Showing papers by "Tawfik A. Saleh published in 2017"

Polyethylenimine modified activated carbon as novel magnetic adsorbent for the removal of uranium from aqueous solution

Abstract: In this study, the polyethyleneimine modified activated carbon/Fe (PAF) was prepared and used as an effective magnetic adsorbent to remove uranium (U(VI)) ions from aqueous solution as a function of batch adsorption parameters. The developed magnetic adsorbent was investigated by FT-IR, SEM, EDX, TG/DSC and BET techniques. The effects of the adsorption parameters on the sorption amount were investigated by using factorial design. In order to study the sorption behavior for U(VI) ions, the Langmuir, and Freundlich isotherm models were applied to fit the equilibrium data. The monolayer adsorption capacity of the magnetic sorbent for U(VI) was determined to be 115.31 mg g−1 at pH 5, 20 °C and 60 min. The kinetic results indicated that the pseudo-second-order kinetic modeling fits the equilibrium data well under employed temperature conditions. The thermodynamic examinations showed exothermic and spontaneous adsorption process. The reusability-cycling test indicated that the magnetic sorbent has good desorption performance. It was also concluded that the PAF magnetic material can be used as an effective adsorbent for the removal of U(VI) ions from wastewaters by taking into account its advantages such as being of cost effective, easy prepare and environmental friendly.

Optimization of parameters with experimental design for the adsorption of mercury using polyethylenimine modified-activated carbon

Abstract: This study reports a facile hydrothermal method to synthesize polyethylenimine-modified activated carbon derived from waste tires (PEI-AC). The obtained material was characterized by Fourier transform infrared spectroscopy (FTIR), Scanning Electron microscopy (SEM) equipped with Energy-Dispersive X-ray spectroscopy (EDX), Thermogravimetric analyzer (TGA), and Brunauer–Emmett–Teller (BET) analyzer. The adsorption efficiency of the new adsorbent for the removal of Hg(II) was evaluated under the effects of its concentration, temperature, adsorption contact time, medium pH and re-usability. The optimum experimental conditions were found under response surface methodology (RSM)using central composite design (CCD). The results of the study show very good adsorption performance and high regeneration efficiency; the adsorption data fitted well into pseudo-second order model. The Langmuir monolayer capacity was determined to be 16.39 mg g−1. The exothermic enthalpy change (ΔH) of −24.65 kJ mol−1 and negative Gibbs free energy change (ΔG) assured the viability of the adsorption process. Therefore, the material leverages its cheap source and ease of regeneration in combination with its high and fast uptake capacities to offer a great promise for wastewater remediation.

Magnetic activated carbon loaded with tungsten oxide nanoparticles for aluminum removal from waters

Abstract: Magnetic activated carbon/tungsten nanocomposite (AC/Fe/W) was prepared as an environmentally friendly cost-effective adsorbent. Its chemical, morphological, thermal degradation and surface properties were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and surface area (BET) techniques. The developed adsorbent was used for the remediation of Al(III) ions from aqueous solution. The optimum experimental conditions were found under response surface methodology (RSM) using central composite design (CCD). The adsorption efficiency was achieved up to 90% within 45 min at pH 5 at 24 °C. To investigate the suitability of the process, the equilibrium data were evaluated by Langmuir and Freundlich isotherm models. The adsorption capacity of AC/Fe/W composite was found to be 184.12 mg g−1. The kinetic examinations showed that the pseudo-second order was the best fitting model to explain the adsorption mechanism. The activation energy of adsorption (Ea) was determined as 2.04 kJ mol−1, indicating that the adsorption process was carried out via physical sorption mechanism. Thermodynamic findings indicated the exothermic and spontaneous nature of the adsorption process and increased randomness at the solid-solution interface. By using 1.0 mol L−1 HCl solution, the adsorbed Al(III) ions were desorbed at high effectiveness and also the composite can be reused up to five cycles. Based on all of the results, it can be concluded that the fabricated composite material is effective and promising adsorbent for the cleaning treatment of Al(III) ions from wastewaters by large-scale designed adsorption system.

Method and Mechanisms of Soil Stabilization Using Electric Arc Furnace Dust.

Abstract: This paper reports the method and mechanism for improving the strength of marl and desert sand utilizing electric arc furnace dust (EAFD), an industrial by-product, in lieu of cement or lime. EAFD was used in conjunction with a small quantity (2%) of cement. The mechanical properties and durability characteristics of marl and sand mixed with 2% cement plus 5-, 10-, 20- or 30%-EAFD, by weight of the soil, were evaluated. The soil-cement-EAFD mixtures were used to determine their unconfined compressive strength (UCS), soaked California Bearing Ratio (CBR) and durability. The risk of leaching of toxic heavy metals, such as lead and cadmium, from the stabilized soils to the groundwater was also investigated. The mechanisms of stabilization of the selected soils due to the use of EAFD along with a small quantity of cement are also elucidated. The usage of 20 to 30% EAFD with 2% cement was noted to considerably improve the mechanical properties and durability of both marl and sand.

Dimethyl diallyl ammonium chloride and diallylamin Co-polymer modified bio-film derived from palm dates for the adsorption of dyes.

