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>

Novel Cd-doped Co/C nanoparticles for electrochemical supercapacitors

Barakat, N.A.M.,El-Deen, A.G.,Shin, G.,Park, M.,Kim, H.Y. North-Holland 2013 Materials letters Vol.99 No.-

Novel cadmium-doped cobalt nanoparticles encapsulated in graphite shell are introduced to be utilized in the electrochemical supercapcitors. Electrochemical characterization for the introduced NPs indicated that the corresponding specific capacitance is 255F/g with good stability. The introduced NPs were synthesized using a simple sol-gel technique. Typically, a sol-gel composed of cadmium acetate, cobalt acetate and poly(vinyl alcohol) was prepared based on the polycondensation property of the acetate anions. The utilized physiochemical characterizations affirmed that drying, grinding and calcination in Ar atmosphere of the prepared gel leads to produce Cd-doped Co nanoparticles encapsulated in a thin graphite layer. Overall, the present study opens a new avenue for the encapsulated bimetallic nanostructures to be used as effective materials in the electrochemical supercapacitors.

Ammonium phosphate as promised hydrogen storage material

Barakat, N.A.M.,Ahmed, E.,Abdelkareem, M.A.,Farrag, T.E.,Al-Meer, S.,Al-Deyab, S.,Elsaid, K.,Nassar, M.M. Pergamon Press ; Elsevier Science Ltd 2015 International journal of hydrogen energy Vol.40 No.32

Most of the reported hydrogen storage materials are either expensive or based on synthetically complicated compounds. Ammonium phosphates are cheap and available product; it is being used as fertilizer. These compounds could be utilized as hydrogen storage materials. Stoichiometrically, mono-, di- and tri-ammonium phosphate can lead to evolve 3.875, 7.867 and 11.903 hydrogen equivalent, respectively. Using Pt/C (20 wt %) leads to produce 17.28, 11.35 and 10.15% from the equivalent hydrogen in the mono-, di- and tri-ammonium phosphate, respectively. Analyzing the obtained gases by GC confirms evolution of pure hydrogen. Moreover, ion chromatography detects and ions in the liquid which indicates hydrolysis of the ammonium phosphate. Ni/C and Co/C NPs can be exploited as catalysts; Ni/C containing 20 wt% metal reveals comparable results to Pt/C. Overall, this study opens promising avenue to develop new catalysts to enhance the hydrolysis of ammonium phosphate to produce hydrogen. Comparing to the reported hydrogen storage materials, ammonium phosphates possess comparable hydrogen content 97.28, 118.3 and 115.72 kg/m<SUP>3</SUP> for mono-, di- and tri-ammonium phosphate, respectively which is very close to the MgH<SUB>2</SUB> (115.5 kg/m<SUP>3</SUP>) and not so far from ammonia borane (148.2 kg/m<SUP>3</SUP>). However, in contrast to these compounds, hydrogen can be released from the introduced storage materials by hydrolysis only using the proper catalyst. Furthermore, the hydrolysis process results in producing different acids; nitrous, nitric and phosphoric acid which should be considered in the reactor construction precautions.

Cadmium-doped cobalt/carbon nanoparticles as novel nonprecious electrocatalyst for methanol oxidation

Barakat, N.A.M.,Abdelkareem, M.A.,Yousef, A.,Al-Deyab, S.S.,El-Newehy, M.,Kim, H.Y. Pergamon Press ; Elsevier Science Ltd 2013 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.38 No.8

Cd-doped Cobalt nanoparticles encapsulated in graphite shell have been synthesized using a simple sol-gel technique. Typically, a sol-gel composed of cadmium acetate, cobalt acetate and poly(vinyl alcohol) has been prepared based on the polycondensation property of the acetates. The utilized physiochemical characterizations affirmed that drying, grinding and calcination in Ar atmosphere of the prepared gel leads to produce Cd-doped Co nanoparticles encapsulated in a thin graphite layer. The prepared nanoparticles revealed good electroactivity towards methanol electrooxidation. High current density (70 mAcm<SUP>-2</SUP>) and considerably low onset potential (~600 mV vs. NHE) were obtained. Moreover, because of the graphite shell, good stability was observed. Considering that the introduced nanoparticles composed of nonprecious metals and the obtained electrochemical results are satisfactory, the introduced study might open new avenues for the cobalt-based nanostructures to be used as novel effective electrocatalysts in the fuel cells applications.

