Efficiency of metabisulfite and a commercial
steel wool as reducing agents in the removal of Cr(VI)
from wastewaters was evaluated. Chromium(VI) was
converted to Cr(III), precipitated with NaOH, and removed
by filtration. A reduction of more than 1.0 9 105 and
4.0 9 105 fold in total Cr and the Cr(VI) concentrations,
respectively, was observed by employing steel wool masses
as low as 0.4420 g to 30-mL solutions of wastewater.
Chromium(III) hydroxide obtained after the treatment was
recycled and used as marker in cattle nutrition studies. The
liquid residue obtained after the treatment was reused as
precipitation agent replacing NaOH.