[The formation of trihalomethanes precursor in anionic surfactant biodegradation].
Trihalomethanes (THMs) formed by chlorination of precursor substances in raw water, are found in drinking water. They are found at concentration levels higher than those of other organic contaminants. In the present study, the relationship between the formation of THM precursors and anionic surfectants biodegradation was investigated. Three anionic surfectants (LAS, AS and soap), dissolved in river
National organic reconnaissance survey for halogenated organics
A contribution submitted to the JOURNAL by James M. Symons (Active Member, AWWA), ch., Stds. Attainment Br., WSRL; Thomas A. Bellar, res. chem., MDQAL: J. Keith Carswell (Active Member, AWWA), res. san. engr., WSRL; Jack DeMarco (Active Member, AWWA), tech. asst., WSRL; Kenneth L. Kropp, engrg. tech., WSRL; Gordon G. Robeck (Honorary Member, AWWA), dir., WSRL; Dennis R. Seeger, res. chem., WSRL; Clois J. Slocum, res. chem., WSRL; Bradford L. Smith, physical sci. tech., WSRL; and Alan A. Stevens (Active Member, AWWA), res. chem., WSRL, all of the EPA, Cincinnati,
Preparation of hydrophilic poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation
Abstract Hydrophilic microporous hollow fiber membranes were prepared via thermally induced phase separation (TIPS). Poly(vinyl butyral) (PVB) and three kinds of polyethylene glycols (PEG) with the molecular weight of 200, 400 and 600 were used as polymer and diluents. In all cases, liquid–liquid (L–L) phase separation occurred and asymmetric cellular structures with the smaller pores at the outer surface were obtained. The properties of membranes such as pore size, water permeability, solute rejection and intensity were investigated by changing molecular weight of PEG, concentration of PVB, composition of the bath and air gap distance. The smaller molecular weight of PEG, the more PEG in the bath and the shorter air gap distance resulted in the higher water permeability, the lower solute rejection property and the lower mechanical strength.