Synthesis of Tantalum Carbide Using Purified Hexane by Titanium Powder.

Hexane is a safe, efficient, and cost-effective alternative to other commercial hydrocarbons for gaseous carburization; however, commercial hexane is not sufficiently pure. Titanium powder can remove oxygen-containing impurities from commercial hexane; however, research on the use of titanium powder remains limited. We investigated the purification of hexane using titanium, copper, and aluminum powders and used the purified hexane for the gaseous carburization of tantalum. Ti exhibited lower activation energy for oxidation (1.55 kJ/mol) than Cu (91.09 kJ/mol) and Al (150.25 kJ/mol) and a significantly higher oxidation rate (0.0269 g/h) in hexane at room temperature than Cu (0.0018 g/h) and Al (0.0001 g/h). The carbon content in tantalum carburized using the purified hexane was comparable to that carburized using unpurified hexane (approximately 6.22%); however, its oxygen content was significantly lower (1.39%), which indicates that the produced tantalum carbide has a higher purity. X-ray diffraction results revealed that the oxidation products of tantalum, such as Ta2O, TaO2, Ta0.8O2, and Ta2O5, were absent in the sample carburized using the purified hexane. Therefore, Ti powder can effectively remove oxygen-containing impurities from commercial hexane and facilitate its use as an effective carburizing medium for the synthesis of high-purity tantalum carbide.

Complete Genome and Plasmid Sequences of Raphidiopsis curvispora Strain GIHE-G1, Isolated from a Drinking Water Reservoir in South Korea.

The complete genome and plasmid sequences of Raphidiopsis curvispora strain GIHE-G1, a coiled filamentous heterocyst-forming cyanobacterium isolated from a drinking water reservoir in South Korea, are reported here. The genome information is expected to improve understanding of this species.