Utilization of low rank coal as oxidation catalyst by controllable removal of its carbonaceous component
Abstract
Controlled removal of carbonaceous component in low rank coal by sulfonation followed by calcination
demonstrated that it is a simple and effective method to utilize this material as catalyst in the oxidation
of styrene. Low rank coal is one of the least utilized categories of coal. However, it shows excellent
potential as a catalyst due to high concentrations of carbon and other elements, such as transition metals,
which are embedded inside its structure. In this research, the low rank coal was treated by sulfonation
followed by calcination in order to activate the transition metals embedded in it. The catalytic activity of
the treated low rank coal was tested in the oxidation of styrene by aqueous hydrogen peroxide. The low
rank coal showed high catalytic activity after sulfonation and calcination at 700 8C, with 3% of styrene
conversion and 97% of selectivity toward benzaldehyde. The transition metal active sites in low rank coal
that play the most important role in the oxidation of styrene were determined by coal mimicking
models. The presence of cobalt oxide and titanium oxide active sites in the low rank coal plays the most
significant role in the oxidation of styrene by aqueous hydrogen peroxide.