从化学品中获取氟：解决PFAS污染问题

译者：Sabrina Ye，麦仕奇香港办公室

全氟及多氟烷基化合物（PFAS）是含有至少一个全氟化的甲基或亚甲基碳原子的氟化物质。因此，PFAS含有多个碳-氟键（C-F键）。这些键高度稳定，并产生了理想的特性如耐高温，这导致了PFAS在灭火泡沫中的广泛使用。碳氟化合物还具有疏水性和疏脂性，所以PFAS也被用作防水和防油的屏障，例如在织物、炊具或食品容器中。

Per- and polyfluoroalkyl substances (PFAS) are fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom. Accordingly, PFAS contain multiple carbon-fluorine bonds (C-F bonds). These bonds are highly stable and give rise to desirable properties, such as tolerance to high temperatures, which has led to widespread use of PFAS in foams for fire suppression. Fluorocarbons are also hydrophobic and lipophobic, and PFAS are also used as water- and oil-resistant barriers, for example in fabrics, cooking utensils or food containers.

PFAS的广泛使用导致了这些化学品对水和土壤的污染。事实上，最近的研究 *1表明，全球各地的雨水都受到了PFAS的污染，其含量超过了饮用水的建议水平（参见BBC关于雨水污染的报道*2）。研究人员得出的结论是，PFAS的地球界限已经被超过，并且“通过尽可能迅速地限制PFAS的使用，避免大规模和长期的环境及人类接触PFAS的问题进一步升级是非常重要的”。反复暴露于低水平的PFAS与健康问题息息相关，包括生育能力的下降、免疫反应的降低和癌症。由于PFAS的稳定性非常高，它很难从体内代谢和排泄出来。因此，PFAS会随着时间的推移进行生物累积，从而增加健康问题的风险。

Extensive use of PFAS has resulted in contamination of water and soil with these chemicals. In fact, recent studies *1 have shown rainwater across the globe to be contaminated with levels of PFAS that exceed drinking water advisory levels (see also the BBC’s report *2 on contamination of rainwater). Researchers conclude that the planetary boundary for PFAS has been exceeded and “it is of great importance to avoid further escalation of the problem of large-scale and long-term environmental and human exposure to PFAS by rapidly restricting uses of PFAS wherever possible”. Repeated exposure to low levels of PFAS has been linked to health problems including reduced fertility, reduced immune responses and cancer. PFAS are very difficult to metabolise and excrete from the body, owing to their very high stability. Consequently, PFAS bioaccumulate over time, increasing the risk of health problems.

*1 https://pubs.acs.org/doi/10.1021/acs.est.2c02765

*2 https://www.bbc.co.uk/news/science-environment-62391069

尽管PFAS具有“永久”的特性，但许多一次性塑料产品都含有PFAS。最近，各种国际间和本国法规已经实施，旨在减少对一次性塑料的依赖，使社会摆脱传统的线性塑料经济（见我们之前的文章《一次性塑料：自成一格》*3）。

Despite the “forever” nature of PFAS, many single-use plastic products contain PFAS. Recently, international and national regulations have been implemented that aim to reduce reliance on single use plastics and to move society away from the traditional linear plastics economy (see our previous article “Single-use plastics: a law unto themselves” *3).

*3 https://www.marks-clerk.com/insights/articles/single-use-plastics-a-law-unto-themselves/

在欧洲，减少PFAS的广泛使用的努力正在进行中。2022年3月，欧洲化学品管理局（ECHA）根据欧盟化学品注册、评估、授权和限制制度（REACH）提交了一份提案 *4，以限制消防泡沫中的PFAS。几个欧盟成员国还打算在2023年1月提交一份更广泛的提案，以限制PFAS的生产、投放市场和使用。

In Europe, efforts are being made to reduce the widespread use of PFAS. In March 2022, the European Chemicals Agency (ECHA) submitted a proposal *4 under EU Registration, Evaluation, Authorisation and Restriction of CHemicals (REACH) to restrict PFAS in firefighting foams. Several EU member states also intend to submit a broader proposal in January 2023 to restrict the manufacture, placing on the market and use of PFAS.

*4 https://echa.europa.eu/-/proposal-to-ban-forever-chemicals-in-firefighting-foams-throughout-the-eu?utm_source=echa-weekly&utm_medium=email&utm_campaign

=weekly&utm_content=20220803

在英国，健康与安全局（HSE）进行了一次证据征集 *5，作为正在进行的关于PFAS的英国REACH法规管理选项分析（RMOA）的一部分。RMOA的建议将于2022年夏天在HSE网站上公布，并可能会表明管制是控制已确定风险的适当措施。有关当局和HSE将在公布后尽快考虑这些建议。

In the UK, the Health and Safety Executive (HSE) conducted a call for evidence *5 as part of the ongoing Regulatory Management Options Analysis (RMOA) on PFAS under UK REACH. The recommendations from the RMOA are due to be published on the HSE website in summer 2022, and may indicate that a restriction is an appropriate measure to control the identified risks. The appropriate authorities, with HSE, will consider the recommendations as soon as possible after publication.

