Nanoparticles industrial applications

Bimetallic nanoparticles (including monometallic ones) have attracted a great interest in scientific research and industrial applications, owing to their unique large sur-face-to-volume ratios and quantum-size effects [1,2,5,182]. Since industrial catalysts usually work on the surface of metals, the metal nanoparticles, which possess much larger surface area per unit volume or weight of metal than the bulk metal, have been considered as promising materials for catalysis. 

In conclusion, it seems that the greatest prospects in the field of gold chemistry for practical or industrial applications lie in the fields of nanoparticles, catalysis or optoelectronic devices. However, this is very difficult to predict because new compounds and new areas of research always appear in surprising ways in gold chemistry. Thirty years ago no one could have imagined the tremendous development of gold chemistry that has taken place in both basic and applied research. 

Nanoparticles have numerous applications in the chemical, food, pharmaceutical, biomedical and semiconductor industries. For example, nanoparticles as drug carriers can increase drug efficacy, and can reduce toxicity and side effect after parenteral administration (Feng et al., 2002). Nanoparticles used for industrial applications should have desirable physical properties, including appropriate size, surface charge, surface area, porosity and mechanical strength. The functionality of... 

Segmented gas-liquid (Taylor) flow was used for particle synthesis within the liquid slugs. Tetraethylorthosilicate in ethanol was hydrolyzed by a solution of ammonia, water and ethanol (Stober synthesis) [329]. The resulting silicic acid monomer Si (OH)4 is then converted by polycondensation to colloidal monodisperse silica nanoparticles. These particles have industrial application, for example, in pigments, catalysts, sensors, health care, antireflective coatings and chromatography. 

Aggregates like polyelectrolyte complexes having positive charges and hydrophobic domains show a broader optimum flocculation concentration range and are considered as new reactive nanoparticles [11-14], Thus, polycations with hydrophobic functionalities represent an interesting class of water-soluble associating polyelectrolytes relevant for controlled stabilization/flocculation of dispersions in numerous industrial applications. 

The development of materials based on hetero polysiloxanes in combination with or without nanoparticles is an interesting route to new materials with interesting aspects and applications. These materials, especially in the initial phase, cannot play the role as mass commodity materials to be produced in large quantities by chemical industry. This might be one of the reasons that the pienetration of this type of material into industrial application is still at its infancy, but anyway, for creating special flmctions or special innovation in the field of materials users, this type of materials has already proven its usefulness for practice. 

A large fraction of practical catalysts consists of transition-metal or metal oxide nanoparticles dispersed onto the surface of insulator or semiconductor oxides that function as support materials. For industrial applications, the supports employed are selected on the basis of their surface area (high surface area is usually, but not always, desirable), high thermal and hydrothermal stability, chemical stability, and mechanical strength. 

Industrial interest in nanomaterials derives from the novel properties they exhibit. These are defined for this entry as materials having engineered discrete particulate domains with diameters in the range of 1 nm to a few hundred nanometers. These domains may appear in many forms, such as dispersions of nanoparticles in a liquid, on surfaces, or embedded in a continuous matrix. The unique properties of nanomaterials are a consequence of the small size and extremely large interfacial areas. In this regime, dramatic variations in the chemical and physical properties of a material may be effected. Representative examples of size-critical properties, enabling new industrial applications, reviewed in this entry include surface and interfacial, catalytic, optical, and mechanical. 

Industrial application of the Au catalysts would be feasible if 10% conversion of propene could be achieved. However, there still remains a number of serious problems low PO 4elds (<2%), low selectivities at high reaction temperature, deactivation with time-on-stream and low H2 efficiency (<30%). The first two problems could be somewhat improved when titania-modified silica and titanosilicates were used as supports for Au nanoparticles. The initial conversion of propene was increased to ca. 5% from 2% or below, when the reaction temperature was raised to 423 K from 353 K or below without considerable loss in PO selectivity [40,402]. To date, only small improvements in the deactivation of Au catalysts with time-on-stream have been reported,... 

This principle has been successfully utilized in an industrial application to achieve a small average particle size (3-5 microns) and a narrow PSD. For impinging jet crystallization, industrial operation is described by Midler et al. (1994), with vtuiants by Lindrud et al. (2001) (impinging jet crystallization with sonication) and by Am Ende et al. (2003) (specific reference to reactive crystallization). Laboratory studies are reported by Mahajan and Kirwan (1996), Benet et al. (1999), Condon (2001), and Hacherl (Condon) (2003), Johnson (2003) and Johnson and Prud homme (2003) report on the use of impinging jets to produce nanoparticles stabilized by block copolymers. 

Polymer-based nanocomposites reinforced with nanoparticles (NPs) have attracted much interest due to their homogeneity, relatively easy processability, and tunable physicochemical properties, such as mechanical, magnetic, electric, thermoelectric, and electronic properties [2,19-36], High particle loading is required for certain industrial applications, such as electromagnetic-wave absorbers [37,38], photovoltaic cells (solar cells) [39,40], photo detectors, and smart structures [41 3]. A nanoparticle core with a polymer shell renders many industrial applications possible, such as nanofluids and magnetic resonance imaging (MRI). 

The need for advanced materials and products with improved quality and for ways of mitigating thermal degradation and stickiness phenomena occurring in common dryers as well as in the environment and human health underpins the growing interest in supercritical fluids in processes such as extraction and purification of bioactive components, isolation and separation of molecules of interest contained in a mixture, and production of micro- and nanoparticles, which are among the main applications. Overall, the key industrial applications are, and will be, further driven by a unique combination of properties and attributes of SC-COj examined earlier. 

For industrial applications, however, this process still has limitations that need further modification and optimization a low collecting efficiency of nanoparticles, difficulty in controlling the size of multicomponent nanoparticles, and the scale-up of the atomizer system [10]. Recent improvements have changed the atomizer from... 

Scaling up strategies of microfluidic processes should be exploited to realize large-scale production of composite nanoparticles for industrial applications. 

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