Investigation of changes in surface properties of bituminous coal during natural weathering processes by XPS and SEM

Insight into the Influence of Surface Roughness on the Wettability of Apatite and Dolomite

“…As know from the literature, the surface chemical properties, such as element composition [15,16], charge [17], and functional group [18], have an important influence on the wettability of minerals.…”

Effects of oxidative weathering on the composition of organic matter in coal and sedimentary rock

“…7). Previous studies also reported a decreasing trend of alkyl-C content in bitumen, kerogen and surface organics of coals (Huffman et al, 1985;Wu et al, 1988;Clemens et al, 1991;Pisupati and Scaroni, 1993;Martínez and Escobar 1995;Xia et al, 2014) and sedimentary rocks (Moss et al, 1988;Faure et al, 1999;Petsch et al, 2000Petsch et al, , 2001b with oxidative weathering. This loss of alkyl-C may be related to the oxidative cleavage of labile alkyl moieties, such as olefinic and benzilic carbon (Rhoads et al, 1983;Wu et al, 1988;Wade, 1995;Hayashi et al, 1997;Faure et al, 1999) in SOM.…”

“…However, carbonyl-C tends to dominate over O-alkyl-C with further oxidative weathering (Pisupati and Scaroni, 1993;Chang and Berner, 1998;Gong et al, 1998;Petsch et al, 2001b;Grzybek et al, 2006;Xia et al, 2014), owing to Oalkyl-C transformations to carbonyl-C (Lynch et al, 1987;Clemens et al, 1991;Gong et al, 1998;Wang et al, 2003). Therefore, FA is not likely to be produced in significant quantities via oxidative weathering of SOM, because FA is characterized by an abundance of O-alkyl-C (Fig.…”

The effects of particle grinding on the burnout and surface chemistry of coals in a drop tube furnace

“…The previous section used bulk analysis techniques to investigate sample changes, but the interfacial gas-solid reaction is fundamental in coal combustion, herein we investigate the surface chemistry using XPS, which looks specifically at the coal surface to a depth of circa 10 nm [40]. A valuable aspect of this technique is the information that it gives regarding the surface chemistry and this has been used previously for coal research to compare the effect of rank, ash mineral associations, and the effect of weathering on the surface of coals [32,[41][42][43][44].…”