Ultrafast Capture of Per- and Polyfluoroalkyl Substances from Water by Mesoporous Zirconium Metal–Organic Frameworks

Per-and polyfluoroalkyl substances (PFAS) are among the most abundant environmental contaminant species.They are widespread due to uncontrolled industrial and commercial use and have been linked to health risks such as cancer.With rising global concerns about the public health effects of PFAS, there is an incentive to develop strategies for reliable monitoring and effective PFAS removal, particularly in drinking water.Traditional PFAS sensing techniques are inefficient due to long measurement times, high labor input, high costs, and limitations to ex situ analysis.Current commercially available sorbents for PFAS removal generally lack the ability to capture PFAS components rapidly and quantitatively.Furthermore, existing sorbents are notably inefficient in removing the more toxic, smaller PFAS chemical chains.Large-scale applications of these methods tend to be costly and resource-intensive.Pacific Northwest National Laboratory has developed unique strategies for PFAS sensing and removal with capture probe technology that has an affinity for fluorocarbons, including PFAS.For both sensing and removal, the customizable capture probes can target specific PFAS compounds since they used a metalorganic framework (MOF)-based technology that can be fine-tuned and molecularly tailored.This tailoring of the materials enables high PFAS sensitivity, selectivity, and faster uptake.PNNL's capture probe materials have been developed into a sensing technique based on the interactions of the capture probes with PFAS at the molecular level and further transduced that to a quantifiable electrochemical response.The materials have been integrated into a sensor platform developed by New Jersey Institute of Technology (NJIT).Tunable capture probes with a range of detection sensitivities allow for faster and more sensitive PFAS detection limits as low as what appears to be 0.5 ng/L (compared to the U.S. Environmental Protection Agency health advisory level of 70 ng/L).Customization of the capture probe results in improved sorption capacities (fast kinetics and high capacities) compared to commercial granular activated carbons.This research applied various experimental and modeling tools to improve understanding the molecular level interactions between the sorbents towards PFAS adsorption properties.

基于阳离子型金属有机骨架膜材料，建立了一种分散膜萃取（DME）与超高效液相色谱-串联质谱（UHPLC-MS/MS）相结合的分析方法，用于同时检测海水中8种全氟及多氟烷基化合物（PFASs）。优化的色谱-质谱条件如下：ACQUITY UPLC BEH C18色谱柱（100 mm×2.1 mm， 1.7 μm），进样体积为10 μL，柱温保持在40 ℃，流速为0.4 mL/min，采用1.0 mmol/L乙酸铵水溶液和乙腈为流动相进行梯度洗脱；在负离子模式下，通过电喷雾离子源（离子源电压-2 500 V，离子源温度300 ℃）进行质谱检测，并使用多反应监测模式采集化合物质谱信息。在最优条件下，8种PFASs在各自的浓度范围内线性关系良好，相关系数均≥0.990 7，方法的检出限为0.07~0.49 ng/L，定量限为0.22~1.63 ng/L。在10、50和100 ng/L加标水平下PFASs的回收率为50.4%~116.4%，日内和日间相对标准偏差分别为1.0%~19.2%和2.2%~19.5%。将该方法应用于胶州湾表层海水中8种PFASs的检测，共检出7种PFASs。其中，全氟-11-氯-3-氧杂十一烷磺酸检出浓度最高，平均质量浓度为17.11 ng/L。与2018年胶州湾表层海水中PFASs的检出结果对比，全氟辛酸的平均质量浓度水平明显降低。同时新型PFASs中全氟-9-氯-3-氧杂壬烷磺酸钾在胶州湾表层海水中被检出，可能与近些年PFASs的生产转型有关。新型PFASs的广泛使用可能带来与传统PFASs类似的环境风险，需引起人们高度关注。综上所述，本方法操作简便、快速且灵敏度高，适用于海水中8种PFASs的分析。

A juxtaposed review on adsorptive removal of PFAS by metal-organic frameworks (MOFs) with carbon-based materials, ion exchange resins, and polymer adsorbents

Per- and polyfluoroalkyl substances (PFAS) face the most stringent drinking water quality standards ever due to their potential toxicity and bioaccumulation potential. Their removal from water is commonly accomplished by adsorption, which is generally ineffective for short-chain PFAS and unreliable for other homologues with diverse physicochemical properties. Here, we present a versatile platform based on zirconium-based metal-organic frameworks (MOFs) to remove PFAS with different chain lengths via crystal-to-crystal transformation. The MOF [Zr6(μ3-O)4(μ3-OH)4PTA3(H2O)4]n (Zr-PTA1, PTA = 4,4',4″,4'″-(4,4'-(1,4-phenylene) bis (pyridine-6,4,2-triyl))tetrabenzoic acid) exhibits exceptional adsorption capacity for C8 PFAS (2945 ± 173mg/g for perfluorooctanoic acid (PFOA) and 2322 ± 28mg/g for perfluorooctane sulfonate (PFOS)), while its crystal-to-crystal transformation product [Zr6(μ3-O)4(μ3-OH)4 PTA2(CH3COO)4]n (Zr-PTA2) with abundant open metal sites (OMS) targets shorter-chain C4 PFAS (375 ± 9mg/g for perfluorobutanoic acid and 414 ± 41mg/g for perfluorobutanesulfonic acid), surpassing all previously reported MOFs. Flow-through column tests demonstrate rapid PFAS removal below 4ng/L. This exceptional performance is due to distinct structural motifs-steric host-guest fit of Zr-PTA1 for long-chain PFAS versus OMS-driven chemisorption of short-chain PFAS by Zr-PTA2. Importantly, the framework facilitates subsequent thermal-catalytic PFAS destruction, achieving 97 ± 5% PFOA degradation efficiency with 79 ± 0.3% fluoride recovery.

