Faculty Publications

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Author: search.filters.author.Kalikeri, S.

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    Visible light-induced photocatalytic degradation of Reactive Blue-19 over highly efficient polyaniline-TiO2 nanocomposite: a comparative study with solar and UV photocatalysis
    (Springer Verlag service@springer.de, 2018) Kalikeri, S.; Kamath, N.; Gadgil, D.J.; Shetty K, V.
    Polyaniline-TiO2 (PANI-TiO2) nanocomposite was prepared by in situ polymerisation method. X-ray diffractogram (XRD) showed the formation of PANI-TiO2 nanocomposite with the average crystallite size of 46 nm containing anatase TiO2. The PANI-TiO2 nanocomposite consisted of short-chained fibrous structure of PANI with spherical TiO2 nanoparticles dispersed at the tips and edge of the fibres. The average hydrodynamic diameter of the nanocomposite was 99.5 nm. The band gap energy was 2.1 eV which showed its ability to absorb light in the visible range. The nanocomposite exhibited better visible light-mediated photocatalytic activity than TiO2 (Degussa P25) in terms of degradation of Reactive Blue (RB-19) dye. The photocatalysis was favoured under initial acidic pH, and complete degradation of 50 mg/L dye could be achieved at optimum catalyst loading of 1 g/L. The kinetics of degradation followed the Langmuir-Hinshelhood model. PANI-TiO2 nanocomposite showed almost similar photocatalytic activity under UV and visible light as well as in the solar light which comprises of radiation in both UV and visible light range. Chemical oxygen demand removal of 86% could also be achieved under visible light, confirming that simultaneous mineralization of the dye occurred during photocatalysis. PANI-TiO2 nanocomposites are promising photocatalysts for the treatment of industrial wastewater containing RB-19 dye. © 2017, Springer-Verlag GmbH Germany, part of Springer Nature.
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    Solar light-driven photocatalysis using mixed-phase bismuth ferrite (BiFeO3/Bi25FeO40) nanoparticles for remediation of dye-contaminated water: kinetics and comparison with artificial UV and visible light-mediated photocatalysis
    (Springer Verlag service@springer.de, 2018) Kalikeri, S.; Shetty K, V.
    Mixed-phase bismuth ferrite (BFO) nanoparticles were prepared by co-precipitation method using potassium hydroxide as the precipitant. X-ray diffractogram (XRD) of the particles showed the formation of mixed-phase BFO nanoparticles containing BiFeO3/Bi25FeO40 phases with the crystallite size of 70 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the formation of quasi-spherical particles. The BFO nanoparticles were uniform sized with narrow size range and with the average hydrodynamic diameter of 76 nm. The band gap energy of 2.2 eV showed its ability to absorb light even in the visible range. Water contaminated with Acid Yellow (AY-17) and Reactive Blue (RB-19) dye was treated by photocatalysis under UV, visible, and solar light irradiation using the BFO nanoparticles. The BFO nanoparticles showed maximum photocatalytical activity under solar light as compared to UV and visible irradiations, and photocatalysis was favored under acidic pH. Complete degradation of AY-17 dyes and around 95% degradation of RB-19 could be achieved under solar light at pH 5. The kinetics of degradation followed the Langmuir–Hinshelhood kinetic model showing that the heterogeneous photocatalysis is adsorption controlled. The findings of this work prove the synthesized BFO nanoparticles as promising photocatalysts for the treatment of dye-contaminated industrial wastewater. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
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    Auto-combustion synthesis of narrow band-gap bismuth ferrite nanoparticles for solar photocatalysis to remediate azo dye containing water
    (Springer Science and Business Media Deutschland GmbH, 2021) Kalikeri, S.; Shetty K, V.
