Hexavalent Chromium

About Hexavalent Chromium

Hexavalent chromium (Cr⁶⁺) is a highly toxic, mobile, and soluble form of chromium commonly found at industrial sites — particularly those with historical metal plating, leather tanning, wood treatment, or cooling tower operations. Cr⁶⁺ is a known human carcinogen and is tightly regulated in drinking water. In contrast, trivalent chromium (Cr³⁺) is essentially non-toxic at environmental concentrations and tends to precipitate and immobilize in the subsurface. Effective remediation converts Cr⁶⁺ → Cr³⁺ through chemical reduction.

Calcium Polysulfide (Remotox CaSx)

Hepure is a premier calcium polysulfide supplier. Our Remotox product is used worldwide for the remediation of sites contaminated with heavy metals, including hexavalent chromium. Calcium polysulfide chemically reduces Cr⁶⁺ to Cr³⁺, which then precipitates in the subsurface as an insoluble chromium hydroxide. Remotox is applied via injection or soil mixing depending on site conditions.

Zero Valent Iron

Ferox ZVI powders reduce hexavalent chromium through electron transfer at the iron surface. Cr⁶⁺ is reduced to Cr³⁺ as iron is oxidized, and the resulting chromium compounds are typically immobilized as Cr-Fe hydroxide precipitates. Ferox PRB is commonly used in permeable reactive barriers for long-term Cr⁶⁺ plume treatment, while Ferox Flow and Target support injection and soil mixing applications.

Ferrous Sulfate

Ferrous sulfate (FeSO4) provides a source of ferrous iron (Fe²⁺) that directly reduces Cr⁶⁺ to Cr³⁺ in aqueous solution. It is often used in combination with alkaline pH adjustment (via sodium hydroxide) to maximize chromium precipitation and immobilization.