Abdelrahman O. Ezzat

Synthesis and application of magnetite polyacrylamide amino-amidoxime nano-composites as adsorbents for water pollutants

In this work, we aimed to develop a feasible method for in situ preparation of a magnetite ionic polymer nanocomposite at room temperature. For this purpose, acrylonitrile (AN) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) monomers were copolymerized and crosslinked using different monomer mol ratios in the presence of N,N-methylenebisacrylamide (MBA) as crosslinker to produce ionic crosslinked polymers P(AN-co-AMPS. The nitrile groups were converted to amine amidoxime by reacting with hydroxylamine to increase the adsorption characteristics of the ionic polymers. The produced polymers were swelled in iron cations produced from the reaction of ferric chloride and potassium iodide, followed by reaction with an ammonium hydroxide solution to produce magnetite nano-polymer composites. We performed FT-IR and XRD analysis to determine the chemical and crystalline structures, and assessed the morphologies and magnetite content using SEM, TEM and TGA analyses. We investigated the adsorption capacity and mechanism of the prepared magnetite nano-composites as adsorbents for methylene blue, Co2+ and Ni2+ cations from water.

Application of stabilized silver nanoparticles as thin films as corrosion inhibitors for carbon steel alloy in 1 M hydrochloric acid

Nanometer scaled materials have attracted tremendous interest as corrosion protective films due to their high ability to form selfassembled films on the metal surfaces. It is well known that the silver nanoparticles have higher reactivity towards aqueous acidic solution. The present work aims to prepare coated silver nanoparticles to protect carbon steel alloys from aqueous acidic corrosive media. In this respect, Ag nanoparticles colloid solutions were produced through reducing AgNO3 separately with trisodium citrate in an aqueous solution or in the presence of stabilizer such as poly(ethylene glycol)thiol and poly(vinyl pyrrolidone). The morphology of the modified silver nanoparticles was investigated by TEM and DLS. UV-Vis absorption spectrumwas used to study the effect of HCl on the stability of the dispersed silver nanoparticles. The corrosion inhibition efficiency of the poly (ethylene glycol)thiol, the self-assembled monolayers of Ag nanoparticles, was determined by polarization method and electrochemical impedance spectroscopy (EIS). Polarization curves indicated that the coated silver poly (ethylene glycol)thiol acted as a mixed type inhibitor. The data of inhibition efficiencies obtained measured by polarization measurements are in good agreement with those obtained with electrochemical impedance.

Synthesis of Silver Nanoparticles by Green Method Stabilized to Synthetic Human Stomach Fluid

Silver nanoparticles (Ag NP) have been attracted much attention in recent years in biomedical applications due to their antimicrobial activity, but their drawbacks include toxicity and instability to aqueous hydrochloric acid solutions. Ag NPs have now been successfully prepared by a simple and “green” synthesis method by reducing Ag+ ions in the presence of modified poly(vinyl alcohol) thiol (PVA-SH) in aqueous acidic solution. In this respect, Ag NPs were stabilized by coating different types of citrate-reduced Ag NPs with different weight ratios (1–3 Wt. %) of PVSH derivatives. The as-prepared Ag NPs were characterized using UV-Visible, high resolution transmission electron microscopy/ energy dispersive X-ray spectroscopy (TEM/EDS), dynamic light scattering (DLS) and X-ray powder diffraction (XRD) combined with Rietveld analysis. The changes in size, shape, and hydrodynamic diameter of Ag NPs after different duration exposure to synthetic stomach fluid (SSF) and1 M HCl were determined using TEM, XRD and UV-Visible analyses. The data indicated that these Ag NPs possessed high stability to SSF for more than 90 days, which was not previously reported in the literature.

Application of Super-Amphiphilic Silica-Nanogel Composites for Fast Removal of Water Pollutants

This work first reports the preparation of super-amphiphilic silica-nanogel composites to reduce the contact angle of water to increase the diffusion of pollutant into adsorbents. In this respect, the silica nanoparticles were encapsulated into nanogels based on ionic and nonionic polyacrylamides by dispersion polymerization technique. The morphologies and the dispersion stability of nanogel composites were investigated to clarify the ability of silica-nanogel composites to adsorb at different interfaces. The feasibility of silica polyacrylamide nanogel composites to act as a high-performance adsorbent for removal of methylene blue (MB) dye and heavy metals (Co2+ and Ni2+) from aqueous solution was investigated. The surface tension, contact angle, average pore size, and zeta potential of the silica-nanogel composites have been evaluated. The MB dye and heavy metal adsorption capacity achieved Qmax = 438–387 mg/g which is considerably high. The adsorption capacity results are explained from the changes in the morphology of the silica surfaces as recorded from scanning electron microscopy (SEM).

Application of New Sodium Vinyl Sulfonate–co-2-Acrylamido-2-me[thylpropane Sulfonic Acid Sodium Salt-Magnetite Cryogel Nanocomposites for Fast Methylene Blue Removal from Industrial Waste Water

Inorganic nanoparticles based on magnetite were used to improve the mechanical, thermal, and magnetic properties of microporous cryogel polymer composites. Here we report the synthesis of microporous cryogel based on the crosslinked sodium vinyl sulfonate (Na-VS) and 2-acrylamido-2-methylpropane sulfonic acid sodium salt (Na-AMPS). The magnetite nanoparticles were incorporated into Na-VS/Na-AMPS cryogel networks either during its crosslinking polymerization or by the in-situ technique after its crosslinking. The morphology, particle sizes, thermal stability, and magnetite contents of Na-VS/Na-AMPS cryogel and its magnetite composite were investigated. The prepared Na-VS/Na-AMPS cryogel and its magnetite composite were used as adsorbents for methylene blue (MB) cationic dye using optimum conditions. The magnetite Na-VS/Na-AMPS cryogel composite prepared by in-situ technique achieved the best adsorption MB removal capacity for 7 cycles among the other adsorbents via chemical adsorption mechanism at room temperature.

Green Synthesis of Hydrophobic Magnetite Nanoparticles Coated with Plant Extract and Their Application as Petroleum Oil Spill Collectors

In this study, an easy, rapid and eco-friendly method was used successfully to synthesize the magnetite nanoparticles (MNPs). In order to fine-tune the synthesized MNPs for the collection of heavy crude oil spills, the particles’ surface was modified with green hydrophobic biocomponents that were extracted from Anthemis pseudocotula (AP). The surface modified reaction carried with that of the MNPs in the presence of n-hexane extract (APH) resulted in the formation of APH-MNPs, while in the presence of chloroform extract (APC), resulted in APC-MNPs formation. The as-formed MNPs were thoroughly characterized using transmittance electron microscopy, X-ray powder diffraction, vibrating sample magnetometer and thermogravimetric analysis. The efficiency of the surface-modified MNPs for the collection of oil spills in the presence of an external magnetic field was evaluated by taking different ratios of MNPs:crude oil. From the analysis of the results, we found that the APH-MNPs particles have higher efficiency in the collection of heavy crude oil than the corresponding APC-MNPs.