The presence of heavy metal ions in water constitutes a serious
environmental problem because many of them are highly toxic and
may accumulate in living organisms, causing severe disorders and
diseases [1]. For example, it is known that nickel compounds are
potentially carcinogenic for humans [2]. Exceeding the critical concentration
of this transition metal (estimated to be 0.05 mg cm−3
in nickel equivalents per 40-h work week) may also cause serious
lung and kidney problems aside from gastrointestinal distress,