1 research outputs found
Effects of Stabilizers and Water Chemistry on Arsenate Sorption by Polysaccharide-Stabilized Magnetite Nanoparticles
Magnetite nanoparticles were synthesized with starch
and sodium
carboxymethyl cellulose (CMC) as a stabilizer, and tested for enhanced
arsenate removal. Starch at ≥0.04 wt % or CMC at ≥0.005
wt % stabilized 0.1 g/L (as Fe) of the nanoparticles. While CMC-stabilized
magnetite displays a highly negative zeta (ζ) potential, starch-stabilized
magnetite shows a nearly neutral surface. Increasing the starch concentration
from 0 to 0.04 wt % doubles the arsenate uptake, yet the nanoparticles
remain settleable by gravity. Further increasing the starch concentration
to 0.1 wt % results in fully dispersed nanoparticles and increases
the arsenate uptake by 14%. Starch-stabilized magnetite offers a much
faster sorption rate and greater capacity than CMC-stabilized magnetite.
The sorption kinetics can be modeled using an intraparticle-diffusion
model. The sorption capacity increases with decreasing pH. Dissolved
organic matter at 20 mg/L as TOC decreases the arsenate uptake by
19.1%. When aged for >1.5 years, the nanoparticles did not show
any
arsenate leaching or particle dissolution