title: Electrochemical treatment of cork boiling wastewater with a boron-doped diamond anode.
abstract: Anodic oxidation at a boron-doped diamond anode of cork boiling wastewater was successfully used for mineralization and biodegradability enhancement required for effluent discharge or subsequent biological treatment, respectively. The influence of the applied current density (30-70 mA/cm2) and the background electrolyte concentration (0-1.5 g/L Na2SO4) on the performance of the electrochemical oxidation was investigated. The supporting electrolyte was required to achieve conductivities that enabled anodic oxidation at the highest current intensities applied. The results indicated that pollutant removal increased with the applied current density, and after 8 h, reductions greater than 90% were achieved for COD, dissolved organic carbon, total phenols and colour. The biodegradability enhancement was from 0.13 to 0.59 and from 0.23 to 0.72 for the BOD/COD ratios with BOD of 5 and 20 days' incubation period, respectively. The tests without added electrolyte were performed at lower applied electrical charges (15 mA/cm2 or 30 V) with good organic load removal (up to 80%). For an applied current density of 30 mA/cm2, there was a minimum of electric conductivity of 1.9 mS/cm (corresponding to 0.75 g/L of Na2SO4), which minimized the specific energy consumption.
authors.affiliation: a UMTP and Department of Chemistry , University of Beira Interior , 6201-001 Covilhã , Portugal.
authors.forename: Annabel
authors.initials: A
authors.lastname: Fernandes
authors.forename: Diana
authors.initials: D
authors.lastname: Santos
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Pacheco
authors.forename: Lurdes
authors.initials: L
authors.lastname: Ciríaco
authors.forename: Rogério
authors.initials: R
authors.lastname: Simões
authors.forename: Arlindo C
authors.initials: AC
authors.lastname: Gomes
authors.forename: Ana
authors.initials: A
authors.lastname: Lopes
mesh_terms: D001895:Boron / Q000737:chemistry; D018130:Diamond / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006358:Hot Temperature; D013696:Temperature; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods; D014934:Wood / Q000737:chemistry*
chemical_list: D001895:Boron; D018130:Diamond; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: BDD; anodic oxidation; biodegradability; cork boiling wastewater; electrolyte concentration