Researchers call for uniform reporting guidelines to enable better comparison of “forever chemical” removal materials
November 18, 2025
An international research team has published a comprehensive framework aimed at standardizing how scientists evaluate and report materials designed to remove PFAS from contaminated water. The guidelines, published in the journal Advanced Materials on November 18, 2025, address a critical bottleneck in developing effective treatments for these persistent environmental pollutants known as “forever chemicals.”
PFAS are considered an environmental crisis worldwide because of their widespread use in consumer products, extreme persistence in the environment, and documented health risks including immune system disruption, increased cancer risk, and developmental effects.
The Challenge of Inconsistent Reporting
Despite substantial investment in PFAS removal technologies, progress has been hindered by inconsistent experimental methods and incomplete reporting among comparable studies. This makes meaningful comparisons among materials by researchers or the reproduction of results virtually impossible, which certainly slows down how quickly promising laboratory discoveries are translated into effective water treatment solutions.
Conventional methods utilizing activated carbon, ion-exchange resins, graphene derivatives, metal-organic frameworks, and tailored polymeric networks for PFAS removal are among the most researched, but inconsistent and incomplete experimental reporting are a major hindrance toward the effective reproducibility and comparison of results.
Because materials are synthesized, characterized, and tested differently, performance results often vary from one study to another.
A Comprehensive Evaluation Framework
The new framework, authored by Zhuojing Yang, Zicheng Su, Kehan Liu, Chunrong Yu, Ziyang Yang, Haipeng Yang, and Cheng Zhang, defines three key domains that researchers should address in reporting new PFAS sorbents: sorbent characterization, water matrix specification and PFAS details, and sorption and regeneration performance evaluation, including flow-through packed-bed testing at both bench and pilot scales.
Characterization of sorbents should be done, according to the guidelines, by full reporting of the synthesis methods, chemical composition, particle shape and size distribution, surface properties including functional groups and surface area, density measurements, and stability under various environmental conditions.
The water matrix specification is especially important since real water matrices, particularly those with high concentrations of co-contaminants such as sulfate, natural organic matter, and metal cations, along with the ultrashort-chain PFAS, present a challenge that is often underestimated in bench-scale evaluations. The guidelines give detailed reporting on the source of water, pH, ionic strength, dissolved organic matter, and presence of competing contaminants.
Addressing the Full PFAS Spectrum
PFAS are partitioned into ultra-short chain <C3, short-chain C4-C7, and long-chain C8 or greater homologues that have markedly different physicochemical and sorption behaviors.
Ultrashort-chain PFAS, such as trifluoroacetic acid, pose unique challenges that are different in fundamental ways from those posed by longer-chain compounds. Recent World Health Organization assessments have highlighted the increased detection frequency and rising ecological concern of ultrashort-chain PFAS, further necessitating targeted studies on their removal mechanisms. Still, current research remains scant, with very few studies focused on materials capable of capturing both ultra-short- and short-chain PFAS simultaneously.
Long-chain PFAS, such as PFOA, PFOS, and perfluorodecanoic acid, exhibit strong hydrophobic interactions, high protein binding, and pronounced bioaccumulation that enhance their capture by carbonaceous materials, ion-exchange resins, and functionalized polymers.
Performance Appraisal Criteria
The framework proposes standard test protocols for performance evaluation, which include measurements of removal efficiency, sorption kinetics by established models, isotherm studies to find the maximum capacity, and most importantly, tests of regeneration and reusability over multiple cycles.
The document particularly places emphasis on the conduct of continuous flow-through column testing, especially the Rapid Small-Scale Column Test. Compared to the pilot-scale studies, the RSSCT has several advantages: it can be performed in considerably shorter time frames using minimal volumes of PFAS-contaminated water while accurately reflecting the performance of the sorbent under continuous applications.
Addressing Regulatory Needs
The framework is timely, coming at a time when regulatory limits for PFAS in drinking water continue to be tightened around the world. The World Health Organization recommends a combined concentration limit for PFOA and PFOS of 0.1 ppb in drinking water, reflecting their severe health implications.
The European Union has set even stricter limits under its drinking water directive, with thresholds of 0.004 ppb for PFOA, 0.002 ppb for PFOS, and a cumulative limit of 0.1 ppb for 20 PFAS compounds, while committing to phase out all non-essential PFAS by 2030.
In the United States, the EPA formally unveiled a recalibration of its drinking water rule in May 2025: it will hold on to the 4 ppt MCLs for PFOA and PFOS, but re-evaluate or potentially withdraw individual limits for other PFAS compounds while extending the compliance deadline from 2029 to 2031 to give water systems additional time for treatment upgrades and funding.
Way Forward
The authors concede that the entire framework could not be undertaken by a single study and suggest a modular adoption approach: Baseline reporting will be established, followed by matrix sensitivity testing, continuous flow evaluation, and multi-cycle regeneration studies to the extent appropriate for specific research questions.
The authors note, “To our knowledge, no published work currently satisfies the whole framework; this gap is precisely why we propose it, so that future studies can converge on a common rigorous standard.”
The team envisions that the community priorities are to achieve consensus on reference water matrices and PFAS test panels, conduct interlaboratory comparison exercises, develop open protocols and data repositories, and harmonize scale-up metrics to connect laboratory measurements to industrial design and cost estimates.
The framework is designed to speed the pace of development of effective PFAS sorbents useful in real-world water treatment by enabling rigorous cross-study comparison through standardization in how PFAS sorbent performance is evaluated and reported.
Source: Yang, Z., Su, Z., Liu, K., Yu, C., Yang, Z., Yang, H., & Zhang, C. (2025). Toward Standardized Evaluation of PFAS Sorbents. Advanced Materials. https://doi.org/10.1002/adma.202516944
