10 research outputs found
Removal of Lead Ions from Aqueous Solutions Using Polyaniline Polystyrene Nanocomposites
No full textWater pollution is an issue of grave importance worldwide, especially in countries that boast of a large number of industries. High concentration of heavy metal ions such as lead, nickel, etc are often found in industrial waste water and can have adverse affects on human health. Over the years a variety of methods, both physical and chemical ones, are reported to have been used for removal of heavy metal ions from water such as filtration and advanced oxidation [1, 2], etc. Adsorption is among the most widely used techniques due to its simplicity, reasonable operational conditions and cost-effective nature. The primary physical property of any absorbent is its surface area and structure. PANI is used due to the presence of primary and secondary amines functional groups which absorb heavy metals. However, due to poor solubility of PANI in common solvents it is made into composite with polystyrene which has strong mechanical properties. In this study a PS/PANI nanocomposite was prepared using the casting method; the composite was then investigated for its heavy metal ion absorption potential.qscienc
Effect of Silicon Nitride and Graphene Nanoplatelets on the Properties of Aluminum Metal Matrix Composites
No full textThis research work aims at investigating the influence of a fixed content of silicon nitride (Si3N4) and varied contents of graphene nanoplatelets (GNPs) on the physical and mechanical properties of Al-Si3N4-GNPs composites. The composites were fabricated by a microwave-assisted powder metallurgy route. The Si3N4 concentration was fixed at (5 wt.%) while the GNPs concentration was varied between (0 wt.%) to (1.5 wt.%) in the Al-Si3N4-GNPs. The structural analysis indicates the formation of phase pure materials with high crystallinity. The microstructural analysis confirmed the presence of the Si3N4 and GNPs showing enhanced agglomeration with the increasing amount of GNPs. Moreover, the surface roughness of the synthesized composites increases with an increasing amount of GNPs reaching its maximum value (RMS = 65.32 nm) at 1.5 wt.% of GNPs. The Al-Si3N4-GNPs composites exhibit improved microhardness and promising load-indentation behavior during nanoindentation when compared to pure aluminum (Al). Moreover, Al-Si3N4-GNPs composites demonstrate higher values of compressive yield strength (CYS) and ultimate compressive strength (UCS) when compared to pure Al despite showing a declining trend with an increasing amount of GNPs in the matrix. Finally, a shear mode of fracture is prevalent in Al-Si3N4-GNPs composites under compression loading
Flexible thermo-electrochemical cells using Iodolyte HI-30 for conversion of low-grade heat to electrical energy
No full textIn this research work, we investigated the flexible thermo-electro chemical cells (TECs) for the conversion of low-grade heat into electrical energy in the temperature range of 20–70 °C. The TECs were fabricated using 30 mM iodide/tri-iodide (Iodolyte HI-30) in acetonitrile as a redox couple. A TEC consists of a carbon/Iodolyte HI-30/carbon structure. The cell contains a flexible polymer tube, filled with the electrolyte, whereas the openings of the tube have been sealed using carbon electrodes. Gradients of temperature (ΔT) up to 50 °C have been created. The Seebeck voltages and short-circuit currents (Isc) were found to be 8–17 mV and 100–425 μA, respectively, in the 20–70 °C temperature range. It was found that the TECs could provide sufficient power to drive low-power electronic devices and could be used for measurement of temperature gradients as well. Furthermore, this work identifies the directions for realizing flexible thermo-electric cells that can be potentially used for several applications in the medical segment where, besides electrical and mechanical stability, flexibility is paramount.Scopu
Extraction and characterization of biofunctional lignocellulosic fibers from Pulicaria undulata plant and the effect of alkali treatment on their bio-physicochemical properties
