Low-temperature persulfate activation by powdered activated carbon for simultaneous destruction of perfluorinated carboxylic acids and 1,4-dioxane

• Published in: Journal of hazardous materials Vol. 442; p. 129966
• Main Authors: Manz, Katherine E., Kulaots, Indrek, Greenley, Caroline A., Landry, Patrick J., Lakshmi, K.V., Woodcock, Matthew J., Hellerich, Lucas, Bryant, J. Daniel, Apfelbaum, Mike, Pennell, Kurt D.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-01-2023
• Subjects: 4-dioxane; DMPO radical adducts; In-situ chemical oxidation (ISCO); Perfluorooctanoic acid (PFOA); Persulfate; Powdered activated carbon (PAC); Spin trapping; 1; PAC; ISCO; DMPO radical adducts; Persulfate; DMPO; 4-dioxane; Perfluorooctanoic acid (PFOA); In-situ chemical oxidation (ISCO); Powdered activated carbon (PAC); Spin trapping; PFOA
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.129966

Carbonaceous materials have emerged as a method of persulfate activation for remediation. In this study, persulfate activation using powdered activated carbon (PAC) was demonstrated at temperatures relevant to groundwater (5–25 °C). At room temperature, increasing doses of PAC (1–20 g L-1) led to increased persulfate activation (3.06 × 10-6s-1 to 2.10 × 10-4 with 1 and 20 g L-1 PAC). Activation slowed at lower temperatures (5 and 11 °C); however, substantial (>70 %) persulfate activation was achieved. PAC characterization showed that persulfate is activated at the surface of the PAC, as indicated by an increase in the PAC C:O ratio. Similarly, electron paramagnetic resonance (EPR) spectroscopy studies with a spin trapping agents (5,5-dimethyl-1-pyrroline N-oxide (DMPO)) and 2,2,6,6-tetramethylpiperidine (TEMP) revealed that singlet oxygen was not the main oxidizing species in the reaction. DMPO was oxidized to form 5,5-dimethylpyrrolidone-2(2)-oxyl-(1) (DMPOX), which forms in the presence of strong oxidizers, such as sulfate radicals. The persulfate/PAC system is demonstrated to simultaneously degrade both perfluorooctanoic acid (PFOA) and 1,4-dioxane at room temperature and 11 °C. With a 20 g L-1 PAC and 75 mM persulfate, 80 % and 70 % of the PFOA and 1,4-dioxane, respectively, degraded within 6 h at room temperature. At 11 °C, the same PAC and persulfate doses led to 57% dioxane degradation and 54 % PFOA degradation within 6 h. Coupling PAC with persulfate offers an effective, low-cost treatment for simultaneous destruction of 1,4-dioxane and PFOA.
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•Persulfate is activated by powder activated carbon (PAC) at temperatures less than 25 °C.•Co-contaminants 1,4-dioxane and perfluorooctanoic acid are degraded at relevant temperatures.•Targeted and non-targeted mass spectrometry are used to establish PFOA degradation mechanism.