Table 1.

Characteristics of the studied metal NPs

NPs	Mn	Cu	Al	ZnO (Singh et al. 2011)
Primary size (nm)	20 ± 7 (Hedberg et al. 2016b)	100 ± 34 (Hedberg et al. 2016b)	70 ± 26 (Hedberg et al. 2016b)	120 ± 90
Isoelectric point (pH)	3.2 ± 0.6 (Hedberg et al. 2016b)	N/A	6.6 ± 0.7 (Hedberg et al. 2016b)	N/A
Zeta potential (mV)	−24 ± 3 (pH 6.5)	10 ± 2 (pH 5.2)	24 ± 3 (pH 5.2)	−26 ± 4 mV
BET surface area (m2/g)	25.5 ± 1.0 (Hedberg et al. 2016b)	7.2 ± 0.7 (Hedberg et al. 2016b)	13.9 ± 0.7 (Hedberg et al. 2016b)	12.4 ± 0.6