Anionic surfactant concentrations

Physicochemical Basis of Quantitative Determination of Anionic Surfactant Concentrations by Using an Autotitrator... 

For treatment process control, initial and residual anionic surfactant concentrations in a water treatment system can be determined by titration methods or colorimetric methods [75,76,80,84,90]. The most recent technical information on management and treatment of the soap and detergent industry waste is available from the state of New York [104]. 

LAS Treatability and Environmental Concentrations. The removal of LAS during sewage treatment was confirmed by monitoring studies in both the United States and Europe. Numerous studies reported anionic surfactant concentrations in surface waters measured by nonspecific analytical techniques such as methylene blue active substance (MBAS). However, the correlation between MBAS and LAS concentrations determined by spe-... 

Predicted Anionic Surfactant Concentrations in Surface Water. 

FIGURE 13.14 Oxide film removal rate versus anionic surfactant concentration. 

Microemulsions were obtained using different types and concentrations of surfactant, cosurfactant, and styrene. An anionic surfactant, sodium dodecyl sulfate (C12H250SO3Na), and two types of nonionic surfactants, Emsorb 6916 (sorbitan monolaurate) and Neodol 91-5 (ethojqrlated alcohol), were used. The surfactant concentration was varied between 5 to 10% (w/w) for the anionic system and between 5 to 15% (w/w) for the nonionic systems. Either 2-pentanol or ethylene glycol monobutyl ether (butyl cellosolve, C4H90CH2CH20H) was used as the cosolvent with the anionic surfactant. The amount of cosurfactant used depended on the anionic surfactant concentration and varied form 12.5 to 25% (w/w). 

The 1980s were rich in innovation. As cationic actives precipitate in the presence of anionic surfactants, thereby losing most of their efficacy, the anionic surfactant concentration in the liquor must be kept as low as possible. Therefore, the fabric softener had to be introduced in the last rinse of the wash cycle, when the detergent carryover is at a minimum. That represented a true constraint if the washer did not contain a dispenser for softener. The user had to stay near the washer to introduce the product at the beginning of the last rinse or had to run an extra rinse at the end of the laundering. 

On the other hand, sodium decyl sulfate, sodium dodecyl sulfate, and a sodium hexadecyl-octadecyl sulfate mixture result in equal PLMA MW for equal surfactant concentrations. These anionic surfactant concentrations are at or above their CMCs. That there is little or no influence on the aggregation number of the mixed micelles as the anionic surfactant tail varies from decyl to octadecyl is an indication of the importance of steric and electrostatic effects in the head-group region in these mixed micelles, at least for the 60 40 nonionic-anionic composition investigated here (34, 35). 

Obviously many variables were not investigated, such as the effect of the type of nonionic surfactant, broader ranges of surfactant concentration, and broader ranges of monomer concentration. However, the results of this work are sufiBcient to demonstrate that the block copolymer architecture can be modified in MHAP by modifying the anionic surfactant concentration and type. These results have supported but not proved the block copolymer theory for this type of polymer-surfactant system. This model system is also a simple means of studying some aspects of mixed surfactant systems, an area of much current interest (e.g., ref 37). 

Using a clean 25-mL graduated cylinder, place 10 mL of an aqueous sample whose anionic surfactant concentration is to be determined into a 50-mL beaker. The aqueous sample could be a blank (i.e., a sample with all reagents added except for the analyte of interest), calibration standard, ICV, fortified (i.e., spiked) sample, or an actual unknown wastewater effluent sample. 

Considering the effect of increasii initial concentration of anionic sur ctant on die cotton fabric (Table 1), the retention appears to consistently increase both as concentration of anionic surfactant increases and as number of washes increases. The difference between the first wash and fifth wash has been statistically tested for significance using a 2 tailed t-test. This has been repeated for each anionic surfactant concentration level. The t-value results and an indication of their significance can be seen in Table 3. 

From these data it follows that, as the anionic surfactant concentration was... 

Fig. 7 Zeta potential of kaolin ( ) and calcium carbonate (a) as a function of the anionic surfactant concentration...

Non-solvent processes have been developed in answer to the high cost of large-scale solvent extraction. Holmes and Lim [61] described the enzymatic process used at Zeneca for the recovery of PHB and PHBV. First, a high-temperature (100 to 150 °C) treatment of the cells provokes cell lysis and denaturation of nucleic acids, which could otherwise interfere with the subsequent steps. Non-PHA biomass is then solubilized with proteolytic enzymes (pepsin, trypsin, papain, others, and mixtures thereof) and anionic surfactants. Concentration of PHA by centrifugation is finally followed by bleaching with H2O2. 

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