Usage of Sorbent-Catalyst to Accelerate the Oxidation of Manganese

The work was supported by National research fund of Ukraine, grant No.144/01.2020.The processes of removal of manganese (II) ions from water using sorbent catalysts, ion exchange materials modified with iron oxides have been studied. It is shown that manganese ions oxidize very slowly in artesian water even when the pH is adjusted to 9.0. Intensive aeration of solutions due to stirring also does not promote oxidation of manganese (II) ions. The degree of manganese extraction due to oxidation is reduced from 20–30 % for solutions with a concentration of manganese ions of 1 and 5 mg/dm3 to 11–15 % for solutions with a concentration of 15 and 30 mg/dm3. A significant increase in the oxidation efficiency of manganese ions was achieved by using magnetite as a sorbent catalyst. The efficiency of water demanganization increases with increasing intensity of water aeration when mixing solutions. It has been established that strongly acid cation exchangers provide efficient extraction of manganese ions from water. At the same time, a high exchange capacity of strong acid cation exchange resin KU-2-8 in acid and salt form was noted. It is shown that the capacity of manganese ions of this cation exchange resin in the Ca2+-form is slightly lower. When using the cation exchange resin KU-2-8 in Ca2+-form to remove manganese ions from the solution already in the first samples, the leakage of manganese ions at the level of 10 mg/dm3 and above was observed. This indicates that this form of ion exchanger is not suitable for deep purification of water from manganese (II) ions. To increase the efficiency of manganese ion extraction from water, increase the duration of the filter cycle, magnetite and magnetite-modified cation exchange resin KU-2-8 were used as a sorbent-catalyst. It was shown that the cation exchange resin modified with magnetite provides the removal of a significant part of manganese ions due to catalytic oxidation on magnetite. The conditions of effective manganese extraction in static and dynamic conditions are determined