Stable and effective super-hydrophilic polysulfone nanofiber mats for oil/water separation

Obaid, M.,Barakat, Nasser A.M.,Fadali, Olfat A.,Al-Meer, Saeed,Elsaid, Khalid,Khalil, Khalil Abdelrazek Elsevier 2015 Polymer Vol.72 No.-

<P><B>Abstract</B></P> <P>Hydrophobicity of polysulfone is the main constraint facing wide application in the most important field; water treatment, although this polymer shows promising characteristics to be used in different separation technologies. In this study, super-hydrophilic polysulfone nanofiber mats are introduced using novel modifications. The introduced nanofibers were synthesized by electrospinning of polysulfone/NaOH/DMF electrospun solution. The prepared electrospun nanofibers have been activated by deposition of a polyamide layer using interfacial polymerization (IP) reaction between m-phenylenediamine and 1,3,5-benzenetricarbonyl chloride. Three different heat treatment methodologies were investigated to enhance the characteristics of the activated nanofiber mats; normal drying at 70 °C, and soaking in boiled water followed by either normal drying at 70 °C or storing in the water. Investigation of the mechanical properties indicated that incorporation of NaOH improves the tensile stress by 40% compared to the pristine polysulfone nanofibers. Interestingly, treatment of the activated nanofiber mats in the boiled water followed by storing in water led to produce super-hydrophilic mats with water contact angle of 3° due to enhancing the IP reaction on the surface of the individual nanofibers. In oil/water separation process, the proposed heat treatment for the modified nanofiber mats resulted in increase the water flux from 8 to 12.21 m<SUP>3</SUP>/m<SUP>2</SUP> day with oil rejection of 99.976%.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Super-hydrophilic membrane based on PSF nanofibers is introduced. </LI> <LI> The membrane was modified using simple and effective heat treatment process. </LI> <LI> The corresponding water flux is very high; 12.21 m<SUP>3</SUP>/m<SUP>2</SUP> day. </LI> <LI> The fabrication process is simple, cheap and applicable. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Silver Nanofibres by a Novel Electrospinning Process: Nanofibres with Plasmon Resonance in the IR Region and Thermal Hysteresis Electrical Conductivity Features

Barakat, Nasser A. M.,Farrag, Taha E.,Kanjwal, Muzafar A.,Park, Soo-Jin,Sheikh, Faheem A.,Yong Kim, Hak WILEY-VCH Verlag 2010 European journal of inorganic chemistry Vol.2010 No.10

<P>In this study, we have introduced electrospinning of a colloidal solution rather than the conventional sol–gel process as a novel strategy to produce silver nanofibres. Typically, a silver acetate/polyvinyl alcohol colloidal solution was successfully electrospun. Electrophoretic light scattering (ELS) and dynamic light scattering (DLS) analyses have affirmed that the electrospun solution is a colloid with a ζ-potential of –2 mV and average particle diameter of 373 ± 1 nm. Moreover, FTIR analysis affirmed that neither the polymer nor silver acetate nanoparticles were affected during the electrospinning process. Calcination of the electrospun mats at 700 °C in an argon atmosphere produced smooth and unbroken pure silver nanofibres. Surface plasmon resonance of the resultant silver nanofibres was detected at 962 nm which is biologically beneficial. Furthermore, the synthesised silver nanofibres revealed thermal hysteresis in the electrical conductivity properties. These advantageous physical features strongly suggest utilising the prepared nanofibres in various fields.</P> <B>Graphic Abstract</B> <P>Electrospinning of a colloidal silver acetate solution rather than the conventional sol–gel process was introduced as a novel strategy to produce silver nanofibres. Electrophoretic light scattering and dynamic light scattering analyses have affirmed that theelectrospun solution is a colloid. Calcination of the electrospun mats produced smooth and unbroken pure silver nanofibres. The advantageous physical features of the fibres suggest utilising the prepared nanofibres in various fields. <img src='wiley_img_2010/14341948-2010-2010-10-EJIC200900453-fig000.gif' alt='wiley_img_2010/14341948-2010-2010-10-EJIC200900453-fig000'> </P>

Amorphous SiO₂ NP-Incorporated Poly(vinylidene fluoride) Electrospun Nanofiber Membrane for High Flux Forward Osmosis Desalination

