Perfluorooctanoic acid (PFOA) removal by flotation with cationic surfactants

Perfluorooctanoic acid (PFOA) was separated and recovered using a foam flotation process aided by cationic surfactants. The PFOA removal efficiency was in the following decreasing order: OTAB (C(8)TAB) > DTAB (C(10)TAB) > CTAB (C(16)TAB) > TBAB, which indicates that cationic surfactants with an alkyl chain that had a similar length to that of PFOA had higher affinities to PFOA. PFOA removal slightly decreased with increasing ionic strength of the surfactant but did not change with the pH. PFOA could be completely removed in 20 min with 1.25 mM of OTAB in actual wastewater. The energy yield value of foam flotation with a cationic surfactant was much higher than those of other methods, which means that using foam flotation with a cationic surfactant as the collector is a simple, fast, and energy-efficient method to separate and recover PFOA from dilute water solutions. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Foam flotation process aided by cationic surfactants proved to be an efficient method for separating and recovering PFOA, with surfactants having alkyl chains similar in length to PFOA showing higher affinities. OTAB was able to completely remove PFOA in 20 minutes in actual wastewater, indicating the potential of this method for industrial applications.