Kottayam, India
Kottayam, India

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Thomas J.,Kuriakose Elias College | Radhika S.,Kuriakose Elias College | Yoon M.,Chungnam National University | Yoon M.,JNT Inc.
Journal of Molecular Catalysis A: Chemical | Year: 2016

Different Nd3+-doped TiO2 nanoparticles incorporated with heteropoly phosphotungstic acid (HPA) (Nd3+-TiO2-HPA nanocomposites) were synthesized, and their structure and optical properties were characterized. UV-vis diffuse reflectance spectra of Nd3+-TiO2-HPA nanocomposites supported that the nanocomposites absorb visible light as well as ultra violet light. Consequently they exhibit efficient photocatalytic degradation of methylene blue (MB) upon illumination by the solar simulator, and the photocatalytic efficiency was found to depend on neodymium doping and heteropoly acid incorporation. These new photocatalysts were applied to the complete degradation of the organochlorine toxic chemical, 4-chlorophenol (4-CP) in water within 60 min upon sunlight illumination, indicating that Nd3+-TiO2-HPA nanocomposites would be very useful for cleaning polluted surface water by sunlight through the advanced oxidation process. Photocatalytic degradation pathway of 4-chlorophenol was examined using mass spectral analysis. © 2015 Elsevier B.V.

Mahalakshmi V.,Smart Materials Analytic Research and Technology SMART Laboratory | Lincy A.,Smart Materials Analytic Research and Technology SMART Laboratory | Thomas J.,Kuriakose Elias College | Saban K.V.,St Aloysius College
Optik | Year: 2015

Crystals of diaqua maleatocalcium (II) (CaC4H2O4·2H2O) have been grown by the controlled diffusion of ionic species in inert hydrosilica gel. The single crystal X-ray diffraction studies reveal that the crystal belongs to orthorhombic system with non-centrosymmetric space group P212121. The unit cell parameters are a = 6.849(5) Å, b = 8.665(5) Å, c = 11.002(5) Å and α = β = γ = 90.000(5)°. The functional groups present in the compound are identified from the FTIR spectrum. Thermogravimetric studies are performed to explore the thermal stability and decomposition pattern of the material. The UV - vis - NIR studies indicate wide transparency window, a befitting material characteristic for optoelectronic applications. The optical band gap of the material was estimated using diffuse reflectance spectroscopy. The second harmonic generation (SHG) efficiency possessed by the crystal is revealed by the Kurtz and Perry powder test. © 2015 Elsevier GmbH.

Lincy A.,Smart Materials Analytic Research and Technology SMART Laboratory | Mahalakshmi V.,Smart Materials Analytic Research and Technology SMART Laboratory | Thomas J.,Kuriakose Elias College | Raghavaiah P.,University of Hyderabad | Saban K.V.,St Aloysius College
Optik | Year: 2016

Single crystals of a new nonlinear optical material, triaquatrismalonatodicerium (III) dihydrate ([3H2O(C3H2O4)3 Ce2]·2H2O), have been grown using gel aided solution growth technique. The functional groups present in the crystal are identified using FTIR spectrum. X-ray diffraction studies on single crystals showed that the compound crystallizes in the monoclinic system with a non centrosymmetric space group P21 with unit cell dimensions a = 7.6795(5)Å, b = 12.9648(7)Å, c = 8.9545(5)Å, α = γ = 90°, β = 101.380(6)°. Thermogravimetric studies reveal the thermal stability and decomposition pattern of the material. The UV - vis spectrum indicates excellent transmittance in the entire visible region. Optical band gap energy of the crystal was evaluated from the diffused reflectance spectrum (DRS). Photoluminescence spectroscopy throws light on the optical emission properties. Excellent second harmonic generation (SHG) efficiency of the crystal was confirmed by Kurtz and Perry powder test. © 2015 Elsevier GmbH.

