A combined current density technique for the electrochemical oxidation of perfluorooctanoic acid (PFOA) with boron‐doped diamond

Abstract

Perfluoroalkyl substances (PFAS) have unique properties that limit their degradability in the environment. One of these PFAS is an acid (PFOA). Electrochemical oxidation is a promising method for remediation, but energy costs are high. To limit the energy consumption, this study used a boron‐doped diamond (BDD) electrode stack and a combined current density technique that employed 50 mA/cm2 for the first 0.25 hours then lowered the current density to 1, 5, or 10 mA/cm2. This technique is similar to one developed previously; however, that method was only developed for compounds comprising of carbon, oxygen and nitrogen, whereas PFAS have the addition of fluorine. For the degradation of PFOA, the combined current density of 50 and 5 mA/cm2 (50&5) allowed for a 37% reduction in energy usage to obtain 75% defluorination compared to using 50 mA/cm2 alone. Further investigation into remediating an ion‐exchange regeneration solution shows great promise.

Electrochemical Oxidation for Treatment of PFAS in Contaminated Water and Fractionated Foam─A Pilot-Scale Study

“…A stirrer was installed for the groundwater tests at 150 L to prevent this issue, leading to more reproducible results. As expected, 32 , 42 the degradation was highly dependent on the specific charge Q (A h L –1 , eq S3 ). Because of the inverse relation between Q and treated volume, the PFAS degradation in both matrices remained lower at a higher volume.…”

“…Scale formation on electrode surfaces prevents the migration of PFAS to the electrode surface, thereby creating a mass transfer limitation that needs to be removed by acid rinsing . Similarly, fluorination of the BDD surface after PFAS degradation causes lower degradation rates but can be reversed by UV irradiation. , Mass transfer limitations can also be reduced by keeping initial PFAS concentrations high or by using innovative turbulence-enhancing reactor designs. , Finally, decreasing the current density over time can help to remain in the reaction-limited regime and thereby provide energy-efficient degradation at the cost of higher treatment times …”

“… 40 , 41 Finally, decreasing the current density over time can help to remain in the reaction-limited regime and thereby provide energy-efficient degradation at the cost of higher treatment times. 42 …”

A Review on Removal and Destruction of Per- and Polyfluoroalkyl Substances (PFAS) by Novel Membranes

“…The following supporting information can be downloaded at: , Table S1: Recently reported adsorption techniques to remove PFAS from wastewater, Table S2: Recently reported studies on ion exchange resins for PFAS removal, SI 1: Destruction techniques. References [ 23 , 46 , 48 , 53 , 56 , 58 , 66 , 128 , 132 , 135 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 153 , 154 , 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 , 171 , 172 , 173 , 174 , 175 , 176 , 177 , 178 , 179 , 180 , 181 , 182 , 183 , 184 , 1...…”