Bindu Mangla; Vitashi Kaul; Nitika Thakur; Sudheesh K. Shukla
Abstract
Nanoparticles (NPs) are strong colloidal particles with diameters ranging from 1nm–100 nm. They comprise of macromolecular materials and can be utilized therapeutically as adjuvant in immunizations or as medication transporters. In this paper two fundamental sorts of nanoparticles are discussed ...
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Nanoparticles (NPs) are strong colloidal particles with diameters ranging from 1nm–100 nm. They comprise of macromolecular materials and can be utilized therapeutically as adjuvant in immunizations or as medication transporters. In this paper two fundamental sorts of nanoparticles are discussed i.e., metallic nanoparticle and polymeric nanoparticle. Metallic nanoparticle is nano-sized metals with measurements (length, width, thickness) inside the size range of 1nm - 100nm. The properties, advantages, disadvantages and characteristics of metal nanomaterials are discussed in brief in this review. Polymers are the most common materials for constructing nanoparticle-based drug carriers. Polymers used to form nanoparticles can be both synthetic and natural polymers. This review summarizes the synthesis and fabrication of nanomaterials. It describes about synthesis of metallic and polymeric nanomaterials as well as synthesis of quantum dots. It gives insights of fabrication of nanomaterials. Applications of nanomaterials are also included in this review mainly focusing on biosensor, gas sensor, wastewater treatment and environmental applications. The tunable surface and optical properties of nanomaterials make the perfect contender for biosensing including the analysis of ailments, cellular imaging of cancerous cell and so on. Gas sensors have been utilized in numerous applications like monitoring the oxygen content in fuel mixture, observing food decay, health monitoring etc. Nanomaterials offer the potential for the productive expulsion of pollutants and biological contaminants thus extremely valuable in environment and wastewater treatment. Nanomaterials are highly recommended in future for these properties, mainly for their use in healthcare sector.
Ghimire Prateek; Yulin Wang; Henggan Li; Yuanfu Ban; Hao Luo; Danping Lin; Jinglong Yang; Shuyan Lin; Zhengyang Pan; Qingwei Su
Abstract
The purpose of this study is to analyse the effective method of dispersion of MWCNTs for the application in cement-based composites. Efficient dispersion of Carbon Nanotubes (CNTs) is one of the most challenging and crucial aspects for the application in cement-based composite. In this study, two different ...
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The purpose of this study is to analyse the effective method of dispersion of MWCNTs for the application in cement-based composites. Efficient dispersion of Carbon Nanotubes (CNTs) is one of the most challenging and crucial aspects for the application in cement-based composite. In this study, two different CNTs, pristine and functionalized (p-MWCNTs and f-MWCNTs) were dispersed in de-ionized water using different surfactants, Polyvinylpyrrolidone (PVP k-30 and PVP k-90) & Sodium Dodecyl Sulfate (SDS) and conducted a comparative investigation of the effects. Dispersion using an ultrasonic, treatment with surfactant and integrated method of both were analysed. The influence of CNTs dispersion on the electrical conductivity of the aqueous solution and to cement composites has been studied. Among the surfactant used PVPk-30 provide the best-dispersing effect while PVPk-30+SDS shows an extraordinary enhancement of conductivity of an aqueous solution. Analysis of electrical conductivity of Various % CNTs’ loaded specimen (0,0.001,0.003,0.025 wt.%) with different curing period (3,7,14,21,28 days) showed that the electrical resistivity decreases with CNTs’ loading. Dispersion effect of surfactant on p-MWCNTs and f-MWCNTs has been characterized by Ultraviolet-visible Spectroscopy (UV-Vis) and electrical resistivity measurement is carried for investigation and comparison on enhancement of electrical conductivity.
Naoki Komatsu
Abstract
Nanocarbons are carbon allotropes with nanometer scale and comprised mainly of 0 – 3 dimensional (0D – 3D) forms; fullerenes (0D), carbon nanotubes (1D), graphene (2D), and nanodiamond (3D). In our group, various surfactants with appropriate size and shape have been developed for the nanocarbons. ...
