Fluidized-bed Fenton-like oxidation of a textile dye using natural magnetite

Degradation of Acid Orange 7 (AO7) as a model azo dye was investigated in a recirculating pilot fluidized-bed reactor by a Fenton-like process using natural magnetite (NM) and potassium persulfate (K₂S₂O₈). Scanning electron microscopy was performed to characterize the magnetite sample. The heterogeneous Fenton-like process (NM/\({\text{S}}_{2} {\text{O}}_{8}^{2 - }\)) is a modified method owing to its enhanced mass transfer. It can be operated reliably and simply by reducing the produced iron oxide sludge in the conventional Fenton process. Degradation efficiency (DE %) of AO7 by NM/ \({\text{S}}_{2} {\text{O}}_{8}^{2 - }\) process was affected by operational parameters. The DE % of 75 % was obtained for the AO7 treatment (15 mg/L) at the desired conditions, such as pH 5, 0.2 mM \({\text{S}}_{2} {\text{O}}_{8}^{2 - }\), and 0.5 g/L NM after 120 min of reaction time. The dye degradation rate in all the experiments followed the pseudo-second-order kinetic with high correlation coefficients (R ² ≥ 0.98). The low released iron concentration, successive reusability at milder pH and the recirculation mode with the proper mixing are the significant advantages of the NM/\({\text{S}}_{2} {\text{O}}_{8}^{2 - }\) process.     

Elastic,thermodynamic, electronic,and optical properties of recently discovered superconducting transition metal boride NbRuB:An ab-initio investigation

The elastic, thermodynamic, electronic, and optical properties of recently discovered and potentially technologically important transition metal boride NbRuB, are investigated using the density functional formalism. Both generalized gradient approximation(GGA) and local density approximation(LDA) are used for optimizing the geometry and for estimating various elastic moduli and constants. The optical properties of NbRuB are studied for the first time with different photon polarizations. The frequency(energy) dependence of various optical constants complement quite well the essential features of the electronic band structure calculations. Debye temperature of NbRuB is estimated from the thermodynamical study. All these theoretical estimates are compared with published results, where available, and discussed in detail. Both electronic band structure and optical conductivity reveal robust metallic characteristics. The NbRuB possesses significant elastic anisotropy. Electronic features, on the other hand, are almost isotropic in nature. The effects of electronic band structure and Debye temperature on the emergence of superconductivity are also analyzed.     

Phase stability,elastic, electronic,thermal and optical properties of Ti3Al1−xSixC2 (0≤x≤1): First principle study

The structural parameters with stability upon Si incorporation and elastic, electronic, thermodynamic and optical properties of Ti₃Al_1−xSi_xC₂ (0≤x≤1) are investigated systematically by the plane wave pseudopotential method based on the density functional theory (DFT). The increase of some elastic parameters with increasing Si-content renders the alloys to possess higher compressive and tensile strength. The Vickers hardness value obtained with the help of Mulliken population analysis increases as x is increased from 0 to 1. The solid solutions considered are all metallic with valence and conduction bands, which have a mainly Ti 3d character, crossing the Fermi level. The temperature and pressure dependences of bulk modulus, normalized volume, specific heats, thermal expansion coefficient, and Debye temperature are all obtained through the quasi-harmonic Debye model with phononic effects for T=0−1000 K and P=0−50 GPa. The obtained results are compared with other results available. Further an analysis of optical functions for two polarization vectors reveals that the reflectivity is high in the visible–ultraviolet region up to ∼10.5 eV region showing promise as a good coating material.     

pH-Responsive Biocompatible Fluorescent Core-Shell Nanogel for Intracellular Imaging and Control Drug Release

This study reports a fluorescence iron core-carbonized biocompatible hybrid poly(ethylene glycol) (PEG)-oriented nanogel (Fe₂O₃@C@PEG-COOH nanogel). The fluorescence Fe₂O₃@C@PEG-COOH nanogel is prepared using a facile one-pot polycondensation reaction without organic solvents or catalysts. The properties of the fluorescenceFe₂O₃@C@PEG-COOH nanogel are investigated by fluorescence spectroscopy, transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis. A change in pH as a stimulus can trigger the release of loaded doxorubicin (DOX). Under acidic conditions, the nanogel releases the highly loaded drug slowly compared to the neutral and basic conditions, which is important for cancer treatment. The synthesized fluorescenceFe₂O₃@C@PEG-COOH nanogel is well dispersed in water and shows fluorescence with high photostability, good biocompatibility with a paramagnetic nature. Furthermore, the nanogel can act as a potential fluorescent probe for cell imaging.     

