Chromium is one of the major contaminants in wastewater as
it is widely used in industries, the most important sources being
pigments, electroplating, leather and mining industries. Chromium
is present in the aqueous environment as Cr3+ and Cr6+. Hexavalent
chromium exists in water as oxyanions such as chromate (HCrO4−)
and dichromate (Cr2O72−)