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Nanocarbons are carbon allotropes with nanometer scale and comprised mainly of 0 – 3 dimensional (0D – 3D) forms; fullerenes (0D), carbon nanotubes (1D), graphene (2D), and nanodiamond (3D). In our group, various surfactants with appropriate size and shape have been developed for the nanocarbons. In order to separate the fullerenes, bowl-shaped surfactants were designed and synthesized to accommodate the 0D spherical nanocarbon, giving C70 selectively as precipitates. On the other hand, gable- and bracket-shaped surfactants formed stable complexes with 1D tubular nanocarbons, dispersing carbon nanotubes with specific diameter, handedness and/or metallicity selectively in solution phase. The flat surfactants worked as an exfoliant and dispersant for graphite in both wet and dry processes; sonication and ball milling, respectively. They gave graphene composites with high concentrations and yield in aqueous solution and low-boiling point organic solvents. The hyper-branched polymer named polyglycerol coated the nanodiamond surface covalently through ring-opening polymerization of glycidol. The chemisorped polymer gave large hydrophilicity to the nanodiamond, dispersing it stably in aqueous solutions such as water and phosphate buffer as well as polar organic solvents such as methanol. Copyright © VBRI Press.
David G. Rickerby
Abstract
An overview is presented of potential improvements in performance that can be achieved by using three different types of nanomaterials in water treatment applications: (i) zerovalent iron for reducing concentrations of chlorinated hydrocarbons and heavy metals in groundwater; (ii) titanium dioxide for ...
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An overview is presented of potential improvements in performance that can be achieved by using three different types of nanomaterials in water treatment applications: (i) zerovalent iron for reducing concentrations of chlorinated hydrocarbons and heavy metals in groundwater; (ii) titanium dioxide for photocatalytic drinking water purification, enabling reduced consumption of chemicals for disinfection; (iii) carbon nanotube membrane filters that transport water molecules at elevated fluxes, while rejecting other molecules and ions. The distinctive characteristics of the nanomaterials, such as high specific surface area, enhanced reactivity and adsorption capacity, have already led to significant increases in efficiency. Future developments are expected based on surface modification of zerovalent iron to improve its reactivity and transport characteristics, advanced chemical synthesis methods to increase the area of photoreactive facets and doping to inhibit electron-hole recombination or to allow visible light photocatalysis in titanium dioxide, and functionalization of carbon nanotubes to increase ion rejection rates. Implementation of these innovative methods for removal of contaminants from water will be contingent on reduction of the present high cost of the nanomaterials and assessment of the possible risks associated with their, as yet only partly understood, toxic and ecotoxic properties.
Hadar Ben-Yoav; Marshall A. Schroeder; Malachi Noked
Abstract
Nanostructured electrodes enable a new generation of electrochemical sensors by increasing their surface area that lead to stronger signals generated by electrochemically-active molecules, such as diagnostic redox-active biomarkers. Yet, the selectivity of these translational sensors is far from being ...
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Nanostructured electrodes enable a new generation of electrochemical sensors by increasing their surface area that lead to stronger signals generated by electrochemically-active molecules, such as diagnostic redox-active biomarkers. Yet, the selectivity of these translational sensors is far from being sufficient for discriminating between individual molecules in multicomponent samples, such as biofluids. Here, we propose an approach to improve the selectivity of nanostructured electrodes using a simple modification with a functional bio-polymer. Specifically, we demonstrate the targeted modification with a bio-polymer chitosan of carbon nanotubes organized in an array on a Au electrode. We describe the fabrication process and we show the characterization of the structural morphology and the electrochemical activity of the fabricated chitosan-modified carbon nanotube arrayed electrode. Electrochemical characterization yielded an increased effective surface area for the optimized carbon nanotube arrayed electrode (0.46 ± 0.03 cm 2 ) that was similar to the area of the unmodified Au electrode (0.48 ± 0.02 cm 2 ). Furthermore, despite decreased electrochemical current characteristics, we demonstrate the feasibility to modify individual carbon nanotubes with chitosan. The modification of the carbon nanostructures with chitosan will enable further functionalization with specific receptors, such as enzymes and antibodies that will provide the required selectivity towards biomarkers in multicomponent biofluids.