Designing metal-organic frameworks (MOFs) for advanced per- and polyfluoroalkyl substances (PFAS) management: Adsorption, detection, and degradation.

Per- and polyfluoroalkyl substances (PFAS) represent a class of emerging anthropogenic pollutants due to their widespread use in consumer and industrial products. Their interfacial nature leads to accumulation in humans and animals via direct and indirect exposure routesAs a result, PFAS exhibit toxicity at very low levels, typically parts per billion, prompting recent legally enforceable limits by the U.S. EPA as low as 4.0 parts per trillion (ppt, ng L-1) in drinking water. The inherent stability of the carbon-fluorine bond classifies PFAS as persistent pollutants, presenting a fundamental challenge for remediation methods, which must be highly selective and efficient in the presence of other chemical species often found in relative excess. Current degradation techniques require high concentrations, necessitating a pre-concentration step for removal from sources like groundwater and enrichment for subsequent degradation reactors. Structurally, the amphiphilic nature of PFAS, with a hydrophobic fluorinated tail and a polar, hydrophilic head, leads to complex environmental distribution and challenges selective sorbent development. Adsorption can occur via weak physical interactions or stronger chemical binding (e.g., hydrogen or ionic bonds). Metal-organic frameworks (MOFs), porous materials constructed from inorganic nodes and organic linkers, offer tunable internal surface chemistry potentially tailored for specific guest molecules. While several studies report efficient PFAS adsorption capacities in MOFs, most investigations focus on high concentrations (> mg L-1 range), making extrapolation to environmentally relevant, low-concentration conditions difficult due to factors like competition from dissolved species and weak interactions, especially for short-chain PFAS. More work is needed to establish structure-selectivity relationships for trace-level removal. We hypothesised that constructing multi-variate MOFs (MV-MOFs), integrating different linkers within the same framework, could enhance adsorption selectivity through potential synergistic effects. Specifically, we targeted the simultaneous interaction of the framework with the PFAS head and tail by combining hydrophobic and polar/ionisable functional groups. We prepared a series of MV-MOFs based on the UiO-67 topology, varying the ratio of 2,2′-diamino[1,1′-biphenyl]-4,4′-dicarboxylic acid (H2L(NH2)2) and 2,2′-trifluoromethyl[1,1′-biphenyl]-4,4′-dicarboxylic acid (H2L(CF3)2) linkers. Herein, we describe the synthesis and characterization (PXRD, elemental analysis, vibrational spectroscopy) of these materials. Adsorption kinetics, isotherms, and regeneration were evaluated using LC-MS for accurate quantification at parts-per-billion levels ranging from sub-ppm to high concentrations. Comparisons with UiO-67 indicate that combining polar (-NH2) and hydrophobic (CF3) functionalities within the MV-MOFs increases adsorption efficiency and binding strength, specifically at low PFAS concentrations.

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals widely used for their resistance to heat, water, and oil, which also confers exceptional environmental persistence and promotes accumulation across ecosystems and organisms. Strong carbon-fluorine bonding and extensive industrial usage contribute toward widespread contamination affecting water quality, food safety, and soil integrity across global environments. PFAS enter the environment through industrial discharges, wastewater treatment plants, landfills, firefighting foams, and consumer products such as non-stick cookware, water-repellent textiles, food packaging, and personal care items. They contaminate water, soil, and air and may enter agricultural systems, thereby influencing crop quality and food safety. Human exposure occurs primarily through consumption of contaminated drinking water and food, with additional exposure via inhalation, skin contact, and ingestion of dust. Freshwater organisms frequently exhibit higher PFAS concentrations than marine species, increasing dietary exposure risks. PFAS exposure has been associated with immune suppression, endocrine disruption, liver damage, reproductive effects, elevated cholesterol levels, and cancer. Ecologically, PFAS alter microbial community structure and accumulate within wildlife and food webs. Conventional water treatment processes show minimal effectiveness against PFAS, intensifying research on adsorbent- and hybrid treatment-based remediation under the pollutant toxic ions and molecules research theme. This review emphasizes progress with activated carbon (AC), ion exchange resins, mineral sorbents, membranes, and destruction technologies, as well as emerging materials such as metal-organic frameworks, covalent organic frameworks, and polymeric or nanocomposite sorbents, while highlighting performance constraints, regeneration challenges, operational limitations, and critical gaps for scalable and sustainable PFAS management.

