Non-ionogenic Surfactants Research Articles

Biodegradation of technical mixtures of oxyethylenated aliphatic alcohols in an aqueous environment

A study of the biodegradability of nonionogenic surfactants of oxyethylenated n-butyl, isobutyl, n-pentyl and isopentyl alcohols was conducted by modified static test according to International Standard Organization method 9888. Degradation was evaluated by changes in concentrations of individual oligomers, ethylene glycols, carboxylic and dicarboxylic acids. Good biological degradability was found, with a “primary” degradability of 75–98% in 10 days. Obtained results, in agreement with our previous work, proved the dominant proportion of degradative scission in the hydrophile part of surfactant molecule. During biological degradation no significant cumulation of mono- to polyethylene glycols appeared neither that of mono- or dicarboxylic acids, and degradation of these components was not a rate-determining degradation factor.

Molecular organization and dynamics of micellar phase of polyelectrolyte–surfactant complexes: ESR spin probe study

Molecular dynamics and organization of the micellar phase of complexes of linear polyelectrolytes with ionogenic and non-ionogenic surfactants was studied by the ESR spin probe method. Complexes of polyacrylic acid (PAA) and sodium polystyrenesulfonate (PSS) with alkyltrimethylammonium bromides (ATAB), as well as complexes of poly- N, N′-dimethyldiallylammonium chloride (PDACL) with sodium dodecylsulfate (SDS) were studied. The micellar phase of such complexes is highly organized molecular system, molecular ordering of which near the polymeric chain is much higher than in the ‘center’ of the micelle, it depends on the polymer–detergent interaction, flexibility of polymeric chain and length of carbonic part of the detergent molecule. Complexes of polymethacrylic acid (PMAA) with non-ionic detergent (dodecyl-substituted polyethyleneglycol), show that the local mobility of surfactant in such complexes is significantly lower than in ‘free’ micelles and depends on the number of micellar particles participating in formation of complexes.

The BAC-process for treatment of waste water Containing non-ionogenic synthetic surfactants

In this paper experimental results on the biological-activated carbon (BAC)-process for biological degradation and adsorption of non-ionogenic surfactants (NISS) in the waste water treatment are discussed. It is shown that the mechanism of the BAC-process is not the simple addition but the synergetic combination of biodegradation and carbon adsorption. The major aspects of such synergism are the biological regeneration (bioregeneration) of the adsorbent and the reduction of the toxic effect of waste water contaminants on microorganisms. It is shown that the basis of the bioregeneration process is the desorption of substances previously adsorbed on the activated carbon. The desorption from micropores takes place because of the reverse concentration gradient, due to the microbial degradation of waste water contaminants in the liquid phase. The desorption from mesopores is also supported by the activity of microorganisms exoenzymes. Thus, the process of bioregeneration is featured by two non-contradictory hypotheses.

Electrokinetic Properties of Cassiterite and Quartz Particles in the Presence of Cationic, Anionic and Non-ionogenic Surfactants

The surface charge properties of cassiterite and quartz particles in primary amine hydrochloride, sodium oleate, sodium dodecyl sulphate, phenyl disodium orthophosphate, 4-nitrophenyl disodium orthophosphate and starch solutions have been monitored using particle microelectrophoresis. The zeta potentials of the oxides and their isoelectric points (IEPs) were determined as a function of pH in the presence of different surfactant concentrations. In general, cassiterite and quartz particles acquired a negative charge in the various aqueous solutions and were dramatically influenced by both pH and the presence of surfactants. The magnitude of the surface charge varied considerably and could adopt positive or negative values. The IEPs also varied depending on the solution properties.

Micelle dissociation kinetics study by dynamic surface tension of micellar solutions

The dynamic surface of sodium tetradecylsulphate and sodium bexadecylsulphate solutions in water and also in Triton X-100 solutions was measured by the maximum bubble-pressure method, using modern computerized instrumentation, for a wide range of surface lifetimes (from 0.001 to 10 s), temperatures (from 30 to 80°C) and surfactant concentrations (from 1 to 200 CMC). On the basis of a previously suggested adsorption kinetics theory for micellar solutions of ionogenic surfactants (V.B. Fainerman, Colloids Surfaces, 62 (1992) 333) a method was developed for the calculation of the micellar dissociation rate constant k. For the surfactants studied, k increases with increasing concentration. Moreover, for ionic surfactants the dependence of k on concentration ( C) becomes more striking for C> (10–30) CMC. This can be explained by a micelle shape transition and by a strengthening of the intermolecular repulsion in micelles. In solutions of the ionic surfactants the constant k increasing with increasing temperature, whereas in Triton X-100 solutions a temperature dependence is absent. This phenomenon is associated with the different nature of the molecular interactions for ionogenic and non-ionogenic surfactants in micelles. The k values, obtained from results of dynamic surface tension measurements, are in satisfactory agreement with the results of a study of the relaxation of micellar solutions published previously.

The Interaction of Azure B with Surfactants

A study was made of the effect of anionogenic, cationogenic and nonionogenic surfactants (tensides) on the absorption spectra of azure B. It was found that the change in the absorption spectra in solutions containing sodium lauryl sulfate are produced by change in the polymerization of the dye. At low tenside concentrations, dimers and higher dye aggregates are formed as a result of a decrease in the dye cation repulsion caused by interaction with tenside monomer anions. Above the critical micelle concentration, the dye is solubilized in the micelles, where the monomer form of azure B predominates. The cationogenic tenside does not affect dye polymerization; monomer formation is preferred in the nonionogenic tenside after micelle formation.

Transformation of microcrystalline hydrocortisone by free and immobilized cells of Arthrobacter simplex.

The transformation of microcrystalline hydrocortisone by free and immobilized cells of Arthrobacter simplex resulted in formation of prednisolone. The effect of medium composition, non-ionogenic surfactants and exogenous electron acceptors on the delta 1-dehydrogenase activity of free and immobilized cells is described.

Determination of free polyethylene glycols in ethoxylated derivatives by liquid chromatography

For various ethoxylated derivatives that form the effective components of non-ionogenic surfactants and detergents, the determination of the fraction of free polyethylene glycol was studied by means of reversed-phase liquid chromatography. Compared with the usual extraction method according to Weibull, reversed-phase liquid chromatography with methanol—water on the polymeric sorbent Spheron 40-S yields more accurate results and is much less labour and time consuming.