Obaid, M.,Ghouri, Zafar Khan,Fadali, Olfat A.,Khalil, Khalil Abdelrazek,Almajid, Abdulhakim A.,Barakat, Nasser A. M. American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.7

<P>Novel amorphous silica nanoparticle-incorporated poly(vinylidine fluoride) electrospun nanofiber mats are introduced as effective membranes for forward osmosis desalination technology. The influence of the inorganic nanoparticle content on water flux and salt rejection was investigated by preparing electrospun membranes with 0, 0.5, 1, 2, and 5 wt % SiO2 nanoparticles. A laboratory-scale forward osmosis cell was utilized to validate the performance of the introduced membranes using fresh water as a feed and different brines as draw solution (0.5, 1, 1.5, and 2 M NaCl). The results indicated that the membrane embedding 0.5 wt % displays constant salt rejection of 99.7% and water flux of 83 L m(-2) h(-1) with 2 M NaCl draw solution. Moreover, this formulation displayed the lowest structural parameter (S = 29.7 mu m), which represents approximately 69% reduction compared to the pristine membrane. Moreover, this study emphasizes the capability of the electrospinning process in synthesizing effective membranes as the observed water flux and average salt rejection of the pristine poly(vinylidine fluoride) membrane was 32 L m(-2) h(-1) (at 2 M NaCl draw solution) and 99%, respectively. On the other hand, increasing the inorganic nanoparticles to 5 wt % showed negative influence on the salt rejection as the observed salt flux was 1651 mol m(-2) h(-1) Besides the aforementioned distinct performance, studies of the mechanical properties, porosity, and wettability concluded that the introduced membranes are effective for forward osmosis desalination technology.</P>

Carbon nanofibers decorated with binary semiconductor (TiO₂/ZnO) nanocomposites for the effective removal of organic pollutants and the enhancement of antibacterial activities

Pant, Bishweshwar,Pant, Hem Raj,Barakat, Nasser A.M.,Park, Mira,Jeon, Kyungsoo,Choi, Yuri,Kim, Hak-Yong Elsevier 2013 CERAMICS INTERNATIONAL Vol.39 No.6

<P><B>Abstract</B></P> <P>A novel photocatalytic and antibacterial carbon nanofiber decorated with TiO<SUB>2/</SUB>ZnO composite NPs was prepared by a simple electrospinning method followed by calcination and hydrothermal treatment. The loading of a small amount of ZnO NPs throughout the fibers prior to electrospinning could provide nucleation sites for the crystal growth of ZnO from its precursor during hydrothermal synthesis and could effectively hold TiO<SUB>2</SUB>/ZnO particles on the surface of the fibers for better stability. The morphology and structure of the as-synthesized particles were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which revealed that TiO<SUB>2</SUB>/ZnO NPs were attached on the surface of the carbon nanofibers. The as-synthesized nanocomposite exhibited a strong photocatalytic activity for the decomposition of methylene blue (MB) under UV irradiation and showed good antibacterial properties as well. The enhanced photocatalytic performance of the developed nanocomposite can be attributed to the adsorption characteristic of carbon nanofiber and the matched band potentials of TiO<SUB>2</SUB> and ZnO. The perfect recovery of the catalyst after the reaction and its unchanged efficiency for cyclic use showed that it will be an economical and environmentally friendly photocatalyst.</P>

Production of Smooth and Pure Nickel Metal Nanofibers by the Electrospinning Technique: Nanofibers Possess Splendid Magnetic Properties

Barakat, Nasser A. M.,Kim, Bongsoo,Kim, Hak Yong American Chemical Society 2009 The Journal of Physical Chemistry Part C Vol.113 No.2

Cobalt nanofibers encapsulated in a graphite shell by an electrospinning process

Barakat, Nasser A. M.,Kim, Bongsoo,Park, S. J.,Jo, Younghun,Jung, Myung-Hwa,Kim, Hak Yong Royal Society of Chemistry 2009 Journal of materials chemistry Vol.19 No.39