Equilibrium and kinetic study of novel methyltrimethoxysilane magnetic titanium dioxide nanocomposite for methylene blue adsorption from aqueous media

Novel magnetic titanium dioxide nanoparticles decorated with methyltrimethoxysilane (Fe₃O₄@TiO₂‐MTMOS) were successfully fabricated via a sol–gel method at room temperature. The synthesized material was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, thermogravimetric analysis and vibrating sample magnetometry. The removal efficiency of the adsorbent was evaluated through the adsorption of methylene blue (MB) dye from water samples. The adsorption isotherm and kinetics were evaluated using various models. The Langmuir model indicated a high adsorption capacity (11.5 mg g^?1) of Fe₃O₄@TiO₂‐MTMOS. The nanocomposite exhibited high removal efficiency (96%) and good regeneration (10 times) compared to Fe₃O₄ and Fe₃O₄@TiO₂ at pH = 9.0. Based on the adsorption mechanism, electrostatic interaction plays a main role in adsorption since MB dye is cationic in nature at pH = 9, whereas the adsorbent acquired an anionic nature. The newly synthesized Fe₃O₄@TiO₂‐MTMOS can be used as a promising material for efficient removal of MB dye from aqueous media.     

An expeditious synthesis of isoxazoline using cetyltrimethylammonium cerium nitrate: A phase transferring oxidative 1, 3-diplor cycloaddition

An expeditious and effective method for synthesis of isoxazoline from aldoximes and activated alkenes using cetyltrimethylammonium cerium nitrate at room temperature is described. Reaction was completed within short time period in high yields at room temperature.     

A simple and rapid high-performance liquid chromatography method for determining furosemide, hydrochlorothiazide, and phenol red: applicability to intestinal permeability studies

A simple reversed-phase high-performance liquid chromatography (HPLC) method with ultraviolet detection at 280 nm was developed for simultaneous quantitation of furosemide and hydrochlorothiazide along with phenol red as a nonabsorbable marker for in situ permeability studies in anaesthetized rats. A jejunal segment of approximately 10 cm was isolated and cannulated in both ends for inlet and outlet solution. The perfusate was collected every 10 min, and samples were analyzed using the developed method. The mobile phase was acetonitrile-water-triethylamine-glacial acetic acid (41.5 + 57.4 + 0.1 + 0.9, adjusted to pH 5.6) at a flow rate of 1 mL/min; the run time was 9 min. The calibration graphs were linear for all 3 compounds (r > 0.999) across the concentration range of 7.93-125 microg/mL for phenol red and 6.25-100 microg/mL for hydrochlorothiazide and furosemide. The limits of quantitation were 7.2, 8.9, and 6.8 microg/mL for furosemide, hydrochlorothiazide, and phenol red, respectively. The coefficients of variation for intraassay and interassay precision were less than or equal to 7.6%, and the accuracy was between 93.2-103.4%. Using the single pass intestinal perfusion technique and the suggested HPLC method for sample analysis, mean values of 0.25 x 10(-4) (+/-0.16) cm/s and 0.22 x 10(-4) (+/-0.13) cm/s were obtained for furosemide and hydrochlorothiazide, respectively.     

Synthesis and Pharmacological Evaluation of Some Novel Imidazo[2,1-b][1,3,4]thiadiazole Derivatives

Synthesis of bis‐1,3‐{6′‐arylimidazo[2,1‐b][1,3,4]thiadiazol‐2‐yl}‐1,2,2‐trimethylcyclopentane ( 3 ), bis‐1,3‐{thiadiazolo[2′,3′:2,1]imidazo[4,5‐b]quinoxalinyl}‐1,2,2‐trimethylcyclopentane ( 5 ) has been achieved by the reaction of bis‐(5′‐amino‐1′,3′,4′‐thiadiazolyl)‐1,2,2‐trimethylcyclopentane with α‐haloketones, 2,3‐dichloroquinoxaline respectively. Bromination of compound 3 furnished bis‐1,3‐{5′‐bromo‐6′‐arylimidazo[2,1‐b][1,3,4]thiadiazol‐2‐yl}‐1,2,2‐trimethylcyclopentane ( 4 ). The structural assignment of these compounds was supported by IR, ¹H NMR and elemental analysis data. The antimicrobial, anti‐inflammatory and antifungal activities of some of the compounds have also been evaluated.