Ahmed M.A. El Naggar

Water decontamination via the removal of Pb (II) using a new generation of highly energetic surface nano-material: Co(+2)Mo(+6) LDH.

CoMo(CO3(2-)) layered double hydroxide of a highly energetic surface, as a new LDH consisting of divalent and hexavalent cations (M(+2)/M(+6)-LDH), was prepared by a homogeneous co-precipitation method. The structure and morphology of the prepared material was confirmed by several analytical techniques namely; X-ray diffraction analysis (XRD), X-ray fluorescence (XRF), Fourier transform infra-red (FT-IR) spectroscopy, differential scanning calorimetry and thermal gravimetric analysis (DSC-TGA), N2 adsorption-desorption isotherm and scanning electron microscope (SEM). The highly energetic surface of the prepared LDH was demonstrated via the X-ray photoelectron spectroscopy (XPS). The surface energy is due to the formation of +4 surface charges in the brucite layer between Co(+2) and Mo(+6). The prepared LDH was applied as a novel adsorbent for the removal of Pb (II) from its aqueous solution at different experimental conditions of time, temperature and initial Pb (II) concentrations. The change of the Pb (II) concentrations; due to adsorption, was monitored by atomic absorption spectrophotometer (AAS). The maximum uptake of Pb (II) by the Co Mo LDH was (73.4 mg/g) at 298 K. The Pb (II) adsorption was found to follow Langmuir isotherm and pseudo second order model. The adsorption process was spontaneous and endothermic. The interference of other cations on the removal of the Pb (II) was studied. Na(+) and K(+) were found to increase the adsorption capacity of the Co Mo LDH toward Pb (II) while it was slightly decreased by the presence of Mn(+2) and Cu(+2). The synthesized LDH showed a great degree of recoverability (7 times) while completely conserving its parental morphology and adsorption capacity. The mechanism of the lead ions removal had exhibited more reliability through a surface adsorption by the coordination between the Mo(+6) of the brucite layers and the oxygen atoms of the nitrates counter ions.

Enhanced hydrogen production from water via a photo-catalyzed reaction using chalcogenide d-element nanoparticles induced by UV light

Hydrogen has the potential to meet the requirements as a clean non-fossil fuel in the future. The photocatalytic production of H2 through water splitting has been demonstrated and enormous efforts have been published. The present work is an attempt to enhance the production of H2 during water splitting using synthesized nanoparticles based on chalcogenide d-element semiconductors via a photochemical reaction under UV-light in the presence of methanol as a hole-scavenger. In general, the enhanced activity of a semiconductor is most likely due to the effective charge separation of photo generated electrons and holes in the semiconductors. Hence, the utilization of different semiconductors in combination can consequently provide better hydrogen production. Accordingly in this research work, two different semiconductors, with different concentrations, either used individually or combined together were introduced. They in turn produced a high concentration of H2 as detected and measured using gas chromatography. Herein, data revealed that the nano-structured semiconductors prepared through this work are a promising candidate in the production of an enhanced H2 flux under visible UV radiation.

Highly Efficient Nano-Structured Polymer-Based Membrane/Sorbent for Oil Adsorption from O/W Emulsion Conducted of Petroleum Wastewater

Wastewater disposal has been an important issue from an environmental perspective in terms of the serious damages and harms its contaminants may cause. Treatment of the wastewater, through the pollutants removal, either before disposal or for the reuse in certain industrial or agricultural purposes, is an essential process. In response to this environmental claim, a novel nano-structured, macro-porous, polymer-based membrane/sorbent was prepared, in terms of its highly open and porous structure with nano-structured sorbent interconnecting walls and based on high internal phase emulsion polymerization. This sorbent was used to remove the oil from polluted wastewater in a laboratory-scale through the application of a new method called flotation–nano-filtration. In order to avoid the water flux decline and simultaneously enhance the oil removal efficiency from the wastewater, the polymeric material, after being prepared and used in sheet form (membrane), was ultimately introduced to the wastewater system as small pieces, as with the intention of physically increasing the area of surface for the oil removal. The material performance studies applied several variables, namely, the physical sectioning of the material surface area, sorbent concentration, mixing speed, and mixing time. An efficiency of 99.75% for the oil removal from the polluted water was successfully achieved at 75 minutes mixing time, a sorbent concentration of 0.158 g/200 mL (each piece with dimensions of 2 mm × 3 mm × 1 mm), and 300 rpm mixing speed. The sorbent structure before and after the oil removal process was examined using scanning electron microscope and x-ray diffraction analysis.

