# Deceased in late 20152
Graphical abstract
Research Highlights1. A new type of ZIF-8/TiO2 core-shell nanocomposite is designed to facilitate not only CO2 adsorption but also its subsequent photoreduction.2. Sequential fluctuation of reactor pressure plays an important role in promoting product desorption and increasing photocatalyst activity.3. This study highlights the significance of engineering variables including mass transfer and reactor design in photocatalytic reactions.
Abstract:A new type of zeolitic imidazolate framework ZIF-8/TiO2 nanocomposites was developed for photocatalytic reduction of CO2 to CH4 and CO in a newly designed photoreactor under intentionally controlled pressure swing. The ZIF-8/TiO2 core-shell structure plays an important role in the adsorption of CO2 by ZIF-8 and subsequent in-situ photocatalytic reduction on TiO2. The introduction of pressure change in the reaction system facilitates the adsorption-desorption process of CO2 and reaction products, which 3 consequently led to improved photoreduction performance. This approach highlights the importance of mass transfer and reactor design for improved photoreduction.
Glass
fiber reinforced polymer (GFRP) composites are widely used
materials in structural and transport applications owing to their
excellent strength-to-weight ratio. In GFRPs, mechanical properties
are mainly governed by the filler-to-matrix interphase region, which
need to be rationally designed and carefully engineered to optimize
the composite performance. However, the structural and chemical parameters
that optimize mechanical performance are partially unknown. Here,
we report on different surface nanoengineering strategies and their
effect on the mechanical properties of GFRPs. Commercial woven glass
fibers (wGFs) are modified with several distinct silica-based nanostructured
coatings that provide different pore sizes, surface areas, and adhesion
energies. To study their mechanical properties, epoxy–wGF laminated
composites are manufactured and characterized using sliding contact,
tensile, and three-point bending tests. Composites based on coated
wGFs generally show improved mechanical performance over those based
on bare wGFs. In particular, wGFs coated with mesoporous silica films
display the highest specific surface areas, pore sizes and adhesion
energies and provide the highest Young’s and flexural modulus,
with up to 31% improvement with respect to composites based on bare
wGFs. The improvement of the composite’s mechanical properties
with the wGFs coating is related to a better stress distribution and
a homogeneous loading transfer at the polymer–GF interphase.
Overall, this study provides insights on how GFRP’s mechanical
properties can be boosted beyond the current state-of-the-art by the
rational design of its interphase.
Ultrasound energy has been successfully employed to synthesize CdSe/ TiO 2 nanocatalysts for the photocatalytic degradation of phenol under solar light irradiation. The photocatalytic performance test was carried out using TiO 2 as well as synthesized CdSe/TiO 2 nanocatalysts. Nanocatalyst characterization was accomplished using XRD, SEM, FTIR, BET and UV-vis spectroscopy. It was shown that the synthesized nanocatalysts have crystal characteristics and are in nano-scale size range. The coupled nanocatalyst has shown a shift in the absorption spectrum from the UV range to the visible range. The results of photocatalytic tests showed that the CdSe/TiO 2 coupled nanocatalyst could remove phenol from wastewater under solar light irradiation, while TiO 2 did not have enough activity in this process. It is also shown that the CdSe nanoparticles act as photosensitizers, not only extending the spectral response of TiO 2 to the visible region but also reducing the electron-hole recombination. Furthermore, the CdSe/TiO 2 synthesized samples provided more photomineralization efficiency than that of TiO 2 in terms of total organic carbon analysis.
Capacitive deionization (CDI) is greatly recommended as a desalination process for its eco-friendly and low energy consuming technique in removing salt ions (NaCl) from salty water. This study reports a Zeolitic Imidazolate Framework-8/Graphene (ZIF-8/G) nanocomposite modified electrode performance in CDI technology. Based on its promising features, like large surface area and good electric conductivity, graphene is an adequate electrode. Interestingly, ZIF-8 is homogeneously well intergrown on the surface of graphene. Hence, electrochemical performance such as electrical conductivity and cyclic voltammetry in CDI unit were examined, and characteristics like the morphology, identification and determining the structure of the prepared materials were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR). As an adsorbent, the prepared ZIF-8/G nanocomposite exhibits the best adsorption capacity about 141.6037 F/g higher than each individually and great electrical conductivity about 672 μs/cm. The high adsorption specific capacity and good reusability of the ZIF-8/G nanocomposite suggests that it can be applied as novel adsorbents showing attractive potential for the CDI technique.
Glass-fiber-reinforced polymer (GFRP) composites represent one of the most exploited composites due to their outstanding mechanical properties, light weight and ease of manufacture. However, one of the main limitations of GFRP composites is their weak inter-laminar properties. This leads to resin delamination and loss of mechanical properties. Here, a model based on finite element analysis (FEA) is introduced to predict the collective advantage that a GF surface modification has on the inter-laminar properties in GFRP composites. The developed model is validated with experimental pull-out tests performed on different samples. As such, modifications were introduced using different surface coatings. Interfacial shear stress (IFSS) for each sample as a function of the GF to polymer interphase was evaluated. Adhesion energy was found by assimilating the collected data into the model. The FE model reported here is a time-efficient and low-cost tool for the precise design of novel filler interphases in GFRP composites. This enables the further development of novel composites addressing delamination issues and the extension of their use in novel applications.
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