Magnetic cobalt and nickel ferrites with graphene nanocomposites (GCF &amp; GNF) were tested for removal of Pb2+ and Cd2+ ions. A highest adsorption was achieved for Pb2+viz. 142.8 and 111.1 mg g−1 and for Cd2+ 105.26 and 74.62 mg g−1 for GCF and GNF.

A Felix

Mathematics

School of Advanced Sciences

Chennai Campus

Velmurugan V

Centre for Nanotechnology Research

Vellore Campus

Nirmala Grace A

Santhosh C

Kollu P

Jeong S.K

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

RSC Advances

With every moving day, the aspect that is going to be the most important for modern science and technology is the means to supply sufficient energy for all the scientific applications. As the resource of fossil fuel is draining out fast, an alternative is always required to satisfy the needs of the future world. Limited resources also force to innovate something that can utilise the resource more efficiently. This work is based on a simple synthesis route of biomass derived hard carbon and to exploring the possibility of using it as electrochemical supercapacitors. A cheap, eco-friendly and easily synthesized carbon material is utilized as electrode for electrochemical energy-storage. Four different hard carbons were synthesized from KOH activated banana stem (KHC), phosphoric acid treated banana stem derived carbons (PHC), corn-cob derived hard carbon (CHC) and potato starch derived hard carbons (SHC) and tested as supercapacitor electrodes. KOH-activated hard carbon has provided 479.23 F/g specific capacitance as calculated from its cycle voltammograms. A detailed analysis is done to correlate the results obtained with the material property. Overall, this work provides an in depth analysis of the science behind the components of an electrochemical energy-storage system as well as why the different characterization techniques are required to assess the quality and reliability of the material for electrochemical supercapacitor applications. © 2019, The Author(s).

Fulltext

Scientific Reports

Natural biomass derived hard carbon and activated carbons as electrochemical supercapacitor electrodes

In this study, cobalt ferrites (C) decorated onto 2D material (porous graphene (PG)) and 1D material (carbon nanofibers (CNF)), denoted as PG-C and CNF-C nanocomposites, respectively, were synthesized using solvothermal process. The prepared nanocomposites were studied as magnetic adsorbents for the removal of lead (cationic) and chromium(VI) (anionic) metal ions. The structural and chemical analysis of synthesized nanocomposites was conducted using different characterization techniques including Brunauer-Emmett-Teller (BET) analysis, field emission-scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), high resolution-transmission electron microscopy (HR-TEM), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Batch mode adsorption studies were conducted with the prepared nanocomposites to examine their maximum adsorption potential for lead and chromate ions. Performance parameters (time, pH, adsorbent dosage and initial ion concentrations) effecting the adsorption capacity of the nanocomposites were optimized. Different kinetic and isotherm models were examined to elucidate the adsorption process. Synthesized nanocomposites exhibited significant potential for the studied metal ions that can be further examined at pilot scale for the removal of metal ions from contaminated water. © 2017 The Author(s).

Removal of cationic and anionic heavy metals from water by 1D and 2D-carbon structures decorated with magnetic nanoparticles

In this study, magnetic nanocomposites viz. SiO2@CoFe2O4 nanoparticles decorated on graphene oxide were synthesized using solvothermal and sol-gel processes. The prepared nanocomposite materials were used as magnetic adsorbents for the removal of organic and inorganic pollutants (acid black 1 dye and Cr(VI) ions as model pollutants) from aqueous solution. The structure, morphology and other physico-chemical properties of nanocomposites were characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), high resolution-transmission electron microscopy (HR-TEM), vibrating sample magnetometer (VSM), X-ray photo spectroscopy (XPS), zeta potential and Fourier transform infrared (FT-IR) spectroscopy. Batch mode adsorption studies were conducted with the prepared nanocomposites to determine the maximum adsorption capacity of acid black 1 dye and Cr(VI) ions as a function of contact time, pH, adsorbent dosage and initial adsorbate concentrations. Different kinetic and isotherm models were tested to describe and elucidate the adsorption mechanisms. Based on the experimental results obtained, the synthesized materials proved to exhibit considerable potential for the removal of acid black 1 and Cr(VI) ions from aqueous solution. © 2017 Elsevier B.V.