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>

Enhanced desalination performance of capacitive deionization using zirconium oxide nanoparticles-doped graphene oxide as a novel and effective electrode

Yasin, A.S.,Mohamed, H.O.,Mohamed, I.M.A.,Mousa, H.M.,Barakat, N.A.M. Elsevier Science B.V 2016 Separation and purification technology Vol.171 No.-

Due to its eco-friendly and low energy technique for removing salt ions from saline water, capacitive deionization (CDI) is highly recommended as a desalination process. Based on its good features, large surface area and good electric conductivity, graphene oxide is a promising electrode in the CDI technology if the specific capacitance could be enhanced. In this study, to improve the electrochemical performances, novel ZrO<SUB>2</SUB> nanoparticles-incorporated graphene oxide nanosheets with different concentrations were successfully synthesized by hydrothermal treatment, their electrosorption characteristics in CDI unit were examined. The morphology, structure and electrochemical performance of the fabricated materials were investigated by scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), cyclic voltammetry and electrochemical impedance spectroscopy. The capacitive and electrosorption performances in NaCl solution were studied. Moreover, the role of ZrO<SUB>2</SUB> loading was investigated. The introduced ZrO<SUB>2</SUB>-doped graphene oxide showed a distinct improvement in the electrosorption capacity and revealed higher specific capacitance compared to the pristine graphene oxide. The obtained results indicated that the synthesized ZrO<SUB>2</SUB>-doped graphene oxide nanocomposite having 10wt.% ZrO<SUB>2</SUB> displayed a significant increase in the specific capacitance as the corresponding value (452.06F/g) was nine folds more than that of the pristine GO at 10mV/s. Moreover, the same electrode exhibits great cycling stability, excellent salt removal efficiency (93.03%), and distinct electrosorptive capacity (4.55mg/g). Overall, the proposed GO/ZrO<SUB>2</SUB> nanoparticle composite electrode is appropriate for utilizing as optimum electrodes for the CDI technique.

Cu⁰/S-doped TiO₂ nanoparticles-decorated carbon nanofibers as novel and efficient photocatalyst for hydrogen generation from ammonia borane

Yousef, A.,Brooks, R.M.,El-Halwany, M.M.,EL-Newehy, M.H.,Al-Deyab, S.S.,Barakat, N.A.M. Ceramurgica ; Elsevier Science Ltd 2016 CERAMICS INTERNATIONAL Vol.42 No.1

Cu<SUP>0</SUP>/S-doped TiO<SUB>2</SUB> nanoparticles (NPs)-decorated carbon nanofibers (CNFs) were introduced as a novel photocatalyst for the hydrolysis of ammonia borane under visible light. Nanofibers were prepared by electrospinning of a solution composed of titanium isopropoxide, polyvinylpyrroliodine, copper acetate tetrahydrate, and ammonium sulfide. Calcination of the formed nanofiber mats in Ar at 800<SUP>o</SUP>C led to thermal decomposition of CuS to Cu<SUP>0</SUP> and S. Finally, the obtained nanofibers revealed a better photocatalytic activity over that of the other used photocatalysts. The hydrogen evolution was approximately 60mL, 35mL, and 20mL in 40min using nanocatalyst and TiO<SUB>2</SUB>-CNFs, and TiO<SUB>2</SUB> NFs, respectively. The good nanofibrous morphology and electron-transfer, and high surface area are the main features of the introduced nanofibers.

NiCu bimetallic nanoparticle-decorated graphene as novel and cost-effective counter electrode for dye-sensitized solar cells and electrocatalyst for methanol oxidation

Motlak, M.,Barakat, N.A.M.,El-Deen, A.G.,Hamza, A.M.,Obaid, M.,Yang, O.B.,Akhtar, M.S.,Khalil, K.A. Elsevier 2015 Applied Catalysis A Vol.501 No.-

NiCu bimetallic nanoparticle-decorated graphene was prepared by hydrothermal treatment to be utilized as an efficient and alternative Pt-free counter electrode (CE) for dye-sensitized solar cells (DSSCs). The results indicated that the performance of the introduced modified graphene as CE strongly depends on the composition of the metallic nanoparticles. Typically, Ni-, Ni<SUB>0.25</SUB>Cu<SUB>0.75</SUB>-, Ni<SUB>0.6</SUB>Cu<SUB>0.4</SUB>- and Ni<SUB>0.75</SUB>Cu<SUB>0.25</SUB>-decorated graphene were synthesized. Investigation of the electrochemical characteristics indicated that the graphene decorated by Ni<SUB>0.75</SUB>Cu<SUB>0.25</SUB> nanoparticles shows the highest catalytic activity and conductivity compared to the other prepared formulations as well as pristine graphene. In DSSC, Ni<SUB>0.75</SUB>Cu<SUB>0.25</SUB> nanoparticle-decorated graphene can remarkably improve the catalytic activity toward triiodide reduction and lower the resistance at the electrolyte-CE interface. Accordingly, the obtained energy conversion efficiencies were 1.72%, 2.39%, 1.24%, 2.87% and 5.1% for pristine, Ni-, Ni<SUB>0.25</SUB>Cu<SUB>0.75</SUB>-, Ni<SUB>0.6</SUB>Cu<SUB>0.4</SUB>- and Ni<SUB>0.75</SUB>Cu<SUB>0.25</SUB>-decorated graphene, respectively. The obtained efficiency for Ni<SUB>0.75</SUB>Cu<SUB>0.25</SUB>-decorated graphene is comparable with Pt-based DSSC fabricated by the same procedure (5.9%) which recommends exploiting the introduced modified graphene as efficient and cost-effective CE for the large-scale fabrication of photovoltaic devices. The catalytic performance of the best formulation was examined toward methanol electrooxidation; the results indicated effective and stable electrocatalytic activity.

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>

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>