No full textThis study aimed to extract and characterize natural fibers from the P. undulata plant and to evaluate their antioxidant and antimicrobial activities, including the influence of alkali treatment on the bio-physicochemical properties. The average yield of raw fibers obtained was 28.1 %. The raw fibers of P. undulata were rich in cellulose (36.2 %), followed by hemicellulose (30.3 %), lignin (16.2 %), moisture (11.1 %), and pectin (3.9 %). However, the alkali treatment removed 75.7 % of hemicellulose and 50.6 % of lignin from the raw fiber sample and also increased its crystallinity and hydrophobicity. Similarly, the degradation temperature of P. undulata fibers also increased from 324.4 °C to 332.6 °C after alkali treatment. The raw fiber showed promising radical scavenging and reducing power properties, and demonstrated antifungal activity against Candida albicans. In contrast, alkali-treated fibers showed a significant decrease in radical scavenging activity (almost 7–8 fold) and reducing power potential (6-fold) and exhibited no antifungal activity, potentially due to the loss of bioactive components such as lignin and essential oils. Overall, the findings of this study highlight the potential applications of raw P. undulata fibers in the healthcare and cosmetics products.This work was supported by Agricultural Research Station (ARS), Qatar University. The authors are thankful to Dr. Noora Al-Qahtani, Head of the Central Laboratories Unit (CLU), and Mr. Essam Shabaan Mohamed Attia (CLU) for their assistance with SEM analysis. Special thanks to Mr. Kafil Hoda Ansaria (ARS) for his support with chemical analysis. The authors also appreciate the help of Mr. Abdul Jaleel Naushad Odam Manniyil and Mr. Abdullah Alashraf Abul Baker from the Center for Advanced Materials for their assistance with XRD, FTIR, and TGA
NASICON based Na4MnV PO4 3/MWCNTs Cathode Materials for Naion Batteries with Improved Electrochemical Performance
No full textAdsorption study of Pb(II) in aqueous medium using polyaniline nanocomposites
No full textThis research work presents a simple and effective way for preparation of polyaniline (PANI) nanofiber composites mixed with polyvinyl alcohol or polystyrene (PS) and their application for lead (Pb) removal from an aqueous medium. Interestingly, PANI/PS porous nanofibers show excellent performance as a one-step Pb removal technique from aqueous solutions. The efficiency of Pb removal is found to be more than 95%, which is pretty higher than the previously reported values of other nanocomposites, as Pb removal adsorbents. Furthermore, when pure PANI nanofibers cannot remove Pb in an efficient way, this is a straightforward method for separation from the solution. This is attributable to the high surface area of PANI-PS composites. This study also provides a simple and effective way for the development of new environmental cleaning materials. The PANI/PS composite nanofiber could be a good candidate for efficient Pb removal from wastewater and for deep purification of polluted water. The composite materials have been investigated in terms of morphology, chemical structure, thermal behavior, and defect evolution using Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry, Thermal Gravimetric Analysis, and Positron Annihilation Spectroscopy, respectively. To measure the adsorption capacity and intensity of adsorption, the adsorption data were fitted in Langmuir, and Freundlich models. J. VINYL ADDIT. TECHNOL., 23:E99-E106, 2017. 1 2016 Society of Plastics Engineers. 1 2016 Society of Plastics EngineersScopu
Structural and mechanical properties of Al-SiC-ZrO2 nanocomposites fabricated by microwave sintering technique
No full text10.3390/cryst10100904Crystals10101-1
Synthesis and Performance Evaluation of Pulse Electrodeposited Ni-AlN Nanocomposite Coatings
