Removal of PFAS from Water

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Wastewater Treatment and Reuse".

Deadline for manuscript submissions: closed (30 June 2022) | Viewed by 17949

Special Issue Editor

College of Environment and Ecology, Xiamen University, Xiamen 361102, Fujian, China
Interests: POPs; PFAS; environmental monitoring; source and fate of pollutants; aquatic biota; ecological risk assessment; human health risk management; sustainable development

Special Issue Information

Dear Colleagues,

The applications of per- and polyfluoroalkyl substances (PFAS) have seen a massive increase in number in the 21st century, enabling many critical products. This has resulted in the widespread emission and distribution of these chemicals and aroused great concerns regarding their health risks. The Stockholm Convention on POPs listed PFOS, PFOA, and their related compounds, which promoted a global restriction on the use of C8 PFAS. Meanwhile, the fluorochemical industry has been developing alternatives such as C4 PFBS and PFBA, C6 HFPO-DA (GenX), and C8 F53B. Especially, the C6 PFAS used in telomer chemistry have already attracted a great deal of attention because of their associated risks, and PFHxS is proposed to be listed under the Stockholm Convention. Each individual PFAS compound has its own unique properties and uses, bringing difficult challenges for the removal of PFAS from water. Additionally, novel removal technologies need to be developed economically so that they can be applied widely.

This Special Issue titled “Removal of PFAS from Water” aims to present the latest technologies for the efficient removal of conventional and emerging PFAS from either wastewater or drinking water, to help to achieve risk management/control and sustainable development goals.

Contributions may focus on, but are not limited to, the following topics:

  • Removal of individual or mixed PFAS;
  • Removal of PFAS from industrial wastewater;
  • Removal of PFAS from domestic wastewater;
  • Removal of PFAS from drinking water;
  • Development of novel removal technology;
  • Balance between removal efficiency and cost;
  • Release of PFAS from treated water.

Dr. Pei Wang
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • PFAS
  • PFOS
  • PFOA
  • alternatives
  • removal
  • WWTP
  • industrial wastewater
  • domestic wastewater
  • drinking water

Published Papers (6 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

12 pages, 1590 KiB  
Article
Insight into the Impacts and Removal Pathways of Perfluorooctanoic Acid (PFOA) in Anaerobic Digestion
by Hongyu Xie, Yuqi Chen, Yuzheng Wang, Zhe Kong, Wenzhi Cao and Yanlong Zhang
Water 2022, 14(14), 2255; https://0-doi-org.brum.beds.ac.uk/10.3390/w14142255 - 18 Jul 2022
Cited by 4 | Viewed by 2379
Abstract
Perfluorooctanoic acid (PFOA) that accumulates in wastewater and excess sludge interact with the anaerobes and deteriorate the energy recovery and pollutants removal performance in the anaerobic digestion (AD) system. However, the interaction between PFOA and microbial metabolism in the AD systems remains unclear. [...] Read more.
Perfluorooctanoic acid (PFOA) that accumulates in wastewater and excess sludge interact with the anaerobes and deteriorate the energy recovery and pollutants removal performance in the anaerobic digestion (AD) system. However, the interaction between PFOA and microbial metabolism in the AD systems remains unclear. This study aimed to clarify the effects and mechanism of PFOA on the AD process as well as the removal pathways of PFOA in an AD system. The results showed that the methane recovery efficiency was inhibited by 7.6–19.7% with the increased PFOA concentration of 0.5–3.0 mg/L, and the specific methanogenesis activity (SMA) was inhibited by 8.6–22.3%. The electron transfer system (ETS) was inhibited by 22.1–37.3% in the PFOA-containing groups. However, extracellular polymeric substance (EPS) gradually increased due to the toxicity of PFOA, and the ratio of protein to polysaccharide shows an upward trend, which led to the formation of sludge aggregates and resistance to the toxic of PFOA. The PFOA mass balance analysis indicated that 64.2–71.6% of PFOA was removed in the AD system, and sludge adsorption was the main removal pathway, accounting for 36.1–61.2% of the removed PFOA. In addition, the anaerobes are proposed to have the potential to reduce PFOA through biochemical degradation since 10.4–28.2% of PFOA was missing in the AD system. This study provides a significant reference for the treatment of high-strength PFOA-containing wastes. Full article
(This article belongs to the Special Issue Removal of PFAS from Water)
Show Figures

