title: Remediation of arsenic and lead with nanocrystalline zinc sulfide.
abstract: Nanocrystalline (1.7 ± 0.3 nm) zinc sulfide with a specific surface area up to 360 m(2) g(-1) was prepared from the thermal decomposition of a single-source precursor, zinc ethylxanthate. Zinc ethylxanthate decomposes to cubic zinc sulfide upon exposure to temperatures greater than or equal to 125 °C. The resulting zinc sulfide was tested as a water impurity extractant. The target impurities used in this study were As(5+), As(3+), and Pb(2+). The reaction of the nanocrystalline ZnS with Pb(2+) proceeds as a replacement reaction where solid PbS is formed and Zn(2+) is released into the aqueous system. Removal of lead to a level of less than two parts per billion is achievable. The results of a detailed kinetics experiment between the ZnS and Pb(2+) are included in this study. Unlike the instance of lead, both As(5+) and As(3+) adsorb on the surface of the ZnS extractant as opposed to an ion-exchange process. An uptake capacity of > 25 mg g(-1) for the removal of As(5+) is possible. The uptake of As(3+) appears to proceed by a slower process than that of the As(5+) with a capacity of nearly 20 mg g(-1). The nanocrystalline zinc sulfide was extremely successful for the removal of arsenic and lead from simulated oil sand tailing pond water.
authors: Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA.
authors: Alan
authors: A
authors: Piquette
authors: Cody
authors: C
authors: Cannon
authors: Allen W
authors: AW
authors: Apblett
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000302:isolation & purification*; D052918:Environmental Restoration and Remediation / Q000379:methods; D007854:Lead / Q000302:isolation & purification*; D053758:Nanoparticles / Q000737:chemistry*; D012989:Soil Pollutants / Q000302:isolation & purification*; D013440:Sulfides / Q000737:chemistry*; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D012989:Soil Pollutants; D013440:Sulfides; D014874:Water Pollutants, Chemical; D017967:Zinc Compounds; D014867:Water; D007854:Lead; C031238:zinc sulfide; D001151:Arsenic