<P>As cobalt is an important ferromagnetic material and the nanofibrous shape greatly improves the magnetic properties, we are introducing cobalt nanofibers encapsulated in graphite shell to gain the advantages of the nanofibrous shape as well as to produce protected materials. An electrospun nanofiber mat consisting of cobalt acetate and poly(vinyl alcohol) has been calcined in argon atmosphere at 850 °C. Calcination of cobalt acetate in an inert atmosphere leads to the production of pure cobalt which strongly enhanced graphitization of the utilized polymer to form a graphite shell. Physicochemical characterization analyses indicated that the final product was pure cobalt nanofibers enveloped in a 10 nm thick graphite shell. The graphite shell did not affect the magnetic properties of the synthesized graphite-encapsulated cobalt nanofibers compared with the bare ones which reveal preeminent magnetic characteristics; moreover the shell modifies some of these properties to be temperature independent.</P> <P>Graphic Abstract</P><P>Graphite-encapsulated cobalt nanofibers have been synthesized by an electrospinning technique. As well as the oxidation-resistant character provided by the graphite shell, it strongly modifies the magnetic properties of the cobalt nanofibers. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b904669k'> </P>

Cobalt/copper-decorated carbon nanofibers as novel non-precious electrocatalyst for methanol electrooxidation

Barakat, Nasser A M,El-Newehy, Mohamed,Al-Deyab, Salem S,Kim, Hak Yong Springer 2014 NANOSCALE RESEARCH LETTERS Vol.9 No.1

<P>In this study, Co/Cu-decorated carbon nanofibers are introduced as novel electrocatalyst for methanol oxidation. The introduced nanofibers have been prepared based on graphitization of poly(vinyl alcohol) which has high carbon content compared to many polymer precursors for carbon nanofiber synthesis. Typically, calcination in argon atmosphere of electrospun nanofibers composed of cobalt acetate tetrahydrate, copper acetate monohydrate, and poly(vinyl alcohol) leads to form carbon nanofibers decorated by CoCu nanoparticles. The graphitization of the poly(vinyl alcohol) has been enhanced due to presence of cobalt which acts as effective catalyst. The physicochemical characterization affirmed that the metallic nanoparticles are sheathed by thin crystalline graphite layer. Investigation of the electrocatalytic activity of the introduced nanofibers toward methanol oxidation indicates good performance, as the corresponding onset potential was small compared to many reported materials; 310 mV (vs. Ag/AgCl electrode) and a current density of 12 mA/cm<SUP>2</SUP> was obtained. Moreover, due to the graphite shield, good stability was observed. Overall, the introduced study opens new avenue for cheap and stable transition metals-based nanostructures as non-precious catalysts for fuel cell applications.</P>

Photocatalytic Activity of ZnO-TiO2 Hierarchical Nanostructure Prepared by Combined Electrospinning and Hydrothermal Techniques

Muzafar A. Kanjwal,Nasser A. M. Barakat,Faheem A. Sheikh,박수진,김학용 한국고분자학회 2010 Macromolecular Research Vol.18 No.3

In this study, a new hierarchical nanostructure consisting of zinc oxide (ZnO) and titanium dioxide (TiO2) was prepared by an electrospinning process followed by a hydrothermal technique for use as a photocatalyst for dye degradation. First, the electrospinning of a colloidal solution consisting of titanium isopropoxide/poly(vinyl acetate)/zinc nanoparticles was performed to produce polymeric nanofibers embedded in solid nanoparticles. Calcination of the obtained electrospun nanofiber mats in air at 600 ºC produced TiO2 nanofibers containing ZnO nanoparticles (i.e., ZnO-doped TiO2 nanofibers). The ZnO nanoparticles formed were then exploited as seeds to produce the outgrowth ZnO branches around the TiO2 nanofibers using the hydrothermal technique. Photodegradation of methyl red and rhodamine B (RB) dyes was examined individually using four photocatalysts:ZnO nanoparticles prepared by the same hydrothermal technique, pristine TiO2 nanofibers, ZnO-doped TiO2 nanofibers and the produced nanostructure. The results showed that the introduced ZnO-TiO2 hierarchical nanostructure can eliminate all the methyl red dye within 90 min and the rhodamine B dye within 105 min. However,the other three nanostructures could not totally remove any of the dyes, even after 3 h. Therefore, the introduced nanostructure has higher photocatalytic activity than any of its ingredients individually, which highlights the advantages of synthesizing this novel structure.