Graphical abstract

19 pages, 4522 KiB  
Article
Effectiveness of Non-Thermal Plasma Induced Degradation of Per- and Polyfluoroalkyl Substances from Water
by Muhammad Jehanzaib Khan, Vojislav Jovicic, Ana Zbogar-Rasic, Alexander Poser, Katharina Freichels and Antonio Delgado
Water 2022, 14(9), 1408; https://0-doi-org.brum.beds.ac.uk/10.3390/w14091408 - 28 Apr 2022
Cited by 5 | Viewed by 2345
Abstract
Per- and polyfluoroalkyl substances (PFAS) are omnipresent synthetic chemicals. Due to their industrial importance and widespread use as a key component in various applications and a variety of products, these compounds can be found today in high concentrations (>1 μg/L) in surface and [...] Read more.
Per- and polyfluoroalkyl substances (PFAS) are omnipresent synthetic chemicals. Due to their industrial importance and widespread use as a key component in various applications and a variety of products, these compounds can be found today in high concentrations (>1 μg/L) in surface and groundwater but also spread throughout the ecosystem, where they represent a serious threat to most living organisms. The removal or degradation of PFAS contaminants from water and soil is becoming a legal obligation in a growing number of countries around the globe. This, however, demands novel techniques for the degradation of PFAS since conventional water treatment techniques are either insufficient or extremely expensive due to the persistent nature of these compounds caused by their extraordinary chemical stability. The goal of this work was therefore to investigate the practical potential of the application-oriented use of atmospheric non-thermal plasma as a powerful advanced oxidation method for the purification of water contaminated with PFAS compounds. Special attention was devoted to the development of the concept that can be scaled up to the capacity level of approximately 100–200 m3 of water per hour, contaminated with PFAS and other contaminants including organic and inorganic material generally present in soil, and surface or groundwater. Our major research interest was to define the minimum required treatment time for optimal purification results, as well as to understand the influence of the initial concentration of PFAS in water and the potential presence of co-contaminants often present in situ on the efficiency of the degradation process. A chemical analysis of the treated samples demonstrated the ability of the atmospheric plasma to reduce more than 50% of the initial PFAS amount in the water samples in less than 300 s of treatment time. PFOA, however, showed more rigidity towards degradation, where a double treatment time was needed to reach similar degradation levels. The obtained results showed that the initial concentration level does not play a major role in the process. However, the PFAS degradation profiles for all tested concentrations show a strongly nonlinear behavior with time, characterized by the fast decrease of the process efficiency in the case of longer treatment times. For prolonged treatment times, a constant increase in the samples’ conductivity was measured, which might be the limiting factor for the degradation rate in the case of prolonged treatment times. Full article
(This article belongs to the Special Issue Removal of PFAS from Water)
Show Figures

