SwePub - search: WFRF:(Uheida Abdusalam)

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1.	Abderrazek, K., et al. (author) Photocatalytic degradation of indigo carmine using [Zn-Al] LDH supported on PAN nanofibres 2015 In: Clay minerals. - : Mineralogical Society. - 0009-8558 .- 1471-8030. ; 50:2, s. 185-197 Journal article (peer-reviewed)abstract Zn-Al layered double hydroxides (LDH), before and after calcination, were tested for the removal of indigo carmine (IC) dye from solution. These LDH photocatalysts were characterized by powder x-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry/differential thermogravimetry (TG/DTG), nitrogen physisorption at -196 degrees C, scanning electron microscopy (SEM) and diffuse reflectance spectrophotometry (DRS). The different photocatalysts were supported on polyacrylonitrile (PAN) nanofibres, so that filtration was unnecessary. The PXRD and FTIR analyses showed that the IC adsorption on c-Zn-Al-3-500 (LDH calcined at 500 degrees C) was enhanced by construction of the hydrotalcite matrix intercalated with the dye. The intercalation was clearly evidenced by the appearance of a peak at low degrees 2 theta values. All of the materials prepared exhibited photocatalytic activity, which for the c-Zn-Al-3-500 was comparable to that of commercial PAN-supported ZnO nanoparticles (100% degradation after 180 min). Kinetic studies showed that the degradation of the IC followed a pseudo-first order rate. The high activity and the ease of both synthesis and separation processes rendered this photocatalyst a promising candidate for environmental remediation.
2.	Ashour, Radwa M., et al. (author) Rare Earth Ions Adsorption onto Graphene Oxide Nanosheets 2017 In: Solvent extraction and ion exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 35:2, s. 91-103 Journal article (peer-reviewed)abstract Graphene oxide (GO) was synthesized and used as a coagulant of rare earth elements (REEs) from aqueous solution. Stability and adsorption capacities were exhibited for target REEs such as La(III), Nd(III), Gd(III), and Y(III). The parameters influencing the adsorption capacity of the target species including contact time, pH, initial concentration, and temperature were optimized. The adsorption kinetics and thermodynamics were studied. The method showed quantitative recovery (99%) upon desorption using HNO3 acid (0.1 M) after a short contact time (15 min).
3.	Ashour, Radwa M., et al. (author) Selective separation of rare earth ions from aqueous solution using functionalized magnetite nanoparticles : kinetic and thermodynamic studies 2017 In: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 327, s. 286-296 Journal article (peer-reviewed)abstract Separation of rare earth ions (RE3+) from aqueous solution is a tricky problem due to their physico-chemical similarities of properties. In this study, we investigate the influence of the functionalized ligands on the adsorption efficiency and selective adsorption of La3+, Nd3+, Gd3+ and Y3+ from aqueous solution using Magnetite (Fe3O4) nanoparticles (NPs) functionalized with citric acid (CA@Fe3O4 NPs) or L-cysteine (Cys@Fe3O4 NPs). The microstructure, thermal behavior and surface functionalization of the synthesized nanoparticles were studied. The general adsorption capacity of Cys@Fe3O4 NPs was found to be high (98 mg g−1) in comparison to CA@Fe3O4 NPs (52 mg g−1) at neutral pH 7.0. The adsorption kinetic studies revealed that the adsorption of RE3+ ions follows a pseudo second-order model and the adsorption equilibrium data fits well to the Langmuir isotherm. Thermodynamic studies imply that the adsorption process was endothermic and spontaneous in nature. Controlled desorption within 30 min of the adsorbed RE3+ ions from both Cys@Fe3O4 NPs and CA@Fe3O4 NPs was achieved with 0.5 M HNO3. Furthermore, Cys@Fe3O4 NPs exhibited a higher separation factor (SF) in the separation of Gd3+/La3+, Gd3+/Nd3+, Gd3+/Y3+ ions compared to CA@Fe3O4 NPs.
4.	Avila, Marta, et al. (author) Surface functionalized nanofibers for the removal of chromium(VI) from aqueous solutions 2014 In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 245, s. 201-209 Journal article (peer-reviewed)abstract Polyacrylonitrile (PAN) nanofibers functionalized with amine groups (PAN-NH2) were prepared using a simple one-step reaction route. The PAN-NH2 nanofibers were investigated for the removal of chromium(VI) from aqueous solutions. The adsorption and the kinetic characteristics were evaluated in batch process. The adsorption process showed pH dependence and the maximum Cr(VI) adsorption occurred at pH = 2. The Langmuir adsorption model described well the experimental adsorption data and estimated a maximum loading capacity of 156 mg/g, which is a markedly high value compared to other adsorbents reported. The kinetics studies indicated that the equilibrium was attained after 90 min and the experimental data followed a pseudo-second order model suggesting a chemisorption process as the rate limiting step. X-ray Photoelectron Spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) revealed that the adsorption of Cr(VI) species on PAN-NH2 was facilitated through both electrostatic attraction and surface complexation. High desorption efficiency (> 90%) of Cr(VI) was achieved using diluted base solutions that may allow the reuse of PAN-NH2 nanofibers.
5.	Aziz, F., et al. (author) Composite nanofibers of polyacrylonitrile/natural clay for decontamination of water containing Pb(II), Cu(II), Zn(II) and pesticides 2017 In: Separation science and technology (Print). - : Taylor & Francis. - 0149-6395 .- 1520-5754. ; 52:1, s. 58-70 Journal article (peer-reviewed)abstract Composite nanofibers containing polyacrylonitrile and natural clay particles were fabricated and investigated for the removal of Pb(II), Cu(II) and Zn(II) from aqueous solutions. The adsorption behavior of Pb(II), Cu(II) and Zn(II) can be well described by the Langmuir adsorption model and high loading capacities at pH 7 were obtained. The kinetics of the adsorption process showed that equilibrium was attained after 60 min and the experimental data followed a pseudo-first-order model. The nanocomposites were also tested for photocatalytic degradation of Monocrotophos pesticides in which high degradation efficiency (>90%) was obtained in less than 60 min.
6.	Burks, Terrance, 1969-, et al. (author) Removal of Chromium(VI) Using Surface Modified Superparamagnetic Iron Oxide Nanoparticles 2013 In: Separation science and technology (Print). - : Informa UK Limited. - 0149-6395 .- 1520-5754. ; 48:8, s. 1243-1251 Journal article (peer-reviewed)abstract This study describes the removal of Chromium(VI) from aqueous solutions using surface tailored superparamagnetic iron oxide nanoparticles (SPION) coated with bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex-301). The synthesized Cyanex-301 coated SPION has been characterized by Transmission Electron Microscopy (TEM), Fourier-Transfer Infrared Spectroscopy (FT-IR), X-ray Photonic Spectroscopy (XPS), and Thermogravimetric Analysis (TGA). The adsorption mechanism was proposed to be via complexation between the thiol group on Cyanex-301 and Cr(VI) ions based on the XPS and FTIR analysis. It has been found that the equilibrium can be attained in less than 2hr. The adsorption behavior of Cr(VI) on the Cyanex-301 coated SPION can be well described by the Langmuir model and the maximum adsorption capacity for Cr(VI) was estimated to be 30.8mg/g. The selectivity of the Cyanex-301 coated SPION adsorbent towards Cr(VI) ions was found to be high and the maximum loading capacity obtained is up to an order of magnitude higher than that of other adsorbents reported in the literature. The desorption studies showed that more than 70% of Cr(VI) can be recovered using HNO3 as eluting solution. Our findings suggest a high potential of the designed adsorbent material for the treatment of industrial wastewater containing Cr(VI).
