Remediation and liquid-liquid phase transfer extraction of chromium(VI). A review

Chromium(VI) is a widely used industrial chemical, and is generally considered to pose a greatest human health risk because it is more toxic, more soluble, and more mobile than chromium(III). Workers in industries that use chromium, in particular stainless steel welding, chromate production, chromium plating, and chrome pigment industries, where exposure via inhalation of aerosols is primarily to hexavalent chromium, are at increased risk of chromium effects. In this article we demonstrate various studies regarding remediation methods in particular liquid-liquid extraction of chromate and dichromate anions with various functionalized calixarenes. This review article briefly discusses various molecular designs of calixarene-type macrocycles for chromium(VI) oxoanion recognition, and gives examples on the relationship between structure and selectivity. The article does not, however, attempt to cover all of the different approaches to chromium(VI) extraction. A review with 73 references.