; but for pH
5.2 ± 0.2 the equilibrium is achieved after 7 days. Now, if the initial
pH is analyzed, it can be noticed that for L. nigrescens there is not a
significant difference in cadmium uptake with pH for the lower
concentration.
This changes when the same biosorbent is used
with higher cadmium concentration, where the difference is about
15% between the retentions when working with initial pH of
3.7 ± 0.2 and 5.2 ± 0.2; with the best uptake at the last value.
With D. antarctica, the cadmium retention once the equilibrium
is achieved does not show significant difference between the initial
pH values used in this work