7.	Burks, Terrance, 1969-, et al. (author) Studies on the adsorption of chromium(VI) onto 3-Mercaptopropionic acid coated superparamagnetic iron oxide nanoparticles 2014 In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 425, s. 36-43 Journal article (peer-reviewed)abstract Chromium (Cr) in the form of Cr(VI) is deemed toxic in water due to its mutagenic and carcinogenic properties. For the successful removal of Cr(VI), we demonstrate a novel adsorbent consisting of superparamagnetic iron oxide nanoparticles (SPION) functionalized with 3-Mercaptopropionic acid (3-MPA). Fourier transform infrared spectroscopy (FT-IR) confirmed the functionalization of nanoparticles and presence of sulfonate groups. Batch adsorption experiments showed that the functionalized adsorbent recovered 45 mg of Cr(VI)/g of 3-MPA coated SPION at initial concentration of 50 mg/L aqueous solution at pH 1 with less than 1% of Fe dissolution from SPION. The results from X-ray photoelectron spectroscopy confirmed that Cr(VI) chemisorbed onto the adsorbent. Hence, the XPS spectra did not indicate any reduction of Cr(VI) to Cr(III) upon adsorption. The adsorption data were better fitted for the Freundlich model. Moreover, the Cr(VI) adsorption kinetics on functionalized SPION followed a pseudo-second order rate, revealing chemisorption as the dominant mechanism. The high Cr(VI) removal, rapid adsorption kinetics and stability of adsorbent indicate that 3-MPA coated SPION could be an efficient adsorbent for the removal of Cr(VI). (C) 2014 Elsevier Inc. All rights reserved.
8.	Giraldo Mejia, Hugo F., et al. (author) Antibacterial performance of hybrid nanocomposite coatings containing clay and silver nanoparticles 2021 In: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 628 Journal article (peer-reviewed)abstract The performance of biocide-based coatings for health care applications, using the drug delivery method, depends primarily on the diffusive properties of storage material. When the active component is ionic silver, supplied from silver nanoparticles, an additional dissolution step must occur in the bulk of the storage material. This article presents the silver release behavior of organic-inorganic sol-gel hybrid coatings and the effect of claynanoparticle composite, added in the sol-type formulation. Hybrid coatings were synthesized from the hydrolytic condensation of (3-glycidoxypropyl)-trimethoxysilane (GPTMS) and tetraethoxysilane in acidic media. Clay nanoparticles, previously silanized with GPTMS, and silver nitrate were used as additives in sol-gel formulations, alternatively. Coatings were deposited on microscope glass slides by the dip-coating process at a constant withdrawal rate and densified at 150 degrees C. Through small angle X-ray scattering from a synchrotronic source, and transmission electron microscopy, the structure of hybrid matrix, silver nanoparticles morphology and the storability behavior of silver nanoparticles under leaching conditions was analyzed. Silver releasing process was analyzed by following the evolution of silver nanoparticles remaining in the coatings, by UV-visible spectroscopy, and the increase of silver ions in the liquid medium, using inductively coupled plasma with optical emission spectroscopy. Microbiological studies showed that the lixiviated silver exhibited inhibitory properties against E. coli in LB broth. The clay nanoparticles worked as a stabilizing agent avoiding the agglomeration of silver both on the sols and on the surface of the thermally densified coatings.
9.	Görlin, Mikaela, et al. (author) Key activity descriptors of nickel-iron oxygen evolution electrocatalysts in the presence of alkali metal cations 2020 In: Nature Communications. - : Springer Nature. - 2041-1723. ; 11:1 Journal article (peer-reviewed)abstract Efficient oxygen evolution reaction (OER) electrocatalysts are pivotal for sustainable fuel production, where the Ni-Fe oxyhydroxide (OOH) is among the most active catalysts for alkaline OER. Electrolyte alkali metal cations have been shown to modify the activity and reaction intermediates, however, the exact mechanism is at question due to unexplained deviations from the cation size trend. Our X-ray absorption spectroelectrochemical results show that bigger cations shift the Ni2+/(3+delta)+ redox peak and OER activity to lower potentials (however, with typical discrepancies), following the order CsOH>NaOH approximate to KOH>RbOH>LiOH. Here, we find that the OER activity follows the variations in electrolyte pH rather than a specific cation, which accounts for differences both in basicity of the alkali hydroxides and other contributing anomalies. Our density functional theory-derived reactivity descriptors confirm that cations impose negligible effect on the Lewis acidity of Ni, Fe, and O lattice sites, thus strengthening the conclusions of an indirect pH effect. It is commonly accepted that electrolyte alkali metal cations modify the catalytic activity for oxygen evolution reaction. Here the authors challenge this assumption, showing that the activity is actually affected by a change in the electrolyte pH rather than a specific alkali cation.
10.	Hidalgo, Manuela, et al. (author) Study of the sorption and separation abilities of commercial solid-phase extraction (SPE) cartridge Oasis MAX towards Au(III), Pd(II), Pt(IV), and Rh(III) 2006 In: Solvent extraction and ion exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 24:6, s. 931-942 Journal article (peer-reviewed)abstract This paper presents a new, simple, and rapid procedure for the separation and preconcentration of Au, Pt, Pd, and Rh based on the adsorption of the metals on a commercial solid-phase extraction (SPE) cartridge, Oasis MAX, which contains a polymeric resin with quaternary ammonium substituents. Adsorption studies revealed that the metal affinity towards the adsorbent ranked according to Au >> Pd > Pt whereas Rh was not retained. The elution of the metals was accomplished by using 0.5 M thiourea in 1 M HCl solution. This sorbent effectively recovered Pd and Pt from a spent car catalyst sample containing large amounts of metals such as Al, Fe, and Ce.