Figure 1

12 pages, 15939 KiB  
Article
Novel Fluorinated Nitrogen-Rich Porous Organic Polymer for Efficient Removal of Perfluorooctanoic Acid from Water
by Gaoxi Liu, Xiaohui Wei, Peiru Luo, Shuyu Dai, Wenfen Zhang and Yanhao Zhang
Water 2022, 14(7), 1010; https://0-doi-org.brum.beds.ac.uk/10.3390/w14071010 - 22 Mar 2022
Cited by 7 | Viewed by 2462
Abstract
The mobility, durability, and widespread use of perfluorinated and polyfluoroalkyl substances (PFAS), notably perfluorooctanoic acid (PFOA), bring about serious contamination of many ground and surface waters. In this study, fluorine and amine-functionalized porous organic polymer (POP-4F) was designed and successfully synthesized as an [...] Read more.
The mobility, durability, and widespread use of perfluorinated and polyfluoroalkyl substances (PFAS), notably perfluorooctanoic acid (PFOA), bring about serious contamination of many ground and surface waters. In this study, fluorine and amine-functionalized porous organic polymer (POP-4F) was designed and successfully synthesized as an adsorbent for PFOA removal in water. The characterization results showed that the synthesized material had an amorphous microporous structure, and the BET surface area was up to 479 m2 g−1. Its versatile adsorption property was evaluated by batch adsorption experiments using PFOA as a probe. The experiments show that the polymer was able to remove 98% of the PFOA in 5 min from water and then desorb within 3 min in methanol ([PFOA]0 = 1 mg L−1; [POP-4F] = 200 mg L−1). Specifically, the adsorption capacity of POP-4F is up to 107 mg g−1, according to the Langmuir fit. The rapid adsorption and desorption of PFOA by POP-4F offers the possibility of economical, environmentally friendly, and efficient treatment of real wastewater. Full article
(This article belongs to the Special Issue Removal of PFAS from Water)
Show Figures

Figure 1

19 pages, 5321 KiB  
Article
Assessment of Reed Grasses (Phragmites australis) Performance in PFAS Removal from Water: A Phytoremediation Pilot Plant Study
by Claudia Ferrario, Cosimo Peruzzi, Alessio Cislaghi, Stefano Polesello, Sara Valsecchi, Roberto Lava, Francesca Zanon, Gianfranco Santovito, Alberto Barausse and Marco Bonato
Water 2022, 14(6), 946; https://0-doi-org.brum.beds.ac.uk/10.3390/w14060946 - 17 Mar 2022
Cited by 5 | Viewed by 3990
Abstract
Per- and polyfluoroalkyl substances (PFASs) have multiple emission sources, from industrial to domestic, and their high persistence and mobility help them to spread in all the networks of watercourses. Diffuse pollution of these compounds can be potentially mitigated by the application of green [...] Read more.
Per- and polyfluoroalkyl substances (PFASs) have multiple emission sources, from industrial to domestic, and their high persistence and mobility help them to spread in all the networks of watercourses. Diffuse pollution of these compounds can be potentially mitigated by the application of green infrastructures, which are a pillar of the EU Green Deal. In this context, a phytoremediation pilot plant was realised and supplied by a contaminated well-located in Lonigo (Veneto Region, Italy) where surface and groundwaters were significantly impacted by perfluoroalkyl acids (PFAAs) discharges from a fluorochemical factory. The investigation involved the detection of perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA), perfluorobutanesulfonic acid (PFBS) and perfluorooctanesulfonic acid (PFOS) inside the inlet and outlet waters of the phytoremediation pilot plant as well as in reed grasses grown into its main tank. The obtained results demonstrate that the pilot plant is able to reduce up to 50% of considered PFAAs in terms of mass flow without an evident dependence on physico-chemical characteristics of these contaminants. Moreover, PFAAs were found in the exposed reed grasses at concentrations up to 13 ng g−1 ww. A positive correlation between PFAA concentration in plants and exposure time was also observed. In conclusion, this paper highlights the potential efficiency of phytodepuration in PFAS removal and recommends improving the knowledge about its application in constructed wetlands as a highly sustainable choice in wastewater remediation. Full article
(This article belongs to the Special Issue Removal of PFAS from Water)
Show Figures