Mitigating PFAS contaminants in water: A comprehensive survey of remediation strategies

A novel ZIF-L/PEI thin film nanocomposite membrane for removing perfluoroalkyl substances (PFASs) from water: Enhanced retention and high flux

Harmful per- and polyfluoroalkyl substances (PFAS) are ubiquitously detected in aquatic environments, but their remediation remains challenging. Metal-organic frameworks (MOFs) have been recently identified as an advanced material class for the efficient removal of PFAS, but little is known about the fundamentals of the PFAS@MOF adsorption process. To address this knowledge gap, we evaluated the performance of 3 different MOFs for the removal of 8 PFAS classes from aqueous film-forming foam-impacted groundwater samples obtained from 11 U.S. Air Force installations. Due to their different pore sizes/shapes and the identity of metal node, MOFs NU-1000, UiO-66, and ZIF-8 were selected to investigate the role of MOF structures, PFAS properties, and water matrix on the PFAS@MOF adsorption process. We observed that PFAS@MOF adsorption is (i) dominated by electrostatic and acid-base interactions for anionic and non-ionic PFAS, respectively, (ii) preferred for long- over short-chain PFAS, (iii) strongly dependent on the nature of PFAS head group functionality, and (iv) compromised in the presence of ionic and neutral co-contaminants by competing for ion-exchange sites and PFAS binding. With this study, we elucidate the PFAS@MOF adsorption mechanism from complex water sources to guide the design of more efficient MOFs for the treatment of PFAS-contaminated water bodies.

Roles of varying carbon chains and functional groups of legacy and emerging per-/polyfluoroalkyl substances in adsorption on metal-organic framework: Insights into mechanism and adsorption prediction

Metal-organic frameworks as platforms for the removal of per- and polyfluoroalkyl substances from contaminated waters

Per‐ and polyfluoroalkyl substances (PFAS), known as “forever chemicals,” present major environmental and health risks due to their extreme stability and dual hydrophobic–hydrophilic character, which complicates remediation. Conventional adsorbents such as activated carbon and ion‐exchange resins show limited performance, particularly for short‐chain PFAS. Metal–organic frameworks (MOFs) have emerged as promising alternatives owing to their tunable porosity, large surface area, and adjustable functionality. Here, we assess the PFAS removal potential of a robust, water‐stable, biologically derived MOF, CuII2(S,S)‐hismox·5H2O (denoted 1), synthesized from L‐histidine. MOF 1 features medium‐sized trapezoidal nanoscale channels exhibiting both hydrophobic and hydrophilic character. It achieved high capture efficiencies (80–100%) for long‐chain PFAS (C₇–C₁2), including PFDA, PFUnDA, PFDoDA, PFOS, and 8:2 FTSA, and remarkable removal rates of 70% (PFBA) and 86% (PFBS) for short‐chain analogues –surpassing conventional adsorbents and other reported MOFs. Excellent reusability and rapid adsorption kinetics were observed under continuous‐flow solid‐phase extraction with contact times under 30 seconds. The high crystallinity of MOF 1 also enabled single‐crystal X‐ray diffraction studies of encapsulated PFBA and PFOS (PFBA@1 and PFOS@1). These findings highlight MOF 1 as a high‐performance, bio‐derived platform for efficient PFAS remediation and advance the development of MOF‐based water treatment technologies.

Per- and polyfluoroalkyl substances (PFAS) are a class of toxic and bioaccumulative compounds affecting environmental and human health. Conventional wastewater treatment processes are ineffective at remediating these persistent chemicals. While functional framework materials have been shown to remove PFAS via adsorption and catalytic degradation, there is an on-going debate about their practical use in water purification. Inspired by recent research on typical functional framework materials, including zeolites, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs), our review summarizes the principles of their design, properties, and applications with a special emphasis on PFAS removal. The potential of framework material for catalytic degradation of PFAS is constructively discussed, based on limited studies thus far. Finally, the challenges of using framework materials to remove and degrade PFAS in wastewater are presented along with sustainable design prospects to improve the technology. The current review provides new insights in advancing framework materials for PFAS elimination from contaminated waters.

Per and polyfluoroalkyl substances (PFAS) have been extensively employed in a broad range of manufacturing and consumer goods due to their highly persistent nature. PFAS exposure is recognized to pose serious health hazards; therefore, addressing PFAS pollution in water has become a top priority for public health and environmental protection organizations. This review article focuses on the efficiency of different removal techniques (activated carbon, biochar, ion exchange resin, membrane filtration, reverse osmosis, metal-organic frameworks, foam fractionation, ozone fractionation, and destruction techniques) for eliminating different types of short- and long-chain PFAS from water. Hydrophobicity and electrostatic interactions are revealed to be the primary mechanisms for the elimination of PFAS. The efficiency of all techniques to eradicate short-chain PFAS is comparatively lower compared to long-chain PFAS. The destruction techniques are the most efficient but have some drawbacks, including the formation of PFAS precursors and high operational costs. According to the findings from the study, it is anticipated that combined methods will be required to effectively remediate PFAS-contaminated water.