Facile sonochemical synthesis of Ag 2 O-guar gum nanocomposite as a visible light photocatalyst for the organic transformation reactions
Silver Oxide (Ag 2 O)Guar gum nanocomposite was fabricated via a simple sonochemical coprecipitation method. The obtained photocatalyst was characterized with various techniques such as Xray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, UVvis diffuse reflectance spectroscopy, photoluminescence spectroscopy, scanning electron microscopy and transmission electron microscopy along with energy dispersion Xray spectroscopy. The findings have demonstrated that Ag 2 O nanoparticles are spherical of 520 nm and were dispersed on the surface of polysaccharide guar gum to form Ag 2 Oguar gum nanocomposite. The assynthesized nanocomposite was enacted as a competent photocatalyst for the reduction of nitrobenzene and oxidation of benzyl alchohol. The conversion efficiency for the reduction of nitrobenzene was 96 % with the addition of sodium borohydride, and the conversion of benzyl alcohol was 98 %. The highly efficient photocatalytic activity was due to the exceedingly dispersed Ag 2 Oguar gum nanocomposite where effective separation rate of energy driven electronhole pairs and stronger light absorption occurs. The possible mechanism of the reactions was implicated in understanding the active species involved in the photocatalytic study.
Synthesis of new imine-linked covalent organic framework as high efficient absorbent and monitoring the removal of direct fast scarlet 4BS textile dye based on mobile phone colorimetric platform
Synthesis of a high adsorption capacity material for pollutions removal is temping research and practical field due to increasing the environmental pollution in industrial communities. In this study, a new covalent organic framework based on triazine rings was synthesized and characterized by FTIR spectra, Xray di raction pattern, elemental analysis, and nitrogen adsorptiondesorption isotherm. Because of the nitrogen riched surface, mesoporous structure, and large surface area, the synthesized Nriched triazinebased COF had a super adsorption capacity. The adsorption properties were examined with the removal of DFS4BS from textile wastewater. The effective parameter on adsorption performance and color removal processes such as pH, contact time, temperature, and adsorbent dosage were optimized with Central Composition Design. The optimum condition was pH 2 Temperature: 35 C Absorbent dosage: 0.01 g and contact time: 360 min. The obtained maximum adsorption capacity was 8501 mg g 1 (850 wt %) that indicates the super adsorption ability of synthesized Nriched TCOF. To reduce the colorimetric test price and develop the presented adsorbent for field applicability, a mobile phone colorimeter was constructed with accessible equipment and investigate the accuracy of that by comparing the data of mobile phones with the obtained result from UVvis spectrometer.
Femtosecond laser ablation-assisted synthesis of silver nanoparticles in organic and inorganic liquids medium and their antibacterial efficiency
Laser ablation from a solid target assists the synthesis of nanoparticles (NPs) as an alternative physical process. This work is attempt to investigate the morphological properties of silver nanoparticles (AgNPs) synthesized by femtosecond pulsed laser ablation in different liquid medium Double Distilled Water (DDW), Deionized Water (DIW), Tetrahydrofuran (THF), and Dimethylformamide (DMF). XRD diffraction peaks that corresponds to (111), (200), (220) and (311) planes confirm the synthesized of AgNPs. The absorption spectra confirm the existence surface plasmon resonance (SPR) peak of AgNPs. The direct optical energy band gap (Eg) values have been calculated according to Taucs equation and equal to 3.97, 3.82, 3.86, and 3.88 eV for synthesized AgNPs by Fs PLAL at different medium DDW, DIW, THF, and DMF, respectively. Also, the influence of different liquid medium on the antibacterial efficiency was studied. In vitro Antibacterial activity of synthesized AgNPs was carried out against four types of bacteria employing agar plate technique. The experiments demonstrated that ablation efficiency, stability, and antibacterial efficiency of AgNPs in DIW medium are higher than those prepared in DDW, THF, and DMF medium.
