Rapid Production of Micro- and Nano-Particles Using Supercritical Water

Thisbookistalkingabouthowtousesupercriticalwater(SCW)torapidlyproduce micro- and nano-particles of metal oxides, inorganic salts, metals and organics. Itcoversbasicprinciples,experimentalmethodologiesandreactors,particlep- duction,characterizationsandapplicationsaswellastherecentadvancement. Fine particlescanbeproducedbybothchemicalandphysicalprecipitationofproducts from SCW. They can be used as catalysts, materials in ceramics and electronic devices andcompositematerials. Particlesareeasilyproduced continuouslyina owreactorinshortreactiontimes(0. 4s?2min)butcanalsobesynthesizedin batchreactorsforlongreactiontimes(e. g. ,12h). Theycanbeeasilystudiedin-situ microscopically(optical/IR/Raman/SR-XRD)inanopticalmicro-reactor,diamond anvilcell. Thesize,sizedistribution,crystalgrowth&structure,andmorphologyof particlescanbecontrolledbychangingtheconcentrationsofstatingmaterials,pH, pressures,temperatures,heating&coolingrates,organicmodi cations,reducingor oxidizingatmospheres, owratesandreactiontimes. Thisisthe rstbooktosystematicallyintroduceusingSCWforproductionof neparticles. Itisanidealreferencebookforengineers,researchersandgraduate studentsinmaterialscienceandengineering. vii Acknowledgments I would like to thank Drs. T. Ogi & T. Minowa (Biomass Technology Research Center,NationalInstituteofAdvancedIndustrialScienceandTechnology,Japan), and Profs. K. Arai, H. Inomata, R. L. Smith Jr. and T. Adschiri (Chemical Engineering,TohokuUniversity,Japan),whoinitiallyintroducedthehydrothermal andsupercritical uidsareastomewhenIworkedinJapanfrom1996to1999. Thanks are also due to Profs. J. A. Kozinski, R. I. L. Guthrie (Materials Engineering,McGillUniversity,Canada)andI. S. Butler(Chemistry,McGill)for theirguidanceinmyworkonhydrothermalprocessduringmyworkinCanadafrom 1999to2007. Profs. W. Bassett (Geological Sciences, Cornell University) and D. Baker (Earth&PlanetarySciences,McGill)forinstructionsregardingDAC,Dr. I-Ming Chou(U. S. GeologicalSurvey)forusefuldiscussionsofthepressurecalculation procedure. Drs. M. Watanabe and T. Sato (Research Center of Supercritical Fluid Technology, Tohoku University, Japan) for discussions about the experimental set-upofthebatchand owreactors. Drs. S. Xu,H. Assaaoudi,R. HashaikehandA. Sobhy,whoworkedwithmeat McGillinCanada. ix Contents 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 2 RapidExpansionofSupercriticalSolution(RESS)Process . . . 4 1. 3 SupercriticalAntisolvent(SAS)Process . . . . . . . . . . . . . 4 1. 4 OtherPhysicalProcesses . . . . . . . . . . . . . . . . . . . . . 5 1. 5 SupercriticalWaterProcess . . . . . . . . . . . . . . . . . . . . 5 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2 Supercritical Water Process. . . . . . . . . . . . . . . . . . . . . . 11 2. 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. 2 BatchReactor . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. 3 FlowReactor. . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2. 4 DiamondAnvilCell(DAC). . . . . . . . . . . . . . . . . . . . 20 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3 Metal Oxides Synthesis. . . . . . . . . . . . . . . . . . . . . . . . . 29 3. 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3. 2 Boehmite(AlOOH) . . . . . . . . . . . . . . . . . . . . . . . . 30 3. 3 Ferrites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

This book shows how to use supercritical water (SCW) to synthesize nano- andmicro- oxides, inorganic salts and metal particles and its recentadvancement. Also polymer/biomass particles can be produced by using themethod of precipitation of solutes from SCW. The particles can be used ascatalysts for biomass conversions, materials in ceramics & electronic devicesand composite materials. Particles are easily produced continuously ina flow reactor in short reaction times or synthesized in a batch reactor in long reaction times. Besides the synthesis process, the book also present studies of the properties of these materials. The size, size distribution, crystal growth & structure, and morphology of particles produced by supercritical water can be controlled by the feed concentrations, pH, pressures, temperatures, heating & cooling rates, organic modifications, reducing or oxidizing atmospheres, flow rates and reaction times.