FUNCTIONAL GROUPS AND ION EXCHANGE PROPERTIES

Publisher Summary This chapter discusses the different functional groups and ion-exchange properties of Victorian brown coals. In Victorian brown coals, however, carbon and oxygen together account for up to 95% of the organic matter with hydrogen accounting for most of the remainder. Sulfur and nitrogen are generally only minor contributors. The oxygen content of Victorian brown coals is usually in the range of 25 to 30 percent (dry basis) and the mode of its occurrence has long been of considerable interest and a challenge. The oxygen containing functional groups, particularly the acidic, carboxyl and phenolic groups in Victorian brown coals have attracted considerable interest, as these two groups, together, account for the larger portion of the total oxygen present in Victorian brown coals and are responsible for the ion-exchange properties of these coals. The carboxyl groups and the associated cations markedly influence the ion-exchange properties of brown coals and, hence, their behavior in use.