用掺硼金刚石(BDD)电极的电化学氧化协同作用和臭氧(O3)的工业废水处理

M.A. García-Morales et al. / Electrochemistry Communications 27 (2013) 34–37
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complex. Samples were collected in plastic containers and cooled down to 4 °C, then transported to the laboratory for analysis and treatment. The pH of the raw wastewater is 8.24 and all treatment and testing were done at this value.
Thus, this study evaluates the synergy of the two processes compared to the efficiency and effectiveness of the individual ones. The effectiveness is evaluated in terms of color, turbidity and chemical oxygen demand (COD) reduction. The influence of operating parameters such as time of treatment, current density, and initial pH is also evaluated.
In recent works we have shown that combining electrocoagulation and ozone produces synergistic effects in wastewater treatment [7,8]. However, the use of electrooxidation with boron-doped diamond (BDD) electrodes in conjunction with ozone for treating industrial effluents has not yet been reported.
⁎ Corresponding author. Tel.: +52 722 2173890; fax: +52 722 2175109. E-mail address: groam@uaemex.mx (G. Roa-Morales).
1388-2481/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.elecom.2012.10.028
© 2012 Elsevier B.V. All rights reserved.
1. Introduction
Industrial effluents are difficult to treat using traditional biological systems due to the high variations in their compositions. Unlike municipal wastewater, industrial sources have higher organic load, color, and pH which fluctuate [1,2]. While traditional biological reactors are very effective in digesting the organic matter in municipal wastewater into carbon dioxide and water, the effectiveness drops considerably when treating industrial wastewater. Biological reactors typically only reduce 50% of the biochemical oxygen demand (BOD5) and 35% of the chemical oxygen demand (COD) [3,4].
a Centro Conjunto de Investigación en Química Sustentable, UAEM-UNAM, Carretera Toluca-Atlacomulco, Km 14.5, Campus San Cayetano, C.P. 50200, Toluca Estado de México, Mexico b Department of Chemistry, Xavier University of Louisiana, New Orleans 70125, LA, USA c Department of Chemical Engineering, Facultad de Ciencias Químicas, Universidad de Castilla-La Mancha, Campus Universitario s/n 13071 Ciudad Real, Spain
article info
Article history: Received 9 October 2012 Received in revised form 22 October 2012 Accepted 23 October 2012 Available online 27 October 2012
Synergy of electrochemical oxidation using boron-doped diamond (BDD) electrodes and ozone (O3) in industrial wastewater treatment
M.A. García-Morales a, G. Roa-Morales a,⁎, Carlos Barrera-Díaz a, Bryan Bilyeu b, M.A. Rodrigo c
Electrochemistry Communications 27 (2013) 34–37
Contents lists available at SciVerse ScienceDirect
Electrochemistry Communications
journal homepage: www.elsevier.com/locate/elecom
Due to the limitations of biological reactors, industrial wastewater is typically pretreated using physical–chemical processes such as coagulation–flocculation. However, these processes generate large quantities of sludge and usually require pH adjustments and chemical reagents, all of which create their own environmental issues [5,6]. Coagulation–flocculation is not efficient in the removal of dissolved (persistent) chemical pollutants.
Keywords: Electrooxidation Ozone BDD Wastewater COD O3-BDD coupled process
abstract
This work evaluates the coupling of electrochemical oxidation and ozonation to reduce the high organic load of industrial wastewater quickly and effectively. Ozonation alone is shown to only reduce the COD of wastewater by about 45%. Electrochemical oxidation using boron-doped diamond electrodes reduces the COD by 99.9%, but requires over 2 h per 0.7 L batch. However, when the two processes are coupled, the COD is reduced by 99.9% along with most color and turbidity in about an hour. The coupled process practically eliminates the COD, color, and turbidity without the addition of chemical reagents or changing the pH and doesn't generate any sludge, so it is both effective and environmentally friendly.
Baidu Nhomakorabea
Both electrooxidation and ozonation are advanced oxidative processes based on the generation of hydroxyl radicals (OH•), which have high oxidation potential and degrade of a wide range of contaminants. In particular, BDD electrodes have high anodic stability, a wide working potential window, and low stable voltammetric background current in aqueous media [9,10]. Therefore, the electrochemical behavior of BDD electrodes have been investigated with the goal of developing applications for wastewater treatment [11,12]. On the other hand, ozonation is an efficient and powerful oxidizing process well known for its degradation of organic compounds. The limitations to these processes are the time required for electrooxidation and the effectiveness of ozonation, so neither alone is truly industrially practical.
2. Materials and methods
2.1. Wastewater samples
Wastewater samples were collected from the treatment plant of an industrial park, which receives the discharge of 144 different facilities. Therefore, the chemical composition of this effluent is rather