Abstract:
An experimental investigation of using hematite to remove natural
organic substances from water was carried out. Hematite sols (iron
oxide, α-Fe₂O₃) prepared in the laboratory were found to form
floes with natural organic substances. Jar tests revealed that when
a 85 mg/L hematite concentration (as Fe) was used, natural organic
substances in the form of fulvic acid (4 mg/L) were totally removed.
Direct filtration experiments using hematite were effective
in removing dissolved organic carbon (DOC) from water; however
the large hematite-organic floes clogged the filter and reduced the
filter run.
A conventional filtration system, which included flocculation
and sedimentation prior to filtration, was found to be very effective
at removing total DOC from water. An 86 mg/L hematite
concentration (as Fe) was found to effectively remove 4 mg/L of
fulvic acid from Milli-Q water. A residual iron concentration in the
final effluent from the filtration unit was well below the allowable Australian drinking water guideline. Further research is warranted
to optimize hematite concentration, pH, and ionic strength for application
of this process in conventional water treatment plants.
