Papers by Keyword: Sequential Extraction Procedure

Abstract: In this paper, the modes of occurrence of the trace elements of Na, K, Fe and Si in SX-Coal and SD-Coal, which were used for COREX process, were analyzed. The coal was treated by wet digestion method and then the content of trace elements was analyzed. After that, the modes of occurrence of the elements were studied by sequential extraction procedure method and analyzed by ICP-OES. The results showed that the content of Na element is the highest and the content of K and Si elements is very low among the four elements in both kinds of coal. Na and K elements mainly exist in the mode of residue in SX-Coal and SD-Coal, and they are tends to enriched in the residue during the pyrolysis. Fe and Si elements mainly exist in the mode of carbonate, iron oxides and manganese oxides in SD-Coal. Fe and Si are tends to be decomposed from the compounds during the pyrolysis.

Abstract: This paper reports a study on distribution characteristics of phosphorus and its species in 20 sediments samples from Lakes Baihua and Aha, based on the technique of sequential extraction. Baihua and Aha, two man-made reservoirs, are key drinking-water sources. The results, compatible with local geophysical characteristics, indicate that in sediments from both lakes, the concentrations of inorganic phosphorus (IP) were higher than those of organic phosphorus (OP), and the IP consisted mainly of calcium-bound phosphorus (Ca-P), which may temporarily control phosphorus release. Moreover, the concentrations of total phosphorus (TP) in both lakes sediments were high, thus phosphorus release potential and bioavailability were highly significant. Further statistical analyses revealed significant correlations with two extractable principal components allowing interpretation of possible origins of phosphorus loadings. Furthermore, available remediation measures were briefly evaluated for both lakes in consideration of their distinctive environmental features.