Microwave hydrothermal processing of the invasive macroalgae Sargassum muticum within a green biorefinery scheme

Through the microwave-hydrothermal processing at 70 °C in 10 min, barium strontium titanate (BST) nanopowders are prepared by using butyl-titanate, barium nitrate and strontium nitrate as raw materials. Two kinds of dispersants namely polyethylene glycol 6000 and OP-10 are added, respectively. The dispersant mechanism and dosage on the crystal phase and microstructure are studied by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM). The results show that the dispersive effect of OP-10 is better than the polyethylene glycol 6000. The long chain of OP-10 can be used to disperse nanopowders through a space steric hindrance mechanism, well-dispersed BST nanopowders are obtained when mass percent ratio of dispersant (OP-10) is 5%.

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Microwave-hydrothermal processing of metal powders

Journal of Materials Research ◽

10.1557/jmr.1995.1687 ◽

1995 ◽

Vol 10 (7) ◽

pp. 1687-1692 ◽

Cited By ~ 87

Author(s):

Sridhar Komarneni ◽

Rajyalakshmi Pidugu ◽

Qing Hua Li ◽

Rustum Roy

Keyword(s):

Ethylene Glycol ◽

Metal Powder ◽

Metal Salts ◽

Hydrothermal Processing ◽

Metal Powders ◽

Ceramic Powders ◽

Powder Synthesis ◽

Microwave Hydrothermal ◽

Order Of Magnitude ◽

Kinetics Of

Novel microwave-hydrothermal processing has been developed by us recently for the synthesis of a wide variety of ceramic powders. Herein, we report the use of microwave-hydrothermal processing to synthesize several metal powders such as Cu, Ni, Co, and Ag by reducing their corresponding metal salts or hydroxides with ethylene glycol. Metal powders have been produced extremely rapidly a (few minutes) by microwave catalysis. The kinetics of metal powder synthesis have been increased by at least an order of magnitude by microwave-hydrothermal processing compared to the conventional refluxing process in ethylene glycol at about 195 °C.

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Microwave-hydrothermal processing for synthesis of electroceramic powders

Journal of Materials Research ◽

10.1557/jmr.1993.3176 ◽

1993 ◽

Vol 8 (12) ◽

pp. 3176-3183 ◽

Cited By ~ 136

Author(s):

Sridhar Komarneni ◽

Q. Li ◽

Karin M. Stefansson ◽

Rustum Roy

Keyword(s):

Chemical Analysis ◽

Processing Technique ◽

Hydrothermal Processing ◽

Ceramic Powders ◽

Inorganic Solids ◽

Microwave Hydrothermal

Microwave-hydrothermal processing has so far been used only to dissolve inorganic solids for chemical analysis. We report herein the use of microwave-hydrothermal processing to synthesize various ceramic powders in binary and polynary systems. We describe the synthesis of some electroceramic powders such as BaTiO3, SrTiO3, Sr0.5Ba0.5TiO3, PbTiO3, BaZrO3, SrZrO3, Pb(Zr0.52Ti0.48)O3, and pyrochlore phases with the Pb(Mg1/3Nb2/3)O3 and Pb(Zn1/3Nb2/3)O3 compositions by this novel microwave-hydrothermal processing technique.

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Microwave-Hydrothermal Synthesis of Transition Metal Tungstates with Nanosized Particles

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.194.209 ◽

2012 ◽

Vol 194 ◽

pp. 209-212 ◽

Cited By ~ 1

Author(s):

Kisla P.F. Siqueira ◽

Anderson Dias

Keyword(s):

Raman Spectroscopy ◽

Structural Changes ◽

Single Phase ◽

Amorphous Matrix ◽

Nanosized Particles ◽

Hydrothermal Processing ◽

X Ray Diffraction ◽

X Ray ◽

Microwave Hydrothermal ◽

Metal Tungstates

Microwave-hydrothermal processing was employed to synthesize Mn and Co tungstates under environmentally friendly conditions. X-ray diffraction showed that crystalline, single-phase materials were produced. Incipient crystallized compounds were also obtained in some conditions, as verified by TEM. For these samples, nanostructured regions could be observed inside the amorphous matrix. Sintered solid-solutions of Mn1-xCoxWO4 compounds were produced to investigate the morphological and structural changes in the resulted ceramic. Raman spectroscopy was used to obtain a reliable set of spectra containing all the Raman-active bands predicted by group-theory calculations.

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Effect of Microwave-Hydrothermal Synthesis on Tin (II) Oxide Properties

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1085.187 ◽

2015 ◽

Vol 1085 ◽

pp. 187-191

Author(s):

Аlina A. Pichugina ◽

Svetlana A. Kuznetsova

Keyword(s):

Photocatalytic Activity ◽

Hydrothermal Synthesis ◽

Methyl Orange ◽

Surface Morphology ◽

Photocatalytic Degradation ◽

Pore Volume ◽

Hydrothermal Processing ◽

Sorption Activity ◽

Microwave Hydrothermal ◽

Degradation Of Methyl Orange

The article demonstrates how time and speed of pressure growth in the course of microwave-hydrothermal processing affect surface morphology and photocatalytic activity of tin (II) oxide. The experiment proved that the materials’ pore size and pore volume influenced their sorption activity and the speed of photocatalytic degradation of methyl orange.

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Microwave-hydrothermal processing of titanium dioxide

Materials Chemistry and Physics ◽

10.1016/s0254-0584(99)00113-3 ◽

1999 ◽

Vol 61 (1) ◽

pp. 50-54 ◽

Cited By ~ 115

Author(s):

Sridhar Komarneni ◽

Rama K Rajha ◽

Hiroaki Katsuki

Keyword(s):

Titanium Dioxide ◽

Hydrothermal Processing ◽

Microwave Hydrothermal

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Microwave-Hydrothermal Processing of BiFeO3 and CsAl2PO6

Journal of the American Ceramic Society ◽

10.1111/j.1151-2916.1996.tb08605.x ◽

1996 ◽

Vol 79 (5) ◽

pp. 1409-1412 ◽

Cited By ~ 70

Author(s):

Sridhar Komarneni ◽

V C. Menon ◽

Q. H. Li ◽

Rustum Roy ◽

F. Ainger

Keyword(s):

Hydrothermal Processing ◽

Microwave Hydrothermal

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Microwave-hydrothermal processing of layered anion exchangers

Journal of Materials Research ◽

10.1557/jmr.1996.0236 ◽

1996 ◽

Vol 11 (8) ◽

pp. 1866-1869 ◽

Cited By ~ 76

Author(s):

Sridhar Komarneni ◽

Q. H. Li ◽

Rustum Roy

Keyword(s):

High Selectivity ◽

Hydrothermal Processing ◽

Basic Salt ◽

Anion Exchangers ◽

Microwave Hydrothermal ◽

Order Of Magnitude ◽

Very High

We have compared the microwave-hydrothermal (M-H) processing with conventional hydrothermal (C-H) processing in the preparation of two layered anion exchangers, i.e., Mg3Al(OH)8NO3 · nH2O and Ni1-xZn2x(OH)2(CH3COO)2x · nH2O. Both these phases can be crystallized more rapidly (an order of magnitude) under M-H processing compared to C-H processing. The above layered mixed basic salt of Ni and Zn was found to exhibit very high selectivity for PO4= (Kd = 15,000). Its order of selectivity for various anions in the presence of 0.1 N̲ NaC1 (ratio of C1- to anion in question is 100) increases as follows: PO4= ≫ SO4= > NO3-.

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