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•BiPO4/Bi2S3 prepared by one-step precipitation with anion exchange method.•Changing the solvent type has a significant role in BiPO4/Bi2S3 morphologies.•The BiPO4/Bi2S3 hybrid in DEG ...showed excellent photoreduction of Cr(VI) to Cr(III).•XPS analysis confirmed the reduction of Cr(VI) to Cr(III).•The presence of TA as holes scavenger enhanced the photocatalytic reduction.
For the first time, a novel BiPO4/Bi2S3 heterostructures with different morphologies have been fabricated through a facile and rapid one pot precipitation route followed by anion-exchange strategy for the photoreduction of toxic Cr(VI) to harmless Cr (III). The hybrid structures systematically investigated using XRD, FE-SEM, EDS, TEM, HRTEM, XPS, FT-IR, UV–vis DRS, and PL. Changing the solvent type has a significant role for controllable morphologies of BiPO4/Bi2S3 hybrid as well as the catalytic activity. The BiPO4/Bi2S3 hybrid synthesized in diethylene glycol (DEG) performed the highest reduction efficiency of Cr(VI) within 20 min, compared with pure hexagonal phase of BiPO4 under visible light. The rate constant for BiPO4/Bi2S3 synthesized in DEG found to be 20.3 times larger than that for pure BiPO4. In addition, the presence of tartaric acid as hole scavenger could enhance the Cr(VI) reduction efficiency to 97.9%. No significant decrease in the catalytic efficiency after recycling up to four cycles. This promising study could present a significant approach towards Cr(VI) photoreduction from water through the novel BiPO4/Bi2S3 photocatalyst.
TEM image of unmodified (U1, U2 and U3) and CTAB modified CaCO3 samples (C1, C2 and C3).
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► No detailed research about the impact of nanosized CaCO4 fillers in papermaking. ► ...Systematical study was carried out to prepare unmodified and CTAB modified CaCO4.
Microsized calcium carbonates, including precipitated and ground calcium carbonates have been widely used in paper industry. One of the most interesting perspectives to filler technology is the development of nano-sized, high performance, and low cost fillers. However, due to the high cost of nano-sized filler, it is critically important to develop a technique that achieve this perspective. The main goals of this study were to prepare unmodified and CTAB modified nano-calcium carbonate fillers. The effect of CaO concentration, CO2 flow rate and CTAB surfactant on size and morphology of the prepared CaCO3 particles were investigated. X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), zeta potential and Fourier transformer infra-red (FT-IR) were used for the characterization of the prepared nano-sized calcium carbonate particles. The results showed that the obtained calcium carbonate was calcite phase. The particle sizes and morphologies of CaCO3 varied from rhombohedral (15–35nm) to scalenohedral (400nm in diameter and 2μm length) with changing the operating variables, CaO concentration, CO2 flow rate and surfactants concentration. CTAB neutralized the negative surface charge developed at the CaCO3 surface and the zeta potential approached to zero. On the other hand, the suggested mechanism of CTAB for synthesis of nano-calcium carbonate was also studied.
Recently, photocathodic protection has been regarded as one of the environment-friendly techniques for metal's anti-corrosion. In this technique, n-type semiconductor photoanode produces ...photogenerated electrons to reparation the lost electrons from metals. Therefore, significant efforts have been made to develop materials with facile methods for improving metals photocathodic protection. Herein, g-C3N4/In2O3/BiVO4 trinary system composite was synthesized through a novel approach. The XRD, UV, and PL techniques were used to confirm the enhancement in photogenerated electrons. Furthermore, the photoelectrochemical results showed that the prepared samples increased the negativity of the 304 SS stainless steel under open circuit potential (OCP) conditions. Additionally, the potential of the 304 SS polarization showed a negative shift from − 505 to − 625 mV and − 635 mV after joined to In2O3/BiVO4 and C3N4/In2O3/BiVO4, respectively. Moreover, the presence of g-C3N4 was provided extra cathodic protection, providing polarization potential more negative during light off. That expects the insertion of this material into the offshore facilities coating to increase its lifetime and decrease corroded metals' discharge into the water bodies.
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•A novel C3N4/In2O3/BiVO4 heterojunction composites were synthesized and fully characterized.•It was used to enhance the photoelectrochemical cathodic protection performance of 304 SS.•A wide range of solar light was used instead of visible light for the protection process.•The presence of g-C3N4 was increases the photoactivity and provided an extra cathodic protection.•The life time increased and the discharge of corroded metals into the water bodies was decreased.
