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  • 1. Abderrazek, K.
    et al.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Seffen, M.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Srasra, N. Frini
    Srasra, E.
    Photocatalytic degradation of indigo carmine using [Zn-Al] LDH supported on PAN nanofibres2015In: Clay minerals, ISSN 0009-8558, E-ISSN 1471-8030, Vol. 50, no 2, p. 185-197Article in journal (Refereed)
    Abstract [en]

    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.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Abdelhamid, Hani Nasser
    Abdel-Magied, Ahmed F.
    Abdel-Khalek, Ahmed A.
    Ali, M. M.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    Zou, Xiaodong
    Dutta, Joydeep
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Rare Earth Ions Adsorption onto Graphene Oxide Nanosheets2017In: Solvent extraction and ion exchange, ISSN 0736-6299, E-ISSN 1532-2262, Vol. 35, no 2, p. 91-103Article in journal (Refereed)
    Abstract [en]

    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.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Functional Materials, FNM. Nuclear Materials Authority, Egypt.
    El-sayed, R.
    Abdel-Magied, A. F.
    Abdel-khalek, A. A.
    Ali, M. M.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Uheida, Abdusalam
    KTH, School of Engineering Sciences (SCI), Applied Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Engineering Sciences (SCI), Applied Physics, Functional Materials, FNM.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Functional Materials, FNM.
    Selective separation of rare earth ions from aqueous solution using functionalized magnetite nanoparticles: kinetic and thermodynamic studies2017In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 327, p. 286-296Article in journal (Refereed)
    Abstract [en]

    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.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Burks, Terrance
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Akhtar, F.
    Department of Materials and Environmental Chemistry, Stockholm Universtiy, Stockholm, Sweden.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Lansåker, P. C.
    Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Surface functionalized nanofibers for the removal of chromium(VI) from aqueous solutions2014In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 245, p. 201-209Article in journal (Refereed)
    Abstract [en]

    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.
    Ouazzani, N.
    Mandi, L.
    Muhammad, M.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Composite nanofibers of polyacrylonitrile/natural clay for decontamination of water containing Pb(II), Cu(II), Zn(II) and pesticides2017In: Separation science and technology (Print), ISSN 0149-6395, E-ISSN 1520-5754, Vol. 52, no 1, p. 58-70Article in journal (Refereed)
    Abstract [en]

    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
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Avila, Marta
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Akhtar, F.
    Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden.
    Götelid, Mats
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Lansåker, P. C.
    Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Studies on the adsorption of chromium(VI) onto 3-Mercaptopropionic acid coated superparamagnetic iron oxide nanoparticles2014In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 425, p. 36-43Article in journal (Refereed)
    Abstract [en]

    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).

  • 7.
    Burks, Terrance
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Eita, Mohamed
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Removal of Chromium(VI) Using Surface Modified Superparamagnetic Iron Oxide Nanoparticles2013In: Separation science and technology (Print), ISSN 0149-6395, E-ISSN 1520-5754, Vol. 48, no 8, p. 1243-1251Article in journal (Refereed)
    Abstract [en]

    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).

  • 8. Hidalgo, Manuela
    et al.
    Uheida, Abdusalam
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Salvado, Victoria
    Fontas, Claudia
    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)2006In: Solvent extraction and ion exchange, ISSN 0736-6299, E-ISSN 1532-2262, Vol. 24, no 6, p. 931-942Article in journal (Refereed)
    Abstract [en]

    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.

  • 9.
    Mohamed, A.
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Cairo University, Egypt; Akhbar El Yom Academy, Egypt.
    Yousef, S.
    Ali Abdelnaby, M.
    Osman, T. A.
    Hamawandi, Bejan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Alexandria University, Egypt.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Photocatalytic degradation of organic dyes and enhanced mechanical properties of PAN/CNTs composite nanofibers2017In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 182, p. 219-223Article in journal (Refereed)
    Abstract [en]

    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.

  • 10.
    Mohamed, Alaa
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM. Mechanical Design and Production Engineering Department, Cairo University, Giza, Egypt.
    El-Sayed, R.
    Osman, T. A.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun A.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water2016In: Environmental Research, ISSN 0013-9351, E-ISSN 1096-0953, Vol. 145, p. 18-25Article in journal (Refereed)
    Abstract [en]

    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.