11.	Karimiyan, Hanieh, et al. (author) Polyacrylonitrile / graphene oxide nanofibers for packed sorbent microextraction of drugs and their metabolites from human plasma samples 2019 In: Talanta. - : Elsevier. - 0039-9140 .- 1873-3573. ; 201, s. 474-479 Research review (peer-reviewed)abstract In the present study, a new graphene based nanofibers material (Polyacrylonitrile/Graphene Oxide (PAN/GO)) was used for microextraction by packed sorbent (MEPS). The PAN/GO nanofiber was synthesized using the electrospinning technique. MEPS online with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was utilized for the extraction and determination of two local anesthetic drugs (lidocaine, prilocaine) and their major metabolites (2,6-xylidine, o-toluidine) in human plasma samples. Parameters affecting the extraction efficiency were investigated and optimized (including sample pH, washing solution and elution solution). The validation of the method was based on FDA (Food and Drug Administration) guidelines for bioanalytical methods. The calibration curve ranged from 2.00 to 2000 nmol/L for lidocaine and prilocaine, and from 10.0 to 2000 nmol/L for 2,6-xylidine and o-toluidine. The coefficient of determination (R-2) values were 0.996, 0.995, 0.995, 0.996 (n = 3) for lidocaine, prilocaine, 2,6-xylidine and o-toluidine, respectively. The extraction recovery was 93.0% for lidocaine, 96.0% for prilocaine, 68.0% for 2,6-xylidine and 69.0% for o-toluidine. The limits of detection (LODs) were 0.25, 0.50, 2.50, 1.25 nmol/L for lidocaine, prilocaine, 2,6-xylidine and o-toluidine, respectively. The lower limits of quantification (LLOQs) were 2.0 nmol/L for lidocaine and prilocaine, and 10 nmol/L for 2,6-xylidine and o-toluidine, respectively. The accuracy values for the quality control (QC) samples were in the range of 91.0-111% for lidocaine, 92.0-118% for prilocaine, 84.0-98.0% for 2,6-xylidine and 82.0-90.0% for o-toluidine. The inter-day precisions for QC samples ranged from 7.0% to 11.8% for lidocaine, from 8.6% to 11.7% for prilocaine, from 8.0% to 10.0% for 2,6-xylidine and from 8.0% to 9.0% for o-toluidine. The matrix effect values were in the range of - 2.3% to - 8.6% for lidocaine, - 2.7% to - 10.2% for prilocaine, 4.8%-5.2% for 2, 6-xylidine and - 8.2% to 9.4% for o-toluidine.
12.	Khalil, Alaa, et al. (author) Surface modified of polyacrylonitrile nanofibers by TiO2/MWCNT for photodegradation of organic dyes and pharmaceutical drugs under visible light irradiation 2019 In: Environmental Research. - : Academic Press. - 0013-9351 .- 1096-0953. ; 179 Journal article (peer-reviewed)abstract This work describes the fabrication of two composite nanofibers systems containing polyacrylonitrile polymer (PAN), Multiwall carbon nanotubes (MWCNT) and Titania (TiO2) nanoparticles. Photodegradation experiments were performed to study the effect of various parameters including pH, catalyst dose, pollutant concentration and reaction time for three model compounds, methylene blue (MB), indigo carmine (IC), and ibuprofen (IBU) under visible light. Morphology and structure of the modified composite nanofibers were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Thermogravimetric analysis (TGA), Photoluminescence (PL) spectroscopy, Raman spectra, and X-ray Photoelectron Spectra (XPS) analyses. The photocatalytic performance was achieved in a rather short time visible light (<30 min) and under low power intensity (125 W) compared to earlier reports. Kinetics data fitted well using pseudo-first order model to describe the mechanism of photocatalytic degradation processes. The stability and flexibility of the fabricated composite nanofibers allow their application in a continuous flow system and their re-use after several cycles.
13.	Mohamed, Alaa, et al. (author) Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water 2016 In: Environmental Research. - : Elsevier. - 0013-9351 .- 1096-0953. ; 145, s. 18-25 Journal article (peer-reviewed)abstract In this study highly efficient photocatalyst based on composite nanofibers containing polyacrylonitrile (PAN), carbon nanotubes (CNT), and surface functionalized TiO2 nanoparticles was developed. The composite nanofibers were fabricated using electrospinning technique followed by chemical crosslinking. The surface modification and morphology changes of the fabricated composite nanofibers were examined through SEM, TEM, and FTIR analysis. The photocatalytic performance of the composite nanofibers for the degradation of model molecules, methylene blue and indigo carmine, under UV irradiation in aqueous solutions was investigated. The results demonstrated that high photodegradation efficiency was obtained in a short time and at low power intensity compared to other reported studies. The effective factors on the degradation of the dyes, such as the amount of catalyst, solution pH and irradiation time were investigated. The experimental kinetic data were fitted using pseudo-first order model. The effect of the composite nanofibers as individual components on the degradation efficiency of MB and IC was evaluated in order to understand the overall photodegradation mechanism. The results obtained showed that all the components possess significant effect on the photodegradation activity of the composite nanofibers. The stability studies demonstrated that the photodegradation efficiency can remain constant at the level of 99% after five consecutive cycles.
14.	Mohamed, Alaaeldin, et al. (author) Photocatalytic degradation of organic dyes and enhanced mechanical properties of PAN/CNTs composite nanofibers 2017 In: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 182, s. 219-223 Journal article (peer-reviewed)abstract This work describes the enhanced mechanical properties of the composite nanofibers and the photodegradation of two organic dyes using PAN/CNTs under UV irradiation at different volume concentration (0.05, 0.1, 0.2, and 0.3 wt.%). The composite nanofibers was performed with polyacrylonitrile (PAN), and carbon nanotubes (CNTs) by electrospinning process. The composite nanofibers structure and morphology is characterized by XRD, FTIR, SEM, and TEM. The result indicates that with increasing CNTs content, the mechanical properties of the composite nanofibers was enhanced, and became more elastic, and the elastic modulus increased drastically. The results of mechanical properties exhibit improvements in tensile strengths, and elastic modulus by 38% and 84% respectively, at only 0.05 wt.% CNTs. Moreover, photocatalytic degradation performance in short time and low power intensity was achieved comparison to earlier reports.
15.	Mohamed, Alaa, et al. (author) Photodegradation of Ibuprofen, Cetirizine, and Naproxen by PAN-MWCNT/TiO2-NH2 nanofiber membrane under UV light irradiation 2018 In: Environmental Sciences Europe. - : SPRINGEROPEN. - 2190-4707 .- 2190-4715. ; 30 Journal article (peer-reviewed)abstract Background: In this study, the photodegradation of three pharmaceuticals, namely Ibuprofen (IBP), Naproxen (NPX), and Cetirizine (CIZ) in aqueous media was investigated under UV irradiation. The photocatalyst used in this work consists of surface functionalized titanium dioxide (TiO2-NH2) nanoparticles grafted into Polyacrylonitrile (PAN)/multi-walled carbon nanotube composite nanofibers. Surface modification of the fabricated composite nanofibers was illustrated using XRD, FTIR, and SEM analyses. Results: Sets of experiments were performed to study the effect of pharmaceuticals initial concentration (5-50 mg/L), solution pH (2-9), and irradiation time on the degradation efficiency. The results demonstrated that more than 99% degradation efficiency was obtained for IBP, CIZ, and NPX within 120, 40, and 25 min, respectively. Conclusions: Comparatively, the photocatalytic degradation of pharmaceuticals using PAN-CNT/TiO2-NH2 composite nanofibers was much more efficient than with PAN/TiO2-NH2 composite nanofibers.