Vellanikaran J.J.,Kuriakose Elias College | Thomas A.P.,Kerala University
Asian Journal of Microbiology, Biotechnology and Environmental Sciences | Year: 2012

Mosquito menace in rural and urban India has reached alarming proportions. Improper urban development has compounded the problem. Extensive use of synthetic insecticides during the last few decades have resulted in environmental hazards and led to the development of physiological resistance in major vector species. Aedes aegypti is seen to transmit Dengue fever. From a selected twelve plant species of Umbelliferae family, extracts of five could induce significant mortality of A. aegypti larvae. Differential larvicidal activity was seen for various solvent extracts and both Hydrocotyle rotundifolia and Eryngium foetidum were found lethal to the larvae , the former was more effective. Synergic effect was observed when the crude extracts of H. rotundifolia and E. foetidum were used together. These two species are potential sources for larvicidal phytochemicals which may be used in mosquito control and eradication of Dengue fever. Crude extracts of three species - Ferula assa, Foetida, E. foetidum and H. rotundifolia exhibited potential larvicidal action. Development of safe biocides in future, may be done by isolation of the active principles from the crude extracts of Umbelliferae family. © Global Science Publications.

Jollyamma M.,Kuriakose Elias College | Sujatha T.S.,Kuriakose Elias College | Sujatha T.S.,Mmnss College
Asian Journal of Chemistry | Year: 2010

Oxidation of binary mixtures of 1-aryl-3-(2',6'-xylyl)thiourea and thiourea in acidic alcoholic solution yields 3-amino-4-aryl-5-(2',6'-xylyl)imino- Δ 2-1,2,4-thiadiazolines. A study of steric and electronic influence of substituents on the formation of 1,2,4-thiadiazolines has also been done. The rearrangement of the bis(formamidine)sulphide to amidinothiourea derivative has been found to be governed by the steric effect.

Joseph P.V.,Kuriakose Elias College | Jacob C.,Alphonsa College
Asian Journal of Chemistry | Year: 2010

A short term, baseline study was undertaken to determine the occurrence of microbial pollution in the Pennar river. Four stations were selected for study on the basis of land use pattern. Bacteriological, fungal and algal examinations were made and the results obtained showed that 8 species of bacteria isolated were opportunistic pathogens and total coliform count ranged from 460-2400/100 mL, thus making the water unsafe to drink unless treated properly. Fecal pollution from non human and human source is one of the major factors that contribute to the degradation of water quality and that restrict its use. Four fungal species were identified which are also opportunistic pathogens. In the present study about 36 different genera comprising 61 species of algae were idetified. High pollution tolerant species like Scenedesmus. Coelastrum, Oscillatoria, Nitzchia paella, Ankistrodesmus, Anabaena, Synedra and Navicula were present in different sites of Pennar river especially in the site I which is highly populated. High socioanthropological activities, clogging of water body due to weeds and agricultural practices in the basins were identified as a contributory factors to the situation.

Thomas J.,Kuriakose Elias College | Ambili K.S.,Kuriakose Elias College
Science of Advanced Materials | Year: 2014

A novel inorganic-organic hybrid material (HQ-Sm-Z) was synthesized by grafting 8-hydroxy quinolinesamarium complex (HQ-Sm) on zeolite Y through hydrothermal or solvothermal route. FTIR analysis reveals that the organic and inorganic components were covalently linked through the Si O bond of zeolite Y in the hybrid material. Optical properties of 8-hydroxy quinoline-samarium complex and the hybrid material were studied by using UV-visible spectroscopy and photoluminescence spectroscopy. We found that the 8-hydroxy quinoline-samarium complex grafted on zeolite through solvothermal route has better optical properties than the complex grafted on zeolite through hydrothermal route. The solid samarium complex and the hybrid material give both ligand based emission and the characteristic fluorescence of Sm3+ ion emission at room temperature. The SEM analysis shows that the hybrid material is homogenous. The mechanism of direct excitation and energy transfer scheme is also discussed. © 2014 by American Scientific Publishers.

