Effects of Fe(OH)3 and MnO2 Flocs on Iron/Manganese Removal and Fouling in Aerated Submerged Membrane Systems

Abstract

Many treatment methods are used to remove iron and manganese from water. Aeration and membrane filtration are two of these methods. In this study, Fe2+ and Mn2+ removal by aeration with different catalysts and instead of simple membrane filtration applied in other studies, the aerated-submerged membrane systems were evaluated separately. When Fe(OH)3 was applied in the aeration step and complete oxidation of Fe2+ was obtained after 27 min, while complete Mn2+ oxidation was obtained in 76 min. However, when MnO2 was applied in the aeration step, complete oxidation of Fe2+ and Mn2+ was relatively slow (36 and 110 min, respectively). According to the results obtained from the aerated membrane system, Fe2+ and Mn2+ removal were extended by Fe(OH)3 via adsorption/surface oxidation. It is clearly shown from the flux, resistance results, scanning electron microscope (SEM) and Fourier transform infrared (FT/IR) spectroscopy observation that manganese oxides were deposited mainly in membrane pores forming membrane fouling by small flocs, while iron oxide particles were deposited on the membrane surface. Although the flux performance of PT PES membrane was higher than HF PP membrane, fouling resistance of HF PP membrane was higher than PT PES.

Investigation of the Effect of Leachate on Permeability and Heavy Metal Removal in Soils Improved with Nano Additives

“…In this study, manganese is the heavy metal with the highest removal rate after iron. Similar to the removal rate of iron, iron hydroxide and manganese dioxide flocks formed in the upper part of the kaolin samples, and the cavities contributed to the adsorption of manganese, thereby increasing the removal rate [42].…”

“…This is related to the high concentration of iron in leachate compared to other metals. Moreover, the reaction of oxygen with iron in leachate and between the cavities of compressed kaolin samples in reactors causes the formation of iron hydroxide flocs, which contribute to the adsorption of iron [42]. Over 90 days, the kaolin + 5% Oltu clay sample showed the best performance in terms of iron removal.…”