ABSTRACT
The metallic elements in high-temperature coal tar pitch (HCTP) will affect the properties of carbon materials produced from the HCTP. The study on the metallic elements in HCTP is essential for the quality improvement of its derived carbon materials. In this paper, the content of 15 metallic elements in HCTP and its four group components, including n-heptane-soluble substance (HS), n-heptane-insoluble-toluene-soluble substance (HI-TS), toluene-insoluble-quinoline-soluble substance (TI-QS), and quinoline-insoluble substance (QI), was determined. The results show that the content of Na, Ca, Fe, Mg, Zn, K, Pb, and Al is more than 100 ppm and is much higher than that of other metallic elements. The content of Ni, V, Cr, Mo, Sb, Cu, and Mn ranges from 0 to 50 ppm. By mass calculation of the contents of four group components in HCTP, it can be concluded that Na and Fe are randomly distributed in the group components. Al, Zn, Pb, V, and Mn are mainly distributed in the inorganic form in the QI component. Ca, Mg, K, Ni, Cr, Mo, Sb, and Cu are mainly distributed in the small molecular group components such as HS and HI-TS.
ABSTRACT
Novel highly active visible light photocatalysts BiOBr-TiO2 nanocomposites were prepared by a facile one-pot solvothermal approach. Series of characterizations verified that the BiOBr nanoscale crystals are highly dispersed in amorphous TiO2 to form the hybrid mesoporous structure. The material shows excellent photocatalytic performance towards photodegradation of Rhodamine B under visible light irradiation. The content ratio between TiO2 and BiOBr plays a key role in the microstructure of the nanocomposites, so as to result in distinguished photocatalytic activity. The sample with a molar ratio of 10 between TiO2 and BiOBr shows the optimum performance. The high photocatalytic activity of BiOBr-TiO2 nanocomposites under visible light could be ascribed to the large surface area, opened mesoporous structure, appropriate band-gap, as well as synergistic effect between TiO2 and BiOBr. Besides, the BiOBr-TiO2 composites render a facile separation due to the three-dimensional superstructure. The BiOBr-TiO2 photocatalyst is very promising for water purification as well as other environmental applications.