Chemical Engineering Journal

Magnetic SiO 2 @CoFe 2 O 4 nanoparticles decorated on graphene oxide as efficient adsorbents for the removal of anionic pollutants from water

Water pollution by various toxic contaminants has become one of the most serious problems worldwide. Various technologies have been used to treat water and waste water including chemical precipitation, ion-exchange, adsorption, membrane filtration, coagulation–flocculation, flotation and electrochemical methods. From past few decades, nanotechnology has gained wide attention and various nanomaterials have been developed for the water remediation. In the present review article, various nanomaterials have been reviewed which have been used for water decontamination. The special emphasis in the review has been given on adsorption, photocatalytic and antibacterial activity of nanomaterials.

Role of nanomaterials in water treatment applications: A review

Achieving optimal morphologies specific for applications continues to be a challenge in the case of mesoporous ceramic oxide materials. It is well known that for several applications, nanograins need to remain un-agglomerated; this is because such particles offer larger specific surface. Here a novel template, economic route has been used for the synthesis of magnetic cobalt iron oxide with a hierarchical (and hence extended surface) morphology. These microspheres exhibit a high surface area of 786 m2 g-1 with large pore density. The particles are found to be excellent adsorbents and catalysts for oxidative-dissociation of Rhodamine B (RhB) and 4-Nitrophenol (4-NP) from water at room temperature. We also report the microwave absorbing capabilities of these materials, in the frequency range 1 MHz to 3 GHz. Interestingly these extended surface microspheres possess fine absorption of microwaves with two broad reflection loss peaks at -59 dB and -49.85 dB in the entire range. This is substantially different from the smooth surface cobalt ferrite that possesses only one absorption peak (-41.9 dB) in the low frequency region. Hence the reported material has plausible applications as magnetic adsorbents for pollution abatement, and also as electromagnetic shields. © 2019 IOP Publishing Ltd.

Materials Research Express

Template synthesis of CoFe2O4 extended surface microspheres for efficient water decontamination and absorption of electromagnetic waves: Twin behavior

Graphene manganese ferrite (MnFe 2 O 4 -G) composite was prepared by a solvothermal process. The as-prepared graphene manganese ferrite composite was tested for the adsorption of lead (Pb(II)) and cadmium (Cd(II)) ions by analytical methods under diverse experimental parameters. With respect to contact time measurements, the adsorption of Pb and Cd ions increased and reached equilibrium within 120 and 180 min at 37°C with a maximum adsorption at pH 5 and 7 respectively. The Langmuir model correlates to the experimental data showing an adsorption capacity of 100 for Pb(II) and 76.90 mg g -1 for Cd(II) ions. Thermodynamic studies revealed that the adsorption of Pb and Cd ions onto MnFe 2 O 4 -G was spontaneous, exothermic and feasible in the range of 27-47°C. Cytotoxicity behavior of graphene against bacterial cell membrane is well known. To better understand its antimicrobial mechanism, the antibacterial activity of graphene and MnFe 2 O 4 -G nanocomposite was compared. Under similar concentration and incubation conditions, nanocomposite MnFe 2 O 4 -G dispersion showed the highest antibacterial activity of 82%, as compared to graphene showing 37% cell loss. Results showed that the prepared composite possess good adsorption efficiency and thus could be considered as an excellent material for removal of toxic heavy metal ions as explained by adsorption isotherm. Hence MnFe 2 O 4 -G can be used as an adsorbent as well as an antimicrobial agent. © 2014 Elsevier B.V. All rights reserved.

Applied Surface Science

Solvothermal synthesis of MnFe 2 O 4 -graphene composite-Investigation of its adsorption and antimicrobial properties

Graphene–Fe3O4 (G–Fe3O4) composite was prepared from graphene oxide (GO) and FeCl3·6H2O by a one-step solvothermal route.

Adsorption, photodegradation and antibacterial study of graphene-Fe 3O4 nanocomposite for multipurpose water purification application

Magnetic Reduced Graphene Oxide-Nickel/NiFe2O4 (RGO-Ni/NF) nanocomposite has been synthesized by one pot solvothermal method. Respective phase formations and their purities in the composite are confirmed by High Resolution Transmission Electron Microscope and X Ray Diffraction, respectively. For the RGO-Ni/NF composite material finite-size effects lead to the anomalous magnetic behavior, which is corroborated in temperature and field dependent magnetization curves. Here, we are reporting the behavior of higher magnetization values for Zero Field Cooled condition to that of Field Cooled for the RGO-Ni/NF nanocomposite. Also, the observed negative and positive moments in Hysteresis loops at relatively smaller applied fields (100Oe and 200Oe) are explained on the basis of surface spin disorder. © 2014 AIP Publishing LLC.

Journal	Data powered by TypesetRSC Advances
Publisher	Data powered by TypesetRoyal Society of Chemistry (RSC)
ISSN	20462069
Open Access	0