Electrocatalytic behavior of a nanocomposite of Ni/Pd supported by carbonized PVA nanofibers towards formic acid, ethanol and urea oxidation: A physicochemical and electro-analysis study

Mohamed, Ibrahim M.A.,Yasin, Ahmed S.,Barakat, Nasser A.M.,Song, Seung A.,Lee, Ha Eun,Kim, Seong Su Elsevier BV * North-Holland 2018 Applied Surface Science Vol.435 No.-

<P><B>Abstract</B></P> <P>A nanocomposite of Ni/Pd supported by carbonized poly-vinyl alcohol (PVA) nanofibers (NFs) was synthesized via electrospinning followed by calcination under an argon atmosphere. The as-synthesized NFs were studied using physicochemical analyses, such as field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), to investigate the morphology, crystallinity, effect of carbonization and surface chemistry of the NFs, respectively. Cyclic voltammetry (CV) and chronoamperometry (CA) were utilized to study the performance of the NFs towards electrooxidation reactions. The designed NFs present superior electrocatalytic behavior in an acid medium towards formic acid oxidation, as well as urea and ethanol oxidation in an alkaline medium. The electrocatalytic performance of the bimetallic NFs appears to arise from the assembly of bimetallic Ni/Pd@NFs based on PVA, which has hydroxyl groups. These hydroxyl groups can decrease the negative processes that occur as a result of metal-metal interactions, such as the aggregation process. This study introduces a novel non-precious electrocatalyst to facilitate the commercialization of fuel cells based on formic acid, urea and ethanol.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni&Pd@C-nanofibers are synthesized via facile two steps; electrospinning followed by carbonization. </LI> <LI> The produced NFs have FCC-crystals with crystal size and d-spacing 18.08 and 0.211 nm, respectively. </LI> <LI> Enhancement on the produced current was observed as increase of formic acid concentration up to 3 mol/l. </LI> <LI> Cyclic voltammetry studies confirm the electrocatalytic performance of the synthesized-NFs towards ethanol and urea in alkaline medium. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Cobalt oxides-sheathed cobalt nano flakes to improve surface properties of carbonaceous electrodes utilized in microbial fuel cells

Mohamed, Hend Omar,Abdelkareem, Mohammad Ali,Obaid, M.,Chae, Su-Hyeong,Park, Mira,Kim, Hak Yong,Barakat, Nasser A.M. Elsevier 2017 Chemical engineering journal Vol.326 No.-

<P><B>Abstract</B></P> <P>A novel nanoflakes of cobalt sheathed with cobalt oxide is electrodeposited on four different carbonaceous anodes; carbon cloth (CC), carbon paper (CP) graphite (G) and activated carbon (AC), to introduce as high-performance anodes of microbial fuel cell (MFC). Interestingly, characterizations results indicated that novel metallic nanoflakes that sheathed by a thin layer of cobalt oxide were formed on the surface of the different anode materials. Moreover, using a simple and effective electrodeposition technique for fabricating of cobalt/cobalt oxide nanoflakes is introduced to overcome the hydrophobicity and the interfacial electron transfer of the anodes. The thin layer of cobalt/cobalt oxide nanoflakes significantly enhanced the microbial adhesion, the wettability of the anode surface and decrease the electron transfer resistance. Alternatively, the toxicity risk of the pure cobalt is overcome by the cobalt oxide layer. The application of the modified anodes in an air-cathode MFCs fed by industrial wastewater resulted in a significant improving in cell performance for the different anode materials. Where, the observed increasing in the power was 103, 137, 173 and 71% for the CC, CP, G and AC electrodes, respectively. This proposed treatment technique represented a high-performance, excellent microbial adhesion, easy fabrication and scale-up anodes for MFC.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cobalt oxides-sheathed cobalt nano flakes was deposited on anodes using electrodeposition. </LI> <LI> The modified anodes were used in MFC to treat the wastewater and produce energy. </LI> <LI> The modified anodes shows promising results in single air-cathode MFC. </LI> <LI> The results of the modified anodes were strongly enhanced compared to the pristine anodes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>