Adsorption and catalytic oxidation removal of Mn by MnO with different crystal structures: Structure-activity relationship and mechanism.

This study investigates the impact of MnO crystal structures on Mn removal in drinking water for the first time. α-, γ-, and δ-MnO phases were synthesized, showing a removal process involving adsorption (Mn was adsorbed as the state of Mn(OH)), saturation, and catalytic oxidation. The adsorption capacity followed δ- > γ- > α-MnO, aligning with the Mn oxidation state.

Comparing Mn-based oxides filters started by KMnO versus KFeO for ammonium and manganese removal: Formation mechanism of active species.

A pilot-scale filtration system was adopted to prepare filter media with catalytic activity to remove manganese (Mn) and ammonium (NH-N). Three different combinations of oxidants (KMnO and KFeO) and reductants (MnSO and FeCl) were used during the start-up period. Filter R3 started up by KMnO and FeCl (Mn→MnO) exhibited excellent catalytic property, and the NH-N and Mn removal efficiency reached over 80% on the 10 and 35 days, respectively.