Poly(S-r-limonene)-coated silica was evaluated as a mercury sorbent over a range of pH values and also in the presence of sodium chloride. The sorbent rapidly removed HgCl2 from water at or near neutral pH. Slightly reduced rates of uptake were observed at both low and high pH, but the sorbent was still effective across this wide pH range. One-reaction or two-reaction kinetic models were fitted to the experimental sorption results. These modes suggest that under low (acid) and neutral pH conditions, mercury sorption is a single reaction process which will ultimately proceed to completion until one or both of the mercury or the sorbent is consumed.