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Hexavalent chromium (VI) is a toxic form of chromium metal generally used in many industrial applications for its anticorrosive properties. Cr (VI) has been deemed to be a class-A human carcinogen. Among all the techniques available, adsorption is one of the most suitable techniques. The efficiency of the process depends on the adsorption medium. Although there are several adsorbents available, there is still huge scope to develop a number of adsorption media for the benefit of the common people. In this study, nanomaterial synthesised from Jawar stem (Agro-Waste) has been used as an adsorbent for removal of Cr (VI) from aqueous solution. The Jawar stem nanofibers have been synthesised using chemical vapour deposition technique (CVD). The characterisation of adsorbent was carried out using various analytical techniques like XRD, BET, SEM, TGA and FTIR. The adsorption capacity of Jawar stem nanofibers was found to be 76.10 m2 gm−1. The removal of hexavalent chromium was studied as a function of contact time, dosage of adsorbent and initial concentration of Chromium (VI). The applicability of Langmuir and Freundlich isotherms was tested. Freundlich isotherm was found to be most suitable for all adsorbent dosages. [ABSTRACT FROM AUTHOR]

Carbon nanofibers, recently recognized pollutants, have been heavily used among the nanomaterials in many industries. Due to the poor suspension-stability, carbon nanofibers tend to sediment at the bottom of waterbodies and hence can be consumed by the bottom-dwellers. The current investigation evaluates the impact of carbon nanofibers at concentrations between 0.1 and 10 mg L−1 on the common bottom dweller spiny loach Lepidocephalichthys thermalis inhabiting Indian rivers. Carbon nanofiber exposure elevated the activities of the hepatic antioxidant enzymes superoxide dismutase, catalase, peroxidase and glutathione S-transferase, as oxidative stress markers. The fish behaviour patterns were examined by testing the effect of carbon nanofibers on predator recognition ability using kairomones, conspecific alarm cues, and dietary cues. The carbon nanofiber-exposed fish showed a loss of predator-recognition abilities. The results collectively demonstrated the carbon nanofiber driven hepatic oxidative damage and impaired predator-recognition ability in L. thermalis. The investigation, first of its kind, highlights the toxic potential of the carbon nanofibers on benthic fishes. [ABSTRACT FROM AUTHOR]

The electrospinning technique was used to prepare nanofibers samples consisting of three groups, each group has a different polystyrene concentration (12, 14, 16 wt.%). Multiwalled carbon nanotubes were added to each group with four ratios to yield four samples comprising (polystyrene/MWCNT) constituents. The UV-Visible test was carried out to know how uniformly nanofibers and Mutli-walled carbon nanotubes were distributed in the polymeric nanofibers and their effect on the final nanofiber's properties through the absorption peaks. The morphological test used "Field Emission Scanning Electron Microscope". The results showed that; MWCNTS has a dominant effect on prepared nanofibers in the (12 wt.% Polystyrene) group, and both (PS, MWCNT) have a shared effect, highest steady absorption curves, and uniformly scattered radiation at (14 wt.% PS) group, and random results at (16 wt.% PS) group. From FESEM results we notice that increasing polymer concentration causes an increase in the nanofiber's diameter and beads formation chance increases at (12,16 wt.% PS) groups. In the group of (14 wt.% Polystyrene), it produces nanofibers with free beads and uniform distribution, the addition of MWCNT lowers the diameter of nanofibers much more and enhances the orientation, and improves their UV absorption, strength, and mechanical properties. [ABSTRACT FROM AUTHOR]

The influence of carbon nanofibers (CNFs) on carbon fiber (CF) reinforced polymer (CFRP) is investigated in this study. A program is developed to generate the finite element model (FEM) for the nanocomposites. The randomness of both CNFs and CF in CFRP is considered. The effects of volume fraction of CNFs and CFs, as well as interfacial strength are analyzed numerically. The improvement in strength and toughness of composites under different loading conditions is investigated. It shows that CNFs lead the redistribution of stress in the matrix, which releases stress concentration between CFs and polymer and increases the initial damage threshold. [ABSTRACT FROM AUTHOR]

An efficient method to increase specific strength of carbon fiber reinforced plastics (CFRP) by using cellulose nanofibers (CNFs) was developed. Eliminating a complex hydrophobic treatment of CNF by using aqueous electrodeposition solution (EDS) containing a polymer with epoxy group, the CFRP with CNF/resin layer was fabricated. The effects of the CNF/resin layer on the bending properties of CFRP were clarified by varying the weight fractions of CNF. The specific flexural rigidity and strength of the CFRP with CNF/resin layer were increased to approximately 3.5 times and 1.8 times those of the CFRP without CNF/resin layer, respectively. [ABSTRACT FROM AUTHOR]

