This suspension
was used as the stock suspension. Turbid water having
35 nephelometric turbidity units (NTU) was prepared by diluting of
stock suspension to 1000 mL tap water just before the coagulation
test. The initial pH of the synthetic water was adjusted to 9.0, 9.5 or
10.0 with 1 mol/L NaOH, in accordance to previous investigations
(ˇS ´ciban et al., 2005) just before experiments.