Materials Science Forum Vol. 1008

Abstract: Carbon dioxide (CO₂) capturing from point sources is currently being proposed as a way to minimize CO₂ emissions to the atmosphere. Carbon dioxide is considered one of the greenhouse gases that affects our environment. Legislations are being enforced in many countries to limit CO₂ emissions to the atmosphere. Two methods are mostly used for CO₂ capturing from flue gases and natural gases; the first method is absorption using amine-based solvents, while the second is membrane separation. The first method is effective for CO₂ separation from gas mixtures with low CO₂ concentration in the range of 10 to 20%, while the other can handle gas mixture with intermediate CO₂ concentration but there is a limit on the CO₂ purity. Hence, such methods cannot be used in pre-combustion and oxy fuel technologies where a more concentrated CO₂ gas stream is produced. Throughout this work, a new method is introduced to separate carbon dioxide from its mixture with nitrogen (N₂) at high concentrations, 90 mol.% CO₂ and 10 mol.% N₂ gas mixture. A customized high-pressure experimental set-up was built. Three temperature were tested: 15 °C, 25 °C and 38 °C at 150 bar. At such condition CO₂ will be in the liquid and the supercritical phase respectively. The composition of the top and bottom streams where analyzed. The amount of CO₂ in the top stream was the smallest at the supercritical condition. In addition, the purity of CO₂ in the bottom stream was the highest at 38 °C and 150 bars, when CO₂ is at the supercritical phase.

Abstract: Polypyrrole nanoparticles prepared in the presence and absence of polyvinylpyrrolidone (PPy/PVP) fine black powders have been synthesized as adsorbents for the removal of copper Cu (Ⅱ) and iron Fe (Ⅲ) ions from aqueous solution. PPy and PPy/PVP were chemically prepared by using ferric chloride as an oxidant, and distillate water as a solvent with and without polyvinylpyrrolidone as a surfactant. The prepared PPy and PPy/PVP adsorbents were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area, and Fourier Transform Infrared spectroscopy (FTIR). The results display BET surface area equals 7.88 and 21.93 for PPy and PPy/PVP, respectively. The data also shows that PPy/PVP acts as flawless adsorbent for the removal of copper and iron ions from aqueous solution with sequestration percentage of 90% and 83% in 2 hours respectively.

Abstract: The effect of four different cathode materials on the anodic deposition of graphene oxide (GO) nanosheets was studied experimentally. First, synthesis of graphite oxide from graphite powder was done by modified Hummers' method. Ultrasonic technique was adopted for the preparation of the stable aqueous suspension of GO by using liquid exfoliation of graphite oxide. Deposition of GO coating on copper sheets (the anode) was done via electrophoretic deposition (EPD) at the same operating condition (5V, 2 min, concentration of 0.5 mg/ml of GO per deionized water) with different cathode materials (copper, stainless steel, aluminum and graphite). The coatings’ morphological and microstructure were investigated using scanning electron microscope (SEM) and the effect of the current density in the EPD process was obtained. The change in the deposition weight was also measured. It was ascertained that the cathode’s material is a major factor can affect the GO’s EPD process and the characteristics of the final coating.

Abstract: Microreactor technology has drawn attention in many industrial applications, especially those that requires the use of low flow rates whereas the flow is considered to be stratified. At such low flow rates, the reactor performance is usually down especially if mass transfer occurs mainly by diffusion. In the present work, the mixing performance of a novel hepatic sinusoids-based microreactor has been investigated using Villermaux–Dushman protocol. The protocol is an iodide/iodate chemical test reaction that relies on testing the absorbance of the product at 352 nm as an indication of the formation of triiodide. The investigation is carried out at low flow rates ranges from 0.5 to 3 ml/min. The novel microreactor has proven to give satisfactory performance and is easy to be fabricated as it consists of a single layer. The absorbance of light ranges between 0.29 to 0.48 resulting on the creation of limited amount of triiodide ions. It is also noticed that the mixing performance of the reactor is nearly the same over the whole studied range of flow rate. The mixing quality is also determined using another system containing 200 ppm congo red aqueous solution and pure distilled water. About 94% to 96% mixing quality is achieved.

Abstract: Silica is one of the most important materials used in many industries. The basic factor on which the selection process depends is the structural form, which is dependent on the various physical and chemical properties. One of the common methods in preparing pure silica is that it needs more than one stage to ensure the preparation process completion. The goal of this research is studying the nucleation technique (Bottom-top) for micro-wires and micro-ribbons silica synthesis. The silica nanoand microstructures are prepared using a duality (one step); a combination of alkali chemical etching process {potassium hydroxide (3 wt %) and n-propanol (30 Vol %)} and the ultra-sonication technique. In addition, the used materials in the preparation process are environmentally friendly materials that produce no harmful residues. The powder product is characterized using XRD, FTIR, Raman spectrum and SEM for determining the shape of architectures. The most significant factor of the nucleation mechanism is the sonication time of silica powder production during the dual technique. The product stages are as follows; silica nanoparticles (21-38 nm), nanoclusters silica (46 – 67 nm), micro-wires silica (1.17 – 6.29 μm), and micro-ribbons silica (19.4 – 54.1 μm). It's allowing for use in environmental applications (multiple wastewater purification, multiple uses in air filters, as well as many industrial applications).

