In-situ synthesis of bimetallic Co/Zn-ZIF on the graphite-felt for electrocatalytic degradation of pharmaceutical pollutants.

In the electro-Fenton process, one of the important challenges is to adjust the pH of the environment in the acidic region so that the system's performance is not affected by side reactions. In this case, it will be necessary to neutralize the solution after the process. One of the solutions is to use a heterogeneous catalyst to widen the pH range. However, recovering the used catalyst itself can be another challenge. Modifying the electrode using electroactive materials can answer both of these challenges. This work modified the bare graphite-felt (GF) electrode using zeolitic imidazolate frameworks (ZIF)-derived carbon material doped with Co and Zn through a rapid, room-temperature, and water-based synthesis method. Various analyses, including XRD, SEM, XPS, and LSV, confirmed the proper modification of bare GF carbon fibers. The modified Co/Zn-N-C@GF electrode showed good performance in removing rifampicin (RFP) during the electro-Fenton process, so about 90 % of the pollutant was removed within 30 min without adding a homo-/heterogeneous catalyst. Optimum conditions for this process were 1.0 V for applied voltage, 40 mg/L for initial concentration of RFP, and 5.6 for pH. Also, LC-MS analysis was performed to confirm the degradation of RFP and investigate its degradation pathway. [Display omitted] • XRD/XPS revealed the presence of Co3+, Co2+, and Co0 in the modified GF. • LSV proved that the modified GF has lower overpotential and higher reaction current. • Co/Zn-N-C@GF significantly enhanced kinetics (> 2 times) despite its small size. • The role of ROSs in pollutant degradation was recognized as 1O2 > O2•− > •OH. [ABSTRACT FROM AUTHOR]