Abstract: For the first time, co-polymer of dimethyl diallyl ammonium chloride and diallylamin (PDDACD) was used to modify the films derived from the waste of palm date fruits, which were then investigated by the purification of colored aqueous solutions. The physico-chemical characteristics were identified using data color, FT-IR spectroscopy, and SEM features. The modified films were evaluated as adsorbents of Methylene Blue (MB), Direct Yellow 50 (DY50), Reactive Blue 198 (RB198) and Naphtol Blue Black (NBB). High retention capacities were achieved in the following order: The equilibrium da DY50 (14 mg g−1) < RB198 (16 mg g−1) < NBB (63.9 mg g−1) < MB (150 mg g−1). The kinetic modeling of the data revealed that the adsorption data follows the pseudo second order model. It was fitted to the Langmuir, Freundlich, Temkin, and Dubinin-Redushkevich equations, and the data best fit the Freundlich model indicating that the adsorption might occur in the heterogeneous adsorption sites. These results reveal that PDDACD modified films are valuable materials for the treatment of industrial wastewater. Moreover, the as-prepared adsorbent is economically viable and easily controllable for pollutant adsorption.

Tailoring hydrophobic branch in polyzwitterionic resin for simultaneous capturing of Hg(II) and methylene blue with response surface optimization.

Abstract: A new highly efficient cross-linked polymer was synthesized via cyclotetrapolymerization of hydrophilic [(diallylamino)propyl]phosphonic acid hydrochloride (72 mol%), hydrophobic N,N-diallyl-1-[6-(biphenyl-4-yloxy)hexylammonium chloride (18 mol%), cross-linker 1,1,4,4-tetraallylpiperazinium dichloride (10 mol%) with an equivalent amount of alternating SO2 units (100 mol%). The pH-responsive resin chemically tailored with the aminopropylphosphonate chelating ligand and hydrophobic chain of (CH2)6OC6H4-C6H5 is designed to capture toxic metal ions and organic contaminants simultaneously. The developed resin was used for the remediation of Hg(II) ions and methylene blue from aqueous solutions as models. The experimental conditions were optimized utilizing the response surface methodology as an environmentally friendly method. The adsorption efficiency for Hg(II) was ≈100% at 10 ppm initial concentration at pH 5 at 25 °C, while it was 80% for removal of the dye in a single pollutant system. Interestingly, the resin demonstrated its remarkable efficacy in the simultaneous and complete removal of Hg(II) and the dye from their mixture. Increased removal of the dye (≈100%) in the presence of Hg(II) was attributed to the synergistic effect. The equilibrium data were evaluated by employing the Langmuir and Freundlich isotherm models.

Corrosion and fouling protection performance of biocide-embedded hybrid organosiloxane coatings on mild steel in a saline medium

Abstract: This work assessed the anticorrosion and antifouling properties of a novel sol-gel derived hybrid coating functionalized with 5 different organic and inorganic biocides. FTIR and NMR analysis of the newly synthesized polymeric base material confirmed the photo-induced organic polymerization of the allyl groups in the allyltrimethoxysilane precursor of the polymer and the inertness of the allyl groups in the allyl glycidyl ether precursor. The parent coating and biocide-embedded coatings were applied on mild steel sheets, cured with UV light, and subjected to thermal, morphological and electrochemical characterization. The cured coatings were thermally stable, and their hydrophobicity increased after immersion in a saline medium, owing to further polymer crosslinking. According to lab-based electrochemical and visual evaluations of the corrosion protection performance of the different formulations, the coating embedded with Irgarol and MOLY-white 101 had an improved performance, compared with the formulations with the other added biocides. Field testing results from the coated samples were consistent with the lab results; i.e., some biocides positively affected the anticorrosion and antifouling behavior of the hybrid coatings, whereas other biocides negatively affected the newly developed hybrid coating. The methodology reported here holds promise for the development of multifunctional hybrid sol-gel coatings for mild steel substrates with interesting anticorrosion and antifouling activities in saline.

Silver nanoparticles embedded in polystyrene-polyvinyl pyrrolidone nanocomposites using γ-ray irradiation: Physico-chemical properties

Abstract: γ-Ray irradiation is used for the synthesis of silver–Polystyrene polyvinyl pyrrolidone nanocomposite microspheres with a controlled shape, size, and functional properties. A monodispersed polystyrene microsphere was synthesized using dispersion polymerization induced by γ-ray irradiation. A polystyrene microsphere surface was used to attract Silver (Ag) nanoparticles in which it is created on it via the continuous reduction of Ag + by γ-ray irradiation. Transmission Electron Microscopy, X-ray Diffraction Analysis, Ultraviolet–Visible Absorption, Thermal Gravimetric Analysis and Fourier Transform Infrared Spectroscopy are used for characterization of the final product. The discussion focuses on the physical–chemical aspects of the method. Special attention is paid to the preparation of nanocomposites with individual (non-aggregated) nanoparticles with a narrow size distribution and versatile morphologies, including the design of nanoparticles and nanocomposites that can perform multifunctional purposes. The focus was also on the problem of the spatial arrangement of nanoparticles and the elucidation of the role of polymers using this method. The synergistic role of the ingredients on the performance of nanocomposites was also discussed.