Productivity of maize (
Zea mays
L.) and nitrogen use efficiency (NUE) as affected by nitrogen application levels and timing were studied. The experimental design was a three-replication randomized ...complete block design (RCBD). The first factor was nitrogen levels (122, 240, 288 and 336 kg N/ha) and the second factor was nitrogen timing (50% of N at sowing and 50% of N before the first irrigation; T
1
, 50% of N at sowing and 50% of N before the second irrigation; T
2
and 50% of N before the first irrigation and 50% of N before the second irrigation; T
3
). Results indicated that plant height, ear length, kernel weight, number of grains/rows, number of grains/ear and grain yields all increased significantly as nitrogen levels increased and the level of 336 kg N/ha significantly exhibiting the highest values in both seasons. In terms of nitrogen application time, maize yield parameters such as plant height, ear length, kernel weight/ear, number of grains/rows, number of grains/ear and grain yield were significantly affected by nitrogen timing, with the highest values obtained at T3 while the lowest values obtained at T1 in both seasons. The interaction had a significant impact on plant height and grain yield/ha, with the tallest plants, the highest yields and its components observed at 336 kg N/ha, with 50% of N applied during the first irrigation and 50% of N applied during the second. Furthermore, under the study conditions, NUE decreased dramatically as nitrogen levels increased and increased significantly as nitrogen application time changed.
A novel BiPO4 photocatalyst has been fabricated via a facile precipitation route using dimethyl sulfoxide (DMSO) as a solvent. The physical and chemical properties of the BiPO4 photocatalyst material ...were analyzed using XRD, Rietveld refinements XRD, FE-SEM, TEM, HR-TEM, EDS, XPS, FT-IR, Raman spectra, UV-Vis (DRS), and PL. The results confirm that hexagonal phase BiPO4 (HBIP) nanorods were successfully synthesized. FE-SEM images reveal that the addition of surfactant “CTAB” during preparation can control the surface morphology of BiPO4. The Rietveld refinement technique revealed the formation of a monazite monoclinic (nMBIP) and monoclinic (mMBIP) phase junction resulting from the calcination of HBIP at 500 °C. The photocatalytic behavior of the as-synthesized hexagonal and monoclinic BiPO4 nanostructures towards aniline blue (AB) degradation under UV light was systematically investigated. Among all catalysts, the phase junction (nMBIP–mMBIP) structure demonstrated the highest photocatalytic activity. The degradation rate of AB over the (nMBIP–mMBIP) phase junction structure was 3.4 times higher than that by HBIP. These results suggested that the surface-phase junction provides a synergistic effect for the electron–hole transfer process.
Abstract
Crocin, a pharmacologically active component of
Crocus sativus
L. (saffron), has been informed to be beneficial in the treatment of stress‐related oxidative impairment. In the present study, ...we examined the protective role of crocin against testicular damage induced by radiation (acute and fractionated) and the alteration of the AKT/FOXO signaling pathway. Male Wister albino rats were exposed to acute dose of 6 Gy and a fractionated dose of gamma radiation (2 Gy every 2 days up to 6 Gy total doses). Rats were pretreated intraperitoneally with crocin in a dose of 50 mg/kg for seven consecutive days prior to exposure to irradiation at a level of 6 Gy and during the fractionated irradiation of rats. Control groups were run concurrently. Ionizing radiation caused changes in the level of oxidative stress biomarkers manifested as elevation of thiobarbituric acid reactive substance, total nitrate/nitrite and reactive oxygen species (ROS) associated with a decrease in catalase as well as in the level of inflammatory parameters (decrease in expression of Nrf2 which was related to a significant increase in expression of NF‐κB p65). Irradiation produced cellular damage characterized by an increase in serum lactate dehydrogenase. These findings were aligned with increased expression of the forkhead box O‐1 (FOXO‐1) and activation of protein kinase B (AKT) pathway. Irradiation of rats led to reduction in serum testosterone level and testicular weights. Pretreatment with the indicated dose of crocin shielded against the changes in all the evaluated parameters. Administration of crocin can be introduced as a novel preclinical approach for regulation of testicular damage induced by radiation; via controlling the ongoing oxidative stress and inflammatory reaction as well as activation FOXO/AKT signaling pathway.
Diospyros kaki L. or Costata cultivar is the main persimmon variety progressively consumed in the Egyptian market and exportation. The objective of this study was to investigate the bioprotective ...effects of the alcoholic extract of fruits as well as leaves of D. kaki using in-vivo rat models. Petroleum ether extracts of fruits and leaves were analytically characterized for saponifiable and unsaponifiable compounds by GC/MS. Main flavonoids were chromatographically isolated from 80% aqueous methanol extract of leaves. Chemical evaluation for fruits and leaves namely, content of moisture, ash, proteins, fatty acids, amino acids, fat and water soluble vitamins, minerals, carotenoids was carried out. Total antioxidant activity was determined by radical scavenging effects using DPPH assay. The effect on biochemical parameters and its biological activity were also performed. Results revealed the identification of the major compounds of saponifiable and unsaponifiable matters of fruits and leaves. Scopoletin, as well as, kaempferol, luteolin, rutin and apigenin 7-O-glucoside were isolated and identified. It showed that this plant can provide a good nutritional value and it is safe regarding the kidney and liver functions, good source that help in enhancing the antioxidant defense against free radicals. No abnormal effects were found in lipids profile on experimental animals and there were good results in the ratio of HDL and LDL cholesterol. Also, this plant can help in optimizing blood sugar, enhancing the level of blood haemoglobin. It is concluded that D. kaki displays a good source of nutrients and bioactive compounds that may contribute to its therapeutic benefits against the risk of disease complications.