Carbon nanofibers are promising green materials for sustainable technology within a wide range of applications including environment, energy, health and high-technology. Accordingly, drug adsorption is an important subject in connection with its environmental and pharmaceutical applications. This study aims to investigate the adsorption performance of carbon nanofibers in batch and fixed bed column processes. Carbon nanofibers were used as adsorbent to remove triflupromazine hdyrochloride from aqueous solutions. Adsorption kinetics were studied using Lagergren first order and Pseudo second order models. Intraparticle diffusion graph was plotted using kinetic data and showed that intraparticle diffusion is the single step controlling the adsorption rate. Experimental equilibrium data was modeled by using Langmuir and Freundlich equations and has a better fit to the Langmuir model. Triflupromazine adsorption on carbon nanofibers was found to be H-type according to Giles classification. The effect of temperature and the effect of pH on adsorption were studied to determine optimum adsorption conditions. Adsorption capacity of carbon nanofibers was decreased with increasing temperature due to the exothermic and physical nature of the process. Thermodynamic parameters confirmed the exothermic nature of the adsorption. Results showed the effective adsorption of drug molecules by carbon nanofibers. Maximum adsorption capacity was calculated as 165.41 mg/g at pH 9 using Langmuir equation. Modeling of the fixed bed column data was done by using Thomas model and Yoon–Nelson model. Results showed the important effect of the operating conditions on the removal performance of carbon nanofibers. Removal capacity was increased with an increase in the flow rate and the increase in the fixed bed length. [ABSTRACT FROM AUTHOR]

Polymeric nanocomposites of polystyrene nanofibers and multiwall carbon nanotubes and natural pigment were synthesized using electrospinning technique the polystyrene concentration was 12 wt.% and multiwall carbon nanotube was added by (0, 100, 140, 200 ppm), and natural pigment added by two drops (0.063 g) to the prepared solutions and many tests were carried out to the prepared solutions and the final samples. The solution tests included viscosity test by using cone-plate viscometer and surface tension test using du-nouy ring method. The nano textiles tests included the Fourier transform infrared spectroscope (FTIR) test, Field emission scanning electron microscopy (FESEM) test, contact angle test, and ultraviolet test to extract the energy bandgap using (tauc plot) method. The tests results showed that the viscosity increased by increasing the multiwall carbon nanotube and natural pigment and surface tension slightly increased at a high ratio of 200 ppm of multiwall carbon nanotube and natural pigment and physical type of reaction between the components were confirmed through FTIR, and the addition of multiwall carbon nanotube and natural pigment makes the fibers smoother and fewer beads formation and increase the multiwall carbon nanotube addition made the samples more hydrophobic and the charts of tauc plot show that increasing the MWCNT with natural pigment addition will increase the electrical sensitivity of the prepared samples in which the energy band gap dropped from 1.18 ev to 0.2 ev for the sample of Polystyrene/200 ppm MWCNT/natural pigment this is regarded as an indication of using it as a typical electrical sensor. [ABSTRACT FROM AUTHOR]

Carbon nanofibers (CNFs) with excellent conductivity and stability have become a promising material to design the strain sensing network. To date, however, the effect of the stacked structure of CNF membrane on the sensing performance has rarely been studied. In this work, we reported a high-performance sensor based on the cross-stacked aligned CNF membrane. The effects of cross-stacked structures on the sensing characteristics were systematically investigated. The flexible strain sensor could capture low detection limit (<0.1%) with a gauge factor (GF) of 4.24 and wide strain range up to 130%. The uniform GF value reached 2050 when the strain was in the range of 100–130%. In addition, the high linearity under 40% strain (>0.998), excellent durability and quick response time (<200 ms) were demonstrated. The excellent comprehensive performances were simultaneously obtained. The sensor could be used in extensive applications, such as monitoring body movements and distinguishing the track of writing. [ABSTRACT FROM AUTHOR]

