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文献摘要翻译：

文摘1：

Particle Formation during Anatase Precipitation of Seeded Titanyl Sulfate Solution Sekhar Sathyamoorthy,? Geoff D. Moggridge,*,? and Michael J. Hounslow?

Department of Chemical Engineering, Cambridge University, Pembroke Street,

Cambridge CB2 3RA, U.K,., and Department of Chemical and Process Engineering,

University of Sheffield, Mappin Street, Sheffield S1 3JD, U.K.

Received July 14, 2000

ABSTRACT: The formation of anatase particles in the Sulfate Process is an important step in the production of white pigment. This paper investigates the mechanisms behind particle formation during anatase precipitation from seeded concentrated titanyl sulfate solution. The process of particle formation was found to be highly dependent on the volume of seeds inoculated. Secondary nucleation played an important role in the production of anatase crystals and, ultimately, overall yield of the precipitation step. Anatase crystals were found to be between 4 and 8 nm from powder diffraction line broadening calculations. Nucleation also influences the structure and size of primary agglomerates consisting of a number of crystals. The final anatase particles recovered from the precipitation are in the form of 1-2μm aggregates, comprised of polycrystalline primary agglomerates.

摘自Crystal Growth & Design,2001,1(2):123~129

文摘2：

Controlling Particle Size During Anatase Precipitation Sekhar Sathyamoorthy and Geoff D. Moggridge

Dept. of Chemical Engineering, Cambridge University, Pembroke Street, Cambridge CB2 3RA, U.K.

Michael J. Hounslow

Dept. of Chemical and Process Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, U.K.

摘自：AIChE Journal ，2001 Vol. 47, No. 9

Titanium dioxide particles in the form of anatase are precipitated from concentrated titanyl sulfate solution in the sulfate process, which are then recovered by a filtration process downstream of the precipitation stage. A pre vious study by Sathyamoorthy et al. showed that the final anatase particles are aggregates(1-2 μm)consisting of numerous crystals(7 ~ 8 nm)arranged in primary agglomerates(60 ~ 100 nm). Pigment quality is determined by crystal and primary agglomerate size. One way of improving filtration rate is by the formation of larger aggregates, while maintaining the crystal and primary agglomerate size at optimum values. In a new seeding procedure proposed, the controlled inoculation of seeds used in industry is combined with a new type of seed (Large Seeds). The new seeding procedure has the

potential to increase downstream filtration efficiency by increasing aggregate size, while maintaining crystal and primary agglomerate sizes close to the values correctly obtained in industry. High yield in the precipitation process is also maintained.

文摘3：

Ordered mesoporous and macroporous inorganic films and membranes

V.V. Guliants?, M.A. Carreon, Y.S. Lin1

Department of C hemical and Materials Engineering, University of Cincinnati, Cincinnati, OH 45221-0012, USA Received 21 April 2003; received in revised form 29 December 2003; accepted 12 January 2004

Abstract

This article reviews synthesis, structures and emerging applications of ordered inorganic meso- and macroporous films and membranes. Thin films or membranes of these groups of porous materials can be prepared by various techniques commonly used for film formation from liquid solution, including solvent evaporation, in situ （原位）growth from solution and other alternative methods. Although these techniques allow control over the thickness and pore structures in thin films or membranes, they currently offer limited control over the pore alignment relative to the substrate surface. The ordered mesoporous and macroporous thin films and membranes are highly promising for a range of potential applications in separations, chemical sensing, heterogenous（非均相的）catalysis, microelectronics and photonics as insulating（绝缘层）layers of low dielectric constant（介电常数）and photonic bandgap （能带隙）materials. Furthermore, functionalization of the internal pore surfaces in these films and deposition of functional nanoparticles within the pores offer numerous new possibilities for molecular engineering of catalytic, photonic, and magnetic materials for advanced nanotechnological applications based on quantum confinement effect （量子限制效应）.

