, which is optimal for the treatment of infected wounds. The pharmacokinetic parameters of the drug were determined: reaction rate of release of active substances; reaction rate constants, half-life. The kinetic processes of ciminals release from the drug are described by the first-order equation.&#x0D; The composition and technology of the ointment have been substantiated on the basis of experimental studies.

Facile synthesis of BiOI/BaNbO3 composite for rapid sonocatalytic degradation of tetracycline hydrochloride

Sonocatalysis, a vibration-induced chemical reaction, has shown great potential for catalytic applications. This study used a water bath method to prepare BiOI/BaNbO3 composites with various mass ratios. Under the influence of sonocatalysis, the BI/B-0.5 catalyst could degrade tetracycline hydrochloride up to 96.5 % after 20 min, and the stability was good. In comparison to pure BiOI and BaNbO3, the reaction rate constants of the BiOI/BaNbO3 catalyst were found to be 7.2 and 13.7 times higher, respectively. Furthermore, we systematically investigated the sonocatalytic degradation effect of BiOI/BaNbO3 on HTC under various conditions. Finally, we propose a possible mechanism for the sonocatalytic degradation of HTC by the BiOI/BaNbO3 composite catalyst. Our results underscore the superior degradation efficiency achieved by the BiOI/BaNbO3 catalyst, demonstrating its potential for efficient removal of organic pollutants.