A Review of Treatment Techniques for Short-Chain Perfluoroalkyl Substances

Yang Liu,Xiaomin Hu,Xin Zhao,Lixin Shao,Mengyuan Lu,Chenglong Li,Jia Bao,Tingyu Li

doi:10.3390/app12041941

Abstract

In recent years, an increasing amount of short-chain perfluoroalkyl substance (PFAS) alternatives has been used in industrial and commercial products. However, short-chain PFASs remain persistent, potentially toxic, and extremely mobile, posing potential threats to human health because of their widespread pollution and accumulation in the water cycle. This study systematically summarized the removal effect, operation conditions, treating time, and removal mechanism of various low carbon treatment techniques for short-chain PFASs, involving adsorption, advanced oxidation, and other practices. By the comparison of applicability, pros, and cons, as well as bottlenecks and development trends, the most widely used and effective method was adsorption, which could eliminate short-chain PFASs with a broad range of concentrations and meet the low-carbon policy, although the adsorbent regeneration was undesirable. In addition, advanced oxidation techniques could degrade short-chain PFASs with low energy consumption but unsatisfied mineralization rates. Therefore, combined with the actual situation, it is urgent to enhance and upgrade the water treatment techniques to improve the treatment efficiency of short-chain PFASs, for providing a scientific basis for the effective treatment of PFASs pollution in water bodies globally.

Highlights

Since the 1950s, perfluoroalkyl substances (PFASs) have been widely used in industrial production and commercial products, involving chrome plating, foam extinguishing agents, aviation hydraulic oil, and food packaging paper [1,2]
This paper showed that the adsorption, electrochemical oxidation, and photocatalytic degradation have certain removal effects on short-chain PFASs by comparisons on various treatment techniques
Considering the removal efficiency, treatment time, energy consumption, and cost, adsorption was the most widely applied technique for the effective removal of short-chain PFASs, which was suitable for a wide concentration range of pollution and to meet the low-carbon policy

Summary

Introduction

Since the 1950s, perfluoroalkyl substances (PFASs) have been widely used in industrial production and commercial products, involving chrome plating, foam extinguishing agents, aviation hydraulic oil, and food packaging paper [1,2]. They are a class of manmade chemicals with all the hydrogen atoms on the carbon skeleton replaced by fluorine atoms, together with a terminal functional group [3]. Long-chain PFASs (C8-C14) and their sodium, as well as ammonium, salts were added into the candidate list of regulatory substances in the EU, and PFOA and PFOS were added in the Stockholm Convention on Persistent Organic Pollutants (POPs) list [5]. With the ban of long-chain PFASs, shortchain PFASs (PFCAs < C8, PFSAs < C7) have been produced and used as substitutes in large quantities

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Conclusion