Water treatment techniques for destructive removal of perfluoroalkyl substances (PFAS) have only recently begun to emerge in the research literature, comprising unconventional advanced oxidation and reduction methods. Photocatalytic degradation of PFAS has not been widely pursued, which is a result of the limited ability of common semiconductor materials to induce C–F bond cleavage in aqueous systems. Herein, degradation of perfluorooctanoic acid (PFOA) by bismuth phosphate photocatalysts under ultraviolet irradiation has been investigated for the first time, including the relatively well-known monoclinic BiPO₄ wide band gap semiconductor, as well as a novel Bi₃O(OH)(PO₄)₂ (BOHP) composition. Compared to BiPO₄ and a β-Ga₂O₃ nanomaterial reference catalyst, BOHP microparticles achieved dramatically faster PFOA degradation and mineralization, despite both a smaller surface area and a lower band gap energy. The rate constant for degradation of PFOA by BOHP in a pure water solution was ∼15 times greater than those of both BiPO₄ and β-Ga₂O₃ (∼20–30 times greater when normalized for surface area) and was on the same order of magnitude as that of phenol degradation by P25 TiO₂ in the same photoreactor. The superior performance of BOHP was primarily related to the surface charge and adsorption behavior of PFOA, in combination with the favorable redox potentials of BOHP charge carriers. The catalyst was further tested at low PFOA concentrations (i.e., microgram per liter range) in the presence of natural organic matter, and rapid degradation of PFOA was also observed, indicating the potential of BOHP to enable practical ex situ destructive treatment of PFAS-contaminated groundwater.

中文翻译：

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新型Petitjeanite Bi ₃ O（OH）（PO ₄）₂微粒紫外光催化剂快速降解和矿化全氟辛酸

用于破坏性去除全氟烷基物质（PFAS）的水处理技术直到最近才开始出现在研究文献中，其中包括非常规的先进氧化和还原方法。PFAS的光催化降解尚未得到广泛的追求，这是由于普通半导体材料在水性体系中引起CF键断裂的能力有限所致。本文中，首次研究了磷酸铋光催化剂在紫外线照射下对全氟辛酸（PFOA）的降解，包括相对著名的单斜BiPO ₄宽带隙半导体，以及新型的Bi ₃ O（OH）（ PO ₄）₂（BOHP）组成。与BiPO ₄相比和的β-Ga ₂ ö ₃纳米材料的参考催化剂，BOHP微粒尽管两个小的表面积和低的带隙能量显着更快的实现PFOA降解和矿化。在纯水溶液中的速率常数为PFOA的降解通过BOHP比那些既BIPO更大〜15倍₄和的β-Ga ₂ ö ₃（~20-30倍时归一表面积），并在相同的P25 TiO ₂降解苯酚的数量级在同一光反应器中。BOHP的优异性能主要与PFOA的表面电荷和吸附行为有关，再加上BOHP载流子的良好氧化还原电势。在存在天然有机物的情况下，在低PFOA浓度（即微克每升范围）下对催化剂进行了进一步测试，并且还观察到PFOA的快速降解，表明BOHP潜在地实现了对PFAS污染的实际异地破坏处理地下水。