A Comparative Investigation on the Structural, Optical and Electrical Properties of SiO2–Fe3O4 Core–Shell Nanostructures with Their Single Components

Bachan, Neena; Asha, A.M.; Jeyarani, W. Jothi; Kumar, D. Arun; Shyla, J. Merline

doi:10.1007/s40195-015-0328-3

Cited by 31 publications

(16 citation statements)

References 52 publications

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“…This phenomenon is known as surface plasmon resonance (SPR). Another band at 485.85 nm is due to the presence of DBSA moiety with Fe 3 O 4 and closely resembles already reported work [54]. The two characteristic bands of PANI can be observed in its spectrum at 333.91 and 633.42 nm.…”

Section: Resultssupporting

confidence: 89%

Comparative Study of the Adsorption of Acid Blue 40 on Polyaniline, Magnetic Oxide and Their Composites: Synthesis, Characterization and Application

2019

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Conducting polymers (CPs), especially polyaniline (PANI) based hybrid materials have emerged as very interesting materials for the adsorption of heavy metals and dyes from an aqueous environment due to their electrical transport properties, fascinating doping/de-doping chemistry and porous surface texture. Acid Blue 40 (AB40) is one of the common dyes present in the industrial effluents. We have performed a comparative study on the removal of AB40 from water through the application of PANI, magnetic oxide (Fe3O4) and their composites. Prior to this study, PANI and its composites with magnetic oxide were synthesized through our previously reported chemical oxidative synthesis route. The adsorption of AB40 on the synthesized materials was investigated with UV-Vis spectroscopy and resulting data were analyzed by fitting into Tempkin, Freundlich, Dubinin–Radushkevich (D–R) and Langmuir isotherm models. The Freundlich isotherm model fits more closely to the adsorptions data with R2 values of 0.933, 0.971 and 0.941 for Fe3O4, PANI and composites, respectively. The maximum adsorption capacity of Fe3O4, PANI and composites was, respectively, 130.5, 264.9 and 216.9 mg g−1. Comparatively good adsorption capability of PANI in the present case is attributed to electrostatic interactions and a greater number of H-bonding. Effect of pH of solution, temperature, initial concentration of AB40, contact time, ionic strength and dose of adsorbent were also investigated. Adsorption followed pseudo-second-order kinetics. The activation energy of adsorption of AB40 on Fe3O4, PANI and composites were 30.12, 22.09 and 26.13 kJmol−1 respectively. Enthalpy change, entropy change and Gibbs free energy changes are −6.077, −0.026 and −11.93 kJ mol−1 for adsorption of AB40 on Fe3O4. These values are −8.993, −0.032 and −19.87 kJ mol−1 for PANI and −10.62, −0.054 and −19.75 kJ mol−1 for adsorption of AB40 on PANI/Fe3O4 composites. The negative sign of entropy, enthalpy and Gibbs free energy changes indicate spontaneous and exothermic nature of adsorption.

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Section: Resultssupporting

confidence: 89%

Comparative Study of the Adsorption of Acid Blue 40 on Polyaniline, Magnetic Oxide and Their Composites: Synthesis, Characterization and Application

2019

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“…The surface plasmon resonance phenomenon occurs due to interactions between incident radiations and valence electrons of the metal atom in Fe 3 O 4 and causes the valence electron of the metal to oscillate with the frequency of the electromagnetic source [57]. The other band at 570.7 nm arises due to the presence of DBSA moieties in the synthesized magnetic oxide particles, as reported earlier [58].…”

Section: Resultsmentioning

confidence: 90%

Basic Blue Dye Adsorption from Water Using Polyaniline/Magnetite (Fe3O4) Composites: Kinetic and Thermodynamic Aspects