*5 https://consultations.hse.gov.uk/crd-reach/pfas-rmoa-001/

然而，即使能够减少PFAS的广泛使用，已经污染饮用水和食品的PFAS也需要被清除并被降解为无害产品。由于PFAS的高稳定性，直到最近，降解方法仍旧需要苛刻的条件，这需要高能量的投入。然而，美国中西大学的B.Trang等人*6最近在《科学》杂志上发表了他们关于分解PFAS的更温和的方法的研究（参见BBC对这项研究的报道*7）。他们报告了作为最大类别的PFAS之一的全氟羧酸（PFCAs），可以在温和的条件下，用廉价的试剂（温度为80至120℃，在环境压力下，水和二甲基亚砜混合物中的氢氧化钠的存在下）分解。同样的方法也被发现可以用于成功降解支链全氟烷基醚羧酸（另一类主要的PFAS），这表明该方法可以适用于一系列不同类别的PFAS。因此，这项研究可以为低成本且简单的减少PFAS污染的方法铺平道路，PFAS是一类（根据设计）相对惰性的化合物，因而难以从环境中去除。

However, even if the widespread use of PFAS is reduced, the PFAS already contaminating drinking water and food products need to be removed and degraded into harmless products. Owing to the high stability of PFAS, degradation methods had until recently required harsh conditions, which require a high-energy input. However, B. Trang et al. *6, of Midwestern University have recently published their research in Science on a milder way to break down PFAS (see also the BBC’s report *7 on this research). They report that one of the largest classes of PFAS, perfluorocarboxylic acids (PFCAs), is broken down under mild conditions and with inexpensive reagents (temperatures of 80 to 120 °C, in the presence of sodium hydroxide in mixtures of water and dimethylsulfoxide under ambient pressure). The same method was also found to successfully degrade branched perfluoroalkyl ether carboxylic acids (another major class of PFAS), suggesting that it could be applicable to a host of different classes of PFAS. This research could therefore pave the way towards low-cost, facile methods of reducing contamination by PFAS, a class of chemical compounds that are (by design) relatively inert and, as such, difficult to remove from the environment.

*6 https://www.science.org/doi/10.1126/science.abm8868

*7 https://www.bbc.co.uk/news/science-environment-62561756

B.Trang等人的论文中提到了一项临时专利申请（US 63/261,772，未公布）。该申请以中西大学的名义提交，描述了降解PFCAs的方法。申请专利是保护创新的有效方式，因为商业化可能会带来潜在的利益。

Mentioned in the paper by B. Trang et al., is a provisional patent application (US 63/261,772, unpublished) that has been filed in the name of Midwestern University, and which describes methods to degrade PFCAs. Filing patents can be an effective way to protect new innovation where commercialisation will likely be of potential interest.

专利申请数据可用于衡量新兴技术的增长和全球趋势。2021年，欧洲专利局发布了一份报告，总结了对塑料行业创新趋势的全方位回顾。报告中的一些关键发现在我们之前的文章《聚合物：向可持续发展的未来过渡》*8中讨论过。例如，化学回收包括将聚合物分解成更小的分子，如B.Trang等人所描述的过程，并有可能用于处理问题更大的废物流（如包含PFAS的废物）。化学回收方法提供的潜力似乎反映在了欧洲专利局报告的专利申请趋势中：化学和生物回收方法在过去十年中产生了该领域最高水平的专利活动。

Patent filing data can be used to gauge growth and global trends in emerging technologies. In 2021, the EPO released a report summarizing a comprehensive review of innovation trends in the plastics sector. Some of the key findings in the report are discussed in our previous article “Polymers: transition to a sustainable future”*8. For example, chemical recycling includes breaking down polymers into smaller molecules, as in the process described by B. Trang et al., and has the potential to be used with more problematic waste streams (such as those comprising PFAS). The potential offered by chemical recycling methods appears to be reflected in the filing trends as reported by the EPO: chemical and biological recycling methods generated the highest level of patenting activities in this area over the last decade.

*8 https://www.marks-clerk.com/insights/articles/polymers-transition-to-a-sustainable-future/

总之，尽管PFAS已经污染了全球的水和土壤，但结合新的立法来减少PFAS的广泛使用，以及最新发现的温和的化学降解方法来降解现有的PFAS，至少有可能消除一些已经造成的损害。专利申请的趋势表明化学塑料回收领域的增长：看起来塑料回收的未来可能是基于化学的。

In summary, whilst PFAS have contaminated water and soil across the globe, a combination of new legislature to reduce widespread use of PFAS, with new-found mild chemical degradation methods to degrade existing PFAS has the potential to undo at least some of the damage done. Patent filing trends suggest a growth in the area of chemical plastic recycling: it seems the future of plastic recycling could be chemical.

如果你想了解更多关于获得专利保护的信息，请联系Kate Appleby (kappleby@marks-clerk.com)，Jian Siang Poh (jpoh@marks-clerk.com)，或你的麦仕奇专利律师。

If you would more information on obtaining patent protection, please contact Kate Appleby (kappleby@marks-clerk.com), Jian Siang Poh (jpoh@marks-clerk.com), or your M&C attorney.