Effects of magnetization on Fe(iii) species in magnetically enhanced coagulation ultrafiltration processes

Abstract

The effects of magnetization on floc properties and membrane fouling in magnetically enhanced coagulation ultrafiltration (MEC-UF) processes for micro-polluted water treatment were investigated in this study. The results showed that the magnetized seeds could influence the distributions of Fe(III) species due to their residual magnetic flux density after magnetization. The hydrolysis products of Fe(III) were affected by the Fe₃O₄ suspension at various magnetization times, which influenced the coagulation performance and floc properties of Fe(III). The magnetized Fe₃O₄ suspension not only increased the quantity of particles in the micro-polluted water but also affected the sum of Fe_a and Fe_b of Fe(III), especially Fe_a. However, online measurement of Fe(III) species showed that the MEC-UF process with 4 min magnetization made the best use of Fe_a. Therefore, the flocs of MEC-UF were much larger with higher strength factor and recovery factor, and the cake layers were looser and more porous. This leads to a better knowledge about magnetically enhanced coagulation for membrane fouling reduction.