In this study, conductive and transparent polycaprolactone (PCL)/carbon black (CB) nanofibers are produced by electrospinning. In order to investigate the effect of solvent system on the optoelectrical properties of PCL/CB nanofibers, the fibers are produced from two different solvent systems; namely, chloroform (CHL) and dimetyl formamid (DMF). For optoelectrical characterization, nanofibers are produced with different deposition times in the range of 1–10 minutes. Surface, optical, electrical and optoelectrical properties of the PCL/CB nanofibers are evaluated. Nanofibers produced from CHL solvent system results in non-uniform nanofibers with higher diameters. They also give a larger diameter distribution. On the other hand, nanofibers with uniform and smaller diameters are obtained from DMF system. UV-spectrophotometer analysis show that nanofiber mats produced from both solvent systems have similar optical transparencies. Lower sheet resistance values are obtained with the nanofiber mats produced from DMF system according to electrical characterizations. Higher Figure of Merit values are calculated for the nanofiber mats produced in DMF solvent system. Considering all the results, it can be concluded that PCL/CB nanofibers produced from DMF solvent system are better candidates compared to the nanofibers produced from CHL solvent system for optoelectrical applications. [ABSTRACT FROM AUTHOR]

CNFs-Bi2WO6 nanocomposite was synthesized by hydrothermal method. The physico-chemical characterization of samples was done by XRD, SEM-EDX, UV-DRS, and PL spectra. CNFs-Bi2WO6 nanocomposite has shown better photodegradation efficiency than pristine Bi2WO6 for Rhodamine B dye under visible light irradiation. The addition of Bi2WO6 to pure carbon nanofibers (CNFs) facilitated absorption of light as well as assisted in separation of electron-hole pairs which ultimately lead to superior photodegradation efficiency. The CNFs-Bi2WO6 nanocomposite displayed excellent photocatalytic efficiency under visible light for dye degradation, owing to the synergistic effect of CNFs and Bi2WO6 with excellent charge separation characteristics and suitable band gap energy. The CNFs-Bi2WO6 nanocomposite was also screened for antimicrobial potential against two bacterial strains and one pathogenic fungal strain Candida albicans. The fabricated CNFs demonstrated antimicrobial activity, which was fortified due to inclusion of Bi2WO6 nanoflakes. [ABSTRACT FROM AUTHOR]

Polystyrene is an important and commonly used synthetic thermoplastic polymer. This state-of-the-art review is an endeavor to describe the unique capabilities of polystyrene to form the high performance nanocomposite nanofibers. Different types of nanofillers have been introduced in polystyrene nanocomposite nanofibers such as carbon nanotube, graphene, nanoclay, and metal nanoparticles. Accordingly, the article introduces the categories of the polystyrene/carbon nanotube, polystyrene/graphene, polystyrene/nanoclay, and polystyrene/metal nanoparticle nanocomposites. The comprehensive deliberations on design, morphology, physical properties, and developments related to polystyrene nanocomposite nanofibers are presented. The nanocomposite characteristics have been considerably enhanced with the addition of the nanoparticles. High performance polystyrene based nanocomposite nanofibers was found to be related to the interactions between the matrix and the nanofillers. The polystyrene nanocomposite nanofibers have found applications for electromagnetic interference shielding, sensors, membranes, and drug delivery. [ABSTRACT FROM AUTHOR]

In recent times, carbon nanofibers (CNF) have been used extensively for the remediation of environment owing to their hollow layered organization, high specific surface area, and strong electrostatic interactions which formulate it as an appropriate adsorbent material. Metallic nanoparticles were blended onto its surface in order to engineer a novel metal-CNF nanocomposite. The study aimed the ultrasonic assisted adsorption of rhodamine B dye (RhB) and pesticide dichlorophenoxyacetic acid (2,4-D) out of aqueous matrix by using silver (Ag) and copper (Cu) based bimetallic composite (Ag-Cu/CNF) material. The synthesized nanocomposites were characterized for its crystalline analysis, textural characteristics, surface chemical bonding, and specific surface area. Ag-Cu/CNF illustrated superior adsorptive efficiency when compared with Ag/CNF and Cu/CNF. Adsorption equilibrium was studied by Freundlich and Langmuir isotherms. Evaluation of the data predicted that Langmuir model described the maximum fit toward equilibrium data with utmost adsorption efficiency of 201 mg/g and 112 mg/g for RhB and 2,4-D, respectively. Also, the comparison between adsorption aided by ultrasound, magnetic stirrer, and vortex shaker assisted methods revealed that sono-sorption is a proficient option for commencement of adsorption phenomenon due to convenient and facile diffusion. [ABSTRACT FROM AUTHOR]