Effect of pH, competitive anions and NOM on the leaching of arsenic from solid residuals

摘要: Implementation of the new arsenic MCL in 2006 will lead to generation an estimated 6 million pounds arsenic-bearing solid residuals (ABSRs) every year, which be disposed predominantly non-hazardous landfills. The Toxicity Characteristic Leaching Procedure (TCLP) is typically used assess whether a waste hazardous and most pass TCLP. However, recent research shows TCLP significantly underestimates mobilization A variety compositional dissimilarities between landfill leachates extractant solution likely play role. Among abiotic factors key role remobilization/leaching from sorbents are pH, concentrations natural organic matter (NOM) anions like phosphate, bicarbonate, sulfate silicate. This study evaluates desorption actual treatment sorbents, activated alumina (AA) granular ferric hydroxide (GFH), representative those predicted for use removal processes, as function specific range pH competitive NOM found influence much more significant than that competing or NOM. An increase one unit may fraction leached by 3-4 times. phosphate replace sorbent surface sites up three orders magnitude silicate, on per mole basis. Effects neither additive nor purely competitive. tests, compare mobilized vis-a-vis realistic synthetic leachate, indicate higher greater all factors, but varying significance, causing extraction