In the pursuit of green chemistry, adequate substitutes for lead acetate and hydrogen sulfide were investigated for use in the ACS test procedure for stabilizer in meta-phosphoric acid. In the current ACS procedure lead acetate is used to form insoluble lead phosphate. In order to remove lead from the solution lanthanum chloride was investigated with positive results. Hydrogen Sulfide is currently used to precipitate lead by forming insoluble lead sulfide. Several substitutes including oxalic acid and sulfuric acid were investigated. Preliminary testing showed that lanthanum chloride and oxalic acid are sufficient in precipitating phosphate and lead out of the sample solution
Atlas, Christopher and Lacock, Ron, "Removal of Pb and H2S from ACS Test Procedure For Meta-Phosphoric Acid" (2015). Student Research Day Abstracts and Posters. 121.