Thermal defluorination behaviors of PFOS, PFOA and PFBS during regeneration of activated carbon by molten salt

doi:10.1007/s11783-022-1524-9

Front. Environ. Sci. Eng.

2022, Vol. 16

Issue (8) : 103 https://doi.org/10.1007/s11783-022-1524-9

RESEARCH ARTICLE

Thermal defluorination behaviors of PFOS, PFOA and PFBS during regeneration of activated carbon by molten salt

Zhichao Shen^1,², Lu Zhan^1,²(

), Zhenming Xu¹

¹. School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
². School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China

Download: PDF(1460 KB) HTML
Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks

Abstract

• New method of mineralizing PFCs was proposed.

• Activated carbon was regenerated while mineralizing PFCs.

• Molten NaOH has good mineralization effect on PFOS and PFBS.

Current study proposes a green regeneration method of activated carbon (AC) laden with Perfluorochemicals (PFCs) from the perspective of environmental safety and resource regeneration. The defluorination efficiencies of AC adsorbed perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutanesulfonate (PFBS) using three molten sodium salts and one molten alkali were compared. Results showed that defluorination efficiencies of molten NaOH for the three PFCs were higher than the other three molten sodium salts at lower temperature. At 700°C, the defluorination efficiencies of PFOS and PFBS using molten NaOH reached to 84.2% and 79.2%, respectively, while the defluorination efficiency of PFOA was 35.3%. In addition, the temperature of molten salt, the holding time and the ratio of salt to carbon were directly proportional to the defluorination efficiency. The low defluorination efficiency of PFOA was due to the low thermal stability of PFOA, which made it difficult to be captured by molten salt.The weight loss range of PFOA was 75°C–125°C, which was much lower than PFOS and PFBS (400°C–500°C). From the perspective of gas production, fluorine-containing gases produced from molten NaOH-treated AC were significantly reduced, which means that environmental risks were significantly reduced. After molten NaOH treatment, the regenerated AC had higher adsorption capacity than that of pre-treated AC.

Keywords PFCs Molten sodium hydroxide Thermal degradation Activated carbon regeneration

Corresponding Author(s): Lu Zhan

About author:

Tongcan Cui and Yizhe Hou contributed equally to this work.

Issue Date: 16 December 2021

Cite this article:

Zhichao Shen,Lu Zhan,Zhenming Xu. Thermal defluorination behaviors of PFOS, PFOA and PFBS during regeneration of activated carbon by molten salt[J]. Front. Environ. Sci. Eng., 2022, 16(8): 103.

URL:

https://academic.hep.com.cn/fese/EN/10.1007/s11783-022-1524-9
https://academic.hep.com.cn/fese/EN/Y2022/V16/I8/103

Fig.1 Actual photo (a) and schematic diagram (b) of the furnace.

Fig.2 The defluorination efficiency of NaOH, Na₂SO₄, Na₂CO₃ and NaCl in removing PFOS, PFOA, PFBS.

Fig.3 TG (blue line) and DTG (red line) curves of PFOS (a), PFOA (b) and PFBS (c).

Fig.4 Effects of temperature (a), residence time (b), and activated carbon amount (c) on defluorination efficiency of PFOS, PFOA and PFBS.

Fig.5 GC-MS total ion chromatograms of gases generated by pyrolysis of PFOS (a), PFOA (b) and PFBS (c) at 600 °C.

Fig.6 GC-MS total ion chromatograms of the gas generated by PFOS (a), PFOA (b) and PFBS (c) after treatment with molten sodium hydroxide at 600 °C.

Fig.7 Adsorption and desorption isotherms (a) and pore size distribution (b) of activated carbon under various regeneration times.

Tab.1 The structural characteristics of activated carbon after several cycles

Fig.8 XRD pattern of the product of PFOS-adsorbed AC treated with molten sodium hydroxide at 600°C for 15 min.

