Soil Washing Potential of a Natural Surfactant

Abstract

Biodegradable natural surfactants obtained from plants can be an attractive alternative to synthetic surfactants in the remediation of contaminated soils. In this research, a plant-based surfactant obtained from the fruit pericarp of Sapindus mukurossi, a tree generally grown in tropical regions of Asia, is tested. A simple and economical method for the preparation of the surfactant is developed. An empirical formula for the surfactant was determined to be (C26H31O10) n . The aqueous solubilities of hexachlorobenzene (HCB) and naphthalene in the natural surfactant solutions were found to vary linearly with the concentration of the surfactant showing trends comparable to that of typical com mercial surfactants. Natural surfactant solutions were also employed for flushing HCB from one-dimensional soil columns. HCB recoveries after 12 pore volumes of flushing with 0.5 and 1% natural surfactant solutions were 20 and 100 times more than that recovered by water flooding. These promising results warrant further research to establish the usefulness of plant-based surfactants for soil washing applications.

Arsenic removal from soil with high iron content using a natural surfactant and phosphate

“…The soil was dried in an oven overnight at 105°C, crushed and passed through a 2-mm sieve following the protocol presented by Roy et al (1997). It was classified according to USDA soil texture triangle.…”

“…The plant-based surfactant saponin was extracted from the soapnut fruit pericarp by water as described by Roy et al (1997). The surface tension and critical micelle concentration (CMC) of surfactants were measured by a ring-type surface tensiometer (Fisher Scientific Manual Model 20 Surface Tensiometer).…”

“…Sapindoside A, Sapindoside B, Sapindoside C, Sapindoside D, Mukorozisaponin E1 and Mukorozisaponin Y1 by LC-MS and also described their molecular structures. Previously, Roy et al (1997) and Kommalapati et al (1997) used soapnut solution for removing hexachlorobenzene and organic pollutants from soil through micellar solubilization and reduced interfacial tension between contaminant and solution Roy et al 1997). However, soapnut has never been used for metal/metalloid removal from soil.…”

Estudo da produção de biossurfactante em caldo de fermentação

“…Vol. 33,No. 7 Determinação da tensão superficial A medida da tensão superficial foi determinada diretamente da superfície do sobrenadante com um tensiômetro de Leconde Du Nouy.…”

“…2 Os micro-organismos sintetizam compostos com propriedades surfactantes como subprodutos metabólicos sendo, neste caso, denominados biossurfactantes e podem ser isolados de amostras de solos contaminados e não contaminados por hidrocarbonetos. 7 As bactérias, juntamente com as arqueobactérias, são os maiores responsáveis pela produção destes compostos tensoativos; bactérias das famílias Pseudomonacea e Bacillacea são capazes de produzirem biossurfactantes eficientes na remoção de petróleo e seus derivados poluentes de água. 8 Os biossurfactantes produzidos por micro-organismos podem ser obtidos utilizando-se procedimentos relativamente simples e substratos baratos, através de processos de fermentação.…”