Rmt Limited

National University of Singapore

Robert R Stanforth

Paul V Knopp

A method for reducing the solubility of lead during digestion or in the environment has been developed. Lead is incorporated into a solid material formed by the in situ oxidation of iron. This can be accomplished by introducing ferrous iron into the soil, either in solid or liquid form, and then oxidizing the iron with either air or an introduced oxidant. Solubility of the lead is significantly reduced even under very acidic conditions by incorporation into the iron oxide material. Acid generated during the oxidation and precipitation of iron can be neutralized using common neutralizing agents such as limestone, lime, magnesium oxide, or magnesium hydroxide. In another method, the calcium or magnesium can be added either as neutral salts or as salts of alkaline anions, e.g., calcium carbonate. The calcium and magnesium ions form strong complexes with digestive enzymes, preventing the lead from forming soluble lead complexes with the enzymes. This reduces the bioavailability of the lead.

Reducing lead bioavailability

The present invention involves a method of removing paint containing heavy metal from a surface without the production of hazardous wastes. Specifically, this method involves applying a coating preparation to the heavy metal containing paint prior to its removal from its surface. The preparation contains lead reactive chemicals such as phosphates, metal sulfides and organic sulfides. The preparation may also contain buffers such as magnesium oxide and magnesium hydroxide. These chemicals react with the heavy metals rendering them nonhazardous. The invention also involves the coating preparation itself.

Growing community of inventors

Singapore, Singapore

Robert R Stanforth