Richa Agrawal; Chunhui Chen; Samantha Dages; Chunlei Wang
Abstract
Reduced graphene oxide-carbon nanotube (rGO-CNT) and anatase TiO2-Li4Ti5O12 (ATO-LTO) composite electrodes were synthesized via electrostatic spray deposition (ESD) and analyzed as cathode and anode vs. lithium, respectively. The rGO-CNT and ATO-LTO electrodes were able to deliver discharge ...
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Reduced graphene oxide-carbon nanotube (rGO-CNT) and anatase TiO2-Li4Ti5O12 (ATO-LTO) composite electrodes were synthesized via electrostatic spray deposition (ESD) and analyzed as cathode and anode vs. lithium, respectively. The rGO-CNT and ATO-LTO electrodes were able to deliver discharge capacities of ca. 63 mAhg -1 and 95 mAhg -1 , respectively for a current rate of 0.1 Ag -1 with superior rate capability and cycle stability. Post electrode analyses, lithium-ion hybrid electrochemical capacitors (Li-HEC) were constructed comprising a prelithiated ATO-LTO anode and an activated rGO-CNT cathode in a carbonate based 1M LiPF6 salt electrolyte. The Li-HEC cells were stable for a cell potential of 0.05-3V and were able to deliver a maximum gravimetric energy density of 33.35 Whkg -1 and a maximum power density of 1207.4 Wkg -1 , where the cell parameters were normalized with the total mass of the anode and cathode active materials. Furthermore the Li-HEC cells were able to retain ~77% of the initial capacity after 100 cycles. The superior Li-HEC performance is attributed to the utilization of a prelithiated lithium-intercalating anode and a double layer cathode in an asymmetric configuration. The feasibility of using a low-cost, facile process like ESD was therefore shown to produce high performance Li-HECs.
Reetu Kumari; Anshika Singh; Rajesh Kumar; Lucky Krishnia; Vinay Kumar; Nitin K. Puri; Pawan K. Tyagi
Abstract
In this report, we have illustrated the synthesis of the Ni-filled multiwalled carbon nanotubes (MWCNTs) on both metallic and non-metallic substrates, by using thermal CVD technique. Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) have been used to characterize the surface morphology and ...
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In this report, we have illustrated the synthesis of the Ni-filled multiwalled carbon nanotubes (MWCNTs) on both metallic and non-metallic substrates, by using thermal CVD technique. Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) have been used to characterize the surface morphology and crystalline nature of the MWCNTs encapsulated with Ni nanorod. These filled MWCNTs have exhibited strong magnetic response due to encapsulation of pure phase of Ni. Magnetic Force Microscopy (MFM) study of such filled tubes reveals the pole formation in the Ni nanorod and confirms magnetization direction perpendicular to tube axis. Filling occurs in a fragmented manner confirmed by MFM and each fragment found to have north and south poles along the axis perpendicular to the tube i.e. radial direction of tube.
Lucky Krishnia; Reetu Kumari; Vinay Kumar; Anshika Singh; Preeti Garg; Brajesh S. Yadav; Pawan K. Tyagi
Abstract
Filled or un-filled multiwalled carbon nanotubes (CNTs) used in this study have been synthesized by the floating catalyst method and fixed catalyst method, respectively. The thermal stability of filled/un-filled carbon nanotubes has been investigated by using Thermogravimetric analysis (TGA) and Derivative ...