16.	Mohamed, Alaa, et al. (author) Removal of chromium (VI) from aqueous solutions using surface modified composite nanofibers 2017 In: Journal of Colloid and Interface Science. - : Academic Press. - 0021-9797 .- 1095-7103. ; 505, s. 682-691 Journal article (peer-reviewed)abstract A novel material composite nanofibers (PAN-CNT/TiO2-NH2) based on adsorption of Cr(VI) ions, was applied. Polyacrylonitrile (PAN) and carbon nanotube (CNTs)/titanium dioxide nanoparticles (TiO2) functionalized with amine groups (TiO2-NH2) composite nanofibers have been fabricated by electrospinning. The nanostructures and the formation process mechanism of the obtained PAN-CNT/TiO2-NH2 composite nanofibers are investigated using FTIR, XRD, XPS, SEM, and TEM. The composite nanofibers were used as a novel adsorbent for removing toxic chromium Cr(VI) in aqueous solution. The kinetic study, adsorption isotherm, pH effect, initial concentration, and thermodynamic study were investigated in batch experiments. The composite nanofibers had a positive effect on the absorption of Cr(VI) ions under neutral and acidic conditions, and the saturated adsorption reached the highest when pH was 2. The adsorption equilibrium reached within 30 and 180 min with an initial solution concentration increasing from 10 to 300 mg/L, and the process can be better described using nonlinear pseudo first than nonlinear pseudo second order model and Intra-particle diffusion. Isotherm data fitted well using linear and nonlinear Langmuir, Freundlich, Redlich-Peterson, and Temkin isotherm adsorption model. Thermodynamic study showed that the adsorption process is exothermic. The adsorption capacity can remain up to 80% after 5 times usage, which show good durability performance. The adsorption mechanism was also studied by UV-vis and XPS.
17.	Mohamed, Alaa, et al. (author) Surface functionalized composite nanofibers for efficient removal of arsenic from aqueous solutions 2017 In: Chemosphere. - : Elsevier Ltd. - 0045-6535 .- 1879-1298. ; 180, s. 108-116 Journal article (peer-reviewed)abstract A novel composites nanofiber was synthesized based on PAN-CNT/TiO2-NH2 nanofibers using electrospinning technique followed by chemical modification of TiO2 NPs. PAN-CNT/TiO2-NH2 nanofiber were characterized by XRD, FTIR, SEM, and TEM. The effects of various experimental parameters such as initial concentration, contact time, and solution pH on As removal were investigated. The maximum adsorption capacity at pH 2 for As(III) and As(V) is 251 mg/g and 249 mg/g, respectively, which is much higher than most of the reported adsorbents. The adsorption equilibrium reached within 20 and 60 min as the initial solution concentration increased from 10 to 100 mg/L, and the data fitted well using the linear and nonlinear pseudo first and second order model. Isotherm data fitted well to the linear and nonlinear Langmuir, Freundlich, and Redlich-Peterson isotherm adsorption model. Desorption results showed that the adsorption capacity can remain up to 70% after 5 times usage. This work provides a simple and an efficient method for removing arsenic from aqueous solution.
18.	Mohamed, Alaa, et al. (author) Visible light photocatalytic reduction of Cr(VI) by surface modified CNT/titanium dioxide composites nanofibers 2016 In: Journal of Molecular Catalysis A. - : Elsevier. - 1381-1169 .- 1873-314X. ; 424, s. 45-53 Journal article (peer-reviewed)abstract In this work we report a highly efficient photocatalytic reduction of Cr(VI) based on PAN-CNT/TiO2-NH2 composite nanofibers fabricated by using electrospinning technique followed by chemical crosslinking of surface modified TiO2 NPs functionalized with amino group. The structure and morphology of the fabricated composite nanofibers were characterized by FTIR, SEM, TEM, TGA, and XPS. The results indicate that the composite nanofibers possess excellent photoreduction performance for Cr(VI) under visible light (125 W) after 30 min, which is much faster than previous reports. The effects of various experimental parameters such as catalyst dose, irradiation time, initial concentration of Cr(VI), and pH on the photoreduction efficiency of Cr(VI) were investigated. The highest photoreduction efficiency of Cr (VI) was obtained at low acidity and low amount of TiO2/CNT photocatalyst. The kinetic experimental data was attained and fitted well with a pseudo-first-order model. The UV–vis spectrophotometer and XPS analyses proved that chromate Cr(VI) was reduced to Cr(III). In addition, it can be concluded that the addition of the phenol enhances the photocatalytic reduction of Cr(VI). Furthermore, the photoreduction mechanism has also been discussed. Finally, the fabricated composite nanofibers were found to be stable after at least five regeneration cycles.
19.	Morillo, D., et al. (author) Arsenate removal with 3-mercaptopropanoic acid-coated superparamagnetic iron oxide nanoparticles 2015 In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 438, s. 227-234 Journal article (peer-reviewed)abstract In the present work, superparamagnetic iron oxide nanoparticles (SPION) surface-coated with 3-merca-ptopropanoic acid (3-MPA) were prepared and their feasibility for the removal of arsenate from dilute aqueous solutions was demonstrated. The synthesized 3-MPA-coated SPION was characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Fourier transform infra-red spectrometry (FTIR). Separation efficiency of the coated nanoparticles and the equilibrium isotherm of arsenate adsorption were investigated. The obtained results reveal the arsenate adsorption to be highly pH-dependent, and the maximum adsorption was attained in less than 60 min. The resulting increase of 3-MPA-coated SPION adsorption capacity to twice the adsorption capacity of SPION alone under the same conditions is attributed to the increase of active adsorption sites. An adsorption reaction is proposed. On the other hand, efficient recovery of arsenate from the loaded nanoparticles was achieved using nitric acid (HNO3) solution, which also provides a concentration over the original arsenate solution.
20.	Murray, Ashley R., et al. (author) Oxidative Stress and Dermal Toxicity of Iron Oxide Nanoparticles In Vitro 2013 In: Cell Biochemistry and Biophysics. - : Springer Science and Business Media LLC. - 1085-9195 .- 1559-0283. ; 67:2, s. 461-476 Journal article (peer-reviewed)abstract A number of commercially available metal/metal oxide nanoparticles (NPs) such as superparamagnetic iron oxide (SPION) are utilized by the medical field for a wide variety of applications. These NPs may able to induce dermal toxicity via their physical nature and reactive surface properties. We hypothesize that SPION may be toxic to skin via the ability of particles to be internalized and thereby initiate oxidative stress, inducing redox-sensitive transcription factors affecting/leading to inflammation. Due to the skin's susceptibility to UV radiation, it is also of importance to address the combined effect of UVB and NPs co-exposure. To test this hypothesis, the effects of dextran-coated SPION of different sizes (15-50 nm) and manufacturers (MicroMod, Rostock-Warnemunde, Germany and KTH-Royal Institute of Technology, Stockholm, Sweden) were evaluated in two cell lines: normal human epidermal keratinocytes (HEK) and murine epidermal cells (JB6 P+). HEK cells exposed to 20 nm (KTH and MicroMod) had a decrease in viability, while the 15 and 50 nm particles were not cytotoxic. HEK cells were also capable of internalizing the KTH particles (15 and 20 nm) but not the MicroMod SPION (20 and 50 nm). IL-8 and IL-6 were also elevated in HEK cells following exposure to SPION. Exposure of JB6 P+ cells to all SPIONs evaluated resulted in activation of AP-1. Exposure to SPION alone was not sufficient to induce NF-kappa B activation; however, co-exposure with UVB resulted in significant NF-kappa B induction in cells exposed to 15 and 20 nm KTH SPION and 50 nm MicroMod particles. Pre-exposure of JB6 P+ cells to UVB followed by NPs induced a significant depletion of glutathione, release of cytokines, and cell damage as assessed by release of lactate dehydrogenase. Altogether, these data indicate that co-exposure to UVB and SPIONs was associated with induction of oxidative stress and release of inflammatory mediators. These results verify the need to thoroughly evaluate the adverse effects of UVB when evaluating dermal toxicity of engineered NPs on skin.
