The use of respirometric measurements to determine the toxicity of textile dyes in aqueous solution and after oxidative decolourisation processes.
Selected results from the degradation of reactive-dye hydrolysates after UV irradiation, ozonation and sodium peroxodisulphate (NaPS) treatment are presented. Reactive dyes with representative chromophores and anchor groups were chosen for the research project. Different stages of oxidative decolourisation were examined and determined by water parameters for biological degradation (BOD). The paper focuses on toxicity tests with Pseudomonas putida to consider whether the oxidative treatments result in products with a risk for the environment. Tests were performed with the AQUALYTIC Sensomat System, which measures biological oxygen demand (BOD). It was determined that the chosen oxidative treatments had as a rule no bearing on respiration of P. putida. Experiments with hydrolysates after short-term UV irradiation resulted in a slightly increased but not long-lasting toxicity in comparison with treatments with ozone or NaPS. Toxic effects were found in tests with hydrolysates of metalliferous dyes. During oxidative treatment, metals were liberated from the chromophores. This did cause complete inhibition of respiration of P. putida. Dye Blue E, a member of a dye class with chlorotriazine anchor groups, was itself found to be toxic, caused by the reactivity of the anchor group. The hydrolysate is only of minor toxicity.
Boschke
Elke
E
Technische Universität Dresden, Institut für Lebensmittel- und Bioverfahrenstechnik, Bergstrasse 120, DE-01069 Dresden, Germany. elke.boschke@tu-dresden.de
Böhmer
Ulrike
U
Lange
Jürgen
J
Constapel
Marc
M
Schellenträger
Marc
M
Bley
Thomas
T
D003116:Color; D004396:Coloring Agents / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity*; D003470:Culture Media; D006868:Hydrolysis; D007700:Kinetics; D008365:Manometry; D008872:Microwaves; D010083:Oxidants, Photochemical / Q000737:chemistry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis*; D010101:Oxygen Consumption / Q000187:drug effects*; D010126:Ozone / Q000737:chemistry; D016958:Pseudomonas putida / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D015203:Reproducibility of Results; D012996:Solutions; D013783:Textile Industry; D014466:Ultraviolet Rays
D004396:Coloring Agents; D003470:Culture Media; D010083:Oxidants, Photochemical; D012996:Solutions; D010126:Ozone; D010100:Oxygen