Faculty Publications
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Item Nickel hydroxide/cobalt-ferrite magnetic nanocatalyst for alcohol oxidation(American Chemical Society service@acs.org, 2014) Bhat, P.B.; Inam, F.; Badekai Ramachandra, B.R.A magnetically separable, active nickel hydroxide (Brønsted base) coated nanocobalt ferrite catalyst has been developed for oxidation of alcohols. High surface area was achieved by tuning the particle size with surfactant. The surface area of 120.94 m2 g-1 has been achieved for the coated nanocobalt ferrite. Improved catalytic activity and selectivity were obtained by synergistic effect of transition metal hydroxide (basic hydroxide) on nanocobalt ferrite. The nanocatalyst oxidizes primary and secondary alcohols efficiently (87%) to corresponding carbonyls in good yields. © 2014 American Chemical Society.Item Nano Fe3O4@APTES@Ni(OH)2 as a catalyst for alcohol oxidation(Royal Society of Chemistry, 2015) Bhat, P.B.; Badekai Ramachandra, B.R.A nanorod shaped nickel hydroxide coated ferrite nanocatalyst was synthesized by a traditional co-precipitation method. The particle size of the nanoferrite was tuned using a variable surfactant ratio to achieve a high surface area. A very high BET surface area (334.55 m2 g-1) was achieved for particles with sizes of 40-130 nm. The superparamagnetic reusable catalyst was found to be active for the selective liquid phase oxidation of alcohols with hydrogen peroxide as a mild oxidant. Nickel hydroxide acted as a Bronsted base working in synergy with the nanoferrite catalyst for alcohol oxidation. The catalytic system was found to catalyse primary and secondary alcohols efficiently (86%) to their corresponding carbonyls in good yields. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2015.Item 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.Item Photocatalytic degradation of Irgalite violet dye using nickel ferrite nanoparticles(IWA Publishing 12 Caxton Street London SW1H 0QS, 2019) Vijay, S.; Mohan Balakrishnan, R.M.; Rene, E.R.; Uddandarao, P.Nanotechnologies have prominent applications in the field of science and technology owing to their size-tunable properties providing a promising approach for degradation of various pollutants. In this scenario, the present work aims to study the effect of nickel ferrite nanoparticles on the degradation of Irgalite violet dye by Fenton’s reaction using oxalic acid as an oxidizing agent in the presence of sunlight. The effect of pH and adsorbent dosage on the rate of dye degradation was monitored. Based on these studies it was observed that 99% dye degradation was achieved for catalyst dosage of 0.2 g, 400 ppm dye concentration and 2.0 mM oxalic acid at pH 3.0 within 60 min. The studies reveal that the degradation follows pseudo-first-order kinetics and the catalyst reusability remained constant almost for five cycles. Further, nickel ferrite nanoparticles are proven to be an efficient alternative for the removal of dyes from coloured solutions. © IWA Publishing 2019Item Reactive magnetron sputtered–assisted deposition of nanocomposite thin films with tuneable magnetic, electrical and interfacial properties(Springer Science and Business Media B.V. editorial@springerplus.com, 2020) Ratnesh, R.K.; Singh, M.; Pathak, S.; Dakulagi, V.In this work, different magnetic thin films of Ni, NiFe and NiFe2O4 are deposited on the SiO2 substrate using sputtering technique. Our experiments confirmed that thin films possess a good nanocrystalline structure. The key deposition parameters controlling their magnetic properties are sheet resistivity, crystalline structure and microtopography of the sputtered thin film. Besides, the reactive gas oxygen (O2) also plays a leading role in transforming the phase and structure of the ferrite film. The nanocrystalline nature of the ferrite film results in the reduction of overall coercivity (HC). The thickness of the sputtered thin film is in the range of 800–1000 Å. The prepared film exhibits roughness in the range of (~ 0.60 to ~ 0.98 nm). Furthermore, the structural transformation study is performed with X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The quite low roughness, high resistivity and low Hc make NiFe2O4 thin film as a potential candidate for the future spintronics, optoelectronics, photocatalysis