21.	Piazza, Veronica, et al. (author) Ecosafety Screening of Photo-Fenton Process for the Degradation of Microplastics in Water 2022 In: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 8 Journal article (peer-reviewed)abstract Microplastic pollution is receiving increased attention due to the realization of its hazards to aquatic and human life. Researchers across the globe are attempting to remove microplastics before its entry into the ecosystem. Therefore, the present work focused on the removal of microplastic from water and studied the potential risks for marine organisms and the ecosystem. The removal of model microplastics, polypropylene (PP) and polyvinyl chloride (PVC), has been studied by using photo-Fenton process. ZnO nanorods coated with SnOx(x < 2) layer and decorated with zero valent iron (Fe-0) nanoparticles was used as heterogeneous catalyst for the removal of the microplastics in continuous water flow device. The obtained results demonstrated that high degradation efficiency of PP and PVC microplastics was achieved in a relatively short time and more than 95% of the average particle volume was reduced after 1 week of irradiation. The environmental impact of the photo-Fenton process of the microplastics degradation was investigated by using an ecotoxicological approach. An ecosafety screening has been performed through a series of experiments (bioassays) under controlled conditions, testing water samples after the photo-Fenton degradation of microparticles using a lab scale device. The ecotoxicological impact has been investigated by applying a battery of certified bioassays (UNI EN ISO/EPA standardized techniques) on aquatic organisms at different trophic levels (bacteria, algae, invertebrates). The results obtained on the three model organisms (A. fischeri, P. subcapitata, and D. magna) revealed no toxic effect for samples collected both before and after the photo-Fenton process, thus showing the absence of toxic by-products development during the degradation process.
22.	Salazar-Alvarez, German, et al. (author) Reversible post-synthesis tuning of the superparamagnetic blocking temperature of gamma-Fe2O3 nanoparticles by adsorption and desorption of Co(II) ions 2007 In: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 17:4, s. 322-328 Journal article (peer-reviewed)abstract The influence of the post-synthesis adsorption of Co(II) ions on the structural and magnetic properties of maghemite (gamma-Fe2O3) nanoparticles with a mean particle size of about 10 nm has been investigated. It is shown that the step-wise adsorption of Co( II) can controllably increase the blocking temperature, T-B, of the system up to 60 K with respect to that of untreated particles, while neither the particle size nor the particle size distribution are significantly modified. This is accompanied by a four-fold increase in the coercivity, H-C, at low temperatures. Using a selective leaching of the previously adsorbed Co(II) ions the T-B and H-C values of the pristine gamma-Fe2O3 nanoparticles are recovered. Hence, a reversible and controllable tailoring of the magnetic properties (e.g., T-B and H-C) of the gamma-Fe2O3 nanoparticles can be achieved by a simple adsorption and desorption process of Co( II) ions after their synthesis.
23.	Sallam, Ahmed, et al. (author) CT Scanning and MATLAB Calculations for Preservation of Coptic Mural Paintings in Historic Egyptian Monasteries 2019 In: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9 Journal article (peer-reviewed)abstract Investigations of Coptic mural paintings in historic churches and monasteries demand a deep understanding of the micro structure of the mural painting layers. The main objective of the present study is to study the efficiency of new avenues of computed X-ray tomography (CT Scan) and MATLAB in the analysis of Coptic mural paintings, either in the form of images or videos made to collect information about the physical characteristics of the material structure of the layers of mural paintings. These advanced techniques have been used in the investigation of samples of Coptic mural paintings dating back to the V-VIII century A.D, which have been collected from several locations in the Coptic monasteries in Upper Egypt. The application of CT-scanning is a powerful non-destructive tool for imaging and investigation which can be applied to the preservation of monuments made from many different materials. The second stage of research will be to characterize the materials through analytical techniques including XRD, XRF, EDX and FTIR to confirm the findings of CT scanning and to provide additional information concerning the materials used and their deterioration processes. This paper presents the results of the first pilot study in which CT scan and MATLAB have been utilized in combination for the non-destructive evaluation and investigation of Coptic mural paintings in Upper Egypt. The examinations have been carried out on mural painting samples from three important Coptic monasteries in Upper Egypt: the Qubbat Al Hawa Monastery in Aswan, the Saint Simeon Monastery in Aswan and the Saint Matthew the Potter Monastery in Luxor. This multi-stranded investigation has provided us with important information about the physical structure of the paintings, grains dimensions, grain texture, pore media characterization which include the micro porosity, BET and TPV, surface rendering, and calculation of the points in the surface through calculations completed using MATLAB. CT scanning assisted in the investigation and analyses of image surface details, and helped to visualize hidden micro structures that would otherwise be inaccessible due to over painting.
24.	Sallam, Ahmed, et al. (author) Studies On The Deterioration Of Coptic Mural Paintings In The Monastery Of Martyrs And The Luxor Temple 2016 In: International Journal of Conservation Science. - 2067-533X .- 2067-8223. ; 7:2, s. 493-500 Journal article (peer-reviewed)abstract In this study the surfaces and cross sections of deteriorated Coptic mural paintings were investigated using Computer Tomography (CT) scan images and video, and points (voids) on the surface were analyzed. To our knowledge, it is the first report on the application of CT scan for the investigation of deteriorated Coptic mural painting surfaces in Upper Egypt. The samples tested were collected from two sites: the Monastery of Martyrs (Deir alShuhada-Esna) and the Luxor temple. The selection of these monasteries was due to their historical importance, which is directly related to Egyptian Coptic heritage. The deteriorated surfaces of the selected mural paintings were characterized using new avenues of computed X-ray tomography (CT scan) in order to gather sufficient information about their composition and structure. The obtained results show that CT scan images provided us with detailed information about the sample porosity and structure. In the case of the Martyrs monastery, it was found that the mural paintings consist of one layer which contains clay minerals (kaolinite, montmorillonite, and illite) in the form of coarse plaster. On the other hand, the Martyrs Monastery showed higher porosity than the Roman Fresco in the Luxor Temple.