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Filled or un-filled multiwalled carbon nanotubes (CNTs) used in this study have been synthesized by the floating catalyst method and fixed catalyst method, respectively. The thermal stability of filled/un-filled carbon nanotubes has been investigated by using Thermogravimetric analysis (TGA) and Derivative thermogravimetric (DTG) analysis. In this report, we have developed a methodology to distinguish between filled and un-filled carbon nanotubes. Filled-CNTs are found to be more resistant to oxidation than the un-filled carbon nanotubes. The calculated activation energy of as-grown filled CNTs, by using differential method, determined to be 3.29 ± 0.04 eV, which is higher than that of highly ordered pyrolytic graphite (HOPG). Carboneous impurities; amorphous carbon, catalyst and CNT of different diameter, which are structurally different, are identified by their reactivity and the resistance to oxidation.
Y. P. Tsai; J. C. Yang; P. C. Chuang; C. C. Chou; J. W. Lin
Abstract
This study used multi-walled carbon nanotubes (MWCNTs), TiO2 and their mixture (TiO2/CNT) to remove humic acids (HA) in water. The thermodynamic parameters with respect to the adsorption of MWCNTs, including free energy of adsorption (ΔG 0 ), enthalpy (ΔH 0 ), and entropy (ΔS 0 ) changes, ...
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This study used multi-walled carbon nanotubes (MWCNTs), TiO2 and their mixture (TiO2/CNT) to remove humic acids (HA) in water. The thermodynamic parameters with respect to the adsorption of MWCNTs, including free energy of adsorption (ΔG 0 ), enthalpy (ΔH 0 ), and entropy (ΔS 0 ) changes, are further calculated in the study. The ΔH 0 data showed the adsorption of HA onto MWCNTs is an endothermic physisorption. The ΔG 0 data indicates the adsorption of HA onto MWCNTs was spontaneous and thermodynamically favorable. Photocatalytic experiments showed 60 mgl -1 of HAs were completely degraded and mineralized as CO2 after 5 h UV irradiation by 0.8 gl -1 of TiO2, indicating the efficiency of TiO2 for the removal of HA is better than CNTs. The experiments of TiO2/CNT indicated the photocatalytic efficiency of TiO2 in the presence of CNTs was not improved, even worse than TiO2 alone. However, the photocatalytic efficiency of TiO2/CNT mixture became better than TiO2 alone due to the supply of oxygen by aeration, ascribing to the reason that the provided oxygen might be adsorbed on the surface of CNTs and accept e- as well as form •O2 - , which also leads to the formation of •OH - in the system.
Siddik Sener; Yasin Caglar; Cagatay M. Belgin; Kadir C. Sener
Abstract
An experimental study consisting 70 tests have been conducted to study the influence of addition of reinforcing fibers on concrete specimens. The experimental program included concrete specimens that were tested with modified Arcan test machine with different notch lengths. The reinforcing effect of ...
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An experimental study consisting 70 tests have been conducted to study the influence of addition of reinforcing fibers on concrete specimens. The experimental program included concrete specimens that were tested with modified Arcan test machine with different notch lengths. The reinforcing effect of highly dispersed multi-walled carbon nanotubes (MWCNTs) in concrete has been investigated. The results revealed that inclusion of CNTs in the design mix improve both the tensile fracture characteristics and compressive strength when not mixed with a surfactant compound. The improvement in the mechanical properties specimens with the addition of CNTs are observed more clearly with increasing curing age. The mixing process to achieve uniformly dispersed and properly mixed mortar however requires specialized equipment, such as ultrasonic mixers. The results also indicated some dependency on the size of the specimens, which is a well known phenomenon that is observed for brittle heterogenous materials such as concrete.
Ritu P. Mahore; Devendra K. Burghate; Subhash B. Kondawar
Abstract
Supercapacitors are recognized as one of the most promising energy storage devices for a wide range of civilian and military applications in electric vehicles, uninterruptible power supplies. Conducting polymer nanocomposites are new functional materials suitable for supercapacitors due to synergistic ...
