Degradation of 4-Chlorophenol in a Batch Electrochemical Reactor Using BDD Electrodes

Abstract

The influence of current density (j) (0.25, 0.30, 0.25 and 0.40 A/cm 2 ), initial pH (2.6, 6.5 and 12), stirring speed (As) (400, 500 and 600 rpm), and initial concentration of 4-chlorophenol ([4-CP] 0 ) (300, 500 and 700 mg/L) on degradation of persistent pollutant in a batch electrochemical cell without divisions is presented in this paper. The electrochemical cell was composed of two boron-doped diamond electrodes (BDD). The results of the study showed that best conditions for total degradation of 4-CP were: j of 0.40 A/cm², initial pH of 6.5, As of 500 rpm, and [4-CP] 0 of 500 mg/L, after 150 min of reaction time. Removal of total organic carbon (TOC) was 83% at these conditions. The byproducts were identified by UHPLC. This allowed for the proposal of a degradation pathway of 4-CP at the best conditions. Furthermore, these results demonstrate that the electrochemical method employed in this study allows high percentages (96%) of degradation of 4-CP and that the process is applicable to wastewater treatment.

Electro-oxidation of 2-chlorophenol with BDD electrodes in a continuous flow electrochemical reactor

“…From these results, it can be concluded that the effect of pH 0 on the 2-CP mineralization extent is negligible. Hence, it is not necessary to modify the pH of the synthetic solution of 2-CP and this is in agreement with previous reports [28].…”

“…Among all, oxalic acid is the one with the highest concentration (2.5 mg L −1 ). It is well known that oxalic acid oxidation requires a high • OH concentration The aforementioned results suggest that 2-CP oxidation under the studied reaction conditions here, follows reaction pathway rather similar to that previously proposed for 4-CP oxidation with BDD electrodes also [28]. In such a scheme, Cl atom removal might produce phenol as the first step.…”

“…This leads to a rapid and efficient destruction of organic pollutants. The high oxidation efficiency of organic pollutants by BDD ( • OH) anode has been demonstrated in many studies [2,24,28]. In electrochemical flow reactors, BDD anode has been reported to work in combination with different cathode materials (such as stainless steel (AISI 304) [31], platinum coated with titanium (Pt/Ti) [24], stainless steel [26], cupper (Cu) [35] and stainless steel or platinized plates [10]), such arrangements have led to achieve high organic compounds removal values, close to 100%.…”

Recent advances in electrocatalysts for halogenated organic pollutant degradation

“…The widely reported carbon-based catalysts include BDD, 21,100,101 graphite, 20,102 activated carbon fiber, 103 carbon nanotubes, 104,105 and granular activated carbon 26,106 . The catalytic performance of representative carbon-based anodes for HOPs degradation is presented in Table 4.…”