    Narrow band gap of ferrites makes it a good photocatalyst, and it plays very prominent role in the level of degradation of organic dyes by photocatalysis. In the current study, bismuth ferrite (BFO) nanoparticles were synthesized by auto-combustion technique. The synthesized BFO particles have the average crystallite size of 33 nm and band gap energy of 1.9 eV. As revealed by microscopic images, uniform, distinct, and hexahedral shaped BFO nanoparticles of 42.7 nm are formed. The BFO nanoparticles exhibited visible and solar light-mediated photocatalytic activity in degrading Acid Yellow-17. The optimum pH and catalyst loading were found to be pH 5 and 0.2 g/L respectively. Around complete degradation under solar and 95% degradation under visible light could be achieved within 135 min of irradiation. Around 85% and 83% chemical oxygen demand (COD) removal could also be achieved under solar and visible light respectively. The degradation followed first-order kinetics in terms of COD removal. The BFO nanoparticles are promising as solar light active catalysts for wastewater treatment. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
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    Visible light active Bismuth ferrite embedded TiO2 nanocomposite structures for dye mineralization by photocatalysis -A strategy to harness solar energy for remediation of water contaminated with mixture of dyes
    (Elsevier B.V., 2023) Kalikeri, S.; Shetty K, V.
    Harnessing solar energy to treat effluents from industries in order to mineralize the organic pollutants by photocatalysis demands the use of photocatalysts which are visible light active. In the present study, Bismuth ferrite embedded TiO2 (BFO/TiO2) nanocomposites have been synthesized with BFO (prepared by co-precipitation method) to Ti molar ratio of 1:2. BFO/TiO2 nanocomposites are crystalline, oval shaped and monodispersed with the average hydrodynamic diameter of 42 nm. Transmission Electron Microscopy (TEM) revealed that BFO nanoparticles have an average shorter dimension of 13.4 nm and longer dimension of 15.5 nm and are embedded in TiO2 matrix with the average coating thickness of 4.8 nm. The apparent band gap energy of BFO/TiO2 is 1.8 eV. BFO/TiO2 nanocomposites were used for the degradation of dyes from mixed dye aqueous solution containing three azo dyes, viz. Methylene Blue (MB), Acid yellow-17 (AY- 17), and Rhodamine- B (Rh-B) dyes under visible light irradiation. The BFO/TiO2 nanocomposites exhibited good photocatalytic activity under visible and solar light. Around 92% of MB, 73.9% of AY-17 and 68.3% of Rh-B dyes were degraded in 210 min from the mixed dye aqueous solution. Chemical Oxygen Demand (COD) removal of 72% could be achieved by photocatalysis confirming the mineralization of dyes. The COD removal kinetics followed first order model with the rate constant of 0.006 min−1. BFO/TiO2 nanocomposites exhibited superior visible light activity compared to BFO or TiO2 (Degussa P25) nanoparticles. The BFO/TiO2 nanocomposites have been proven to be promising in remediation of wastewater contaminated with mixture of dyes by photocatalysis. © 2022 Elsevier B.V.
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    Enhancing Strength Properties of Hydroxyapatite Composites with Bentonite Clay
    (Taylor and Francis Ltd., 2025) Satish, P.; Hadagalli, K.; Nowl, M.S.; Siddeswara, R.; Kalikeri, S.; Mandal, S.
    The main inorganic component of human hard tissues is hydroxyapatite (HA, Ca10(PO4)6(OH)2) and the mechanical and biological performance of HA can be improved by incorporating clay minerals to create HA-clay composite scaffolds. This study demonstrates a high-strength biocomposite of HA and bentonite with a significant reduction of open porosity, considering bentonite clay for its biocompatibility. Prawn shells (Fenneropenaeus indicus - marine resource) were utilized as a sustainable source of calcium to synthesize high-purity HA through a wet-chemical process, offering an innovative approach to valorize bio-waste. HA-bentonite clay composites were made by compacting 10-40 wt% of bentonite clay with HA using uniaxial pressing, followed by sintering at 1100°C for 2 h. Characterization techniques like X-ray diffraction, Raman, Fourier transform infrared spectroscopy and field emission scanning electron microscopy verified the phases, structures, vibrational bonds and morphology of the synthesized materials. Energy dispersive X-ray spectroscopy and inductively coupled plasma mass spectrometry analysis were performed for elemental composition and heavy metal detection, respectively. The HA-bentonite (30 wt%) composite achieved an exceptional compressive strength of 155 MPa and an open porosity of 7%, surpassing bare HA. Adding 30% bentonite increased compressive strength six fold and decreased open porosity by 51% compared to bare HA. This novel approach to HA-bentonite scaffolds promises enhanced wear resistance and cellular proliferation in bone tissue engineering. © 2025 Indian Ceramic Society.