Activated carbons and low cost adsorbents for remediation of
tri- and hexavalent chromium from water.
Hexavalent chromium is a well-known highly toxic metal, considered a priority pollutant. Industrial sources of Cr(VI) include leather tanning,
cooling tower blowdown, plating, electroplating, anodizing baths, rinse waters, etc. The most common method applied for chromate control is
reduction of Cr(VI) to its trivalent form in acid (pH∼2.0) and subsequent hydroxide precipitation of Cr(III) by increasing the pH to ∼9.0–10.0
using lime. Existing overviews of chromium removal only cover selected technologies that have traditionally been used in chromium removal. Far
less attention has been paid to adsorption. Herein, we provide the first review article that provides readers an overview of the sorption capacities
of commercial developed carbons and other low cost sorbents for chromium remediation.
After an overview of chromium contamination is provided, more than 300 papers on chromium remediation using adsorption are discussed
to provide recent information about the most widely used adsorbents applied for chromium remediation. Efforts to establish the adsorption
mechanisms of Cr(III) and Cr(VI) on various adsorbents are reviewed. Chromium’s impact environmental quality, sources of chromium pollution
and toxicological/health effects is also briefly introduced. Interpretations of the surface interactions are offered. Particular attention is paid to
comparing the sorption efficiency and capacities of commercially available activated carbons to other low cost alternatives, including an extensive
table.