Table 2.

ζ-potential and pH values of Au1 samples over the five-week experimental period.

Week	ζ –potential [mV]	pH
1	− 24.1 ± 0.5	2.19
2	− 21.9 ± 1.7	2.15
3	− 20.8 ± 0.6	1.77
4	− 20.2 ± 1.4	2.03
5	− 19.9 ± 1.4	2.01