Electrochemical Reduction of Bromate by a Pd Modified Carbon Fiber Electrode: Kinetics and Mechanism

Abstract

a b s t r a c tThe electroreduction of bromate (BrO 3 − ) was investigated at a Pd modified carbon fiber (Pd/C) electrode prepared from PdCl 2 via electrodeposition method. Pd particles distributed on the carbon fiber substrate uniformly. Under various cathode potentials, electroreduction removal of BrO 3 − at pure carbon fiber electrode and the Pd/C electrode were firstly compared. It was observed that nearly no BrO 3 − removal was observed within the bias potential of -2.0 V at the carbon fiber electrode. At the Pd/C electrode, the removal efficiency of BrO 3 − was sharply increased from 24.0% to 58.4% at the cathode potential of -1.0 to -1.5 V, which was further increased to be 87.2% at -2.0 V. The electrochemical reduction of BrO 3 − was strongly pH-dependent at -0.5 V and the reduction rate could be enhanced at low pH. While at the potential of -2.0 V, a slight pH effect was observed. BrO 3 − electroreduction follows pseudo first-order kinetics; the rate constant k was firstly increased from 0.016 to 0.031 min −1 with the increase of the Pd loading amount from 0.31 to 0.73 mg/cm 2 , and then was decreased to 0.018 min −1 at a higher Pd loading amount of 1.05 mg/cm 2 . The Pd(0) nanoparticles played a significant role in forming atomic H* to realize indirect BrO 3 − reduction. The electrochemical reduction of BrO 3 − produces accumulated intermediates of HOBr and OBr − , which were subsequently reduced to Br − with the time evolution.

Reductive dechlorination of trichloroacetic acid (TCAA) by electrochemical process over Pd-In/Al2O3 catalyst

“…Although the presence of bubbles did not damage the electrode, they could still interfere with TCAA diffusion to the catalyst [39]. In addition, as active Pd-In sites are vital for TCAA removal [40], the TCAA electrochemical removal rate was observed to increase gradually as the Pd-In/Al 2 O 3 dosage increased from 0.2 g/L to 1.0 g/L (Fig. 5(b)), and the removal rate achieved a relatively stable value when more catalyst (1.5 g/L) was used, where the current density restricted the further enhancement of TCAA reduction.…”

Reductive Sequestration of Toxic Bromate from Drinking Water using Lamellar Two-Dimensional Ti3C2TX (MXene)

“…To avoid hazardous waste, subsequent reduction of BrO 3 – to Br – has been proven an efficient method to control BrO 3 – pollution in water supply . Some classical processes have been proposed for the degradation of BrO 3 – such as hydrogenation reduction , and electron beam treatment. , Other combined approaches were proposed as more efficient methods for bromate removal such as, adsorption–reduction, − chemical reduction, electrochemical reduction using modified carbon electrodes, ,, microbial reduction, zerovalent metal (ZVM) reduction, , and catalytic reduction . Alternatively, free-standing or supported TiO 2 nanoparticles have been used for the photocatalytic reduction of BrO 3 – to Br – under UV light irradiation. , However, photocatalysts usually suffer from rapid decay of catalytic activity due to charge recombination and narrow band gap.…”

“…8 Some classical processes have been proposed for the degradation of BrO 3 − such as hydrogenation reduction 9,10 and electron beam treatment. 11,12 Other combined approaches were proposed as more efficient methods for bromate removal such as, adsorption−reduction, 13−15 chemical reduction, 16 electro-chemical reduction using modified carbon electrodes, 2,4,17 microbial reduction, 18 zerovalent metal (ZVM) reduction, 13,19 and catalytic reduction. 20 Alternatively, free-standing or supported TiO 2 nanoparticles have been used for the photocatalytic reduction of BrO 3 − to Br − under UV light irradiation.…”

Гибридные Системы Очистки Воды: Комбинированные Методы Для Эффективного Удаления Загрязнителей

“…Третье преимущество гибридных систем заключается в возможности интеграции новых технологий и инноваций в области очистки воды, что может привести к дополнительным улучшениям производительности и снижению затрат [6]. Например, разработка и внедрение новых материалов и процессов, таких как нанотехнологии и биотехнологии, может усилить эффективность гибридных систем и сделать их более устойчивыми к различным видам загрязнителей.…”