An alternative treatment method for fluorosurfactant-containing wastewater by aerosol-mediated separation.

The treatment of fluorosurfactant-containing wastewater is still challenging nowadays. Here, a method is presented to remove fluorosurfactants from water, amongst others from electroplating wastewater. This elimination technique is based on the generation of gas bubbles in solution, enrichment and scavenging of fluorosurfactants by transport of the gas bubbles to the water surface. Finally the bubbles collapse and release an aerosol which is enriched with fluorosurfactants. By sampling of the released aerosols a mass balance was established for 6:2 fluorotelomer sulfonic acid (6:2 FTSA). Thereby 99.8% of the initial amount was revocered in the collected aerosols. Fluorosurfactant concentration in solution decreased exponentially with half-lives ranging from 2 to 6 min for 6:2 FTSA as well as perfluorooctane carboxylate (PFOA) and perfluorooctane sulfonate (PFOS). Elimination rate in defined matrix (0.2 M H2SO4) within 60 min was 99.6, 99.9 and 99.8% for 6:2 FTSA, PFOA and PFOS, respectively. The removal rate of 6:2 FTSA increased in solutions with higher ionic strength. Different wastewater from an electroplating industry containing 6:2 FTSA was treated with the described method without any sample pre-treatment and elimination of 6:2 FTSA took place with the same effectiveness as in synthetic matrices.

Degradation of reactive dyes in wastewater from the textile industry by ozone: analysis of the products by accurate masses.

The present work describes the use of ozone to degrade selected reactive dyes from the textile industry and the analysis of the resulting complex mixture by liquid chromatography/mass spectrometry (LC-MS). To allow certain identification of the substances detected in the wastewater, the original dyes were also investigated either separately or in a synthetic mixture of three dyes (trichromie). Since the reactive dyes are hydrolyzed during the dyeing process, procedures for the hydrolysis were worked out first for the individual dyes. The ozonated solutions were concentrated by solid-phase extraction, which separated very polar or ionic substances from moderately polar degradation products. The latter, which are the primary degradation products, were investigated by liquid chromatography/mass spectrometry with a tandem quadrupole time-of-flight mass analyzer. Accurate masses, which in most cases could be determined with a deviation of

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.

A silica-based monolithic column in capillary HPLC and CEC coupled with ESI-MS or electrospray-atmospheric-pressure laser ionization-MS.

We describe the successful coupling of CEC and capillary HPLC with the recently developed atmospheric-pressure laser ionization (APLI) method. APLI is suitable for selectively and sensitively ionizing nonpolar aromatic compounds at ambient pressure for subsequent mass-selective detection. The polycyclic aromatic hydrocarbons used as analytes are first separated either by CEC on a silica-based monolithic column or by capillary HPLC. The eluent, along with a sheath flow, is volatilized by microelectrospray and then selectively ionized by excimer laser (KrF*) radiation via two-photon excitation. A QTOF-MS is used as mass-selective detector. This interface combination makes soft ionization of thermally labile nonpolar aromatic analytes possible.