Abstract: Micro-porous hydrophilic membranes were successfully fabricated using polystyrene waste by phase inversion casting. Four concentrations (20, 25, 30, and 35 wt%) of recycled high-impact polystyrene (HIPS-R) in N, N-dimethyl formamide (DMF) solution were employed to prepare the membranes. The effect of polystyrene concentration on the characteristics of the different membranes was thoroughly studied. Based on the Fourier transform infrared spectroscopy (FTIR) results, the chemical composition of HIPS-R was analogous to that of pure high-impact polystyrene HIPS raw material of the previous studies. Also, field-emission scanning electron microscopy (FESEM) was employed to study the morphology and porosity of the prepared membranes. The membranes cross-section showed a sponge structure with longitudinal macro voids. The solid walls around these voids have a sponge-like structure, especially for high concentration polystyrene membranes. Furthermore, the number of pores into the membrane surface decreased with the increase of polystyrene concentration. The membranes surface pores size was ranged from 150 nm to 550 nm with the different used concentrations. Water contact angle (CA) of the prepared membrane's surface were measured. All the measured CA of the prepared membranes, except the 35 wt% showed CA of 91^o, showed a hydrophilic behavior. Thus, the results suggest effective membranes could be obtained using recycled polystyrene. And then, solve the polymer waste accumulation problem in parallel with help in drinking water crisis solution.

Abstract: Magnesium oxide (MgO) nanoparticles were synthesized using the sol-gel technique then characterized. Cetyl Trimethyl Ammonium Bromide (CTAB) surfactant was added to reduce Van der Waal forces among MgO nanoparticles and distilled water forming a stable nanofluid using two-step method with aid of ultrasound sonication. Pure distilled water and nanofluids with different volume fractions of 0.25, 0.5, 0.75, and 1% are used as working fluids. Thermophysical properties of prepared nanofluids were measured experimentally and determined theoretically. Effect of solid volume fraction on the thermophysical properties; including thermal conductivity, heat capacity, viscosity, and density of MgO-water nanofluids are discussed. Moreover, experimental results have been compared with the suitable correlations for MgO-water nanofluid. The findings show that thermal conductivity, viscosity, and density of nanofluid increases with increasing solid volume fraction.

Abstract: Nanofluids have been an attractive field of study due to its important effect on enhancing the thermal conductivity when used in heat transfer applications. Titanium dioxide based nanofluid specifically has been a focus of study due to its distinguished properties as it results in a very good heat transfer enhancement with low viscosity and low-pressure drop while maintaining a very good stability of dispersion for a long time. Also, Titanium dioxide is relatively cheap and non-toxic so using it as a nanofluid will be more economical and safer in many industries. This review represents the most recent synthesis methods of titanium dioxide based nanofluid in both pure and Mixed (hybrid system) base fluids along with the analysis of its properties and the outcome findings. All of which will be discussed in this paper coherently and thoroughly which will be a good reference and makes it easier for other researchers to investigate and choose the suitable synthesis conditions that give them the required nanofluid properties and stability.

Abstract: The office buildings in Egypt, especially in Upper Egypt, reflect serious problems in achieving for energy efficiency as a result of increasing the use of mechanical refrigeration devices in office rooms, due to solar radiation and rising summer temperatures in recent years. Smart windows can play an important role in reducing significantly the energy consumption and maintaining energy inside buildings, also helps to control incoming solar radiation in order to minimize solar gain, especially in summer as well as ensuring the best natural lighting conditions without glare inside a room. This paper aims to evaluate the most efficient daylight and thermal performance of various types of the smart glazing and its impact on the energy consumption in the climatic conditions of one of the office buildings (Diwan governorate) in Sohag governorate as one of Upper Egypt governorates, with determining the best smart glass types for efficient use of energy. The paper follows the theoretical, applied, by studying types of smart glazing and their relation to achieving the energy efficiency. Then using (Energy Plus) simulation tool, which has been used in utilizing its modeling orientation (Design Builder) to study using types of smart glazing on the model of an office room in Building of Diwan governorate of Sohag in the four different orientations (North, East, South and West), when window-to-floor ratios (WFRs) (8%, 16%, 24% and 32%). The paper ends with a presentation of the most important results, recommendations and determination the best types of smart glass that provides energy, daylight without glare and providing greater comfort to users.