  • 11.
    Mohamed, Alaa
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Cairo University, Egypt.
    Nasser, W. S.
    Osman, T. A.
    Toprak, Muhammet
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Muhammed, Mamoun
    KTH, School of Engineering Sciences (SCI), Applied Physics. Alexandria University, Egypt.
    Uheida, Abdusalam
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Removal of chromium (VI) from aqueous solutions using surface modified composite nanofibers2017In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 505, p. 682-691Article in journal (Refereed)
    Abstract [en]

    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.

  • 12.
    Mohamed, Alaa
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Akhbar El Yom Academy, Egypt.
    Osman, T. A.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Yilmaz, E.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Visible light photocatalytic reduction of Cr(VI) by surface modified CNT/titanium dioxide composites nanofibers2016In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 424, p. 45-53Article in journal (Refereed)
    Abstract [en]

    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.

  • 13. Mohamed, Alaa
    et al.
    Osman, T. A.
    Toprak, Muhammet Sadaka
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Surface functionalized composite nanofibers for efficient removal of arsenic from aqueous solutions2017In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 180, p. 108-116Article in journal (Refereed)
    Abstract [en]

    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.

  • 14. Mohamed, Alaa
    et al.
    Salama, Ahmed
    Nasser, Walaa S.
    Uheida, Abdusalam
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Photodegradation of Ibuprofen, Cetirizine, and Naproxen by PAN-MWCNT/TiO2-NH2 nanofiber membrane under UV light irradiation2018In: Environmental Sciences Europe, ISSN 2190-4707, E-ISSN 2190-4715, Vol. 30, article id 47Article in journal (Refereed)
    Abstract [en]

    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.

  • 15. Morillo, D.
    et al.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Perez, G.
    Muhammed, Mamoun Ali
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Valiente, M.
    Arsenate removal with 3-mercaptopropanoic acid-coated superparamagnetic iron oxide nanoparticles2015In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 438, p. 227-234Article in journal (Refereed)
    Abstract [en]

    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.

  • 16. Murray, Ashley R.
    et al.
    Kisin, Elena
    Inman, Alfred
    Young, Shih-Houng
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Burks, Terrance
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Tkach, Alexey
    Waltz, Micah
    Castranova, Vincent
    Fadeel, Bengt
    Kagan, Valerian E.
    Riviere, Jim E.
    Monteiro-Riviere, Nancy
    Shvedova, Anna A.
    Oxidative Stress and Dermal Toxicity of Iron Oxide Nanoparticles In Vitro2013In: Cell Biochemistry and Biophysics, ISSN 1085-9195, E-ISSN 1559-0283, Vol. 67, no 2, p. 461-476Article in journal (Refereed)
    Abstract [en]

    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.

  • 17.
    Sallam, Ahmed
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Aswan Univ, Fac Archaeol, Aswan, Egypt..
    Hemeda, Sayed
    Cairo Univ, Fac Archaeol, Conservat Dept, Cairo 12613, Egypt..
    Toprak, Muhammet
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Muhammed, Mamoun
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Hassan, Moustapha
    Karolinska Inst, Dept Lab Med, S-14186 Stockholm, Sweden..
    Uheida, Abdusalam
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    CT Scanning and MATLAB Calculations for Preservation of Coptic Mural Paintings in Historic Egyptian Monasteries2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 3903Article in journal (Refereed)
    Abstract [en]

    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.

  • 18. Sallam, Ahmed
    et al.
    Zhao, Ying
    Hassan, Moustapha
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Studies On The Deterioration Of Coptic Mural Paintings In The Monastery Of Martyrs And The Luxor Temple2016In: International Journal of Conservation Science, ISSN 2067-533X, E-ISSN 2067-8223, Vol. 7, no 2, p. 493-500Article in journal (Refereed)
    Abstract [en]

    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.