Figure 1

19 pages, 3025 KiB  
Article
Laboratory and Semi-Pilot Scale Study on the Electrochemical Treatment of Perfluoroalkyl Acids from Ion Exchange Still Bottoms
by Vanessa Y. Maldonado, Michael F. Becker, Michael G. Nickelsen and Suzanne E. Witt
Water 2021, 13(20), 2873; https://0-doi-org.brum.beds.ac.uk/10.3390/w13202873 - 14 Oct 2021
Cited by 9 | Viewed by 2914
Abstract
The ubiquitous presence of perfluoroalkyl acids (PFAAs) in the environment remains a serious environmental concern. In this study, the electrochemical oxidation (EO) of PFAAs from the waste of ion exchange (IX) still bottoms was assessed at the laboratory and semi-pilot scales, using full [...] Read more.
The ubiquitous presence of perfluoroalkyl acids (PFAAs) in the environment remains a serious environmental concern. In this study, the electrochemical oxidation (EO) of PFAAs from the waste of ion exchange (IX) still bottoms was assessed at the laboratory and semi-pilot scales, using full boron-doped diamond (BDD) electrochemical cells. Multiple current densities were evaluated at the laboratory scale and the optimum current density was used at the semi-pilot scale. The results at the laboratory scale showed >99% removal of total PFAAs with 50 mA/cm2 after 8 h of treatment. PFAAs treatment at the semi-pilot scale showed 0.8-fold slower pseudo-first-order degradation kinetics for total PFAAs removal compared to at the laboratory scale, and allowed for >94% PFAAs removal. Defluorination values, perchlorate (ClO4) generation, coulombic efficiency (CE), and energy consumption were also assessed for both scales. Overall, the results of this study highlight the benefits of a tandem concentration/destruction (IX/EO) treatment approach and implications for the scalability of EO to treat high concentrations of PFAAs. Full article
(This article belongs to the Special Issue Removal of PFAS from Water)
Show Figures

Graphical abstract

Review

Jump to: Research

14 pages, 2767 KiB  
Review
Removal of Per- and Polyfluoroalkyl Substances by Electron Beam and Plasma Irradiation: A Mini-Review
by Linke Jiang, Siqin Wang, Wenzheng Chen, Jiang Lin, Xin Yu, Mingbao Feng and Kun Wan
Water 2022, 14(11), 1684; https://0-doi-org.brum.beds.ac.uk/10.3390/w14111684 - 25 May 2022
Cited by 7 | Viewed by 2624
Abstract
The global prevalence and environmental risks of per- and polyfluoroalkyl substances (PFASs) have caused increasing concern regarding their strategic elimination from aqueous environments. It has recently been recognized that advanced oxidation–reduction technologies (AO/RTs) exhibit superior removal performance for these ubiquitous pollutants. However, the [...] Read more.
The global prevalence and environmental risks of per- and polyfluoroalkyl substances (PFASs) have caused increasing concern regarding their strategic elimination from aqueous environments. It has recently been recognized that advanced oxidation–reduction technologies (AO/RTs) exhibit superior removal performance for these ubiquitous pollutants. However, the detailed mechanisms and product risks have not been well summarized and systematically deciphered. In this mini-review article, the basic operating principles of two typical AO/RTs (electron beam and plasma irradiation) and their reported applications in the abatement of PFASs are described in detail. It is noteworthy that these reductive treatments induced remarkable defluorination efficiency of PFOA and PFOS with the generation of short-chain congeners in water. The reaction mechanisms mainly included desulfonization, decarboxylation, H/F exchange, radical cyclization, and stepwise losses of CF2 groups. Unexpectedly, partial degradation products manifested high potential in triggering acute and chronic aquatic toxicity, genotoxicity, and developmental toxicity. Additionally, high or even increased resistance to biodegradability was observed for multiple products relative to the parent chemicals. Taken together, both electron beam and plasma irradiation hold great promise in remediating PFAS-contaminated water and wastewater, while the secondary ecological risks should be taken into account during practical applications. Full article
(This article belongs to the Special Issue Removal of PFAS from Water)
Show Figures

Figure 1

Back to TopTop