1	G Cagnetta, J Robertson, J Huang, K Zhang, G Yu (2016). Mechanochemical destruction of halogenated organic pollutants: A critical review. Journal of Hazardous Materials, 313: 85–102 https://doi.org/10.1016/j.jhazmat.2016.03.076 pmid: 27054668
2	J Chen, P Y Zhang, J Liu (2007). Photodegradation of perfluorooctanoic acid by 185 nm vacuum ultraviolet light. Journal of Environmental Sciences (China), 19(4): 387–390 https://doi.org/10.1016/S1001-0742(07)60064-3 pmid: 17915698
3	S Dai, Y Zheng, Y Zhao, Y Chen, D Niu (2019b). Molten hydroxide for detoxification of chlorine-containing waste: Unraveling chlorine retention efficiency and chlorine salt enrichment. Journal of Environmental Sciences (China), 82: 192–202 https://doi.org/10.1016/j.jes.2019.03.007 pmid: 31133264
4	S J Dai, Y C Zhao, D J Niu, Q Li, Y Chen (2019a). Preparation and reactivation of magnetic biochar by molten salt method: Relevant performance for chlorine-containing pesticides abatement. Journal of the Air & Waste Management Association (1995), 69(1): 58–70 https://doi.org/10.1080/10962247.2018.1510441 pmid: 30095366
5	C Douvris, O V Ozerov (2008). Hydrodefluorination of perfluoroalkyl groups using silylium-carborane catalysts. Science, 321(5893): 1188–1190 https://doi.org/10.1126/science.1159979 pmid: 18755971
6	B O Fagbayigbo, B O Opeolu, O S Fatoki, T A Akenga, O S Olatunji (2017). Removal of PFOA and PFOS from aqueous solutions using activated carbon produced from Vitis vinifera leaf litter. Environmental Science and Pollution Research International, 24(14): 13107–13120 https://doi.org/10.1007/s11356-017-8912-x pmid: 28382450
7	L Flandinet, F Tedjar, V Ghetta, J Fouletier (2012). Metals recovering from waste printed circuit boards (WPCBs) using molten salts. Journal of Hazardous Materials, 213–214: 485–490 https://doi.org/10.1016/j.jhazmat.2012.02.037 pmid: 22398030
8	K Harada, K Inoue, A Morikawa, T Yoshinaga, N Saito, A Koizumi (2005). Renal clearance of perfluorooctane sulfonate and perfluorooctanoate in humans and their species-specific excretion. Environmental Research, 99(2): 253–261 https://doi.org/10.1016/j.envres.2004.12.003 pmid: 16194675
9	C P Higgins, P B McLeod, L A MacManus-Spencer, R G Luthy (2007). Bioaccumulation of perfluorochemicals in sediments by the aquatic oligochaete Lumbriculus variegatus. Environmental Science & Technology, 41(13): 4600–4606 https://doi.org/10.1021/es062792o pmid: 17695903
10	P C Hsu, K G Foster, T D Ford, P H Wallman, B E Watkins, C O Pruneda, M G Adamson (2000). Treatment of solid wastes with molten salt oxidation. Waste Management, 20(5–6): 363–368 https://doi.org/10.1016/S0956-053X(99)00338-4
11	M Y Khan, S So, G da Silva (2020). Decomposition kinetics of perfluorinated sulfonic acids. Chemosphere, 238: 124615
12	P J Krusic, A A Marchione, D C Roe (2005). Gas-phase NMR studies of the thermolysis of perfluorooctanoic acid. Journal of Fluorine Chemistry, 126(11–12): 1510–1516 https://doi.org/10.1016/j.jfluchem.2005.08.016
13	M Li, F Sun, W Shang, X Zhang, W Dong, T Liu, W Pang (2019a). Theoretical studies of perfluorochemicals (PFCs) adsorption mechanism on the carbonaceous surface. Chemosphere, 235: 606–615 https://doi.org/10.1016/j.chemosphere.2019.06.191 pmid: 31276873
14	P Li, D Zhi, X Zhang, H Zhu, Z Li, Y Peng, Y He, L Luo, X Rong, Y Zhou (2019b). Research progress on the removal of hazardous perfluorochemicals: A review. Journal of Environmental Management, 250: 109488 https://doi.org/10.1016/j.jenvman.2019.109488 pmid: 31499465
15	H Lv, N Wang, L Zhu, Y Zhou, W Li, H Tang (2018). Alumina-mediated mechanochemical method for simultaneously degrading perfluorooctanoic acid and synthesizing a polyfluoroalkene. Green Chemistry, 20(11): 2526–2533 https://doi.org/10.1039/C8GC00854J
16	E Mahieu, R Zander, G C Toon, M K Vollmer, S Reimann, J Mühle, W Bader, B Bovy, B Lejeune, C Servais, P Demoulin, G Roland, P F Bernath, C D Boone, K A Walker, P Duchatelet (2013). Spectrometric monitoring of atmospheric carbon tetrafluoride (CF4) above the Jungfraujoch station since 1989: Evidence of continued increase but at a slowing rate. Atmospheric Measurement Techniques Discussions. 6, 7535–7563
