title: Electrochemical treatment of textile dyes and dyehouse effluents.
abstract: The electrochemical oxidation of textile effluents over a titanium-tantalum-platinum-iridium anode was investigated. Batch experiments were conducted in a flow-through electrolytic cell with internal recirculation at current intensities of 5, 10, 14 and 20A, NaCl concentrations of 0.5, 1, 2 and 4% and recirculation rates of 0.81 and 0.65 L/s using a highly colored, synthetic effluent containing 16 textile dyes at a total concentration of 361 mg/L and chemical oxygen demand (COD) of 281 mg/L. Moreover, an actual dyehouse effluent containing residual dyes as well as various inorganic and organic compounds with a COD of 404 mg/L was tested. In most cases, quantitative effluent decolorization was achieved after 10-15 min of treatment and this required low energy consumption; conversely, the extent of mineralization varied between 30 and 90% after 180 min depending on the operating conditions and the type of effluent. In general, treatment performance improved with increasing current intensity and salinity and decreasing solution pH. However, the use of electrolytes not containing chloride (e.g. FeSO4 or Na2SO4) suppressed degradation. Although the acute toxicity of the actual effluent to marine bacteria Vibrio fischeri was weak, it increased sharply following treatment, thus suggesting the formation of persistent toxic by-products.
authors.affiliation: Department of Environmental Engineering, Technical University of Crete, Polytechneioupolis, GR-73100 Chania, Greece.
authors.forename: Efthalia
authors.initials: E
authors.lastname: Chatzisymeon
authors.forename: Nikolaos P
authors.initials: NP
authors.lastname: Xekoukoulotakis
authors.forename: Alberto
authors.initials: A
authors.lastname: Coz
authors.forename: Nicolas
authors.initials: N
authors.lastname: Kalogerakis
authors.forename: Dionissios
authors.initials: D
authors.lastname: Mantzavinos
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects; D004396:Coloring Agents / Q000633:toxicity; D004563:Electrochemistry; D007220:Industrial Waste; D012965:Sodium Chloride; D013783:Textile Industry; D018508:Water Purification
chemical_list: D004396:Coloring Agents; D007220:Industrial Waste; D012965:Sodium Chloride