Evaluation of Physico-Chemical Interactions between Linear Alkylbenzene Sulfonate (LAS) and Alcohol Ethoxylates

Abstract

Linear alkylbenzene sulfonate (LAS) is the most widely used surfactant in household products. The dominance of LAS is particularly apparent in laundry detergents, dishwashing liquids, household cleaners, and institutional/industrial cleaners, where it accounts for over 3 million tons per year worldwide consumption. However, detergency performance of LAS is decreased in hard water due to lower solubility and surfactant loss in the presence of calcium and magnesium ions. In this study behavior of an aqueous binary surfactant mixture composed LAS and nonionic surfactants was investigated. Ethoxylated alcohols (C12–C14) with 7 EO and 2 EO units were mixed with LAS in laundry detergent formulations, and performance factors including detergency, solubility, and efficiency and effectiveness of surface tension reduction were examined. Analysis of surface tension data indicated strong molecular interaction between LAS and nonionic surfactant. The results indicated that the addition of low amounts of the nonionic surfactant lowers significantly CMC of the mixed surfactant system, and causes the formation of mixed micelles containing predominantly nonionic molecules which provide water hardness protection for LAS. The overall improvement in detergency appears to be due to: lower CMC of the mixed surfactant system which improves soil solubilization, solubilization of Ca(LAS)2, and reduction of free calcium ions which frees up soluble LAS in solution to adsorb at fabric-soil interfaces for enhanced soil removal.

Review of the years 2011/2012

“…Großes Interesse fanden Beiträge aus dem Bereich der Reinigungstechnologie, speziell zu den Themen Niedrigtemperaturwäsche [1], Einsatz von Weichspülern [4,17] und Entwickung eines Protokolls für vergleichende Waschmitteltests [6]. Weitere gefragte Themen beschäftig-ten sich mit der Anwendung [2,16,20] und Umweltchemie [7,15,18] sowie mit der Entwicklung, Synthese und den physiko-chemischen Eigenschaften von neuen Tensiden wie Biotensiden und Geminitensiden, aber auch von konventionellen Tensiden wie LAS [3,9,11,13,14,19]. Zu den Top-20 der beiden vergangenen Jahren gehçren auch der detaillierte EDC/SEPAWA-Konferenzbericht 2011, der sich mit Biotensiden, neuen Inhaltstoffen in Formulierungen, der Nachhaltigkeit von Tensiden, Waschmitteln und Kosmetika beschäftigt, und die zusammenfassende Präsentation der Forschungsarbeiten der "Colloid & Interface Science Group" an der Universität Stuttgart [12].…”

“…Other topics attracting great interest were those papers which reported on the application of surfactants [2,16,20], environmental chemistry of surfactants [7,15,18], development, synthesis and physico-chemical properties of novel surfactants such as Biosurfactants, Gemini surfactants as well as conventional surfactants like LAS [3,9,11,13,14,19]. Among the twenty most requested contributions are the in-depth report on the EDC/SEPAWA conference in 2011, which deals with biosurfactants, new ingredients and formulations, sustainability of surfactants, detergents and cosmetics [8] and the presentation of the Colloid & Interface Science Group at Stuttgart University [12].…”

Avaliação da influência da fonte suplementar de carbono na remoção de alquilbenzeno linear sulfonado de água de lavanderia e comunidade microbiana relacionada em reator anaeróbio de leito fluidificado

“…Particularmente, é o surfactante predominante na composição de detergentes para lavagem de roupa, louça e produtos de limpeza em geral (MALIHI et al, 2011).…”

Reator de leito fluidificado em escala aumentada para tratamento de água residuária de lavanderia comercial em co-digestão com esgoto doméstico: otimização das condições operacionais e caracterização taxonômica e funcional dos microrganismos do biofilme

“…O LAS está enquadrado na categoria dos surfactantes aniônicos, possui carga negativa, estando relacionado, sobretudo, à síntese de produtos de limpeza, higiene pessoal e lavagem de roupas (MALIHI et al, 2011). A sua produção representa 45% do total de tensoativos aniônicos produzidos anualmente (MOLDOVAN et al, 2011) A problemática da toxicidade dos surfactantes e suas restrições são abordadas de forma distinta por cada nação.…”