Synthetic and Natural Surfactants for Potential Application in Mobilization of Organic Contaminants: Characterization and Batch Study

Abstract

In this paper, we investigated the abilities of five sugar-based synthetic surfactants and biosurfactants from three different families (i.e., alkyl polyglycoside (APG), sophorolipid (SL), and rhamnolipid (RL)) to dissolve and mobilize non-aqueous phase liquid (NAPL) components, i.e., toluene and perchloroethylene (PCE), adsorbed on porous matrices. The objective of this study was to establish a benchmark for the selection of suitable surfactants for the flushing aquifer remediation technique. The study involved a physicochemical characterization of the surfactants to determine the critical micelle concentration (CMCs) and interfacial properties. Subsequently, a batch study, through the construction of adsorption isotherms, made it possible to evaluate the surfactants’ capacities in contaminant mobilization via the reduction of their adsorptions onto a reference adsorbent material, a pine wood biochar (PWB). The results indicate that a synthetic surfactant from the APG family with a long fatty acid chain and a di-rhamnolipid biosurfactant with a shorter hydrophobic group offered the highest efficiency values; they reduced water surface tension by up to 54.7% and 52%, respectively. These two surfactants had very low critical micelle concentrations (CMCs), 0.0071 wt% and 0.0173 wt%, respectively; this is critical from an economical point of view. The batch experiments showed that these two surfactants, at concentrations just five times their CMCs, were able to reduce the adsorption of toluene on PWB by up to 74% and 65%, and of PCE with APG and RL by up to 65% and 86%, respectively. In general, these results clearly suggest the possibility of using these two surfactants in surfactant-enhanced aquifer remediation technology.

Biochar/Biopolymer Composites for In-Situ Groundwater Remediation

“…The appropriate amount of surfactant was visually chosen upon stability tests within 7 days in the presence of 0.3 g/L of raw biochar, and results presented in Figure S4. Evaluating ten different APG2 concentrations (0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 2.0, 5.0 %v/v) above its critical micelle concentration (0.0071 wt% for APG2 [42]), the highest stability was shown by 1% v/v dispersion, thus being selected for BC@PST composites preparation. The properties of PST and APG2 combination allowed to obtained stable composites, in which sedimentation is far below 30% (14 ± 1%) within 7 days of storage.…”

“…To improve physicochemical properties of potato starch-based composite, an alkylpolyglucosidebased surfactant (APG2, a non-ionic surfactant) was added in a 0.1-5.0% v/v range. APG-based surfactant was chosen according to its eco-friendliness, nontoxicity, and biodegradability [42]. Raw pine wood biochar (BC) and the as-prepared composite materials were characterized via fieldemission scanning electron microscopy (FE-SEM), N2 adsorption/desorption measurements, and UV-Visible spectroscopy, whereas infrared (FT-IR) spectroscopy was used further to confirm the composite chemical structure and interaction among counterparts.…”

A mini-review on biosurfactants from natural-based resources: Sources, production, and application in oil industries

“…Synthetic biosurfactants including lignin and essential oils are generally obtained from laboratory chemical reactions (Amanat et al, 2022) which are widely used for commercial and industrial applications (Hamza et al, 2017). They are synthesised directly from natural components of living matter.…”