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•Inexpensive and simple fabrication route for flexible composite nanofibers system.•Photodegradation of MG was studied using rice straw and diatomite nanosilica membrane.•High ...photodegradation efficiency was obtained compared to other reported studies.•Under solar light malachite green was degraded within 15 min.•The flexibility of the nanofibers allows use in a continuous operation mode.
In this work surface modified polyacrylonitrile nanofibers/biogenic silica composites were investigated for their promising and efficient photocatalytic degradation of malachite green (MG) dye. This photocatalyst was based on polyacrylonitrile (PAN) nanofibers fabricated using electrospinning technique, then crosslinked with two kinds of biogenic silica, diatomite and rice husk nanosilica. The photocatalytic activities of MG dye were compared for the two biogenic silica. The prepared membranes was analyzed using SEM, TEM, EDAX, FTIR, and XRD techniques. The photocatalysis performance investigations of malachite green were carried out under visible light illumination in aqueous solutions. Moreover, several factors affecting the degradation were studied including; dye concentration, solution pH, and irradiation time. The results indicated that the investigated composite nanofibers have excellent photodegradation performance for Malachite green. The highest photodegradation efficiency of the MG was obtained at pH 7 and it is relatively a very fast process.
A new heterocyclic azo dye ligand (L) was synthesized by the combination of 4-amino antipyrine with 4-aminophenol. The new Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) ...complexes were synthesized in excellent yields. The metal chelate structures were elucidated using elemental analyses, FT-IR,
H-NMR, mass, magnetic moment, diffused reflectance spectral and thermal analysis (TG-DTG), and molar conductivity measurement. According to the FT-IR study, the azo dye ligand exhibited neutral tri-dentate behavior, binding to the metal ions with the azo N, carbonyl O, and protonated phenolic OH. The
H-NMR spectral study of the Zn(II) complex supported the coordination of the zo dye ligand without proton displacement of the phenolic OH. Diffused reflectance and magnetic moment studies revealed the octahedral geometry of the complexes, as well as their good electrolytic nature, excepting the Zn(II) and Cd(II) complexes, which were nonelectrolytes, as deduced from the molar conductivity study. The theoretical calculations of optimized HOMO-LUMO energies, geometrical parameters, electronic spectra, natural atomic charges, 3D-plots of MEP, and vibrational wavenumbers were computed and elucidated using LANL2DZ and 6-311G (d, p) basis sets of density functional theory (DFT) with the approach of B3LYP DFT and TD-DFT methods. The ligand and complexes have been assayed for their antimicrobial activity and compared with the standard drugs. Most of the complexes have manifested excellent antimicrobial activity against various microbial strains. A molecular docking investigation was also performed, to acquire more information about the binding mode and energy of the ligand and its metal complexes to the
receptor using molecular docking. Altogether, the newly created ligand and complexes showed positive antibacterial effects and are worth future study.
This paper evaluated the efficiency and reusability of multiwall carbon nanotubes (MWNTs) on removal of cationic and anionic dyes under effect of pH, dose of MWNTs and concentration of dyes. The ...characterization of MWNTs is characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectra and BET (Brunauer, Emmett and Teller) surface area. SEM and TEM analyses showed that MWNTs had size within nano scale range of 10–50 nm. The experimental results indicated that the efficiency of removal of MWNTs increase under condition of normal pH, at contact time 60 min with agitation speed 240 rpm and initial concentration of dyes 10 mg/l. Under these optimal conditions, the removal reached 98.7% and 97.2% for anionic dyes and cationic dyes, respectively. For economic use, MWNTs can be used more than one time where the same experiments with the already used MWNTs was repeated and it was found that the percent removal is almost the same.
Many analytical techniques, such as X-ray fluorescence spectrometry, inductively coupled plasma-atomic emission spectrometry, and even traditional spectroscopic and fluorimetric methods, are used for ...the measurement of Cr(III) ions. These methods are sophisticated and very expensive, so the cheapest and low-cost ion selective electrodes were used.
The quantification of Cr(III) ions in various samples of petroleum water using ion selective electrodes was suggested. Nano chromium modified carbon paste sensor (MCPE) and nano chromium modified screen printed sensor (MSPE) based on Schiff base Cr(III) complex are developed.
The developed nano Cr(III) Schiff base chelate was characterized using elemental, spectroscopic, and thermal analysis techniques. The proposed nano Cr(III) has good properties for antibacterial and antifungal activity. The modified carbon paste and screen-printed sensors were fabricated for determination of Cr(III) ion.
