Photocatalytic degradation of perfluoroalkyl substances in water by using a duo-functional tri-metallic-oxide hybrid catalyst

The recalcitrant nature of perfluoroalkyl substances (PFASs) urges scientists to discover solutions to permanently remove PFAS contaminations from water with less energy in contrast to incineration. Herein, a duo-functional tri-metallic-oxide (f-TMO) hybrid photocatalyst was developed via a facile process, which displayed both high adsorption capacity and high defluorination rate of a series of PFASs including PFOA, PFOS, PFHpA, PFHxA and PFBA due to the generated holes/electrons (h(+)/e(-)) and multi-radicals such as O(2)(center dot-)and SO4 center dot-. Particularly the Langmuir adsorption capacities up to 827.84 and 714.46 mg g(-1) along with the adsorption efficiency of 99.8% and 99.4% for PFOS and PFOA were respectively achieved. A defluorination ratio of as high as 74.8% with PFOA and a ratio up to 67.6% with PFOS were respectively received. Over 98% PFOA molecules were degraded within as fast as 15 min under initial concentrations ranging from 1 ppb to 1000 ppb, which demonstrates an excellent degradation kinetics. As for the sulfonic acid of PFOS, an as high as 95.5% degradation efficiency was obtained within 300 min. The degradation rates were 4.5 mg L-1 h(-1) for PFOA and 0.54 mg L-1 h(-1) for PFOS, respectively. In parallel, the f-TMO photocatalyst still exhibited a >96.2% degradation efficiency after eight regeneration cycles. The high physical adsorption capacity and high defluorination rate make this f-TMO catalyst promising applications in removing various PFASs from a broad range of residential and industrial water systems.

Automated summary

The developed f-TMO hybrid photocatalyst shows efficient removal of various PFAS contaminants in water with high adsorption capacity and defluorination rate, making it promising for applications in residential and industrial water systems.