Thomas A.K.,Smart Materials Analytical Research and Technology SMART Laboratory | Abraham K.,Smart Materials Analytical Research and Technology SMART Laboratory | Thomas J.,Kuriakose Elias College | Saban K.V.,Mary Matha Arts and Science College
Ceramics International | Year: 2015

Abstract The effect of doping the A site (Ca) with La and B site (Ti) with Nb, on the grain formation, crystallographic structure, electrical properties and dielectric behaviour of CaCu3Ti4O12 is investigated over wide ranges of temperature (27-150°C) and frequency (50 Hz to 5 MHz). Microstructure investigation of the cast compound, Ca(1-3x)La2xCu3Ti(4-5x)Nb4xO12 (x=0, 0.02 and 0.04), using Scanning Electron Microscopy (SEM) showed that co-doping would result in grain growth inhibition. Rietveld refinement of the powder diffraction data confirmed a cubic, single phase structure with space group Im3. The steady increase in the lattice volume with increasing dopant concentration confirms the incorporation of the bigger dopant molecules in the lattice. Dielectric studies using HIOKI 3552-50 LCR Hi-Tester show that the room temperature dielectric constant would considerably increase due to co-doping. Impedance spectroscopic studies reveal that the compound is electrically heterogeneous, with semi conductive grain interior and insulating grain boundaries. Doping resulted in a decrease in grain boundary resistance and consequent increase in dielectric loss at low frequency. The dielectric behaviour of compound is explained on the basis of the Internal Barrier Layer Capacitance (IBLC) model. © 2015 Elsevier Ltd and Techna Group S.r.l.

Thomas J.,Kuriakose Elias College | Ambili K.S.,Kuriakose Elias College
Journal of Molecular Structure | Year: 2015

A new metal-organic framework with empirical formula C43H30NO12Sm was solvothermally synthesized using SmCl(, fluorescein and N, N-Dimethyl formamide (DMF) and characterized by single crystal X-ray diffraction, powder X-ray diffraction, infrared spectroscopy, UV-Visible spectroscopy, scanning electron microscopy, optical microscopy, photoluminescence spectroscopy, CHN elemental analysis and thermogravimetric analysis. Single crystal X-ray diffraction revealed that the crystal structure belongs to the triclinic system, P-1 space group with a = 12.113 (6) Å, b = 12.1734 (7) Å, c = 13.2760(8) Å, α = 67.930(3)<>, β = 87.779(3)< >, γ = 77.603(3)< > and V = 1769.71 (17) Å3. The photoluminescence spectrum showed emission peaks at 550 nm, 600 nm and 647 nm due to the characteristic transitions 4G5/2 to 6H5/2, 4G5/2 to 6H7/2 and 4G5/2 to 6H9/2 respectively, when excited at 398 nm. © 2015 Elsevier B.V. All rights reserved.

Thomas J.,Kuriakose Elias College | Chitra K.R.,Kuriakose Elias College
Advanced Materials Research | Year: 2014

Novel nanogold doped TiO2 nanoparticles are found to be highly efficient for the photocatalytic degradation of organic pollutants. TiO2 nanoparticles were synthesized from titanium (IV) isopropoxide through hydrothermal route. Gold nanoparticles were prepared by chemical reduction and stabilization employing D-glucosamine, and were doped in TiO2 nanoparticles. The analysis revealed that the diameter of gold nanoparticles used for doping is around 5 nm. Undoped and gold doped samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, UVVis diffuse reflectance spectra (DRS) and field emission scanning electron microscopy (SEM). DRS study showed that nanogold doping in titania nanoparticles induces a shift of absorption edge to the visible range and reduces the band gap. Complementing our earlier finding that noble metal doping in titania nanoparticles enable photocatalytic activity in the visible region, it is showed that gold doping enhances photocatalytic activity of the titania nanoparticles. This was confirmed by the degradation of the dye methylene blue repeatedly using gold doped nanoparticles under direct sunlight. Further, the nanoparticles were used to study the degradation of the persistent organic pollutant, β endosulfan, and near complete degradation were observed in an hour. Regenerated nanoparticles were found effective for the degradation of the pesticide for more than three cycles. © (2014) Trans Tech Publications, Switzerland.

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