Towards a Definition of Harmless Nanoparticles from an Environmental and Safety Perspective

Figure 3

((a)–(c)) Nitrate removal efficiency in the reactors with different concentrations of Si NPs. Nitrate removal efficiency of (a) the first cycle, (b) the third cycle, and (c) the sixth cycle. ((d)–(f)) Nitrate removal efficiency in the reactors with different concentrations of Fe₂O₃ NPs. Nitrate removal efficiency of (d) the first cycle, (e) the third cycle, and (f) the sixth cycle. Mean ± standard.

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