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Porównanie przebiegu fotolizy i fotoutleniania roztworów wodnych niejonowych i anionowych środków powierzchniowo czynnych

Perkowski J., Szadkowska-Nicze M.

Prace Instytutu Elektrotechniki

2010

Z. 245

167-183

Zbadano i porównano proces fotolizy, jak i fotoutleniania dwu środków powierzchniowo czynnych: SDBS (dodecylobenzenosulfonian sodu) i Triton X-100 (produkt kondensacji tlenku etylenu z p-(1,1,3,3 tetrametylobutylo)fenolem w roztworze wodnym. Wydajność fotolizy była badana w zależności od stężenia surfaktantu, mocy lampy UV i długości fali światła. Wyznaczono wydajności kwantowe rozkładu obu surfaktantów. Proces fotochemicznego rozkładu surfaktantów w roztworze wodnym śledzono analizując między innymi: zmiany absorbancji roztworu, chemicznego zapotrzebowania na tlen i ogólnego węgla organicznego. Stwierdzono, że procesy fotolizy obu surfaktantów przebiegają wolno z podobną wydajnością.

Photolysis and photooxidation of two detergents: SBDS (sodium dodecylbenzenesulfonate) and Triton X-100 (polyoxyethylene(10)isooctylphenyl ether) in aqueous solutions were examined and compared. Photolysis efficiency was studied depending on surfactant concentration, power of UV lamp, and light wavelength. Quantum yields of decomposition for both surfactants were estimated. Photochemical decomposition of surfactants in aqueous solutions were investigated by absorption spectroscopy, chemical oxygen demand and total organic carbon analysis. It was observed that photolysis of both surfactants proceed slowly with similar yield.

Zastosowanie polimerowych membran ultrafiltracyjnych do usuwania substancji powierzchniowo czynnych z roztworów wodnych

Kowalska I.

Rocznik Ochrona Środowiska

2008

Tom 10

593-604

Celem przeprowadzonych badań było określenie skuteczności polimerowych membran ultrafiltracyjnych w usuwaniu substancji powierzchniowo czynnych z roztworów wodnych w zakresie stężeń poniżej i powyżej krytycznego stężenia micelizacji. Zbadano również wpływ obecności soli mineralnych będących podstawowym wypełniaczem kompozycji detergentowych na skuteczność eliminacji SPC z roztworów wodnych w procesie ultrafiltracji.

Surface active agents, also called surfactants, are amphiphilic compounds that contain both a hydrophobic and a hydrophilic portion. In aqueous solutions, surfactant monomers aggregate into structures called micelles with hydrophobic groups in the interior of the micellar structures. The minimum concentration at which micellization occurs is called the critical micelle concentration (CMC). At higher concentrations than CMC, monomers and micelles coexist in equilibrium. Surface active agents are used in large quantities in household products, detergent formulations, industrial application and as additives to improve the effectiveness of agrochemicals. The consumption of surfactants for both industrial and domestic purpose has resulted in a worldwide production of approximately 17 million tonnes in 2000 (including soap), with expected future growth rates of 3-4% per year globally and of 1.5-2.0% in the EU [19]. As a consequence of their widespread use surfactants may persist in wastewater treatment systems at relatively high concentrations [13, 18]. In order to meet legislative requirements and to discharge effluents into communal systems or directly into the river an efficient treatment process must be applied. Due to the diversity of surfactants and their physico-chemical properties it is difficult to develop a single and an effective treatment method of detergent wastewater. From among techniques which were studied in this research area [3, 5, 10, 14, 16] can be listed biodegradation, coagulation, foaming, oxidation, adsorption, ion-exchange and membrane processes. Numerous reports indicate that membrane technology is emerging as one of the leading contenders in the recovery of water and concentrated products from the rinsing waters used in the batch production of surfactants and detergents or as a polishing step before the effluents are discharged. The aim of the study was to evaluate the removal efficiency of anionic surfactant from water solutions by means of ultrafiltration. Polymer membranes made of polyethersulfone and cellulose with molecular weight cut-off of 5, 10 and 30 kDa were used. Both transport and separation properties of the polymers were tested for surfactant solutions in concentration range of 0.1-3.0 CMC in a presence of mineral salt (NaCl). It was found that the surfactant concentration was a crucial parameter determining effectiveness of ultrafiltration process. With the increase in surfactant concentration, the retention coefficients and hydraulic performance decreased, with a rise around the CMC value. The UP005 membrane was found to be very effective in anionic surfactant removal in a wide range of concentrations - the retention coefficient amounted to 82-90%. During the permeation experiments in the presence of mineral salt, the increase in retention coefficient was observed for a given dose of mineral salt along with the increase in surfactant concentration in the feed