New insights into the combination of Fe(III) and xanthan gum in dewatering of coal slurry: Molecular self-assembly

Abstract

Aggregation is an economical and widely existing method to in fine coal particles dewatering, but the effect of cations on the flocculation activity of different bio-flocculant was inconformity. In this work, the aggregation behavior of coal slurry using XG combination Fe3+ was investigated. The adsorption of FeCl3·6H2O and XG was investigated via wetting heats, water contact angle, Zeta potential and SEM-EDS testing. The results show that the combination of FeCl3·6H2O and XG could build up layer-by-layer self-assembly multilayers on coal particles surface. Further, solution chemistry, FTIR and XPS analyses were performed to detect the adsorption mechanism. The results indicate that Fe(OH)3(s) covering and coordination reaction of the Fe active sites with the polar groups of XG are the main driving force for the self-assembly. The obtained settling tests results show a great potential of the combination of XG combination Fe3+ in the dewatering of coal slurry. The flocculation dewatering model of coal with FeCl3·6H2O and XG was drawn.