The pH of the Hg (II) solutions was
varied in the range of 4.0–10.5. The maximum sorption of Hg (II)
occurred at pH 8.0, as illustrated in Fig. 1. In an acidic environment
the formation of the complex is not observed, possibly due to competition
with H3O+ in active sites of the sorbent. At pH values above
9.0 the signal decreases due to hydroxide formation, thereby
decreasing the formation of the mercury complex.