Scalable synthesis of Ca-doped alpha-Fe2O3 with abundant oxygen vacancies for enhanced degradation of organic pollutants through peroxymonosulfate activation
In this work, a costeffective and ecofriendly calciumdoped alphaFe2O3 (CaFe2O3) with abundant oxygen vacancies was fabricated using a scalable precipitationcalcination method to activate peroxymonosulfate (PMS) for wastewater purification. Density functional theory calculations revealed that the incorporation of Ca2 into the alphaFe2O3 structure enhances the electron transfer from alphaFe2O3 to PMS, facilitating the activation of PMS. The degradation of Rhodamine B by 5%CaFe2O3 proceeded with a reaction constant 8 times higher than that of pristine alphaFe2O3. This can be attributed to the increased generation of O1(2) and O2(center dot), increased specific surface area and enhanced electrical conductivity. The applicability of the 5%CaFe2O3PMS system was investigated including its operating parameters and stability, and the intermediates involved in the reaction were identified. The 5%CaFe2O3PMS system exhibited excellent degradation efficiency in natural water samples. This work opens up new perspectives for designing highly efficient catalysts and renders iron oxides potential candidates for environmental remediation.
Synthesis of porous metal-organic framework composite adsorbents and pollutant removal from multicomponent systems
Herein, MIL101 (Fe)phosphotungstic acid (PA) composites were synthesized and characterized. Materials Institute Lavoisier (MIL101 (Fe)) composites as metalorganic frameworks (MOFs) with 0, 0.347, 0.694 and 1.042 mmol of PA were synthesized and denoted as MIL, MP1, MP2, and MP3, respectively. The synthesized MOFs were used to remove organic contaminants from binary systems (BB:Basic Blue 41 and MB:Methylene Blue). The synthesized materials were characterized in detail. Pollutant removal obeyed the Langmuir isotherm and pseudosecondorder kinetic. The free energy of adsorption for MP2 at 298, 308, 318 and 328 K was 15.24,15.93, 16.63 and 17.32 kJmol for BB and 15.04, 15.02, 15.01 and 14.99 kJmol for MB, respectively. Adsorption by the synthesized materials was spontaneous and endothermic process. The multicomponent dye removal data indicated that the synthesized MIL101 (Fe)phosphotungstic acid (PA) composites could be used as efficient adsorbents for treating colored wastewater. In addition, the synthesized MOFs were recyclable and regenerable adsorbents.
Synthesis, structural, growth, optical, electrical, thermal and third order nonlinear optical properties of a novel organic single crystal: p-Toluidinium malonate
Novel organic nonlinear optical material pToluidinium malonate (PTM) was grown from aqueous solution by slow evaporation technique. The lattice parameters were evaluated from single crystal Xray diffraction analysis and found that crystal system belongs to monoclinic with centrosymmetric space group P2(1)c. The solid state parameters valence electrons, Plasma energy, Penn gap and Fermi energy were evaluated theoretically. These estimated values are used to calculate the electronic polarizability of PTM crystal. The functional groups exist in the compound were identified using FTIR and FTRAMAN spectroscopy. PTM crystal showed transmittance in the entire visible region with lower cut off wavelength of 311 nm and band gap energy of 3.8 eV. The photoluminescence spectrum was recorded to explore the emission and thermal behaviour of PTM crystal by employing TGDTA analysis. Dielectric measurement was carried out on the grown crystal at different temperatures to evaluate electrical properties. The thirdorder nonlinear optical parameters were estimated by Zscan technique using 532 nm diode pumped CW Nd:YAG Laser. (C) 2019 Elsevier B.V. All rights reserved.
In-situ synthesis of metal nanoparticles@metal−organic frameworks: Highly effective catalytic performance and synergistic antimicrobial activity
M-NP@Zn-BIF (M-NP = Ag or Cu nanoparticle; Zn-BIF is a zinc-based boron imidazolate framework, Zn 2 (BH(2-mim) 3 ) 2 (obb); 2-mim = 2-methylimidazole; obb = 4,4′-oxybis(benzoate)) composites were successfully in-situ synthesized by utilizing the reducing ability of the B[sbnd]H bond contained in the Zn-BIF at room temperature without any additional chemical reduction reagents. These composites (225 μg/mL) exhibited excellent catalytic activity to convert 4-nitrophenol to 4-aminophenol in 2.5 min and 6 min with a conversion rate of 99.9 %, respectively. In addition, Ag@Zn-BIF (50 μg/mL) showed highly synergistic antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) with a bactericidal rate of approximately 99.9 %. An antibacterial mechanism was proposed for the generation of intracellular reactive oxygen species (ROS) levels. Superoxide radicals (O 2– ) and hydroxyl radicals ( [rad] OH) formed during the antibacterial process were shown to accelerate the death of bacteria. They also exhibited highly photocatalytic activity for Rhodamine B (RhB). When the concentration of the composites is 1000 μg/mL, the photocatalytic efficiency of Ag@Zn-BIF and Cu@Zn-BIF increased by 31.62 and 18.13 times compared with Zn-BIF, respectively. All in all, this study developed a simple and versatile integrated platform for the removal of nitrophenols, organic dyes, and the effective inactivation of bacteria in water.
