Electrochemical oxidation of perfluorobutane sulfonate using boron-doped diamond film electrodes

Abstract

This research investigated oxidation of perfluorobutane sulfonate (PFBS) at a boron-doped diamond (BDD) film anode. PFBS oxidation produced carbon dioxide, sulfate, fluoride, and trace amounts of trifluoroacetic acid (TFA). Rate constants for PFBS oxidation as a function of current density and temperature were measured using a rotating disk electrode (RDE) reactor. Reaction rates in the RDE reactor were zeroth order with respect to PFBS concentration, which is indicative of a reaction limited by the availability of reactive sites. The apparent electron transfer coefficient and apparent activation energy were used to evaluate the rate-limiting step for PFBS oxidation. Density functional simulations were used to calculate the reaction energies and activation barriers for PFBS oxidation by hydroxyl radicals and by direct electron transfer. Simulation results indicated that the experiments were performed at sufficiently high overpotentials that the rate-limiting step was an activationless direct electron transfer reaction.

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

“…For remediation, high current and voltage are needed; limiting the availability of electrode materials. One of the most explored materials is boron‐doped diamond (BDD) (Carter and Farrell, 2008; Liao and Farrell, 2009; Lin et al ., 2013; Ochiai et al ., 2011a; 2011b; Xiao et al ., 2011; Zhuo et al ., 2012; Chaplin, 2014; Trautmann et al ., 2015; Urtiaga et al ., 2015; Niu et al ., 2016; Gomez‐Ruiz et al ., 2017; 2018; Schaefer et al ., 2017; Soriano et al ., 2017). BDD can withstand the high current and potential, while behaving as a weak absorber of hydroxyl radicals.…”

“…Various current densities, 0.04‐50 mA/cm 2 , have been explored using BDD anodes to degrade various fluorinated compounds (Carter and Farrell, 2008; Liao and Farrell, 2009; Ochiai et al ., 2011a; 2011b; Xiao et al ., 2011; Zhuo et al ., 2012; Trautmann et al ., 2015; Urtiaga et al ., 2015; Niu et al ., 2016; Gomez‐Ruiz et al ., 2017; Soriano et al ., 2017; Schaefer et al ., 2017; Gomez‐Ruiz et al ., 2018). For PFOA, literature shows that increasing the current density increases the degradation rate (Urtiaga et al ., 2015; Schaefer et al ., 2017).…”

“…One research group investigated using an elevated temperature of 80‐120 ºC and found increased the mineralisation of PFOA (Xiao et al ., 2011). Time frames for these experiments have spanned up to 120 hours (Liao and Farrell, 2009, Zhuo et al ., 2012; Trautmann et al ., 2015). PFOA typically displayed a 1 st or pseudo 1 st order kinetic reaction rate (Carter and Farrell, 2008; Ochiai et al ., 2011a; Xiao et al ., 2011; Urtiaga et al ., 2015).…”

Electrochemical Advanced Oxidation Processes (EAOP) to degrade per- and polyfluoroalkyl substances (PFASs)

“…When the carbon chain is shorter, such as PFBS, the degradation process is much slower (0.004 mM/h of PFBS vs. 0.0123 mM/h of PFOS in terms of Zeroth order), which has been confirmed by the simulation too [60].…”

First principles calculation of lithium-phosphorus co-doped diamond

“…By incorporating the boron atoms into a diamond, the diamond thin films can acquire shallow acceptor impurity levels near the top of its valence band, and become the p-type semiconductors. Recently, the p-type diamonds have received a lot of developments, and have had a wide range of applications in the industry, such as the applications of electrodes [1], the detection applications [2,3] and the preparations of semiconductor devices [4], and so on. In the last two years, the superconducting characteristics of the boron-doped diamond thin films have attracted a great deal of attention [5][6][7].…”