The proposed MCPE (sensor I) and MSPE (sensor II) obeys Nernstian equation upon incorporating nano Cr(III) ionophore in the paste at 25°C with a trivalent cationic slope of 18.8 ± 0.2 and 20.0 ± 0.4 mV/decade. They have showed fast response time around 8 and 5 s, and they may be used for at least 98 and 240 days without significant changes in MCPE and MSPE potential, respectively. The sensors I and II showed good selectivity for Cr(III) ion toward a wide variety of metal ions or anions as confirmed by potentiometric selectivity coefficients values. The detection and quantification limits were defined alongside the other process validation parameters. The results have been compared well to those obtained by atomic absorption spectrometry (AAS), and the data of F- and t-test indicated no significant difference between the proposed and AAS methods.
These sensors have been used to determine Cr(III) ions in genuine spiked different petroleum well water samples with satisfactory percentage recoveries, low standard, and relative standard deviation values using direct potentiometric and standard addition methods. The proposed method of producing nano Cr(III) complex as a sensor material possesses the distinct advantages of being simple, easily reproducible, appropriate for operation, and highly selective and sensitive.
Modified carbon paste and screen-printed electrodes were fabricated based on nano Cr(III) complex as ionophore. The electrodes follow Nernstian behavior, and they optimized according to IUPAC recommendation. They showed a high selectivity for Cr(III) ion over many bi- or trivalent metal ions and anions. The results obtained compared well with those obtained using AAS. They successfully applied for determination of Cr(III) in petroleum water samples.
Abstract
An important industrial process that often occurs on the surface of a heterogeneous catalyst using thermochemical or photochemical could help in the oxidation of methanol-based wastewater to ...formaldehyde. Titania-based photocatalysts have drawn a lot of interest from scientists because they are a reliable and affordable catalyst material for photocatalytic oxidation processes in the presence of light energy. In this study, a straight-forward hydrothermal method for producing n-TiO
2
@α-Fe
2
O
3
composite photocatalysts and hematite (α-Fe
2
O
3
) nanocubes has been done. By adjusting the ratio of n-TiO
2
in the prepared composite photocatalysts, the enhancing influence of the nitrogen-doped titania on the photocatalytic characteristics of the prepared materials was investigated. The prepared materials were thoroughly characterized using common physiochemical methods, such as transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), X-ray photoelectrons spectroscopy (XPS), physisorption (BET), and others, in order to learn more about the structure The results obtained showed that nitrogen-doped titania outperforms non-doped titania for methanol photooxidation. The addition of nitrogen-doped titania to their surfaces resulted in an even greater improvement in the photooxidation rates of the methanol coupled with hematite. The photooxidation of methanol in the aqueous solution to simulate its concentration in the wastewater has been occurred. After 3 h, the four weight percent of n-TiO
2
@α-Fe
2
O
3
photocatalyst showed the highest rate of HCHO production.
Mononuclear chelates of Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II) and Cd(II) resulted from new tridentate Schiff base ligand, ...4‐((1‐(5‐acetyl‐2,4‐dihydroxyphenyl)ethylidene)amino)‐1,5‐dimethyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐one, were synthesized. Metal to ligand ratio was found to be1 : 1, which was revealed via elemental analysis and characterized via various spectroscopic tools. IR has point out that the coordination of the ligand towards the metal ions was carried out via NOO donor atoms. UV‐Vis, 1H NMR spectral data, molar conductivity measurements, BET surface area, melting points and theoretically through density function theory were used such as characterizing techniques in supporting further interpretation of the complexes structures. The complexes were octahedral except Cu(II) and Ni(II) complexes were tetrahedral as suggested from the magnetic moment measurement. The complexes were found to have surface area, pore volume and particle radius of 23–176 m2 g−1, 0.02‐0.33 cc/g and 8.71‐4.32 nm, respectively, as pointed out from BET measurement. Schiff base ligand and metal complexes were tested in vitro to estimate their antimicrobial activity opposed to Gram‐negative and Gram‐positive bacterial and fungal organisms. MOE 2008 was used headed for screen potential drugs with molecular docking by the protein sites of new coronavirus and the study was constructed to molecular docking without validation through MD simulations.