and solar cell applications. © 2020, Springer Nature B.V.Item 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.Item Adsorption of selective fluoroquinolones by cysteine modified silane magnetic nanocomposite from the aqueous phase(Institute for Ionics, 2023) Senathiraja, T.; Lolla, S.A.; Singh, Y.; Kollarahithlu, S.C.; Mohan Balakrishnan, R.M.Elevated levels of pharmaceutical pollutants in the aquatic environment have caused detrimental effects on water quality and biodiversity. Nanomaterials are among the most promising technologies to detect, adsorb, and remove these pollutants from the aqueous systems. The current work explores the applicability of nickel ferrite nanocomposite functionalized with L-cysteine attached 3-glycidyloxypropyltrimethoxysilane to remove a selective class of antibiotics known as fluoroquinolones (Lomefloxacin, Ciprofloxacin, and Norfloxacin). 20 mg of this nanocomposite achieve maximum removal efficiencies of 61%, 67%, and 75% for 40 mg L−1 of lomefloxacin, norfloxacin, and ciprofloxacin, respectively. The nanocomposites also show good regeneration capacity with negligible reduction in the efficiencies up to three cycles. Furthermore, adsorption isotherms such as Langmuir and Freundlich isotherms were used to characterize the removal of fluoroquinolones from the aqueous phase by the nanocomposites. The results show that the adsorption process was in good agreement with the Langmuir isotherm, thus confirming its monolayer sorption process and also reveals that adsorption kinetics follows a pseudo-second-order model. The maximum adsorption capacity of functionalized nickel ferrite nanocomposites are 122 mg g−1, 135 mg g−1, and 150 mg g−1 for lomefloxacin, norfloxacin, and ciprofloxacin, respectively. Overall, all the results obtained indicate that the nickel ferrite nanocomposite functionalized with L-cysteine attached 3-glycidyloxypropyltrimethoxysilane is an effective adsorbent to remove fluoroquinolones from the aqueous systems and could be potentially incorporated in water treatment processes under well-defined parameters. © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.Item Stimulation of peroxymonosulfate using nickel ferrite nanoparticles for the degradation of Lomefloxacin hydrochloride and caffeine(Springer Science and Business Media Deutschland GmbH, 2025) Ilango, I.; Mohan Balakrishnan, R.; Visvanathan, C.; Bui, X.-T.Lomefloxacin Hydrochloride (LFH), an antibacterial agent, and caffeine (CAF), a cognitive enhancer, are excreted by humans and end up in municipal sewage effluents and surface waters. This pharmaceutical concentration in bodies of water/treatment plants poses a serious threat to both aquatic habitats and humans. A laboratory batch study on the degradation of LFH, CAF and LC (CAF and LFH mixed solution) was carried out using NFO nanoparticles to stimulate potassium peroxymonosulfate (PMS). The NFO nanoparticles were synthesized through a co-precipitation method and characterised using FTIR, XRD, FESEM/EDX, TGA/DTA/DTG, BET, AFM, VSM, and Zeta potential. The particle size distribution from FESEM (using ImageJ software) revealed that 83.3% of particles are ? 100 nm, its mean and standard deviation were estimated to be 43.87 nm and 20 to 25 nm. The NFO nanoparticles’ specific surface area was estimated to be 112.02 m2/g, and the magnetic properties of the NFO nanoparticles were investigated using VSM analysis. The parametric study included bare NFO, PMS without catalyst, pH, catalyst dosage, PMS variation with optimized catalyst, initial concentration of LFH and CAF, and reaction time, with nearly 94.34% LFH was degraded in 220 min, 100% CAF was degraded in 80 min, 78.07% LC was degraded in 40 min. The degraded compounds m/z of LFH, CAF and LC were identified using LC–MS. The recycling and regeneration of NFO nanoparticles were investigated to determine the stability of the NFO nanoparticles in the degradation of LFH and CAF in which the degradation efficiency decreased to 90.68% and 64.1% respectively upon the third wash with distilled water. As a result, the NiFe2O4/PMS system showed improved degradation even after three recycle runs, making it an efficient and economical system for degrading LFH, CAF and even to multi-pharmaceutical pollutants. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.