Scoping candidate minerals for stabilization of arsenic-bearing solid residuals.
Arsenic Crystallization Technology (ACT) is a potentially eco-friendly, effective technology for stabilization of arsenic-bearing solid residuals (ABSRs). The strategy is to convert ABSRs generated by water treatment facilities into minerals with a high arsenic capacity and long-term stability in mature, municipal solid waste landfills. Candidate minerals considered in this study include scorodite, arsenate hydroxyapatites, ferrous arsenates (symplesite-type minerals), tooeleite, and arsenated-schwertmannite. These minerals were evaluated as to ease of synthesis, applicability to use of iron-based ABSRs as a starting material, and arsenic leachability. The Toxicity Characteristic Leaching Procedure (TCLP) was used for preliminary assessment of candidate mineral leaching. Minerals that passed the TCLP and whose synthesis route was promising were subjected to a more aggressive leaching test using a simulated landfill leachate (SLL) solution. Scorodite and arsenate hydroxyapatites were not considered further because their synthesis conditions were not found to be favorable for general application. Tooeleite and silica-amended tooeleite showed high TCLP arsenic leaching and were also not investigated further. The synthesis process and leaching of ferrous arsenate and arsenated-schwertmannite were promising and of these, arsenated-schwertmannite was most stable during SLL testing. The latter two candidate minerals warrant synthesis optimization and more extensive testing.
Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85641-0011, USA.
Madhumitha
M
Raghav
Jilei
J
Shan
A Eduardo
AE
Sáez
Wendell P
WP
Ela
D001149:Arsenates / Q000737:chemistry; D001151:Arsenic / Q000737:chemistry*; D003460:Crystallization; D052918:Environmental Restoration and Remediation; D005290:Ferric Compounds / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D058085:Iron Compounds / Q000737:chemistry; D008422:Materials Testing; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods*; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry; D013696:Temperature; D064091:Waste Disposal Facilities; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
D001149:Arsenates; D005290:Ferric Compounds; D058085:Iron Compounds; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; C511969:schwertmannite; C477679:tooeleite; C092844:ferric oxyhydroxide; D007501:Iron; D001151:Arsenic; C025657:arsenic acid
ABSRs; ACT; Arsenic residuals; BAT; Best Available Technologies; CA-WET; California Waste Extraction Test; DI; EDX Spectroscopy; EPA; Environmental Protection Agency; FA; Ferrous arsenate; ICDD; ICPMS; International Centre for Diffraction Data; Landfills; MSW; PS; SEM; SLL; SSRL; ST-XRD; Schwertmannite; Stanford Synchrotron Radiation Lightsource; TC; TCLP; Tooeleite; X-ray diffraction; XRD; arsenic crystallization technology; arsenic-bearing solid residuals; deionized; energy dispersive X-ray spectroscopy; ferrisymplesite; inductively coupled plasma mass spectrometer; municipal solid waste; parasymplesite; scanning electron microscopy; simulated landfill leachate; synchrotron transmission X-ray diffraction; toxicity characteristic; toxicity characteristic leaching procedure