Mass Transport and Potential Studies in a Flow-through Porous Electrode Reactor. A Comparative Study of Reticulated Vitreous Carbon and Graphite Felt Used as Cathode

 

J. L. Nava,^1,* A. Recéndiz,¹ L. G. González,² G. Carreño,² F. Martínez²

 

¹ Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Química, C.P. 09340, México D.F., México

²Universidad de Guanajuato, Facultad de Ingeniería en Geomática e Hidráulica, Av. Juárez No. 77, CP. 36000, Guanajuato, Guanajuato, México

 

Received 25 April 2008; accepted 20 November 2008

 

Abstract

This paper deals with the use of reticulated vitreous carbon (RVC) and graphite felt (GF) as porous electrode for the removal of 20 ppm Cu(II) in 0.5 mol dm^-3 Na₂SO₄ at pH 2 (which resembles a rinsing wastewater generated by a plating industry). The experimental mass transport characterization (k_ma 3Dbu^c) showed that for 100 ppi (RVC), the value of the coefficient b, associated with magnitude of porous electrode, is 0.88, while for (GF) is 3.38. On the other hand, c value for 100 ppi (RVC) is 0.06, while for (GF) is 0.62, indicating that the flow pattern is a complex function of the shape of the electrode. The experimental potential drop for 100 ppi (RVC) and (GF) (1.2 cm thick), indicated the absence of hydrogen evolution. Current efficiencies for RVC and GF were function of convection, giving values comprised between 45 £ f £ 68% and 51 £ f £ 73%, respectively, and energy consumption values of 0.3 < E_cons < 1.7 and 0.4 < E_c < 1.1 kWh m^-3, respectively. Theoretical number of identical cells in the stack (N) necessary to the cupric depletion from 20 to 1 ppm, for 100 ppi (RVC) and (GF) were calculated.

Keywords: metal ion removal, rinsing wastewater, flow-through porous electrode reactor, mass transport characterization, potential drop.

 

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* Corresponding author. E-mail address: jlnm@xanum.uam.mx