Chromium, zinc, copper, lead, cadmium, mercury and arsenic are among the most common metal contaminants found on remediation project sites. REMOTOX® (a Calcium Polysulfide Solution) precipitates these highly soluble metals as less soluble, less toxic metal sulfides. In the case of chromium, the metal precipitates as chromium hydroxide. See Elements and their Potential In-Situ Precipitates.
Calcium Polysulfide is a NSF (NSF International) approved reagent for drinking water treatment. Over the past 30 years, numerous applications have been successfully conducted at various remediation sites around the world. No detrimental impact to the environment and public health and safety have been observed. Calcium Polysulfide is also widely used in agricultural applications on fruit trees and berries, and as a soil conditioner for treating sodic and saline-sodic soils.
When introduced into the environment, Calcium Polysulfide dissociates to form bisulfide, aqueous hydrogen sulfide and other sulfur compounds, Heavy metal ions are precipitated as less soluble, less toxic metal sulfides by these breakdown products. Metal hydroxides change solubility with changes in pH. Metal sulfides remain insoluble within a wide pH range. See Solubility of Metal Hydroxides and Sulfides as a Function of pH. While effective treatment can be achieved over a wide pH range, best results are typically obtained within pH 7-10. Adjustments to pH of the treatment system can enhance the metal precipitation process. See Treatment of Soluble Metal Streams.
The US EPA has identified calcium polysulfide as a reagent suitable for use in in-situ chemical reduction (ISCR), stabilization and solidification of multiple contaminants. Several abstracts and studies are available through CLU-IN, the Hazardous Waste Clean-Up Information website, sponsored by the US EPA.
Bench scale evaluation and case studies on Calcium Polysulfide for the remediation of hexavalent chromium in chromite ore processing residue (COPR) can also be found in the Chromium (VI) Handbook. Purchasing information available at CRC Press Online or at Amazon.com.
Furthermore, we are pleased to announce we now have a Principal Scientist/Geohydrologist with extensive experience in site investigation and remediation to provide better technical assistance and support to our valued customers.