@article { ISI:000266648400001, title = {Chlorophyll-based photocatalysts and their evaluations for methyl orange photoreduction}, journal = {Journal of Photochemistry and Photobiology A-Chemistry}, volume = {204}, number = {2-3}, year = {2009}, month = {MAY}, pages = {83-89}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

Immobilization of chlorophyll on different functionalized mesoporous materials has been attempted. The replacement of butanediol with monoethanol amine has resulted in increase in chlorophyll loading by a factor of two. The maximum immobilization of chlorophyll was on MCM-41 functionalized with monoethanolamine MCM-41/MEA/Chl) as compared to other mesoporous materials. This material has been characterized using XRD, UV-vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM-EDX) and fluorescence spectroscopy. The photocatalytic reduction of methyl orange (MO)was studied using MCM-41/MEA/Chl as photocatalyst under the visible light. The photocatalytic reduction of MO was 0.396 mg/g of MCM-41/MEA/Chl photocatalyst as compared to 0.508 mg/g of TiO(2) for that of Degussa P-25 photocatalyst. The effect of various operating parameters like catalyst loading, initial concentration and intensity of light has also been studied. Photocatalytic property of chlorophyll-based photocatalytic material indicates that chlorophyll acts as a reaction center, which absorbs visible light and generates electron, which is transferred to different electron acceptors reducing MO into derivative of hydrazine. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {Chlorophyll-based photocatalyst, Mesoporous material, Methyl orange, Photoreduction}, issn = {1010-6030}, doi = {10.1016/j.jphotochem.2009.01.016}, author = {Joshi, Meenal M. and Kamble, Sanjay R. and Labhsetwar, Nitin K. and Parwate, D. V. and Rayalu, Sadhana S.} } @article { ISI:000267546200006, title = {Structural characterization of azoic dye hosted layered double hydroxides}, journal = {Zeitschrift fur Kristallographie}, volume = {224}, number = {5-6}, year = {2009}, month = {JAN}, pages = {282-286}, publisher = {OLDENBOURG VERLAG}, address = {LEKTORAT MINT, POSTFACH 80 13 60, D-81613 MUNICH, GERMANY}, abstract = {

The removal of methyl orange (MO) from an aqueous solution was performed using layered double hydroxides (LDHs) in a move to develop cleaning processes of effluents contaminated with dye molecules. The intercalation of the guest anionic MO species into host M(II)/Al(III) LDHs differing by the nature of the divalent cations (M(II) = Mg, Ni or Zn) was achieved by anionic exchange of the initially NO(3)(-) present in the interlayer space and led to MO/LDH intercalation compounds. The exchange process was followed by XRD and UV-visible absorption spectroscopy at different stages. Almost all MO in solution is uptaken by the Mg-containing LDH in the concentration range corresponding to its anionic exchange capacity (AEC). A lower exchange is reached with the Ni- and Zn-containing LDHs, for which the diffusion of MO is limited due to a larger crystallite size. MO-Zn/Al LDH intercalation compounds exhibit the highest crystallinity and display a remarkable stacking of the layers at maximal MO exchange. This behaviour can be assigned to the higher intrinsic charge density of the host layers in agreement with its lower M(II)/Al(III) molar ratio (Zn(II)/Al(III) approximate to 1.5 whereas Mg(II)/Al(III) and Ni(II)/Al(III) = 2). The maximum amount of MO retained by the different LDHs is higher for Mg-containing LDH, than for Ni- and Zn-containing LDH, reaching respectively 1.15, 0.84 and 0.77 g/g.

}, keywords = {Anionic exchange, Depollution, layered double hydroxides, Methyl orange, X-ray diffraction}, issn = {0044-2968}, doi = {10.1524/zkri.2009.1150}, author = {Mandal, Sujata and Lerner, Dan A. and Marcotte, Nathalie and Tichit, Didier} } @article { ISI:000309644400011, title = {Enhanced photocatalytic activity of multi-doped TiO2 for the degradation of methyl orange}, journal = {Applied Catalysis A-General}, volume = {443}, year = {2012}, month = {NOV}, pages = {96-102}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

We report the synergistic effect of dopants like Gd, N and Sin enhancing the photocatalytic activity of TiO2. Nanosized TiO2 doped at both cationic and anionic sites by Gd, N and S exhibited increased photocatalytic activity compared to TiO2 doped with either Gd or N and S. All the doped TiO2 existed as anatase phase and no separate phase due to Gd2O3 was seen up to a Gd concentration of 2\%. The particle size as seen from the transmission electron micrograph was similar to 25 nm. The optical absorption property of TiO2 was improved by doping and redshift of the absorption edge is seen for all doped samples compared to pristine TiO2. The red shift of the absorption edge was the highest for the multiple ion-doped sample. Presence of bonded N and S in TiO2 was detected by X-ray photoelectron spectroscopy. Fluorescence lifetime studies indicated an enhanced lifetime for the charge carriers in the doped system compared to pristine TiO2. Photocatalytic activity study showed that the multi-doped sample has the highest activity for the degradation of methyl orange compared to Gd-TiO2, NS-TiO2 and pristine TiO2. The enhanced photocatalytic activity of the multi-doped TiO2 is attributed to factors such as improved optical absorption property and improved lifetime of the charge carriers. (C) 2012 Elsevier B.V. All rights reserved.

}, keywords = {Fluorescence lifetime, Gd N S doped TiO2, Methyl orange, Photocatalyst, Photodegradation}, issn = {0926-860X}, doi = {10.1016/j.apcata.2012.07.032}, author = {Charanpahari, A. and Umare, S. S. and Gokhale, S. P. and Sudarsan, V. and Sreedhar, B. and Sasikala, R.} }