Nitrate-Reducing Magnetic Hybrid Coagulant for Rapid and Advanced
Wastewater Treatment and its Mechanistic Investigation
Abstract
Dissolved contaminants (NO3--N, etc.)
in municipal sewage effluent and polluted water resources need to be
further removed, but common advanced water treatment technologies
usually have unsatisfactory performance and large process footprints.
Magnetic seeding coagulation (MSC) has a rapid settling speed; however,
it is less effective for removing dissolved contaminants and cannot
recovers effective components. Herein, a novel covalently bound magnetic
hybrid coagulant (MHC) was synthesized and used to treat secondary
biological effluent. MHC settling time was 2/3 shorter than traditional
MSC and showed high removal efficiencies for conventional coagulation
indicators and dissolved contaminants such as
NO3--N and organic nitrogen. The
NO3--N removal mechanisms included
NO3--N capture through the
electrostatic attraction and the collision efficiency enhancement. MHC
integral structure can be bioregenerated for multiple cycles. Because of
its effectiveness in removing dissolved contaminants rapidly, MHC has
potential application in advanced water treatment, especially in
land-scarce areas.