Rapid Synthesis of Quantum-Sized Organic–Inorganic Perovskite Nanocrystals in Glass
A bulk sample of an organic–inorganic (OI) perovskite crystal of (C 6 H 5 C 2 H 4 NH 3 ) 2 PbBr 4 with a layered structure showing excellent luminescent properties was rapidly synthesised. The raw materials of OI crystal were impregnated into nanoporous glass having 4-nm pores and dried, obtaining a translucent sample of OI nanocrystals in glass (OIiG). An absorbance shoulder was observed at E = 3.04 eV for OIiG, which was attributed to exciton bands, and photoluminescence (PL) duration times of τ 1 = 2.8 ns and τ 2 = 8.6 ns were recorded for OIiG. In contrast, for a single-crystal sample, E = 2.94 eV, τ 1 = 4.1 ns, τ 2 = 11.0 ns. Compared to those of the single-crystal sample, the OIiG has a higher absorbance energy, and the duration time was shorter. The exciton activation energy was 195 meV for OIiG, in contrast with 121 meV for single crystal. We propose that these changes are due to the size effect because the particle size (3–4 nm in diameter) in the OIiG is close to the Bohr radius of layer-structured OI crystals.
Synthesis, characterization, and CO 2 adsorption properties of metal–organic framework NH 2 –MIL–101(V)
NH 2 –MIL–101(V), an amine-functionalized vanadium-based metal–organic framework (MOF) material, was successfully synthesized using a solvothermal strategy. The obtained material was characterized by X-ray diffraction (XRD), N 2 adsorption–desorption isotherms, Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques. The CO 2 and N 2 adsorption properties of the material were measured using the Micromeritics ASAP 2020 apparatus under ambient conditions. Compared to the previously reported method for synthesizing this MOF, we performed synthesis under a lower reaction temperature. Despite this, pure-phase NH 2 –MIL–101(V) nanocrystals with diameters of 40–60 nm were achieved. The synthesized sample had a large specific surface area (2340 m 2 /g), denoting a substantial enhancement to the literature value of the corresponding analogue. In addition, the NH 2 –MIL–101(V) possessed a high CO 2 uptake of 1.9 mmol/g at 25 °C and a pressure of 100 kPa and exhibited high CO 2 /N 2 selectivity as well as moderate CO 2 isosteric heat of adsorption.
One-pot synthesis of Bi 2 O 3 /Bi 2 O 4 p-n heterojunction for highly efficient photocatalytic removal of organic pollutants under visible light irradiation
Construction of p-n heterojunction is an effective strategy to obstacle the rapid recombination of photo-generated carriers for single photocatalyst. Herein, visible-light-active Bi 2 O 3 /Bi 2 O 4 p-n junction was prepared by a one-pot hydrothermal method, using Bi(NO 3 ) 3 ·5H 2 O, KCl, and NaBiO 3 ·2H 2 O as precursors. The in-situ formed BiOCl reacts with NaBiO 3 ·2H 2 O during the hydrothermal process, producing the target product of Bi 2 O 3 /Bi 2 O 4 p-n heterojunction. As expected, the obtained Bi 2 O 3 /Bi 2 O 4 heterojunction photocatalysts exhibited higher photocatalytic activity than Bi 2 O 4 for the degradation of MO (methyl orange) and phenol under visible-light irradiation. The superior photocatalytic performance of Bi 2 O 3 /Bi 2 O 4 hybrid is mainly attributed to the improved separation efficiency of e - -h + pair induced by the internal electric field of p-n junction. The present work may provide a rational and facile strategy to construct a highly efficient Bi 2 O 4 -based p-n heterojunction photocatalyst toward pollutant removal.