Efficient dechlorination of 2,4-dichlorophenol in an aqueous media with a mild pH using a Pd/TiO2NTs/Ti cathode

Abstract

In this study, palladium-loaded titania nanotubes was fabricated on a titanium plate (Pd/TiO 2 NTs/Ti) for efficient electrodechlorination of 2,4-chlorophenol with a mild pH condition. The nature of Pd/TiO 2 NTs/Ti electrodes was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) techniques. The characterization results indicated the generation of Pd 0 nanoparticles which were evenly dispersed on titania nanotubes arrays on the Pd/ TiO 2 NTs/Ti surface. An effective degradation efficiency of up to 91% was achieved within 60 min at cathode potential of -0.7 V (vs. SCE) and initial pH of 5.5. The effects of the applied cathode potential and initial pH on the degradation efficiency were studied. A near neutral condition was more favorable since very low and very high pHs were not conducive to the dechlorination process. Furthermore, the intermediates analysis showed that the Pd/TiO 2 NTs/Ti electrode could completely remove chlorine from 2, 4-dichlorophenol since only phenol was detected as the byproduct and the concentration of released chlorine ions indicated near-complete dechlorination. This work presents a good alternative technique for eliminating persistent chlorophenols in polluted wastewater without maintaining strong acidic environment.

Metallic nanoparticles for electrocatalytic reduction of halogenated organic compounds: A review

“…Indeed, ethanol can dissociatively chemisorb on Ag to form Ag ethoxide at room temperature [185]. Meanwhile, Du et al [24] showed that the removal rate of 2,4-DCP on Pd/TiO 2 NTs/Ti electrode decreased from 91% to 35% after 5 cycles reuse. This result was ascribed to the poisoning effect of the phenol produced and the formation of palladium oxide.…”

“…It is well-known that the presence of chlorine atoms in organic compounds is related to their toxicity [23]. Therefore, the removal of chlorine atoms from organohalogenated compounds is expected to decrease their toxicity and improve their biodegradability [24]. By selectively targeting carbon-chlorine bonds, reductive dechlorination is thus a promising approach to reduce the toxicity of chlorinated organic compounds prior to a biological treatment.…”

Electrochemical Degradation of N-Nitrosodimethylamine (NDMA) by Ti-Based Nano-Electrode: Kinetics, Mechanism and Effect on NDMA Removal

“…21 Recently, novel TiO 2 nanotubes have received increasing attention owing to their large specific surface area, high chemical stability, environmentally friendly characteristics and excellent ion-exchange ability. [22][23][24] Titanium dioxide nano-electrodes have been studied as promising materials, exhibiting impressive electrochemical performance in the degradation of organic compounds in wastewater and the generation of hydrogen via water splitting. 25,26 In our previous study, we have synthesized a Ti nano electrode with a large specific surface area used for nitrate removal, which achieved a nitrate reduction efficiency around 105%-154% higher than that of the untreated electrode.…”