17	P Meng, X Fang, A Maimaiti, G Yu, S Deng (2019). Efficient removal of perfluorinated compounds from water using a regenerable magnetic activated carbon. Chemosphere, 224: 187–194 https://doi.org/10.1016/j.chemosphere.2019.02.132 pmid: 30825849
18	S M Mitchell, M Ahmad, A L Teel, R J Watts (2014). Degradation of perfluorooctanoic acid by reactive species generated through catalyzed H2O2 propagation reactions. Environmental Science & Technology Letters, 1(1): 117–121 https://doi.org/10.1021/ez4000862
19	V Ochoa-Herrera, R Sierra-Alvarez (2008). Removal of perfluorinated surfactants by sorption onto granular activated carbon, zeolite and sludge. Chemosphere, 72(10): 1588–1593 https://doi.org/10.1016/j.chemosphere.2008.04.029 pmid: 18511099
20	E Olsen, V Tomkute (2013). Carbon capture in molten salts. Energy Science & Engineering, 1(3): 144–150 https://doi.org/10.1002/ese3.24
21	G B Post, P D Cohn, K R Cooper (2012). Perfluorooctanoic acid (PFOA), an emerging drinking water contaminant: A critical review of recent literature. Environmental Research, 116: 93–117 https://doi.org/10.1016/j.envres.2012.03.007 pmid: 22560884
22	L Rodriguez-Freire, R Balachandran, R Sierra-Alvarez, M Keswani (2015). Effect of sound frequency and initial concentration on the sonochemical degradation of perfluorooctane sulfonate (PFOS). Journal of Hazardous Materials, 300: 662–669 https://doi.org/10.1016/j.jhazmat.2015.07.077 pmid: 26282221
23	P C Sasi, A Alinezhad, B Yao, A Kubátová, S A Golovko, M Y Golovko, F Xiao (2021). Effect of granular activated carbon and other porous materials on thermal decomposition of per- and polyfluoroalkyl substances: Mechanisms and implications for water purification. Water Research, 200: 117271 https://doi.org/10.1016/j.watres.2021.117271 pmid: 34082264
24	S Sühnholz, F D Kopinke, B Weiner (2018). Hydrothermal treatment for regeneration of activated carbon loaded with organic micropollutants. Science of the Total Environment, 644: 854–861 https://doi.org/10.1016/j.scitotenv.2018.06.395 pmid: 30743883
25	M Trojanowicz, I Bartosiewicz, A Bojanowska-Czajka, K Kulisa, T Szreder, K Bobrowski, H Nichipor, J F Garcia-Reyes, G Nalecz-Jawecki, S Meczynska-Wielgosz, J Kisala (2019). Application of ionizing radiation in decomposition of perfluorooctanoate (PFOA) in waters. Chemical Engineering Journal, 357: 698–714 https://doi.org/10.1016/j.cej.2018.09.065
26	F Wang, X Lu, X Y Li, K Shih (2015). Effectiveness and Mechanisms of defluorination of perfluorinated alkyl substances by calcium compounds during waste thermal treatment. Environmental Science & Technology, 49(9): 5672–5680 https://doi.org/10.1021/es506234b pmid: 25850557
27	N Wang, H Lv, Y Zhou, L Zhu, Y Hu, T Majima, H Tang (2019). Complete defluorination and mineralization of perfluorooctanoic acid by a mechanochemical method using alumina and persulfate. Environmental Science & Technology, 53(14): 8302–8313 https://doi.org/10.1021/acs.est.9b00486 pmid: 31149813
28	W Wang, Z Du, S Deng, M Vakili, L Ren, P Meng, A Maimaiti, B Wang, J Huang, Y Wang, G Yu (2018). Regeneration of PFOS loaded activated carbon by hot water and subsequent aeration enrichment of PFOS from eluent. Carbon, 134: 199–206 https://doi.org/10.1016/j.carbon.2018.04.005
29	D Wu, X Li, J Zhang, W Chen, P Lu, Y Tang, L Li (2018). Efficient PFOA degradation by persulfate-assisted photocatalytic ozonation. Separation and Purification Technology, 207: 255–261 https://doi.org/10.1016/j.seppur.2018.06.059
30	F Xiao, P C Sasi, B Yao, A Kubatova, S A Golovko, M Y Golovko, D Soli (2020). Thermal stability and decomposition of perfluoroalkyl substances on spent granular activated carbon. Environmental Science & Technology Letters, 7(5): 343–350 https://doi.org/10.1021/acs.estlett.0c00114
31	Z Yao, J Li, X Zhao (2011). Molten salt oxidation: A versatile and promising technology for the destruction of organic-containing wastes. Chemosphere, 84(9): 1167–1174 https://doi.org/10.1016/j.chemosphere.2011.05.061 pmid: 21726891

[1]

FSE-21117-OF-SZC_suppl_1

Download

[1]	Lutz AHRENS, Merle PLASSMANN, Zhiyong XIE, Ralf EBINGHAUS. Determination of polyfluoroalkyl compounds in water and suspended particulate matter in the river Elbe and North Sea, Germany[J]. Front Envir Sci Eng Chin, 2009, 3(2): 152-170.

Viewed

Full text

Abstract

Cited

Shared

Discussed