sc8b03593_si_001.pdf (840.29 kB)
Nanoscale Zero-Valent Iron Coated with Magnesium Hydroxide for Effective Removal of Cyanobacteria from Water
journal contribution
posted on 2018-09-27, 00:00 authored by Jiajia Fan, Yi-bo Hu, Xiao-yan LiThe
effects of nanoscale zero-valent iron (NZVI, as a benchmark)
and a novel core–shell structured nanoparticle, magnesium hydroxide
coated NZVI (NZVI@Mg(OH)2), on the removal and viability
of a cyanobacterium, Microcystis aeruginosa, in water
were investigated. Dosing of these two nanoparticles at concentrations
between 20 and 100 mg/L led to various degrees of sedimentation of
cyanobacterial cells from the water column. NZVI@Mg(OH)2 exhibited much better ability to remove cyanobacteria than NZVI.
A cell removal efficiency of 86.6% was achieved after 0.5 h with the
lowest dosage (20 mg/L) of NZVI@Mg(OH)2, whereas the highest
dosing concentration of NZVI (100 mg/L) resulted in the removal of
only 57.5% of cells. This improved effectiveness can be attributed
to the reduction in electrostatic repulsion between the cyanobacterial
cells and NZVI@Mg(OH)2. The membrane integrity of the settled
cyanobacterial cells in the sediment was significantly disrupted after
the addition of a 100 mg/L dose of NZVI, which may lead to the release
of unwanted intracellular metabolites. In contrast, the viability
of the settled cyanobacteria was nearly unaffected after treatment
with NZVI@Mg(OH)2. It can be concluded that NZVI@Mg(OH)2 is highly effective in the removal of cyanobacteria from
the water column. The Mg(OH)2 coating not only protects
the NZVI cores from corrosion in water but also reduces the toxicity
of NZVI toward cyanobacterial cells when NZVI technology is applied
for cyanobacteria control and removal in water supply and treatment.