et al. 2019

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Owing to its exciting physicochemical properties and doping–dedoping chemistry, polyaniline (PANI) has emerged as a potential adsorbent for removal of dyes and heavy metals from aqueous solution. Herein, we report on the synthesis of PANI composites with magnetic oxide (Fe3O4) for efficient removal of Basic Blue 3 (BB3) dye from aqueous solution. PANI, Fe3O4, and their composites were characterized with several techniques and subsequently applied for adsorption of BB3. Effect of contact time, initial concentration of dye, pH, and ionic strength on adsorption behavior were systematically investigated. The data obtained were fitted into Langmuir, Frundlich, Dubbanin-Rudiskavich (D-R), and Tempkin adsorption isotherm models for evaluation of adsorption parameters. Langmuir isotherm fits closely to the adsorption data with R2 values of 0.9788, 0.9849, and 0.9985 for Fe3O4, PANI, and PANI/Fe3O4 composites, respectively. The maximum amount of dye adsorbed was 7.474, 47.977, and 78.13 mg/g for Fe3O4, PANI, and PANI/Fe3O4 composites, respectively. The enhanced adsorption capability of the composites is attributed to increase in surface area and pore volume of the hybrid materials. The adsorption followed pseudo second order kinetics with R2 values of 0.873, 0.979, and 0.999 for Fe3O4, PANI, and PANI/Fe3O4 composites, respectively. The activation energy, enthalpy, Gibbs free energy changes, and entropy changes were found to be 11.14, −32.84, −04.05, and −0.095 kJ/mol for Fe3O4, 11.97, −62.93, −07.78, and −0.18 kJ/mol for PANI and 09.94, −74.26, −10.63, and −0.210 kJ/mol for PANI/Fe3O4 respectively, which indicate the spontaneous and exothermic nature of the adsorption process.

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“…The observed red shift suggests a reduction in the band gap upon increasing the amount of surfactant. The reduction in the band gap is related to the increased silica particle size upon increasing the amount of surfactant, 42 which is also evident by close networking of hybrid silica wires observed in scanning electron microscopy (SEM) results.…”

Section: Introductionmentioning

confidence: 92%

“…The UV–visible spectrum of silica wires prepared without any surfactant shows no absorption peak in the visible region (Figure 6), which is due to its wide band gap as glasses have high optical transparency or low absorptivity in the visible range. 41,42…”

Section: Introductionmentioning

confidence: 99%

Transparent Hydrophobic Hybrid Silica Films by Green and Chemical Surfactants

et al. 2019

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Monodispersed and transparent hybrid silica wires were synthesized by the sol–gel method using the chemical surfactant trimethoxyoctylsilane (C 8 TMOS or C 11 H 26 O 3 Si) and, for the first time, by green surfactants ( Nelumbo nucifera /lotus leaf extract). The purpose was to introduce a less toxic, cost-effective, and one-step easy approach to get superhydrophobic silica films. Each of the surfactants was used at two different concentrations to investigate hydrophobicity of the films. Assembly of silica wires was obtained by dip-coating and vacuum filtration methods on glass and cellulose acetate filter paper as substrates, respectively. The water contact angle (CA) up to 154° was measured for hybrid silica films on filter paper, which revealed their superhydrophobicity as compared to hydrophobic behavior of those films coated on a glass substrate with CA up to 135°. Chemical, optical, and structural properties of prepared films were characterized by Fourier transform infrared spectroscopy, UV–vis spectroscopy, scanning electron microscopy, thermogravimetry, and differential scanning calorimetry. The hybrid silica wires prepared displayed good transparency, low surface energy, and superhydrophobicity. These silica assemblies can create outstanding and multifunctional structures with superhydrophobic coatings for waterproof electronic devices, military uniforms, self-cleaning surfaces, etc.

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A Comparative Investigation on the Structural, Optical and Electrical Properties of SiO2–Fe3O4 Core–Shell Nanostructures with Their Single Components

Cited by 31 publications

References 52 publications

Comparative Study of the Adsorption of Acid Blue 40 on Polyaniline, Magnetic Oxide and Their Composites: Synthesis, Characterization and Application

Comparative Study of the Adsorption of Acid Blue 40 on Polyaniline, Magnetic Oxide and Their Composites: Synthesis, Characterization and Application

Basic Blue Dye Adsorption from Water Using Polyaniline/Magnetite (Fe3O4) Composites: Kinetic and Thermodynamic Aspects

Transparent Hydrophobic Hybrid Silica Films by Green and Chemical Surfactants

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