  • 19. Shi, Jingwen
    et al.
    Karlsson, Hanna L.
    Johansson, Katarina
    Gogvadze, Vladimir
    Xiao, Lisong
    Li, Jiangtian
    Burks, Terrance
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Garcia-Bennett, Alfonso
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Mathur, Sanjay
    Morgenstern, Ralf
    Kagan, Valerian E.
    Fadeel, Bengt
    Microsomal Glutathione Transferase 1 Protects Against Toxicity Induced by Silica Nanoparticles but Not by Zinc Oxide Nanoparticles2012In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 6, no 3, p. 1925-1938Article in journal (Refereed)
    Abstract [en]

    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.

  • 20.
    Sugunan, Abhilash
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Guduru, Veerendra K.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    A ‘Continuous flow’ Photochemical Water Treatment System Based on Radially Oriented ZnO Nanowires on Flexible Poly-L-Lactide NanofibersManuscript (preprint) (Other academic)
    Abstract [en]

    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.

  • 21.
    Sugunan, Abhilash
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Guduru, Veerendra K.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Radially Oriented ZnO Nanowires on Flexible Poly-L-Lactide Nanofibers for Continuous-Flow Photocatalytic Water Purification2010In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 93, no 11, p. 3740-3744Article in journal (Refereed)
    Abstract [en]

    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.

  • 22.
    Uheida, Abdusalam
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Selective Separation of Metal Ions by Solvent Extraction, Liquid Membranes and Magnetic Nanoparticles2006Doctoral thesis, comprehensive summary (Other scientific)
  • 23.
    Uheida, Abdusalam
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Iglesias, Monica
    Fontas, Claudia
    Hidalgo, Manuela
    Salvado, Victoria
    Zhang, Yu
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Muhammed, Mamoun
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sorption of palladium(II), rhodium(III), and platinum(IV) on Fe3O4 nanoparticles2006In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 301, no 2, p. 402-408Article in journal (Refereed)
    Abstract [en]

    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).

  • 24.
    Uheida, Abdusalam
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Iglesias, Mònica
    Fontàs, Claudia
    Zhang, Yu
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Muhammed, Mamoun
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Adsorption Behavior of Platinum Group Metals (Pd, Pt, Rh) onNonylthiourea-Coated Fe3O4 Nanoparticles2006In: Separation science and technology (Print), ISSN 0149-6395, E-ISSN 1520-5754, Vol. 41, p. 909-923Article in journal (Refereed)
    Abstract [en]

    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.

  • 25.
    Uheida, Abdusalam
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Mohamed, Alaa
    Cairo Univ, EGNC, Egypt Nanotechnol Ctr, 6th October City 12588, Egypt.;Akhbar El Yom Acad, Prod Engn & Printing Technol Dept, Giza 12655, Egypt..
    Belaqziz, Majdouline
    Cadi Ayyad Univ, Natl Ctr Study & Res Water & Energy, BP 511, Marrakech 40000, Morocco..
    Nasser, Walaa S.
    Res Inst Med Entomol, Giza 12611, Egypt..
    Photocatalytic degradation of Ibuprofen, Naproxen, and Cetirizine using PAN-MWCNT nanofibers crosslinked TiO2-NH2 nanoparticles under visible light irradiation2019In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 212, p. 110-118Article in journal (Refereed)
    Abstract [en]

    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.

  • 26.
    Uheida, Abdusalam
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Salazar-Alvarez, German
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Bjorkman, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Zhang, Yu
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Muhammed, Mamoun
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Fe3O4 and gamma-Fe2O3 nanoparticles for the adsorption of Co2+ from aqueous solution2006In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 298, no 2, p. 501-507Article in journal (Refereed)
    Abstract [en]

    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)

  • 27.
    Uheida, Abdusalam
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Zhang, Yu
    KTH, Superseded Departments, Chemistry.
    Muhammed, Mamoun
    KTH, Superseded Departments, Materials Science and Engineering.
    Extraction of platinum(IV) with nonylthiourea dissolved in chloroform from hydrochloric acid media2003In: Solvent extraction and ion exchange, ISSN 0736-6299, E-ISSN 1532-2262, Vol. 21, no 6, p. 827-840Article in journal (Refereed)
    Abstract [en]

    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.

