Electrochemical incineration of cresols: A comparative study between PbO2 and boron-doped diamond anodes

We previously reported that total mineralization of cresols is feasible using the solar photoelectro-Fenton method in which complexes of Fe(III) with generated carboxylic acids are efficiently photodecomposed by UV irradiation of sunlight

Cristina Flox; Conchita Arias; Enric Brillas; André Savall; Karine Groenen-Serrano


Scholarcy highlights

  • Phenol and its derivatives are the major constituents of industrial wastewater produced by oil refineries, petrochemicals, polymeric resins, pharmaceuticals, coal conversion plants and chemical industries
  • A series of comparative electrolyses for all cresols was performed using the boron-doped diamond anode to test if the relative position of – CH3 and –OH groups has any effect on the oxidation rate of these compounds
  • Solutions containing 415 mg LÀ1 dissolved organic carbon of each cresol of pH 4.0 were treated at 40 mA cmÀ2, 25 °C and liquid flow rate of 126 L hÀ1 by prolonging the electrolysis time to attain almost overall decontamination
  • For m-cresol degradation, 2-methylhydroquinone and 2-methyl-p-benzoquinone are detected as aromatic intermediates, whereas a mixture of short linear carboxylic acids evolving to oxalic and formic acids as ultimate products are identified and quantified
  • Acetic acid is very persistent using a BDD anode, but it is largely accumulated with PbO2, because it cannot be attacked by PbO2(ÅOH)
  • That means that the final electrolyzed solution with BDD is mainly composed of acetic acid with less than 2% of the initial DOC
  • An energy consumption of 165 kW h mÀ3 is needed for achieving the total disappearance of aromatic intermediates, along with almost total mineralization of the m-cresol solution, with BDD, which is slightly higher than 139 kW h mÀ3 required for the removal of this pollutant and its aromatic intermediates with PbO2 giving an effluent with a highly detoxified organic load that may be treated by a post biological treatment

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