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Supercapacitors are recognized as one of the most promising energy storage devices for a wide range of civilian and military applications in electric vehicles, uninterruptible power supplies. Conducting polymer nanocomposites are new functional materials suitable for supercapacitors due to synergistic effect of individual components. In present work, polypyrrole/CNT nanocomposites have been prepared by an in-situ chemical polymerization method and studied for supercapacitor. CNTs were well functionalized using 3:1 ratio of H2SO4 and HNO3 before polymerizing the pyrrole. Analytical techniques such as SEM, UV-VIS and FTIR were used to characterize the synthesized materials. The SEM images reveal that the materials have rough and granular morphology. The composites showed good interaction based on the shift to longer wavelengths in the electronic transition, indicating the interaction between PPy and functionalized CNTs as observed in their UV-VIS and FTIR spectra. The electrochemical performance was evaluated by using cyclic voltammetry (CV) in 1M Na2SO4 electrolyte and specific capacitance was obtained at 0.5 V/s for pure polypyrrole and PPy/CNT nanocomposites. Nanocomposite showed the enhanced electrochemical performance as compared to that of pure polypyrrole. The specific capacitance obtained at the scan rate 0.5V/s was found to be 0.825 F/cm -2 for pure polypyrrole and 1.0619 F/cm -2 for PPy/CNT nanocomposite material respectively, indicates that PPy/CNT nanocomposite is suitable material as electrode for supercapacitor as compoared to pure polypyrrole.
S. Kumari; A. Kumar; P. R. Sengupta; P. K. Dutta; R. B. Mathur
Abstract
Multiwalled carbon nanotubes (MWCNT)- reinforced carbon/copper (C/Cu) composites were developed by powder metallurgy technique and mixed powders of C and Cu were consolidated into plates without using any extra binder followed by sintering at 1000 o C in inert atmosphere. Samples were characterized for ...
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Multiwalled carbon nanotubes (MWCNT)- reinforced carbon/copper (C/Cu) composites were developed by powder metallurgy technique and mixed powders of C and Cu were consolidated into plates without using any extra binder followed by sintering at 1000 o C in inert atmosphere. Samples were characterized for structural, mechanical, electrical and thermal properties w.r.t. different mass fraction of MWCNT in C-Cu matrix. In comparison to C/Cu composite, addition of minute amount (0.25 wt%) of CNT in C-Cu substantially improved the mechanical, electrical and thermal properties of composites. These composites were mechanically stable and strong and exhibited high bending strength of 162 MPa, indicating a homogeneous dispersion of MWCNTs in the C-Cu matrix. Maximum thermal conductivity of 37.60 W/mK perpendicular to the pressing direction was obtained for 0.50 wt% CNT reinforced C-Cu composite exhibiting an improvement of 45% over pure C-Cu composite processed under identical conditions. High thermal conducting and mechanically strong composites can be used as heat sink for long time.
Li Chen; Guangshui Yua;Jianming Zhanga; Xiujiang Pangb
Abstract
Multi-walled carbon nanotubes (MWNTs) were in-situ coated with anatase TiO2 via sol-gel process followed by annealing of the composites using infrared (IR) lamp. SEM results showed that MWNTs were coated with 15-45 nm thick TiO2 layer depending on the composite ratios. Based on the XRD results, MWNTs ...
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Multi-walled carbon nanotubes (MWNTs) were in-situ coated with anatase TiO2 via sol-gel process followed by annealing of the composites using infrared (IR) lamp. SEM results showed that MWNTs were coated with 15-45 nm thick TiO2 layer depending on the composite ratios. Based on the XRD results, MWNTs were found to show heterogeneous nucleation for anatase TiO2 and promote the formation of larger anatase TiO2 crystalline particles with higher crystalline degree. The UV-Vis- NIR characterization indicated the MWNTs also enhanced the sensitivity of TiO2 matrix for both UV and visible light, and the bond edge absorption position of the TiO2 composites shifted toward higher wavelengths with the decrease of MWNTs content. The method could be utilized to fabricate MWNTs /TiO2 composites conveniently.
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