ABSTRACT
In this chapter, formation and sorption properties of iron oxides and manganese oxyhydroxide are discussed. In particular, synthesis of the hematite particles and formation of maghemite particles and their properties are discussed, and experimental results are presented. Next, main characteristics of manganese oxyhydroxide synthesis in alkaline solutions, as well as synthesis of manganese dioxide, are presented, and the obtained features and sorption capability are described. At the end, sorption characteristics of iron oxides and manganese dioxide and oxyhydroxide are presented. It was found that the magnetite phase formation is dependent substantially on the precipitation temperature. The obtained particle shape was spherical irrespective of the precipitation conditions, and their dimensions were between 7 and 15 nm. Larger particles with higher magnetization were noted to be formed in higher precipitation temperatures and lower iron concentrations. Compared with the iron oxides, manganese oxyhydroxide particles perform substantially better sorption capacity toward the metals. Sorption capacity of iron oxides does not depend on phase composition but is increased when specific surface area (SSA) is larger. On the other hand, changes in particles of manganese oxyhydroxide SSA have no effect on their sorption capacity. However, sorption properties of the manganese oxyhydroxide particles worsen very fast.
