Valentina Rosetti

Highly conductive Ni steam reforming catalysts prepared by electrodeposition

New highly conductive, active and stable Ni steam reforming catalysts were prepared through a method consisting of the calcination of a hydrotalcite-like compound electrodeposited in a single step on FeCrAlloy foams.

SiC as stable high thermal conductive catalyst for enhanced SR process

1. Abstract Silicon carbide has been chosen as a support for steam methane reforming (SMR). In fact, its good conductive properties may improve the temperature profile, while decreasing the high AT caused by the high endothermicity of the reaction and, at the same time, increasing the heat transfer from external furnace, reactor wall and catalyst particles. 10 wt % Ni was deposited on the SiC support by incipient wetness impregnation. The sample was calcined at different temperatures in order to study both the chemical-physical properties and the interaction between the support and active phases. The sample calcined at 700°C was tested in a SMR laboratory plant under different operative conditions, in order to evaluate the activity and stability with time-on-stream. On a laboratory scale, the catalyst shows good results, although, at very high temperatures (960°C) the support shows a slight SiO 2 formation.

Microwave-assisted catalysts for the CPO of methane

Catalytic activity in the partial oxidation (CPO) of methane of some catalysts containing Ni or Rh/Ni active metals obtained by the calcination and reduction of hydrotalcite-like compounds was investigated. In particular, two hydrotalcite-like compounds subjected to the microwave-hydrothermal method (MWHT) were studied in order to evaluate the role of the synthesis method of the precursors on the catalytic activity and catalyst stability as compared to catalysts prepared by the conventional method. The tests carried out at 750°C do not evidence any difference among catalysts. However, when the temperature is reduced to 500°C a better catalytic performance is observed for the microwave-assited catalysts containing nickel, whereas for the bimetallic catalyst the best activity is achieved with the conventional method.

New catalysts for the syngas production obtained by hydrotalcite type precursor containing silicate

Publisher Summary Ni and/or Rh based catalysts (ex-HT) derived by hydrotalcite precursor are considered to be effective catalysts in the catalytic partial oxidation (CPO) reaction. This chapter discusses new stable ex-HT catalysts prepared by inserting silicate instead of CO 3 2- anions in the interlayer. The amount of silicates is not limited by the charge balance of the cations, because, an excess of silicates leads to the formation of polysilicate anions. The insertion of silicates affects the structure of the calcined samples, because, unlike CO 3 2- , the silicates remain in the structure and contribute to the formation of the final catalysts. Catalysts with innovative structure are obtained by HT precursor prepared using silicate as interlayer anion. The calcined catalysts showed two phases—a mixed oxide type structure and a new M-silicate structure, where the cations of the active metal are partially soluted. The Rh catalyst prepared by HT silicate was more active and selective than the one prepared by CO 3 2- .

Hearing Growth Defects in Turner Syndrome

Turner syndrome (TS) is one of the most common chromosomal abnormalities, occurring in about 50 per 100,000 female live births characterized by the total or partial loss of one X-chromosome in all or some cells. Frequently observed manifestations of TS include short stature, lymphedema, cardiac abnormalities, gonadal dysgenesis, dysmorphic features, ear and hearing problems, and a variety of other problems. Conductive hearing loss (CHL) in patients (pts) with TS is due to recurrent otitis media with effusion, chronic middle ear infection, and cholesteatoma probably as the result of malfunction of the Eustachian tube associated with lymphedema and anatomic shortening of the skull base. The high prevalence of middle ear infections and CHL in TS are probably due to growth disturbances of the structures from the first and second branchial arches. Sensorineural hearing loss (SNHL) is also reported in TS and the hearing decline seems to consist of two patterns: a mid-frequency dip (0.5–3 kHz region) (MF-HL) and a high-frequency loss (>3 kHz region) (HF-HL). SNHL is associated with genotype and phenotype. It seems that SNHL in these pts can become clinically evident during childhood or adolescence, progressive with time, and is independent of middle ear diseases. The evaluation in follow-up of hearing impairment shows that the high-frequency HL remained stable in time. Instead, SNHL with typical dip had a progressive decline. The rate of hearing loss is high at all frequencies but most prominent in the mid-frequency region and the presence of a mid-frequency dip is an especially strong predictor for a progressive decline of hearing. Hearing loss (HL) could have an important impact on social functioning for pts with TS. Clinicians proposed a regular audiological follow-up in TS, especially during childhood, to prevent important middle ear anatomic sequelae and to identify HL at an early stage.