Effective ultrasound electrochemical degradation of methylene blue wastewater using a nanocoated electrode.
A novel sonoelectrochemical catalytic oxidation-driven process using a nanocoated electrode to treat methylene blue (MB) wastewater was developed. The nano-scale (nanocoated) electrode generated more hydroxyl radicals than non-nano-scale (non-nanocoated) electrodes did. However, hydroxyl radicals were easily adsorbed by the nanomaterial and thus were not able to enter the solution. Supersonic waves were found to enhance the mass-transfer effect on the nanocoated electrode surface, resulting in rapid diffusion of the generated hydroxyl radicals into the solution. In solution, the hydroxyl radicals then reacted with organic pollutants in the presence of ultrasonic waves. The effect of the nanocoated electrode on the MB wastewater treatment process was enhanced by ultrasound when compared to the non-nanocoated electrode used under the same conditions. The synergy of the nanocoated electrode and ultrasonic waves towards MB degradation was then studied. The optimum operating conditions resulted in a 92% removal efficiency for TOC and consisted of a current of 600 mA, an ultrasound frequency of 45 kHz, and a supersonic power of 250 W. The mechanism of ultrasound enhancement of the nanocoated electrode activity with respect to MB treatment is discussed. The reaction intermediates of the sonoelectrochemical catalytic oxidation process were monitored, and degradation pathways were proposed. The sonoelectrochemical catalytic oxidation-driven process using nanocoated electrodes was found to be a very efficient method for the treatment of non-biodegradable wastewater.
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment (SKLESPC), Tsinghua University, Beijing 100084, China.
Bo
B
Yang
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment (SKLESPC), Tsinghua University, Beijing 100084, China. Electronic address: younbo@gmail.com.
Jiane
J
Zuo
National University of Singapore, Department of Civil and Environmental Engineering, Centre for Water Research, Singapore 117576, Singapore.
Xinhua
X
Tang
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment (SKLESPC), Tsinghua University, Beijing 100084, China.
Fenglin
F
Liu
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment (SKLESPC), Tsinghua University, Beijing 100084, China.
Xin
X
Yu
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment (SKLESPC), Tsinghua University, Beijing 100084, China.
Xinyao
X
Tang
State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China.
Hui
H
Jiang
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment (SKLESPC), Tsinghua University, Beijing 100084, China.
Lili
L
Gan
Hydroxyl radicals; Nanocoated electrode; Ultrasound