  • 28.
    Uheida, Abdusalam
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Zhang, Yu
    KTH, Superseded Departments, Chemistry.
    Muhammed, Mamoun
    KTH, Superseded Departments, Materials Science and Engineering.
    Selective extraction of palladium(II) from chloride solutions with nonylthiourea dissolved in chloroform2002In: Solvent extraction and ion exchange, ISSN 0736-6299, E-ISSN 1532-2262, Vol. 20, no 6, p. 717-733Article in journal (Refereed)
    Abstract [en]

    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.

  • 29.
    Uheida, Abdusalam
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Zhang, Yu
    KTH, Superseded Departments, Materials Science and Engineering.
    Muhammed, Mamoun
    KTH, Superseded Departments, Materials Science and Engineering.
    Thermodynamic modeling of extraction equilibria of platinum and palladium with nonylthiourea from hydrochloric acid media2004In: Separation science and technology (Print), ISSN 0149-6395, E-ISSN 1520-5754, Vol. 39, no 15, p. 3665-3677Article in journal (Refereed)
    Abstract [en]

    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.

  • 30.
    Uheida, Abdusalam
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Zhang, Yu
    KTH, Superseded Departments, Chemistry.
    Muhammed, Mamoun
    KTH, Superseded Departments, Materials Science and Engineering.
    Transport of palladium(II) through hollow fiber supported liquid membrane facilitated by nonylthiourea2004In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 241, no 2, p. 289-295Article in journal (Refereed)
    Abstract [en]

    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.

  • 31.
    Yazdi, Milad Ghadami
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Ivanic, M.
    Rudjer Boskovic Inst, Div Marine & Environm Res, Zagreb, Croatia..
    Mohamed, Alaa
    Cairo Univ, Egypt Nanotechnol Ctr, EGNC, 6Th October City 12588, Egypt.;Karlsruhe Inst Technol, Inst Funct Interfaces IFG, Membrane Technol Dept, D-76344 Karlsruhe, Germany.;Akhbar El Yom Acad, Prod Engn & Printing Technol Dept, Giza 12655, Egypt..
    Uheida, Abdusalam
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Surface modified composite nanofibers for the removal of indigo carmine dye from polluted water2018In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, no 43, p. 24588-24598Article in journal (Refereed)
    Abstract [en]

    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.

  • 32.
    Yohai, L.
    et al.
    UNMdP, CONICET, INTEMA, Div Ceram, B7608FDQ, Mar Del Plata, Buenos Aires, Argentina.
    Giraldo Mejía, Hugo
    Procaccini, R.
    Pellice, S.
    Laxman Kunjali, Karthik
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Uheida, Abdusalam
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Nanocomposite functionalized membranes based on silica nanoparticles oss-linked to electrospun nanofibrous support for arsenic(v) sorption from contaminated underground water2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 15, p. 8280-8289Article in journal (Refereed)
    Abstract [en]

    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.

  • 33.
    Zohdi, Zeynab
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Karolinska Inst, Dept Clin Neurosci, Ctr Psychiat Res, SE-17176 Solna, Sweden ; Univ Bu Ali Sina, Dept Chem, Hamadan 65174, Iran.
    Hashemi, Mahdi
    Univ Bu Ali Sina, Dept Chem, Hamadan 65174, Iran..
    Uheida, Abdusalam
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Moein, Mohammad Mahdi
    Karolinska Inst, Dept Clin Neurosci, Ctr Psychiat Res, SE-17176 Solna, Sweden..
    Abdel-Rehim, Mohamed
    KTH, School of Engineering Sciences (SCI), Applied Physics. Karolinska Inst, Dept Clin Neurosci, Ctr Psychiat Res, SE-17176 Solna, Sweden Dept Appl Phys, SE-16440 Stockholm, Sweden..
    Graphene Oxide Tablets for Sample Preparation of Drugs in Biological Fluids: Determination of Omeprazole in Human Saliva for Liquid Chromatography Tandem Mass Spectrometry2019In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, no 7, article id 1191Article in journal (Refereed)
    Abstract [en]

    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.

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