25.	Shi, Jingwen, et al. (author) Microsomal Glutathione Transferase 1 Protects Against Toxicity Induced by Silica Nanoparticles but Not by Zinc Oxide Nanoparticles 2012 In: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 6:3, s. 1925-1938 Journal article (peer-reviewed)abstract Microsomal glutathione transferase 1 (MGST1) is an antioxidant enzyme located predominantly in the mitochondrial er membrane and endoplasmk reticulum and has been shown to protect cells from lipid peroxidation induced by a variety of cytostatic drugs and pro-oxidant stimuli. We hypothesized that MGST1 may also protect against nanomaterial-induced cytotoxicity through a specific effect on lipid peroxidation. We evaluated the induction of cytotoxicity and oxidative stress by TiO2, CeO2, SiO2, and ZnO in the human MCF-7 cell line with or without overexpression of MGST1. SiO2 and ZnO nanoparticles caused dose- and time-dependent toxicity, whereas no obvious cytotoxic effects were induced by nanoparticles of TiO2 and CeO2. We also noted pronounced cytotoxicity for three out of four additional SiO2 nanoparticles tested. Overexpression of MGST1 reversed the cytotoxicity of the main SiO2 nanoparticles tested and for one of the supplementary SiO2 nanoparticles but did not protect cells against ZnO-induced cytotoxic effects. The data point toward a role of lipid peroxidation In SiO2 nanoparticle-induced cell death. For ZnO nanoparticles, rapid dissolution was observed, and the subsequent interaction of Zn2+ with cellular targets is likely to contribute to the cytotoxic effects. A direct inhibition of MGST1 by Zn2+ could provide a possible explanation for the lack of protection against ZnO nanoparticles in this model. Our data also showed that SiO2 nanoparticle-induced cytotoxicity is mitigated in the presence of serum, potentially through masking of reactive surface groups by serum proteins, whereas ZnO nanoparticles were cytotoxic both In the presence and in the absence of serum.
26.	Sugunan, Abhilash, 1980-, et al. (author) A ‘Continuous flow’ Photochemical Water Treatment System Based on Radially Oriented ZnO Nanowires on Flexible Poly-L-Lactide Nanofibers Other publication (other academic/artistic)abstract Several oxide ceramics, notably ZnO and TiO2 are known to catalyze decomposition of organic molecules in water under ultra-violet irradiation. Here we describe fabrication of highly flexible ZnO-based hierarchical nanostructure obtained by growing radially oriented ZnO nanowires on poly-L-lactide nanofibers. Utilizing the flexibility and high surface area of polymeric nanofibers as novel ‘substrate’ for growth of the photochemically active ZnO nanowires we show a proof-of-principle demonstration of a ‘continuous flow’ water treatment set-up. We have monitored photocatalytic decomposition of known organic pollutants, such as methylene blue, monocrotophos and diphenylamine under illumination with ultraviolet light using this highly flexible hierarchical nanostructure.
27.	Sugunan, Abhilash, et al. (author) Radially Oriented ZnO Nanowires on Flexible Poly-L-Lactide Nanofibers for Continuous-Flow Photocatalytic Water Purification 2010 In: Journal of The American Ceramic Society. - : Wiley. - 0002-7820 .- 1551-2916. ; 93:11, s. 3740-3744 Journal article (peer-reviewed)abstract Several oxide ceramics, notably ZnO and TiO2 are known to catalyze decomposition of organic molecules in water under ultraviolet (UV) irradiation. Here we describe fabrication of highly flexible ZnO-based hierarchical nanostructure obtained by growing radially oriented ZnO nanowires on poly-L-lactide nanofibers. Utilizing the flexibility and high surface area of polymeric nanofibers as novel substrate for growth of the photochemically active ZnO nanowires we show a proof-of-principle demonstration of a continuous flow water treatment setup. We have monitored photocatalytic decomposition of known organic pollutants, such as methylene blue, monocrotophos, and diphenylamine under illumination with UV light using this highly flexible hierarchical nanostructure.
28.	Uheida, Abdusalam, et al. (author) Adsorption Behavior of Platinum Group Metals (Pd, Pt, Rh) onNonylthiourea-Coated Fe3O4 Nanoparticles 2006 In: Separation science and technology (Print). - : Informa UK Limited. - 0149-6395 .- 1520-5754. ; 41, s. 909-923 Journal article (peer-reviewed)abstract Magnetite nanoparticles coated with nonylthiourea (NTH) were synthesizedand analyzed for the separation and recovery of platinum group metals (PGMs) fromdiluted aqueous chloride solutions. Physical characterizations of the coated nanoparticleswere performed by Transmission Electron Microscopy (TEM), ThermogravimetricAnalysis (TGA) and FT-IR Spectrometry. Separation efficiency of the coatednanoparticles and the equilibrium adsorption isotherm of PGMs were investigated.The maximum adsorption was attained in less than 30 minutes, and the maximumloading capacity of NTH-coated Fe3O4 nanoparticles for Pt(IV) and Pd(II) was determinedto be 10.7 and 8.1 mg g21, respectively. The recovery of PGMs from the loadednanoparticles was examined using different eluting solutions, including HNO3,thiourea, and NaClO4.
29.	Uheida, Abdusalam, et al. (author) Extraction of platinum(IV) with nonylthiourea dissolved in chloroform from hydrochloric acid media 2003 In: Solvent extraction and ion exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 21:6, s. 827-840 Journal article (peer-reviewed)abstract The extractant nonylthiourea (NTH) in chloroform has been investigated for the extraction of Pt(IV) from chloride solutions at ionic strength of I = 4.0 M and at 22degreesC. It has been found that chloride concentration has a negative effect on the extraction equilibrium, while proton concentration has no effect. The numerical analysis of the equilibrium data has shown that the extraction of PtCl62- with NTH can be interpreted by the formation Of PtCl4(NTH) and PtCl4(NTH)(4) species with their respective equilibrium constants of log K-11 = 5.06 +/- 0.01 and log K-14 = 14.12 +/- 0.04 in 4 M HCl. FTIR spectra of the free NTH and the NTH-Pt(IV) complex were studied to obtain some information on the interaction between Pt(IV) ions and NTH molecules.
30.	Uheida, Abdusalam, et al. (author) Fe3O4 and gamma-Fe2O3 nanoparticles for the adsorption of Co2+ from aqueous solution 2006 In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 298:2, s. 501-507 Journal article (peer-reviewed)abstract The adsorption of Co2+ ions from nitrate solutions using iron oxide nanoparticles of magnetite (Fe3O4) and maghemite (gamma-Fe2O3) has been studied. The adsorption of Co2+ ions on the surface of the particles was investigated under different conditions of oxide content, contact time, Solution pH. and initial Co2+ ion concentration. It has been found that the equilibrium can be attained in less than 5 ruin. The maximum loading capacity of Fe3O4 and gamma-Fe2O3 nanoparticles is 5.8 x 10(-5) and 3.7 x 10(-5) mol m(-2), respectively, which are much higher than the previously Studied. iron oxides and conventional ion exchange resins. Co2+ ions were also recovered by dilute nitric acid from the loaded gamma-Fe2O3 and Fe3O4 with an efficiency of 86 and 30%. respectively. That has been explained by the different mechanisms by including both the surface and Structural loadings of Co2+ ions. The Surface adsorption of Co2+ on Fe3O4 and gamma-Fe2O3 nanoparticles has been found to have the same mechanism of ion exchange reaction between Co2+ in the solution and proton bonded on the particle Surface. The conditional equilibrium constants of surface 2-adsorption of Co2+ on Fe3O4 and gamma-Fe-O-2(3) nanoparticles have been determined to be log K = -3.3 +/- 0.3 and -3.1 +/- 0.2, respectively. The Structural loading of Co2+ ions into Fe3O4 lattice has been found to be the ion exchange reaction between CO2+ and Fe2+ while that into gamma-Fe2O3 lattice to fill its vacancy. The effect of temperature on the adsorption of Co2+ was also investigated, and the value of enthalpy change was determined to be 19 kJ mol(-1)
31.	Uheida, Abdusalam, et al. (author) Photocatalytic degradation of Ibuprofen, Naproxen, and Cetirizine using PAN-MWCNT nanofibers crosslinked TiO2-NH2 nanoparticles under visible light irradiation 2019 In: Separation and Purification Technology. - : ELSEVIER SCIENCE BV. - 1383-5866 .- 1873-3794. ; 212, s. 110-118 Journal article (peer-reviewed)abstract In this work the photocatalytic degradation of pharmaceuticals (Ibuprofen, Cetirizine, and Naproxen) was evaluated using surface modified TiO2 nanoparticles immobilized on polyacrylonitrile/multiwall carbon nanotubes composite nanofibers. The photocatalytic degradation was studied under visible light (0.1 W/cm(2)) irradiation. Comparatively, the photocatalytic degradation of pharmaceuticals using PAN-CNT/TiO2-NH2 composite nanofibers was much more efficient than with PAN/TiO2-NH2 composite nanofibers under visible light irradiation. The results obtained showed that the photocatalytic efficiency of the studied pharmaceuticals is pH dependent in which more than 99% degradation was obtained at pH 2. Complete degradation of IBP, CTZ, and NPX was achieved within 200, 50, and 90 min, respectively under visible light.