Keywords:Mesoporous; Macroporous; Pore structures

摘自：Journal of Membrane Science 235 (2004) 53–72

文摘4：

Thermal decomposition of fibrous（纤维状）TiOSO4.2H2O to TiO2 Mats Johnsson, Pernilla Pettersson, Mats Nygren

Abstract

Fibres （纤维）of TiOSO4.2H2O are used as precursor material for the preparation of TiO2fibres and/or particles with controlled morphology. This is

achieved by heat treatment in air in the temperature range 580-1250°C for times ranging from 0.1 to 100 h. Thermogravimetric studies showed that water was expelled （去除）at temperatures below 500°C, and the conversion of TiOSO4 to TiO2took place in the temperature range 540 to 580°C. Heat treatment at temperatures below 650°C yielded anatase, whereas rutile started to appear after extended holding times (100 h) at 650°C. Heat treatment at 950°C and higher yielded monophasic rutile samples. In the temperature region 650-950°C, both anatase and rutile appeared in the product in various relative amounts depending on the temperature and time of annealing （热处理）.

The original fibre morphology was preserved in the low-temperature region where anatase was formed. In the rutile region, however, the fibres became degraded due to growth of TiO2 particles, resulting in pearl strings of particles. The final morphology of the product depended strongly on the time and temperature of heat treatment.

The time dependence of the conversion of anatase to rutile at 750°C was monitored. The rate of conversion is rather high in the beginning of the process but substantially slower at the end. The obtained data can be fitted by the extended rate law proposed by Prout-Tomkins.

摘自：Thermochimica Acta 298 (1997) 47-54

文摘5：

Growth kinetics: a thermodynamic approach

Rajeev Mohan, Allan S. Myerson

Abstract

The analysis and development of industrial crystallization processes requires knowledge of the kinetics of the crystal growth process. This has led to a large number of studies of crystallization kinetics in a variety of systems. A review of these studies reveals the general use of an empirical (经验的) power-law （幂律定律）model for crystal growth kinetics, along with a variety of different definitions of supersaturation. In this work, supersaturation, the driving force for crystallization has been examined from a thermodynamic perspective (观点) and combined with the Burton–Cabrera–Frank crystal growth model to obtain a simplified and consistent method to analyze crystal growth data and obtain kinetics with only a single constant. This method is applied to a number of systems employing kinetic data obtained from the literature and thermodynamic data measured in this laboratory. The results demonstrate the simplicity and utility of the method.

摘自：Chemical Engineering Science 57 (2002) 4277 – 4285

文摘6：

Improvement of Thermal Stability of Porous Titania Films Prepared by

Electrostatic Sol-Spray Deposition (ESSD)

Mikihiro Nomura,*,? Ben Meester,? Joop Schoonman,? Freek Kapteijn,? and Jacob A. Moulijn?

A porous titania film with uniform pores of micrometer size was obtained on a dense stainless steel substrate by the electrostatic sol-spray deposition (ESSD) method. A porous film without cracks was obtained from the parent titania sol after more than 5 h of aging. This porous structure comprised an aggregation of fibrous titania. The pore size and the surface morphology were controlled by changing the aging period of the parent sol. The as-deposited films were shown to be amorphous titania by XRD analysis. They were calcined in order to obtain anatase or rutile titania. The structures of the porous films were damaged during the calcination at 873 K in air. Improved thermal stability of the porous titania films was obtained from a parent sol made by mixing fresh reactive titania sol and aged sol. Additionally, small particle structures were observed intergrown with the fibrous structures. The surface morphology of these films was not damaged by calcination at 873 and 1273 K in air. After calcination at 873 K, only the anatase phase was observed by the XRD measurement, whereas only the rutile phase was found after calcination at 1273 K. Porous anatase or rutile films can be produced using ESSD and proper calcination.

摘自：Chem. Mater. 2003, 15, 1283-1288