Water Science & Technology Vol 66 No 2 pp 422–428 © IWA Publishing 2012 doi:10.2166/wst.2012.165

Modeling approach to phenol oxidation by a sand-based packed-bed electrode system (SPBEs)

Lizhang Wang, Peng Li and Qian Yan

A comparative study of phenol oxidation using pure electrolysis (PEs) and sand-based packed-bed electrode systems (SPBEs) was performed under conditions of phenol concentration 800 mg L⁻¹, initial pH 6.5, current density 100 A m⁻² and sodium sulfate (Na₂SO₄) 3.0% (w/w) on IrO₂–Ta₂O₅/Ti anode. The results show quartz sand, a non-conducting material is incapable of expanding the electrode area and the phenol oxidation in SPBEs commences only at the electrode surface. From the theoretical description of the mass transport coefficient and chemical oxygen demand (COD), we confirm that the enhancement of the COD removal efficiency, current and space–time yields in SPBEs is due to the improvement of mass transport properties. The proposed SPBEs shows superiority to the PEs on saving energy at the same applied voltage, however, when operated under the same applied current density the energy consumption of the former would be much higher than that of the latter because of the rise of the applied cell voltage.

Keywords: energy consumption; mass transport property; phenol oxidation; pure electrolysis (PE); sand-based packed-bed electrode system (SPBEs)

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