32.	Uheida, Abdusalam, et al. (author) Selective extraction of palladium(II) from chloride solutions with nonylthiourea dissolved in chloroform 2002 In: Solvent extraction and ion exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 20:6, s. 717-733 Journal article (peer-reviewed)abstract The extraction of Palladium(II) [Pd(II)] from hydrochloric acid solutions with nonylthiourea (NTH) dissolved in chloroform at a constant ionic strength of LOM has been studied. The extraction of Pd(II) has been investigated as a function of the concentration of the extractant, chloride ion, and proton concentrations as well as extraction temperature. The distribution data have been treated graphically and numerically. The analysis of the experimental data has shown that Pd(II) is extracted as PdCl2 . (NTH) and PdCl2 . (NTH)(2) species with the respective extraction constants of log K-11 = 5.0 +/- 0.1 and log K-12 = 9.1 +/- 0.1. The back-extraction of Pd(II) from the organic phase using different stripping reagents has been examined. The selectivity of NTH for Pd(II) against Pt(IV), Rb(III), Cu(II), Fe(III), and Zn(II) has also been investigated.
33.	Uheida, Abdusalam (author) Selective Separation of Metal Ions by Solvent Extraction, Liquid Membranes and Magnetic Nanoparticles 2006 Doctoral thesis (other academic/artistic)
34.	Uheida, Abdusalam, et al. (author) Sorption of palladium(II), rhodium(III), and platinum(IV) on Fe3O4 nanoparticles 2006 In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 301:2, s. 402-408 Journal article (peer-reviewed)abstract The adsorption of palladium(II), rhodium(III), and platinum(IV) from diluted hydrochloric acid solutions onto Fe3O4 nanoparticles has been investigated. The parameters studied include the contact time and the concentrations of metals and other solutes such as H+ and chloride. The equilibrium time was reached in less than 20 min for all metals. The maximum loading capacity of Fe3O4 nanoparticles for Pd(II), Rh(III), and Pt(IV) was determined to be 0.103, 0.149, and 0.068 mmol g(-1), respectively. A sorption mechanism for Pd(II), Rh(III), and Pt(IV) has been proposed and their conditional adsorption equilibrium constants have been determined to be log K = 1.72, 1.69, and 1.84, respectively. Different compositions of eluting solution were tested for the recovery of Pt(IV), Pd(II), and Rh(III) from Fe3O4 nanoparticles. It was found that 0.5 mol L-1 HNO3 can elute all of the metal ions simultaneously, while 1 mol L-1 NaHSO3 was an effective eluting solution for Rh(III), and 0.5 mol L-1 NaClO4 for Pt(IV). In competitive adsorption, the nanoparticles showed stronger affinity for Rh(III) than for Pd(II) and Pt(IV).
35.	Uheida, Abdusalam (author) Studies on liquid-liquid extraction and liquid membrance transport of palladium and platinum 2003 Licentiate thesis (other academic/artistic)
36.	Uheida, Abdusalam, et al. (author) Thermodynamic modeling of extraction equilibria of platinum and palladium with nonylthiourea from hydrochloric acid media 2004 In: Separation science and technology (Print). - : Informa UK Limited. - 0149-6395 .- 1520-5754. ; 39:15, s. 3665-3677 Journal article (peer-reviewed)abstract Models of extraction equilibria of Pt(IV) and Pd(II) with Nonylthiourea (NTH) from HCl media have been studied. The conditional equilibrium constants and the stoichiometry of the extracted species of Pt(IV) with NTH at different ionic strengths obtained by numerical analysis using the LETAGROP-DISTR program are reported. The dependence of the extraction constant values on the ionic strength has been analysed using the Specific Interaction Theory (SIT), from which the respective thermodynamic equilibrium constants of the extraction of Pt(IV) and Pd(II) with NTH have been determined. The thermodynamic equilibrium constants determined for Pt(IV) are log K-11o=5+/-1 and log K-14(o)=14.6+/-0.2, while for Pd(II) log K-11(o)=4.9+/-0.1 and log K-12(o)=9.17+/-0.08. The interaction coefficients, epsilon, for the pairs (H+, PtCl62-) and (H+, PdCl42-) have also been estimated to be 0.30+/-0.08 and 0.41+/-0.02, respectively.
37.	Uheida, Abdusalam, et al. (author) Transport of palladium(II) through hollow fiber supported liquid membrane facilitated by nonylthiourea 2004 In: Journal of Membrane Science. - : Elsevier BV. - 0376-7388 .- 1873-3123. ; 241:2, s. 289-295 Journal article (peer-reviewed)abstract The facilitated transport of Pd(II) from chloride media has been investigated through a hollow-fiber supported liquid membrane using nonylthiourea (NTH) as a carrier. The influence of the chemical conditions on the permeability of Pd(II) is reported. A model is presented that describes the transport mechanism, consisting of diffusion through a feed aqueous diffusion layer, a fast interfacial chemical reaction, and diffusion of carrier and its metal complex through the organic membrane. The diffusion resistances through organic membrane (Delta(org)) and through aqueous layer (Delta(aq)), respectively, have been calculated from the proposed model. The permeability of Pd(II) seems to be governed by the diffusion of Pd(II) species through the hollow fiber supported liquid membrane with PdCl2(NTH)(2) as a predominant carrier and PdCl2(NTH)to a lesser extent, though both have similar diffusion coefficients.