Through the condensation of isatin (indoline-2, 3-dione) and aniline in a 1:1 ratio, a Schiff base ligand was synthesized and characterized via (
H-NMR, mass, IR, UV-Vis) spectra. Elemental analyses, ...spectroscopy (
H-NMR, mass, UV-Vis), magnetic susceptibility, molar conductivity, mass spectra, scanning electron microscope (SEM), and thermal analysis have all been used to characterize a series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) metal complexes derived from the titled ligand. The metal-to-ligand ratio is 1:1, according to the analytical data. The Schiff base ligand displayed bidentate behavior with NO coordination sites when it bonded to metal ions, as seen by the IR spectra. The magnetic moment measurement and UV-Vis spectral investigation showed the octahedral geometry of the Cr(III), Fe(III), Co(II), Ni(II), and Zn(II) complexes, whereas they suggested the tetrahedral geometry of the Mn(II), Cu(II), and Cd(II) complexes. The thermal analysis study confirmed the presence of both hydrated and coordinated water molecules in all the compounds, except for the Mn(II) complex, and showed that the complexes decomposed in three or five decomposition steps leaving the corresponding metal oxide as a residue. The ligand and its metal complexes' antibacterial efficacy were evaluated. The findings showed that the metal complexes had stronger antibacterial properties than the ligand alone. The ligand and its metal complexes' anticancer properties were also investigated. A DFT investigation is also reported to gather information regarding the electronic features of the ligand and its metal complexes. Finally, drug-likeness and ADME characteristics were also calculated as parameters.
•Prepared composite nanofiber membrane possesses a good photocatalyst performance.•High degradation activity of organic dyes under visible light.•The composite nanofibers membrane possessed excellent ...recovery and reuse.•The free-standing membrane is flexible and easy to handle.•The flexibility of the composite nanofibers allows use in a continuous operation.
This study proposed an effective method by using photocatalytic composite nanofiber membranes in order to degrade malachite green (MG) and acid red 27 (AR 27) to harmless products. The photocatalytic composite nanofiber membrane, Polyacrylonitrile (PAN) was incorporated with catalyst SiO2 and TiO2 photocatalyst. The PAN/SiO2-TiO2-NH2 nanofiber membrane was synthesized by electrospinning technique followed by chemical crosslinking. The results of SEM, EDX, FTIR and XRD confirmed the successful preparation of nanofiber membrane. XRD analysis shows the confirmation of SiO2 and TiO2 peaks. The result shows that PAN/SiO2-TiO2-NH2 nanofiber membrane exhibit the highest degradation with a good distribution of SiO2 and TiO2 on the PAN nanofiber membrane surface. The results showed that the complete photodegradation of MG and AR 27 with artificial visible-light was achieved after 9 and 25 min, respectively. In addition, the nanofiber membrane exhibited good stability and reusability for MG and AR 27 photodegradation and has potential to be applied in industrial application.
•Mercapto compound alone or assembled on silver nanoparticles was used as modifier.•Two modified screen printed electrodes were constructed.•The electrodes follow Nernstian behavior and they ...optimized according to IUPAC recommendation.•They showed a high selectivity for La(III) ion over many bi or trivalent metal ions and anions.•They successfully applied for determination of La(III) in real spiked water samples.
A mercapto compound, 3-amino-5-mercapto-1,2,4-triazole (AMT), was self-assembled on silver nanoparticles and used as a modifier to construct a modified screen-printed electrode. The self-assembled ionophore exhibits a high selectivity for lanthanum ion (La(III)), in which the sulfur and nitrogen atoms in their structure play a role as the effective coordination donor sites for the lanthanum ion. The proposed potentiometric method was based on the fabrication of modified sliver nanoparticles-screen-printed electrode (SNPs-MSPE) and modified screen-printed electrode with AMT (MSPE). The sensors have characteristic performance with working concentration range of 1.0×10−6–1.0×10−2 and 1.0×10−8–1.0×10−1molL−1 and a Nernstian slope of 17.5±0.1 and 20.2±0.1mVdecade−1 of lanthanum ion using MSPE and SNPs-MSPE, respectively. The detection limit was found to be 1.9×10−7 and 1.5×10−9molL−1 and potential response was pH independent across the range of 3.5–8.5 and 3.0–9.5 for MSPE and SNPs-MSPE, respectively. The application of the prepared sensors has been demonstrated for the determination of lanthanum ions in spiked real water samples. The results obtained were compared well with those obtained using inductively coupled plasma atomic absorption spectrometry (ICP-AES).
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