A method to coat plastic catheters with bioactive silver nanoparticles was developed. These catheters are non-toxic and are capable of targeted and sustained release of silver at the implantation site. Because of their demonstrated antimicrobial properties, they may be useful in reducing the risk of infectious complications in patients with indwelling catheters.

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Supercritical Fischer-Tropsch Synthesis (SC-FTS) using a potassium-promoted iron-based catalyst has been shown to produce large amounts of heavy (C10+) aldehydes and methyl ketones, while traditional gas phase FTS does not produce these compounds in significant amounts under either fixed or slurry bed operation. In order to better understand this behavior, a series of studies was undertaken to determine the effect of process conditions (H2/CO ratio, temperature, pressure, and supercritical hexanes media ratio) on the performance of iron-based SC-FTS generally, and on aldehyde formation specifically. Over the range of process conditions studied, heavy aldehyde selectivity was found to decrease with increasing temperature, while both elevated pressure and increased media ratio favored aldehyde production. Changes in the H2/CO ratio had little influence on syncrude functionality. The role of potassium promotion was also investigated by operating a potassium-free iron-based catalyst under SC-FTS conditions. In the absence of potassium promotion, no heavy aldehydes were detected.

A gas-expanded-liquid technique (GXL) was applied to the preparation of supported iron catalysts for Fischer− Tropsch synthesis (FTS). A mixture of presynthesized iron oxide nanoparticles with an average size of 12 nm was deposited onto a SiO 2 support in a manner such that nanoparticles smaller than 5 nm were excluded from the final catalyst product. A series of SiO 2 -supported iron oxide nanoparticle catalysts were prepared with iron loadings of 11.4, 18.0, 24.0, and 28.8 wt %. Catalysts were characterized by nitrogen adsorption, inductively coupled plasma optical emission spectrometry, H 2 temperatureprogrammed reduction (H 2 -TPR), X-ray diffraction (XRD), trasmission electron microsopy (TEM), X-ray photoelectron spectroscopy, and carbon monoxide temperature-programmed desorption. TEM analysis showed that iron oxide nanoparticles were well-distributed over the surface of the SiO 2 support with an increase in the iron loading resulting in the formation of multilayers and three-dimensional islands of iron oxide nanoparticles. H 2 -TPR indicated that the reducibility of the iron oxide nanoparticles increased monotonically with iron loading. According to XRD results, the increase in the iron loading resulted in an increase in the iron oxide crystallite size, and iron carbides were present in the used catalysts after solvent treatment. FTS was carried out in a fixed-bed reactor at reaction conditions of 230 °C, 2 MPa, H 2 /CO = 1.70, and GHSV = 3000 L/kg cat /h. For the catalysts studied, the highest syngas conversion and iron time yield were observed at intermediate (18, 24 wt %) iron loadings. The C 5+ selectivity and carbon chain growth probability factor were approximately 68% and 0.76, respectively, for each catalyst. A 16 wt % iron on SiO 2 catalyst prepared by the same GXL technique was promoted with 0.7 wt % potassium using the incipient wetness method. As expected, K promotion resulted in a slight decrease in FTS activity and increased selectivity toward CO 2 and C 5+ selectivity.