Biomass to fuel gas conversion through a low pyrolysis temperature induced by gamma radiation: an experimental and simulative study

Currently, 80% of global energy is supplied by carbon-based fossil fuels, which has led to concerns over the environmental impact of increasing atmospheric CO2 levels and has sparked ever-growing interest in renewable energy sources. The aim of this study is in line with adding value to low or negative valued biomass feedstocks by converting them into marketable bio-fuel gases, to replace the current one, as a renewable resource for energy via the pyrolysis technology. As a promising thermal conversion method in terms of high reliability, good flexibility through processing and production of versatile range of products pyrolysis is considered to be an important process for the generation of sustainable energy and chemicals from biomass. The pyrolysis process converts biomass carbon-containing materials into a combustible gas, which is primarily composed of carbon monoxide, hydrogen, and methane. However, the literature available over the last few decades have reported that the pyrolysis process should be carried out at elevated temperatures, which is at least 500 °C. The current study is focused on the conversion of some biomass into certain fuel gases at low operational temperatures assisted by γ radiation. First, using raw untreated biomass, gas mixtures composed of different percentages of carbon dioxide and methane were obtained under different operating conditions of time and temperature. In practical, the maximum temperature and time of 300 °C and four hours, respectively, were applied through this conversion process. A complete shift in the produced gas composition towards pure methane (natural gas) was obtained under the same operating conditions via the introduction of gamma ray-treated biomass samples in the pyrolysis system. On the other hand, nano-carbon black particles were obtained as the by-product of the thermal conversion of the irradiated biomass, whereas amorphous structured carbon was obtained when untreated biomass was applied. The gas composition analysis was conducted using a GC instrument equipped with a TC detector and carbon particle characterization was carried out using both HR TEM and Raman spectroscopy.

Mesoporous waste-extracted SiO2–Al2O3-supported Ni and Ni–H3PW12O40 nano-catalysts for photo-degradation of methyl orange dye under UV irradiation

Rather than looking at wastes as “unwanted materials,” this study considers their potential positive value and explores the production of waste-based catalysts. Herein, mesoporous SiO2–Al2O3 was prepared from both rice husk (source for silica) and waste aluminum foils using isophthalic acid as a textural modifier. X-ray diffraction and BET surface analyses of the as-prepared aluminosilicate demonstrated an amorphous structure with an average pore radius of 5.4 nm. The FTIR spectrum revealed the existence of SiO2–Al2O3 interaction. To produce an efficient photocatalyst, Ni nanoparticles were subsequently loaded onto the aluminosilicate surface by reduction of NiCl2 using hydrazine. Another catalyst, namely Ni–H3PW12O40/aluminosilicate, with strong Bronsted acid sites was also prepared by impregnating the support with an aqueous solution of H3PW12O40. TEM images of the as-prepared materials show that the aluminosilicate particles are slab-like, and the loading of Ni and H3O40PW12 has conserved the morphology of the mesoporous support due to metal–metal interaction. The prepared catalysts were then employed in the purification of water throughout the photocatalytic degradation of methyl orange (MO) dye. The maximum MO adsorption on the surface of the prepared materials was first determined in the absence of UV radiation (dark). The photoactivity of the three materials under the effect of UV irradiation was then detected. The Ni/aluminosilicate catalyst exhibits highest rate of MO removal among the employed materials. A maximum removal of 86% was obtained after an irradiation time of 180 min using the catalyst at a dose of 3 g L−1.

Assembling of hydrophilic and cytocompatible three-dimensional scaffolds based on aminolyzed poly(L-lactide) single crystals

Poly(L-lactide) exhibits good biocompatibility and processability, but its surface lacks proper hydrophilicity for cell growth and proliferation, which hinders its use as a tissue engineering scaffold. Surface aminolysis has been reported to improve the surface hydrophilicity and cytocompatibility of polymers. However, the aminolysis of 2D substrates has been achieved on the surface to only low depths, and aminolysis of 3D scaffolds does not guarantee homogenous distribution of amine functionality on their surfaces. Thus, herein, we address these problems by developing 3D scaffolds based on pre-aminolyzed poly(L-lactide) single crystals. The scaffolds are fabricated using the simple compression molding salt leaching technique in the absence of heat and gluing materials. Mechanical and morphological studies show that the scaffolds are mechanically stable with well interconnected open-porous structures. Furthermore, the ninhydrin test confirms homogenous spatial distribution of amine groups. The biological behavior of the scaffolds is investigated by seeding them with fibroblast cells. The aminolyzed single crystals offer a better interface for fibroblasts to adhere, proliferate and migrate than the pristine crystals and hence result in a promising 3D porous structure for tissue engineering applications.