Sorption of arsenic from soil-washing leachate by surfactant-modified zeolite

Post-treatment of leachate from soil-washing remedial actions may be necessary depending on the amounts of dissolved contaminants present. Uptake of arsenic species by surfactant-modified zeolite (SMZ) from a synthetic soil leachate (pH of approximately 12 [NaOH]) was measured as a test of SMZ as a...

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Bibliographic Details
Published in:Journal of environmental quality 2003-11, Vol.32 (6), p.2387-2391
Main Authors: Sullivan, E.J, Bowman, R.S, Legiec, I.A
Format: Article
Language:English
Subjects:
Adsorption
Applied sciences
arsenic
Arsenic - analysis
Arsenic - chemistry
chemical treatment
Exact sciences and technology
Humans
leaching
Other wastewaters
polluted soils
Pollution
remediation
Soil Pollutants - analysis
soil pollution
soil washing
sorption
Surface-Active Agents - chemistry
surfactants
washing
Waste Management - methods
Wastewaters
Water treatment and pollution
zeolites
Zeolites - chemistry
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Summary:Post-treatment of leachate from soil-washing remedial actions may be necessary depending on the amounts of dissolved contaminants present. Uptake of arsenic species by surfactant-modified zeolite (SMZ) from a synthetic soil leachate (pH of approximately 12 [NaOH]) was measured as a test of SMZ as a post-treatment sorbent. Batch sorption isotherms were prepared using leachate to SMZ ratios from 40:1 to 4:1, and temperatures of 25 and 15 degrees C. Equilibrium levels of dissolved and total solution arsenic were similar. At each temperature, sorption appeared to reach a plateau or maximum, then decreased at the highest solution concentration, corresponding to the lowest amount of zeolite added (2.5 g). A maximum sorption value of 72.0 mmol of arsenic per kg of SMZ (5400 mg/kg) was observed at 25 degrees C, and 42.1 mmol/kg (3150 mg/kg) at 15 degrees C. Total arsenic recoveries varied from 74 to 125%. Surfactant-modified zeolite removed up to 97% of dissolved organic carbon and decolorized the leachate solutions. Excluding the points for the highest arsenic to SMZ ratio, the sorption isotherms were well described by the linearized form of the Langmuir equation, with coefficients of determination greater than 0.90 at both temperatures. Sorption of arsenic by SMZ is attributed to anion exchange with counterions on the surfactant head groups, and/or partitioning of organic carbon-complexed arsenic into the surfactant bilayer.
ISSN:0047-2425
1537-2537
DOI:10.2134/jeq2003.2387