38.	Uheida, Abdusalam, et al. (author) Visible light photocatalytic degradation of polypropylene microplastics in a continuous water flow system 2021 In: Journal of Hazardous Materials. - : Elsevier B.V.. - 0304-3894 .- 1873-3336. ; 406 Journal article (peer-reviewed)abstract Microplastic pollution of water and ecosystem is attracting continued attention worldwide. Due to their small sizes (≤5 mm) microplastic particles can be discharged to the environment from treated wastewater effluents. As microplastics have polluted most of our aquatic ecosystems, often finding its way into drinking water, there is urgent need to find new solutions for tackling the menace of microplastic pollution. In this work, sustainable green photocatalytic removal of microplastics from water activated by visible light is proposed as a tool for the removal of microplastics from water. We propose a novel strategy for the elimination of microplastics using glass fiber substrates to trap low density microplastic particles such as polypropylene (PP) which in parallel support the photocatalyst material. Photocatalytic degradation of PP microplastics spherical particles suspended in water by visible light irradiation of zinc oxide nanorods (ZnO NRs) immobilized onto glass fibers substrates in a flow through system is demonstrated. Upon irradiation of PP microplastics for two weeks under visible light reduced led to a reduction of the average particle volume by 65%. The major photodegradation by-products were identified using GC/MS and found to be molecules that are considered to be mostly nontoxic in the literature.
39.	Yazdi, Milad Ghadami, et al. (author) Surface modified composite nanofibers for the removal of indigo carmine dye from polluted water 2018 In: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 8:43, s. 24588-24598 Journal article (peer-reviewed)abstract Surface coated magnetite nanoparticles (Fe3O4 NPs) with 3-mercaptopropionic acid were immobilized on amidoximated polyacrilonitrile (APAN) nanofibers using electrospinning followed by crosslinking. The prepared composite nanofibers were characterized with Scanning Electron Microscopy (SEM), and Fourier Transform Infrared analysis (FTIR). The composite nanofiber was evaluated for the removal of indigo carmine dye from aqueous solutions. The effects of contact time, initial dye concentration, solution pH and adsorption equilibrium isotherms were studied. The adsorption of indigo carmine was found to be greatly affected by solution pH. The maximum loading capacity was determined to be 154.5 mg g(-1) at pH = 5. The experimental kinetic data were fitted well using a pseudo-first order model. The adsorption isotherm studies showed that the adsorption of indigo carmine fits well with the Langmuir model. The reuse of the composite nanofiber was also investigated in which more than 90% of indigo carmine was recovered in 5 min. The results of stability studies showed that the adsorption efficiency can remain almost constant (90%) after five consecutive adsorption/desorption cycles.
40.	Yohai, L., et al. (author) Nanocomposite functionalized membranes based on silica nanoparticles oss-linked to electrospun nanofibrous support for arsenic(v) sorption from contaminated underground water 2019 In: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 9:15, s. 8280-8289 Journal article (peer-reviewed)abstract Nanocomposite functionalized membranes were synthesized using surface functionalized mesoporous silica nanoparticles (MCM-NH2 or MCM-PEI) cross-linked to a modified polyacrylonitrile (mPAN) nanofibrous substrate for the removal of 1 mg L-1 of As(V); a concentration much higher than what has been reported for underground water in Argentina. Adsorption studies were carried out in batch mode at pH 8 with nanoparticles in colloidal form, as well as the nanoparticles supported on the modified PAN membranes (mPAN/MCM-NH2 and mPAN/MCM-PEI). Results indicate a twenty-fold improvement in As(V) adsorption with supported nanoparticles (nanocomposite membranes) as opposed to their colloidal form. The adsorption efficiency could be further enhanced by modifying the nanocomposite membrane surface with Fe3+ (mPAN/MCM-NH2-Fe3+ and mPAN/MCM-PEI-Fe3+) which resulted in more than 95% arsenic being removed within the first 15 minutes and a specific arsenic adsorption capacity of 4.61 mg g(-1) and 5.89 mg g(-1) for mPAN/MCM-NH2-Fe3+ and mPAN/MCM-PEI-Fe3+ nanocomposite membranes, respectively. The adsorption characteristics were observed to follow a pseudo-first order behavior. The results suggest that the synthesized materials are excellent for quick and efficient reduction of As(V) concentrations below the WHO guidelines and show promise for future applications.
41.	Zohdi, Zeynab, et al. (author) Graphene Oxide Tablets for Sample Preparation of Drugs in Biological Fluids : Determination of Omeprazole in Human Saliva for Liquid Chromatography Tandem Mass Spectrometry 2019 In: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 24:7 Journal article (peer-reviewed)abstract In this study, a novel sort of sample preparation sorbent was developed, by preparing thin layer graphene oxide tablets (GO-Tabs) utilizing a mixture of graphene oxide and polyethylene glycol on a polyethylene substrate. The GO-Tabs were used for extraction and concentration of omeprazole (OME) in human saliva samples. The determination of OME was carried out using liquid chromatography-tandem mass spectrometry (LC-MS/MS) under gradient LC conditions and in the positive ion mode (ESI+) with mass transitions of m/z 346.3 -> 198.0 for OME and m/z 369.98 -> 252.0 for the internal standard. Standard calibration for the saliva samples was in the range of 2.0-2000 nmol L-1. Limits of detection and quantification were 0.05 and 2.0 nmol L-1, respectively. Method validation showed good method accuracy and precision; the inter-day precision values ranged from 5.7 to 8.3 (%RSD), and the accuracy of determinations varied from -11.8% to 13.3% (% deviation from nominal values). The extraction recovery was 60%, and GO-Tabs could be re-used for more than ten extractions without deterioration in recovery. In this study, the determination of OME in real human saliva samples using GO-Tab extraction was validated.
42.	Zohdijamil, Zeynab, et al. (author) Functionalized graphene oxide tablets for sample preparation of drugs in biological fluids : Extraction of ritonavir, a HIV protease inhibitor, from human saliva and plasma using LC–MS/MS 2021 In: BMC Biomedical chromotography. - : Wiley. - 0269-3879 .- 1099-0801. ; 35:12 Journal article (peer-reviewed)abstract In this work, graphene oxide–based tablets (GO-Tabs) were prepared by applying a thin layer of functionalized GO on a polyethylene substrate. The GO was functionalized with amine groups (–NH2) by poly(ethylene glycol)bis(3-aminopropyl) terminated (GO-NH2-PEG-NH2). The functionalized GO-Tabs were used for the extraction of ritonavir (RTV) in human saliva samples. RTV in plasma and saliva samples was analyzed using LC–MS/MS. Gradient LC system with MS/MS in the positive-ion mode [electrospray ionization (ESI+)] was used. The transitions m/z 721 → 269.0 and m/z 614 → 421 were used for RTV and the internal standard indinavir, respectively. This study determined the human immunodeficiency virus protease inhibitor RTV in human saliva samples using functionalized GO-Tab and LC–MS/MS, and the method was validated. The standard calibration curve for plasma and saliva samples was constructed from 5.0 to 2000 nmol L−1. The limit of detection was 0.1 nmol L−1, and the limit of quantification was 5.0 nmol L−1 in both plasma and saliva matrices. The intra- and inter-assay precision values were found to be between 1.5 and 5.8%, and the accuracy values ranged from 88.0 to 108% utilizing saliva and plasma samples. The extraction recovery was more than 80%, and the presented functionalized GO-Tabs could be reused for more than 10 extractions without deterioration in recovery.

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