Journal of Applied Electrochemistry

, Volume 35, Issue 11, pp 1087–1093

Electrochemical incineration of oxalic acid: Reactivity and engineering parameters

Article

DOI: 10.1007/s10800-005-9003-0

Cite this article as:
MARTÍNEZ-HUITLE, C., FERRO, S. & DE BATTISTI, A. J Appl Electrochem (2005) 35: 1087. doi:10.1007/s10800-005-9003-0

Abstract

Mass transfer measurements were carried out to test a disk-shaped parallel-plate electrochemical cell, based on a new design. The impinging-jet-cell concept, confined between parallel plates, was adapted to a configuration with one central inlet and several peripheral exit sections, leading to more effective hydrodynamics within the cell. Measurements of mass transfer coefficient were performed using the limiting diffusion current technique based on ferro-cyanide ion oxidation, and overall mass transfer coefficients were correlated to Reynolds numbers ranging from 30 to 200.

 A comparison with literature on similar devices showed higher mass transfer coefficients can be obtained in the cell described in the present work. From the mass transfer standpoint, this type of cell could be a valuable tool in electrochemical wastewater treatment applications.

 The electrochemical oxidation of oxalic acid was tested at different anode materials (Pb/PbO2, boron-doped diamond, Ti/Pt and Ti/IrO2–Ta2O5), showing that the new cell design enables limitations usually encountered with conventional batch cells to be overcome. However, the nature of the anode material remains an important parameter for the elimination of organic substrates.

Key words:

anode materialelectrochemical incinerationflow cellmass transfer coefficientoxalic acid

List of symbols

A

electrode surface area (m2)

C

bulk species concentration (mol m−3)

D

diffusion coefficient (m2 s−1)

dN

diameter of the nozzle (m)

F

faradic constant (96487 C mol−1)

H

nozzle height (m)

IL

electrolysis limiting current (A)

K

mass transfer coefficient (m s−1)

r

radial coordinate measured from the stagnation point (m)

R

radius of the disk electrode (cm)

Re

Reynolds number

Red

nozzle Reynolds number

Rer

radial Reynolds number

s

inter-electrode distance (m)

Sc

Schmidt number

Sh

Sherwood number

Shd

nozzle Sherwood number

Shr

radial Sherwood number

z

electrons exchanged in electrode reaction

VN

mean fluid velocity in cell or channel (m s−1)

Q

volumetric flow rate (m3 s−1)

Greek letters

ρ

fluid density (kg m−3)

ν

kinematics viscosity of the fluid (m2 s−1)

μ

dynamic viscosity (kg s−1 m−1)

Copyright information

© Springer Science+Business Media, Inc. 2005

Authors and Affiliations

  • C.A. MARTÍNEZ-HUITLE
    • 1
  • S. FERRO
    • 1
  • A. DE BATTISTI
    • 1
  1. 1.Department of ChemistryUniversity of FerraraFerraraItaly