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ABSTRACT The present work investigates the effect of various solution parameters and electrospinning parameters on the characteristics of electrospun nanofibrous membranes. Scanning electron microscopy was used to analyze the surface morphology of the nanofibrous membrane. Adsorption test on methyl orange was also carried out and analyzed using the UV-vis. Results showed that increasing voltage decreased mean nanofiber diameter. Meanwhile, increasing PMMA concentration, feed rate, distance between collector-and-needle tip increased mean nanofiber diameter. Zeolite concentration and needle size did not affect the surface morphology significantly. The UV-vis spectra of the adsorption test showed that ∼93%, 85.5%, and 78% of methyl orange were adsorbed for 30, 50, and 100 mg L−1 initial dye concentration, respectively, within 11 min. The maximum adsorption capacity was found to be 95.33 mg g−1. Therefore, PMMA/zeolite nanofibrous membranes possess the adsorption capability toward effective dye removal. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44450. [ABSTRACT FROM AUTHOR]

Maghemite-silica particulate nanocomposites were prepared by modified 2-step sol-gel process. Superparamagnetic maghemite nanoparticles were successfully produced using Massart’s procedure. Nanocomposites consisting of synthesized maghemite nanoparticles and silica were produced by dispersing the as-synthesized maghemite nanoparticles into the silica particulate form. The system was then heated at 140 °C for 3 d. A variety of mass ratios of Fe 2O 3/SiO 2 was investigated. Moreover, no surfactant or other unnecessary precursor was involved. The nanocomposites were characterized using XRD, BET and AGM. The XRD diffraction patterns show the reflection corresponding to maghemite nanoparticles and a visible wide band at 2 θ from 20° to 35° which are the characteristics of the amorphous phase of the silica gel. The patterns also exhibit the presence of only maghemite and SiO 2 amorphous phase, which indicates that there is no chemical reaction between the silica particulate gel and maghemite nanoparticles to form other compounds. The calculated crystallite size for encapsulated maghemite nanoparticles is smaller than the as-synthesized maghemite nanoparticles indicating the dissolution of the nanoparticles. Very high surface area is attained for the produced nanocomposites (360–390 m 2/g). This enhances the sensitivity and the reactivity of the nanocomposites. The shapes of the magnetization curves for nanocomposites are very similar to the as-synthesized maghemite nanoparticles. Superparamagnetic behaviour is exhibited by all samples, indicating that the size of the maghemite nanoparticles is always within the nanometre range. The increase in iron content gives rise to a small particle growth. [ABSTRACT FROM AUTHOR]

TiO2 nanofiber photocatalysts offer a highly efficient and stable method of dye degradation through photogenerated radicals. Through electrospinning, the synthesis of the nanofibers with high surface area (i.e., low fiber diameter) and particle crystallinity (e.g., crystallite size and crystal phases) is highly desired to yield the best degradation performance. In this study, it is demonstrated that a synergistic combination of low fiber diameter, high crystallite size, and mixed anatase/rutile ratio is obtained to yield an optimal methylene blue degradation rate constant of 0.04100 min−1. The optimization is conducted with the aid of response surface analysis of electrospinning parameters (flow rate, applied voltage, and tip‐to‐collector distance (TCD)) toward the obtained fiber diameter response. The nanofiber diameter is observed to be from 177.3 to 310.4 nm across the studied range of parameters. The change in nanofiber diameter exhibits linear relationship with the applied voltage while quadratic relationships are observed for both solution flow rate and TCD. Through selective comparison, the lowering of fiber diameter has an adverse effect on the crystallinity and phase transformation (anatase‐rutile) of TiO2 particles. This relationship is shown to have a significant effect on the photocatalytic performance of the TiO2 nanofibers. [ABSTRACT FROM AUTHOR]

The energy scarcity is exacerbating and needs an urgent solution. The most plausible solution to address the forthcoming energy scarcity is to diversify the energy sources. Developing the water-splitting process (WSP) efficiency depends on solar energy representing "21st-century dream technology". We present a comprehensive review of related papers employing graphitic carbon nitride (g-C 3 N 4) as pure, doped, or composite nanostructure in the evolution of hydrogen from water dissociation under simulated sunlight irradiation, mainly in the last ten years. Herein, after a concise introduction to the main principle of the water-splitting process, the methods to synthesize, modify and upgrade the photocatalytic performance of g-C 3 N 4 were reviewed in detail. Moreover, the main challenges of using g-C 3 N 4 -based photocatalytic material in WSP have been mentioned. The report mainly targets the g-C 3 N 4 character, synthesis method, photocatalytic activity, and strategies toward enhancing photoreactivity under visible light, along with the reusability of the fabricated nanohybrid catalysts. Above and over, this review suggests the potential of g-C 3 N 4 to produce green H 2 from water at a competitive price, which can contribute to satisfying the global energy sector demand and suppressing global warming. [Display omitted] • The synthesis and applications of polymeric-based semiconductive. • Principles and thermodynamics of photocatalysis and main solar systems. • The synthesis routes, precursor source, and thermal treatment effects the performance of the g-C 3 N 4 -based photocatalyst. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of different species of oil palm shell (OPS) coarse aggregates on the properties of high strength lightweight concrete (HSLWC). Original and crushed OPS coarse aggregates of different species and age categories were investigated in this study. The research focused on two OPS species (dura and tenera), in which the coarse aggregates were taken from oil palm trees of the following age categories (3-5, 6-9, and 10-15 years old). The results showed that the workability and dry density of the oil palm shell concrete (OPSC) increase with an increase in age category of OPS species. The compressive strength of specimen CD3 increases significantly compared to specimen CT3 by 21.8%. The maximum achievable 28-day and 90-day compressive strength is 54 and 56 MPa, respectively, which is within the range for 10-15-year-old crushed dura OPS. The water absorption was determined to be within the range for good concrete for the different species of OPSC. In addition, the ultrasonic pulse velocity (UPV) results showed that the OPS HSLWC attain good condition at the age of 3 days.

Maghemite (γ-Fe2O3) nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), alternating gradient magnetometry (AGM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension.