B. Nagabhushana | Visweswaraya Technological University (original) (raw)

Papers by B. Nagabhushana

Applied Physics B, 2012

Gd 2 O 3 :Eu 3+ (4 mol%) co-doped with Bi 3+ (Bi = 0, 1, 3, 5, 7, 9 and 11 mol%) ions were synthe... more Gd 2 O 3 :Eu 3+ (4 mol%) co-doped with Bi 3+ (Bi = 0, 1, 3, 5, 7, 9 and 11 mol%) ions were synthesized by a low-temperature solution combustion method. The powders were calcined at 800°C and were characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), Fourier transform infrared and UV-Vis spectroscopy. The PXRD profiles confirm that the calcined products were in monoclinic with little cubic phases. The

Gd 2 O 3 :Eu 3+ (4 mol%) co-doped with Bi 3+ (Bi = 0, 1, 3, 5, 7, 9 and 11 mol%) ions were synthe... more Gd 2 O 3 :Eu 3+ (4 mol%) co-doped with Bi 3+ (Bi = 0, 1, 3, 5, 7, 9 and 11 mol%) ions were synthesized by a low-temperature solution combustion method. The powders were calcined at 800°C and were characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), Fourier transform infrared and UV-Vis spectroscopy. The PXRD profiles confirm that the calcined products were in monoclinic with little cubic phases. The

Journal of Magnetism and Magnetic Materials, 2013

CoFe 2 O 4 nanoparticles were prepared by solution combustion method. The nanoparticle are charac... more CoFe 2 O 4 nanoparticles were prepared by solution combustion method. The nanoparticle are characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). PXRD reveals single phase, cubic spinel structure with Fd3m (227) space group. SEM micrograph shows the particles are agglomerated and porous in nature. Electron paramagnetic resonance spectrum exhibits a broad resonance signal g ¼ 2.150 and is attributed to super exchange between Fe 3 þ and Co 2 þ. Magnetization values of CoFe 2 O 4 nanoparticle are lower when compared to the literature values of bulk samples. This can be attributed to the surface spin canting due to large surface-to-volume ratio for a nanoscale system. The variation of dielectric constant, dielectric loss, loss tangent and AC conductivity of as-synthesized nano CoFe 2 O 4 particles at room temperature as a function of frequency has been studied. The magnetic and dielectric properties of the samples show that they are suitable for electronic and biomedical applications.

Gd 2 O 3 :Eu 3+ (4 mol%) nanophosphor co-doped with Li + ions have been synthesized by low-temper... more Gd 2 O 3 :Eu 3+ (4 mol%) nanophosphor co-doped with Li + ions have been synthesized by low-temperature solution combustion technique in a short time. Powder X-ray diffractometer (PXRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), UV-VIS and photoluminescence (PL) techniques have been employed to characterize the synthesized nanoparticles. It is found that the lattice of Gd 2 O 3 :Eu 3+ phosphor transforms from monoclinic to cubic as the Li +-ions are doped. Upon 254 nm excitation, the phosphor showed characteristic luminescence 5 D 0 → 7 F J (J = 0-4) of the Eu 3+ ions. The electronic transition located at 626 nm (5 D 0 → 7 F 2) of Eu 3+ ions was stronger than the magnetic dipole transition located at 595 nm (5 D 0 → 7 F 1). Furthermore, the effects of the Li + co-doping as well as calcinations temperature on the PL properties have been studied. The results show that incorporation of Li + ions in Gd 2 O 3 :Eu 3+ lattice could induce a remarkable improvement of their PL intensity. The emission intensity was observed to be enhanced four times than that of with out Li +-doped Gd 2 O 3 :Eu 3+ .

ABSTRACT Nano-ceramic phosphorCaSiO3 doped with Pb and Mn was synthesized by the low temperature ... more ABSTRACT Nano-ceramic phosphorCaSiO3 doped with Pb and Mn was synthesized by the low temperature solution combustion method. The materialswere characterized by Powder X-Ray Diffraction (XRD),Thermo–gravimetric and Differential Thermal Analysis(TG–DTA), ScanningElectronMicroscopy(SEM)andTransmissionElectronMicroscopy(TEM).TheElectronParamagneticResonance (EPR) spectrumoftheinvestigatedsampleexhibitsabroadresonancesignalcenteredat g¼1.994. Thenumberofspinsparticipatingin resonance (N) and its paramagnetic susceptibility(w) have been evaluated.Photoluminescence of doped CaSiO3 was investigated when excited byUVradiationof256nm.Thephosphorexhibitsanemissionpeakat353nmintheUVrangeduetoPb2þ. Further,abroad emission peakinthevisiblerange550–625nmcanbeattributedto 4T1-6A1 transition ofMn2þ ions. The investigation reveals that doping perovskite nano-ceramics with transition metal ions leads to excellent phosphor materials for potential applications.

Single-step low-temperature solution combustion (LCS) synthesis was adopted for the preparation o... more Single-step low-temperature solution combustion (LCS) synthesis was adopted for the preparation of LaMnO3+δ (LM) nanopowders. The powders were well characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), surface area and Fourier transform infrared spectroscopy (FTIR). The PXRD of as-formed LM showed a cubic phase but, upon calcination (900°C, 6 h), it transformed into a

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 5, 2014

A series of Dy(3+) (1-5mol.%) activated Sr2SiO4 nanophosphors were prepared by low temperature so... more A series of Dy(3+) (1-5mol.%) activated Sr2SiO4 nanophosphors were prepared by low temperature solution combustion method using oxalyl dihydrazide (ODH) as a fuel. The obtained phosphor was well characterized by powder X-ray diffraction, scanning electron microscopy, and UV-visible spectroscopy. The average crystallite sizes were estimated by Debye-Scherrer formula and Williamson-Hall plots and found to be in the range 20-32nm. Energy band gap was found to be widened with increase of Dy(3+) ion dopant. Photoluminescence spectra consist of three main groups of peaks in 460-500nm (blue), 555-610nm (yellow) and 677nm (red) respectively. These peaks were assigned to transition of (4)F9/2→(6)H15/2,13/2,11/2. The critical distance between Dy(3+) ions and quenching site was found to be ∼16.71Ǻ. The chromaticity co-ordinates of all the prepared phosphors were located in white light; as a result Dy(3+) activated Sr2SiO4 is a promising single phased phosphor for white light emitting diodes. T...

ChemInform, 2014

ABSTRACT Porous and irregular shaped nanoparticles of Sr2SiO4:Eu3+ and Sr2SiO4:Eu3+:M+ (M: Na, K,... more ABSTRACT Porous and irregular shaped nanoparticles of Sr2SiO4:Eu3+ and Sr2SiO4:Eu3+:M+ (M: Na, K, Li) are prepared by low temperature combustion synthesis of an aqueous solution of metal nitrates and oxalyl dihydrazide as the fuel (muffle furnace, 500 °C, 5 min) followed by grinding and heating of the resulting powder (900 °C, 2 h).

Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy, 2012

Gd(1.95)Eu(0.04)M(0.01)O(3) (M=Li(+), Na(+), K(+)) nanophosphors have been synthesized by a low t... more Gd(1.95)Eu(0.04)M(0.01)O(3) (M=Li(+), Na(+), K(+)) nanophosphors have been synthesized by a low temperature solution combustion (LSC) method. Powder X-ray diffraction pattern (PXRD), scanning electron microscopy (SEM), UV-vis and photoluminescence (PL) measurements were carried out to characterize their structural and luminescent properties. The excitation and emission spectra indicated that the phosphor could be well excited by UV light (243 nm) and emit red light about 612 nm. The effect of alkali co-dopant on PL properties has been examined. The results showed that incorporation of Li(+), Na(+) and K(+) in to Gd(2)O(3):Eu(3+) phosphor would lead to a remarkable increase of photoluminescence. The PL intensity of Gd(2)O(3):Eu(3+) phosphor was improved evidently by co-doping with Li(+) ions whose radius is less than that of Gd(3+) and hardly with Na(+), K(+) whose radius is larger than that of Gd(3+). The effect of co-dopants on enhanced luminescence was mainly regarded as the result of a suitable local distortion of crystal field surrounding the Eu(3+) activator. These results will play an important role in seeking some more effective co-dopants.

a b s t r a c t Europium (Eu) doped Calcium fluoride (CaF 2 ) nanoparticles are synthesized by co... more a b s t r a c t Europium (Eu) doped Calcium fluoride (CaF 2 ) nanoparticles are synthesized by co-precipitation method and characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Also, optical absorption and photoluminescence (PL) results on gamma irradiated Eu doped CaF 2 nanoparticles are presented. The PXRD patterns confirmed the cubic crystallinity of the samples and the particle size is found to be ∼25 nm. The purity of the synthesized nanoparticles is confirmed from FTIR spectrum. The morphological features studied using SEM revealed that nanoparticles are agglomerated and porous. Optical absorption spectrum shows that ␥-rayed Eu doped CaF 2 nanoparticles exhibit absorption bands at ∼279, 360 and 434 nm. The PL studies showed emission at ∼420, 525 and 552 nm.

... c , H. Nagabhushana d * , HB Premkumar e , C. Shivakumara f , Chikkahanumantharayappa g &... more ... c , H. Nagabhushana d * , HB Premkumar e , C. Shivakumara f , Chikkahanumantharayappa g & RPS Chakradhar h pages 589-597. ... Kumar, V, Kumar, R, Lochab, SP and Singh, N. 2006. J. Phys. D. Appl. Phys. , 39: 5137 [CrossRef], [Web of Science ®] View all references. ...

3d-metal fluorosulphates that have a tavorite-type structure (e.g., LiFeSO 4 F) were recently rep... more 3d-metal fluorosulphates that have a tavorite-type structure (e.g., LiFeSO 4 F) were recently reported as attractive positive electrode candidates for future Li-ion batteries aimed at large volume markets. These new fluorosulphates had to be synthesized via ionothermal synthesis owing to both their thermal instability at temperatures greater than 300°C and their water solubility. In an attempt to depart from ionothermal synthesis, low-temperature solid-state reactions and solvothermal processes were successfully tried. The latter technique, which is reported herein, proceeds with water as the solvent and has led to a new family of fluorosulphates NaMSO 4 F 3 2H 2 O that crystallize in a monoclinic unit cell (SG =P2 1 /m) similar to the uklonskovite-type structure earlier proposed for NaMgSO 4 F 3 2H 2 O. These new phases show no electrochemical activity with either Li or Na metal and have room temperature ionic conductivities on the order of 1 Â 10 -9 S cm -1 . Additionally, we have discovered the feasibility, upon controlled dehydration of the NaMSO 4 F.2H 2 O phases, to prepare NaMSO 4 F phases adopting a derived tavoritetype structure and displaying ionic conductivities around 10 -7 S cm -1 . Finally, this finding opens the possibility to achieve Li-based fluorosulphates via two-step synthetic pathways.

Analytical and Bioanalytical Chemistry, 2002

The bidentate ligand diformylhydrazine (OHC-HN-NH-CHO), DFH, combines with iron(II) and iron(III)... more The bidentate ligand diformylhydrazine (OHC-HN-NH-CHO), DFH, combines with iron(II) and iron(III) in alkaline media in the pH range 7.3-9.3 to form an intensely colored red-purple iron(III) complex with an absorption maximum at 470 nm. Beer's law is obeyed for iron concentrations from 0.25 to 13 µg mL -1 . The molar absorptivity was in the range 0.3258×10 4 -0.3351×10 4 L mol -1 cm -1 and Sandell's sensitivity was found to be 0.0168 µg cm -2 . The method has been applied to the determination of iron in industrial waste, ground water, and pharmaceutical samples.

Nanocrystalline meta-zinc titanate (ZnTiO 3 ) ceramic was prepared using a self-propagating solut... more Nanocrystalline meta-zinc titanate (ZnTiO 3 ) ceramic was prepared using a self-propagating solution combustion synthesis (SCS) for the first time using urea as fuel. The product was calcined at 800 • C for 2 h to improve the crystallinity. Powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), high resolution transmission electron microscopy (HR-TEM) and UV-vis absorption spectroscopy were used to characterize the final product. PXRD results show that the ilmenite type rhombohedral structure was formed when the sample was calcined at 800 • C for 2 h. Adsorption experiments were performed with cationic malachite green (MG) dye. ∼96% dye was adsorbed onto nanocrystalline ZnTiO 3 ceramic at pH 9 for 30 min of the contact time. The optimum adsorbent dose was found to be 0.45 g/L of dye. Langmuir-Hinshelwood model was used to study adsorption kinetics and first order kinetic model best describes the MG adsorption on ZnTiO 3 . Antibacterial activity was investigated against gram negative Klebsiella aerogenes, Pseudomonas desmolyticum, Escherichia coli, and gram positive Staphylococcus aureus bacteria by agar well diffusion method. Nanocrystalline ZnTiO 3 ceramic showed significant effect on all the four bacterial strains at the concentration of 1000 and 1500 g per well.

Applied Physics B, 2012

Gd 2 O 3 :Eu 3+ (4 mol%) co-doped with Bi 3+ (Bi = 0, 1, 3, 5, 7, 9 and 11 mol%) ions were synthe... more Gd 2 O 3 :Eu 3+ (4 mol%) co-doped with Bi 3+ (Bi = 0, 1, 3, 5, 7, 9 and 11 mol%) ions were synthesized by a low-temperature solution combustion method. The powders were calcined at 800°C and were characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), Fourier transform infrared and UV-Vis spectroscopy. The PXRD profiles confirm that the calcined products were in monoclinic with little cubic phases. The

Gd 2 O 3 :Eu 3+ (4 mol%) co-doped with Bi 3+ (Bi = 0, 1, 3, 5, 7, 9 and 11 mol%) ions were synthe... more Gd 2 O 3 :Eu 3+ (4 mol%) co-doped with Bi 3+ (Bi = 0, 1, 3, 5, 7, 9 and 11 mol%) ions were synthesized by a low-temperature solution combustion method. The powders were calcined at 800°C and were characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), Fourier transform infrared and UV-Vis spectroscopy. The PXRD profiles confirm that the calcined products were in monoclinic with little cubic phases. The

Journal of Magnetism and Magnetic Materials, 2013

CoFe 2 O 4 nanoparticles were prepared by solution combustion method. The nanoparticle are charac... more CoFe 2 O 4 nanoparticles were prepared by solution combustion method. The nanoparticle are characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). PXRD reveals single phase, cubic spinel structure with Fd3m (227) space group. SEM micrograph shows the particles are agglomerated and porous in nature. Electron paramagnetic resonance spectrum exhibits a broad resonance signal g ¼ 2.150 and is attributed to super exchange between Fe 3 þ and Co 2 þ. Magnetization values of CoFe 2 O 4 nanoparticle are lower when compared to the literature values of bulk samples. This can be attributed to the surface spin canting due to large surface-to-volume ratio for a nanoscale system. The variation of dielectric constant, dielectric loss, loss tangent and AC conductivity of as-synthesized nano CoFe 2 O 4 particles at room temperature as a function of frequency has been studied. The magnetic and dielectric properties of the samples show that they are suitable for electronic and biomedical applications.

Gd 2 O 3 :Eu 3+ (4 mol%) nanophosphor co-doped with Li + ions have been synthesized by low-temper... more Gd 2 O 3 :Eu 3+ (4 mol%) nanophosphor co-doped with Li + ions have been synthesized by low-temperature solution combustion technique in a short time. Powder X-ray diffractometer (PXRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), UV-VIS and photoluminescence (PL) techniques have been employed to characterize the synthesized nanoparticles. It is found that the lattice of Gd 2 O 3 :Eu 3+ phosphor transforms from monoclinic to cubic as the Li +-ions are doped. Upon 254 nm excitation, the phosphor showed characteristic luminescence 5 D 0 → 7 F J (J = 0-4) of the Eu 3+ ions. The electronic transition located at 626 nm (5 D 0 → 7 F 2) of Eu 3+ ions was stronger than the magnetic dipole transition located at 595 nm (5 D 0 → 7 F 1). Furthermore, the effects of the Li + co-doping as well as calcinations temperature on the PL properties have been studied. The results show that incorporation of Li + ions in Gd 2 O 3 :Eu 3+ lattice could induce a remarkable improvement of their PL intensity. The emission intensity was observed to be enhanced four times than that of with out Li +-doped Gd 2 O 3 :Eu 3+ .

ABSTRACT Nano-ceramic phosphorCaSiO3 doped with Pb and Mn was synthesized by the low temperature ... more ABSTRACT Nano-ceramic phosphorCaSiO3 doped with Pb and Mn was synthesized by the low temperature solution combustion method. The materialswere characterized by Powder X-Ray Diffraction (XRD),Thermo–gravimetric and Differential Thermal Analysis(TG–DTA), ScanningElectronMicroscopy(SEM)andTransmissionElectronMicroscopy(TEM).TheElectronParamagneticResonance (EPR) spectrumoftheinvestigatedsampleexhibitsabroadresonancesignalcenteredat g¼1.994. Thenumberofspinsparticipatingin resonance (N) and its paramagnetic susceptibility(w) have been evaluated.Photoluminescence of doped CaSiO3 was investigated when excited byUVradiationof256nm.Thephosphorexhibitsanemissionpeakat353nmintheUVrangeduetoPb2þ. Further,abroad emission peakinthevisiblerange550–625nmcanbeattributedto 4T1-6A1 transition ofMn2þ ions. The investigation reveals that doping perovskite nano-ceramics with transition metal ions leads to excellent phosphor materials for potential applications.

Single-step low-temperature solution combustion (LCS) synthesis was adopted for the preparation o... more Single-step low-temperature solution combustion (LCS) synthesis was adopted for the preparation of LaMnO3+δ (LM) nanopowders. The powders were well characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), surface area and Fourier transform infrared spectroscopy (FTIR). The PXRD of as-formed LM showed a cubic phase but, upon calcination (900°C, 6 h), it transformed into a

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 5, 2014

A series of Dy(3+) (1-5mol.%) activated Sr2SiO4 nanophosphors were prepared by low temperature so... more A series of Dy(3+) (1-5mol.%) activated Sr2SiO4 nanophosphors were prepared by low temperature solution combustion method using oxalyl dihydrazide (ODH) as a fuel. The obtained phosphor was well characterized by powder X-ray diffraction, scanning electron microscopy, and UV-visible spectroscopy. The average crystallite sizes were estimated by Debye-Scherrer formula and Williamson-Hall plots and found to be in the range 20-32nm. Energy band gap was found to be widened with increase of Dy(3+) ion dopant. Photoluminescence spectra consist of three main groups of peaks in 460-500nm (blue), 555-610nm (yellow) and 677nm (red) respectively. These peaks were assigned to transition of (4)F9/2→(6)H15/2,13/2,11/2. The critical distance between Dy(3+) ions and quenching site was found to be ∼16.71Ǻ. The chromaticity co-ordinates of all the prepared phosphors were located in white light; as a result Dy(3+) activated Sr2SiO4 is a promising single phased phosphor for white light emitting diodes. T...

ChemInform, 2014

ABSTRACT Porous and irregular shaped nanoparticles of Sr2SiO4:Eu3+ and Sr2SiO4:Eu3+:M+ (M: Na, K,... more ABSTRACT Porous and irregular shaped nanoparticles of Sr2SiO4:Eu3+ and Sr2SiO4:Eu3+:M+ (M: Na, K, Li) are prepared by low temperature combustion synthesis of an aqueous solution of metal nitrates and oxalyl dihydrazide as the fuel (muffle furnace, 500 °C, 5 min) followed by grinding and heating of the resulting powder (900 °C, 2 h).

Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy, 2012

Gd(1.95)Eu(0.04)M(0.01)O(3) (M=Li(+), Na(+), K(+)) nanophosphors have been synthesized by a low t... more Gd(1.95)Eu(0.04)M(0.01)O(3) (M=Li(+), Na(+), K(+)) nanophosphors have been synthesized by a low temperature solution combustion (LSC) method. Powder X-ray diffraction pattern (PXRD), scanning electron microscopy (SEM), UV-vis and photoluminescence (PL) measurements were carried out to characterize their structural and luminescent properties. The excitation and emission spectra indicated that the phosphor could be well excited by UV light (243 nm) and emit red light about 612 nm. The effect of alkali co-dopant on PL properties has been examined. The results showed that incorporation of Li(+), Na(+) and K(+) in to Gd(2)O(3):Eu(3+) phosphor would lead to a remarkable increase of photoluminescence. The PL intensity of Gd(2)O(3):Eu(3+) phosphor was improved evidently by co-doping with Li(+) ions whose radius is less than that of Gd(3+) and hardly with Na(+), K(+) whose radius is larger than that of Gd(3+). The effect of co-dopants on enhanced luminescence was mainly regarded as the result of a suitable local distortion of crystal field surrounding the Eu(3+) activator. These results will play an important role in seeking some more effective co-dopants.

a b s t r a c t Europium (Eu) doped Calcium fluoride (CaF 2 ) nanoparticles are synthesized by co... more a b s t r a c t Europium (Eu) doped Calcium fluoride (CaF 2 ) nanoparticles are synthesized by co-precipitation method and characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Also, optical absorption and photoluminescence (PL) results on gamma irradiated Eu doped CaF 2 nanoparticles are presented. The PXRD patterns confirmed the cubic crystallinity of the samples and the particle size is found to be ∼25 nm. The purity of the synthesized nanoparticles is confirmed from FTIR spectrum. The morphological features studied using SEM revealed that nanoparticles are agglomerated and porous. Optical absorption spectrum shows that ␥-rayed Eu doped CaF 2 nanoparticles exhibit absorption bands at ∼279, 360 and 434 nm. The PL studies showed emission at ∼420, 525 and 552 nm.

... c , H. Nagabhushana d * , HB Premkumar e , C. Shivakumara f , Chikkahanumantharayappa g &... more ... c , H. Nagabhushana d * , HB Premkumar e , C. Shivakumara f , Chikkahanumantharayappa g & RPS Chakradhar h pages 589-597. ... Kumar, V, Kumar, R, Lochab, SP and Singh, N. 2006. J. Phys. D. Appl. Phys. , 39: 5137 [CrossRef], [Web of Science ®] View all references. ...

3d-metal fluorosulphates that have a tavorite-type structure (e.g., LiFeSO 4 F) were recently rep... more 3d-metal fluorosulphates that have a tavorite-type structure (e.g., LiFeSO 4 F) were recently reported as attractive positive electrode candidates for future Li-ion batteries aimed at large volume markets. These new fluorosulphates had to be synthesized via ionothermal synthesis owing to both their thermal instability at temperatures greater than 300°C and their water solubility. In an attempt to depart from ionothermal synthesis, low-temperature solid-state reactions and solvothermal processes were successfully tried. The latter technique, which is reported herein, proceeds with water as the solvent and has led to a new family of fluorosulphates NaMSO 4 F 3 2H 2 O that crystallize in a monoclinic unit cell (SG =P2 1 /m) similar to the uklonskovite-type structure earlier proposed for NaMgSO 4 F 3 2H 2 O. These new phases show no electrochemical activity with either Li or Na metal and have room temperature ionic conductivities on the order of 1 Â 10 -9 S cm -1 . Additionally, we have discovered the feasibility, upon controlled dehydration of the NaMSO 4 F.2H 2 O phases, to prepare NaMSO 4 F phases adopting a derived tavoritetype structure and displaying ionic conductivities around 10 -7 S cm -1 . Finally, this finding opens the possibility to achieve Li-based fluorosulphates via two-step synthetic pathways.

Analytical and Bioanalytical Chemistry, 2002

The bidentate ligand diformylhydrazine (OHC-HN-NH-CHO), DFH, combines with iron(II) and iron(III)... more The bidentate ligand diformylhydrazine (OHC-HN-NH-CHO), DFH, combines with iron(II) and iron(III) in alkaline media in the pH range 7.3-9.3 to form an intensely colored red-purple iron(III) complex with an absorption maximum at 470 nm. Beer's law is obeyed for iron concentrations from 0.25 to 13 µg mL -1 . The molar absorptivity was in the range 0.3258×10 4 -0.3351×10 4 L mol -1 cm -1 and Sandell's sensitivity was found to be 0.0168 µg cm -2 . The method has been applied to the determination of iron in industrial waste, ground water, and pharmaceutical samples.

Nanocrystalline meta-zinc titanate (ZnTiO 3 ) ceramic was prepared using a self-propagating solut... more Nanocrystalline meta-zinc titanate (ZnTiO 3 ) ceramic was prepared using a self-propagating solution combustion synthesis (SCS) for the first time using urea as fuel. The product was calcined at 800 • C for 2 h to improve the crystallinity. Powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), high resolution transmission electron microscopy (HR-TEM) and UV-vis absorption spectroscopy were used to characterize the final product. PXRD results show that the ilmenite type rhombohedral structure was formed when the sample was calcined at 800 • C for 2 h. Adsorption experiments were performed with cationic malachite green (MG) dye. ∼96% dye was adsorbed onto nanocrystalline ZnTiO 3 ceramic at pH 9 for 30 min of the contact time. The optimum adsorbent dose was found to be 0.45 g/L of dye. Langmuir-Hinshelwood model was used to study adsorption kinetics and first order kinetic model best describes the MG adsorption on ZnTiO 3 . Antibacterial activity was investigated against gram negative Klebsiella aerogenes, Pseudomonas desmolyticum, Escherichia coli, and gram positive Staphylococcus aureus bacteria by agar well diffusion method. Nanocrystalline ZnTiO 3 ceramic showed significant effect on all the four bacterial strains at the concentration of 1000 and 1500 g per well.