Precious metals, Au, Pt, and Pd, were successfully deposited on highly ordered mesoporous SBA-15. Two different reduction routes were employed to deposit precious metals: (1) under H
2
and (2) using ...sodium citrate. Samples prepared using sodium citrate exhibit a uniform particle size of 10 nm while samples synthesized under H
2
show high dispersion with a particle size of 8 and 20 nm for Pt and Pd, respectively. The surface area and pore volume of the mesoporous SBA-15 were significantly reduced due to the impregnation of the precious metals. Detailed TEM and XPS analyses reveal a uniform distribution of particles with a metallic valence state and no evidence of metallic oxides. The prepared catalysts were used to reduce
p
-nitrophenol (PNP) into
p
-aminophenol (PAP) where two trends were observed. The catalytic reduction efficiency for PNP reduction using the catalyst prepared with sodium citrate as a reducing agent is in the order of Au > Pt > Pd with a rate constant of 3.24 10
1
s
1
for Au/SBA-15. On the other hand, the catalyst prepared with H
2
as a reducing agent showed a reverse trend Pd > Pt > Au with a rate constant of 7.15 10
1
s
1
for Pd/SBA-15. The highest catalyst efficiency was observed for the case of Pd/SBA-15 synthesized
via
the H
2
route with a rate constant of 7.15 10
1
s
1
. Also the reaction rate of Pd/SBA-15 synthesized
via
the H
2
route was 2.2 times higher than that of Au/SBA-15 prepared using the sodium citrate route.
Precious metals (Au, Pd and/or Pt/SBA-15) have been synthesized by two pathways for catalytic reduction of
p
-nitrophenol. The catalytic reduction efficiency is in the order Au > Pt > Pd for samples reduced by sodium citrate and in the order Pt > Pd > Au for samples reduced by H
2
gas.
•Internal spontaneous polarization of BiVO4 photocatalyst can be modulated in the presence of polyvinylpyrrolidone at various concentrations.•The polarization field can drive the electrons and holes ...to transfer along opposite directions.•The charge separation and interfacial migration can be promoted and thus enhance the photocatalytic performance.
Photocatalytic performance can be improved by optimizing the morphology and surface texture of the photocatalyst or forming different p-n and/or n-n heterojunctions. Although the heterojunction system enhances photocatalytic property; however, an internal spontaneous polarization electric field may be much more effective due to the separation of electron-hole pairs when the polarization field forces them to move in different directions. The present study demonstrated this insight where the BiVO4 synthesis condition and polarization field forces were controlled via homogeneous precipitation in the presence of polyvinylpyrrolidone (PVP). The as-synthesized BiVO4 photocatalysts' structure and morphology were investigated using XRD, SEM, Raman, DRS, and PL. The result revealed that the increase of PVP concentration reformed the shaping to the truncated bipyramid-like shape and creates a spontaneous internal polarization that enhanced BiVO4 photocatalytic performance. The photocatalytic activity of BiVO4 was evaluated by monitoring the photocurrent enhancement using chronoamperometry, electrochemical impedance spectra and the photodegrading of methylene blue (MB) aqueous solution to harmless compounds in the presence of light. The spontaneous polarization between the different facets of BiVO4 crystal enhances the e−/h+ separation during internal facets homojunction and leads to four times photocurrent enhancement and the MB photocatalytic degradation rate increased from 0.43 to 1.92 min−1.
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The improved modified extended tanh‐function approach was used to study optical stochastic soliton solutions and other exact stochastic solutions for the nonlinear Schrödinger‐Hirota equation with ...multiplicative white noise. The derived solutions include stochastic bright solitons, stochastic singular solitons, stochastic periodic solutions, stochastic singular periodic solutions, stochastic exponential solutions, stochastic rational solutions, and stochastic Jacobi elliptic doubly periodic solutions. Constraints on the parameters were taken into account to ensure the existence of the obtained stochastic soliton solutions. Additionally, selected solutions were presented graphically to illustrate the physical characteristics of the stochastic solutions. In this paper, we used Mathematica (11.3) packages to find the coefficients and Matlab (R2015a) packages to plot the graphs.
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