No full textThis research work presents the microscopic analysis of pulse electrodeposited Ni-AlN nanocomposite coatings using SEM and AFM techniques and their performance evaluation (mechanical and electrochemical) by employing nanoindentation and electrochemical methods. The Ni-AlN nanocomposite coatings were developed by pulse electrodeposition. The nickel matrix was reinforced with various amounts of AlN nanoparticles (3, 6, and 9 g/L) to develop Ni-AlN nanocomposite coatings. The effect of reinforcement concentration on structure, surface morphology, and mechanical and anticorrosion properties was studied. SEM and AFM analyses indicate that Ni-AlN nanocomposite coatings have dense, homogenous, and well-defined pyramid structure containing uniformly distributed AlN particles. A decent improvement in the corrosion protection performance is also observed by the addition of AlN particles to the nickel matrix. Corrosion current was reduced from 2.15 to 1.29 μA cm−2 by increasing the AlN particles concentration from 3 to 9 g/L. It has been observed that the properties of Ni-AlN nanocomposite coating are sensitive to the concentration of AlN nanoparticles used as reinforcement.</jats:p
Highly porous PtPd nanoclusters synthesized via selective chemical etching as efficient catalyst for ethanol electro-oxidation
No full textDirect ethanol fuel cells (DEFCs) have received great interest owing to their high power density and environmental friendness. Nevertheless, the designing of active, durable, and efficient anode for DEFCs is a profound challenge. In this context, we reported the synthesis of PtPd porous nanoclusters (PtPd PNCs) as electrocatalyst for ethanol oxidation reaction (EOR). This was implemented through two-step synthesis. Firstly, ternary AgPtPd nanodendrites (NDs) were synthesized via ultrasound-assisted co-reduction of the metal precursors using ascorbic acid (AA) as a mild reductant and Pluronic F127 as structure-directing agent. Thereafter, PtPd PNCs were created by selective chemical etching of AgPtPd nanocrystals in 1 M HNO3. The textural properties, morphology, and elemental composition of the studied electrocatalysts were investigated, and their catalytic activities towards ethanol electrooxidation were examined. PtPd PNCs revealed a high surface area of 83.0 m2 g−1 and high porosity compared to its counterparts. Additionally, it depicted enhanced catalytic performance towards ethanol electrooxidation in 1 M KOH with mass activity of 1.8 A mg−1 compared to PtPd NDs (0.97 A mg−1), Pt NDs (0.51 A mg−1), and Pt/C (0.33 A mg−1). The enhanced catalytic performance of PtPd PNCs was ascribed to high surface area, high porosity, and increased active sites.Scopu
Synthesis and performance evaluation of nanostructured NaFe(x)Cr(1−X)(SO(4))(2) cathode materials in sodium ion batteries (SIBs)
No full textThis research work focuses on the synthesis and performance evaluation of NaFe(x)Cr(1−X)(SO(4))(2) (X = 0, 0.8 and 1.0) cathode materials in sodium ion batteries (SIBs). The novel materials having a primary particle size of around 100–200 nm were synthesized through a sol–gel process by reacting stoichiometric amounts of the precursor materials. The structural analysis confirms the formation of crystalline, phase pure materials that adopt a monoclinic crystal structure. Thermal analysis indicates the superior thermal stability of NaFe0(.8)Cr(0.2)(SO(4))(2) when compared to NaFe(SO(4))(2) and NaCr(SO(4))(2). Galvanostatic charge/discharge analysis indicates that the intercalation/de-intercalation of a sodium ion (Na(+)) into/from NaFe(SO(4))(2) ensues at about 3.2 V due to the Fe(2+)/Fe(3+) active redox couple. Moreover, ex situ XRD analysis confirms that the insertion/de-insertion of sodium into/from the host structure during charging/discharging is accompanied by a reversible single-phase reaction rather than a biphasic reaction. A similar sodium intercalation/de-intercalation mechanism has been noticed in NaFe(0.8)Cr(0.2)(SO(4))(2)which has not been reported earlier. The galvanostatic measurements and X-ray photoelectron spectroscopy (XPS) analysis confirm that the Cr(2+)/Cr(3+) redox couple is inactive in NaFe(x)Cr(1−X)(SO(4))(2) (X = 0, 0.8) and thus does not contribute to capacity augmentation. However, suitable carbon coating may lead to activation of the Cr(2+)/Cr(3+) redox couple in these inactive materials
