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The Chemical Technology of Wool Finishing
Published in Menachem Lewin, Stephen B. Sello, Handbook of Fiber Science and Technology: Chemical Processing of Fibers and Fabrics, 2018
Trevor Shaw, Max A. White, L. Benisek, M. A. Rushforth, J. R. Christoe, I. M. Russell
Anionic surfactants are, in general, better wetting agents than either nonionic or cationic surfactants. Sulfates are the least satisfactory of the anionics and are seldom chosen as scouring agents when rapid wetting and good detergency are required. Alkylbenzene sulfonates are widely used because of their low cost and good wetting properties. Linear alkyl sulfonates are biodegradable and usually used in preference to branched products. When rapid wetting characteristics are necessary, sulfo-succinates, particularly the di-isooctyl ester, methyl taurineoleates, and phosphate esters are used. Most phosphate esters are made from alcohol ethoxylates, and synergistic blends of phosphated alcohols and alcohol ethoxylates are frequently used. Anionic surfactants are substantive to the wool fiber and can be used to produce a softening effect. However, residual surfactant, particularly if nonuniformly distributed, can cause problems in subsequent dyeing and thorough rinsing after scouring is important.
Bioremediation
Published in Domenic Grasso, Hazardous Waste Site Remediation, 2017
The chemical structure of the contaminant has a profound effect on its biodegradability and biodegradation kinetics. The environmental degradation of organic compounds involves a complex interplay of organism type, degradation environment, chemical structure, and biochemical reactions. Hence, isolating the affect of chemical structure on degradation is usually difficult, except when strict experimental protocols are used to minimize the impact of the other parameters. Qualitatively, compounds containing highly branched alkyl chains degrade slowly when compared with straight chains. Functional groups, such as hydroxyl and carboxylate groups on benzene rings, increase biodegradability, while halogen, nitro, and sulfonate groups decrease biodegradability. Ortho-substituted aromatic compounds are slightly more biodegradable than para-substituted compounds, and the meta-substituted compounds have the least biodegradable substitution pattern. The information also suggests that compounds containing either pattern are resistant to biodegradation. Other qualitative relationships imply that, as a general rule, water soluble chemicals are usually more biodegradable than insoluble chemicals. These qualitative relationships have facilitated the synthesis and development of compounds which may be discharged to the environment with some degree of safety. For example, the replacement of alkyl benzene sulfonate surfactants with linear alkyl sulfonate surfactants in detergents has been based on biodegradability considerations.
Removal of linear alkylbenzene sulfonate (LAS) by a cetyltrimethylammonium bromide (CTAB)-aided coagulation-filtration process
Published in Environmental Technology, 2022
Naoyuki Kishimoto, Shinya Hamamoto
Surfactants are amphiphilic chemicals containing a hydrophilic group and a hydrophobic group, and can alter the surface energy of solids and liquids. Therefore, they can be widely used as surface-active agents for improving the efficiency of various processes. Global surfactant consumption amounted to 13 million tons in 2006 [1]. Linear alkylbenzene sulfonate (LAS) is an alkyl sulfonate-type anionic surfactant. In Germany, the annual production of LAS amounted to 100,000 tons/year in 1996, which occupied 14% of total surfactant production [2]. In Japan, the annual production and consumption of alkyl sulfonate-type surfactants mainly composed of LAS were 92,461 and 44,552 tons/year in 2018, respectively. The latter comprised 20% of the total annual surfactant consumption in Japan (Figure 1, Ministry of Economy Trade and Industry [3]). Thus, LAS is one of the most popular surfactants in the world, and it is often detected in domestic and industrial wastewaters at a typical concentration range of 1–21 mg/L [4].
Flotation of Iron Ores: A Review
Published in Mineral Processing and Extractive Metallurgy Review, 2021
Xiaolong Zhang, Xiaotian Gu, Yuexin Han, N. Parra-Álvarez, V. Claremboux, S. K. Kawatra
Anionic collectors dissociate in water to hold a net negative charge, which is subsequently attracted to positive surfaces. There are a large variety of anionic collectors available for use with iron ore and can be broadly divided based on their chemistries, the most common of which are listed below (Zhang and Dai 2012): Carboxylic acids and their salts (-RCOOH, -RCOONa, -RCOOK, etc.). Common examples are fatty acids, e.g. oleic acids and sodium oleates.Alkyl sulfonates and their salts (-RSO3H, -RSO3Na, -RSO3K, etc.), such as sodium petroleum sulfonate.