title: Biobased surfactant-like molecules from organic wastes: the effect of waste composition and composting process on surfactant properties and on the ability to solubilize Tetrachloroethene (PCE).
abstract: In this work, four surfactant-like humic acids (HAs) obtained from garden lignocellulose wastes and kitchen food wastes mixed with garden-lignocellulose wastes, both before and after composting, were tested for surfactant properties and the ability to solubilize tetrachloroethene (PCE). The waste-derived HAs showed good surfactant properties, lowering the water surface tension from 74 mN m(-1) to 45.4 +/- 4.4 mN m(-1), with a critical micelle concentration (CMC) of 1.54 +/- 1.68 g L(-1), which is lower than many synthetic ionic surfactants. CMC was affected by both waste origin and composting processes. The addition of food waste and composting reduced CMC by adding alkyl-C (measured by CP MAS 13C NMR) and N- and S-HA contents (amide molecules), so that a multistep regression was found [CMC = 24.6 - 0.189 alkyl C - 2.64 (N + S); R2 = 0.77, P < 0.10, n = 6]. The four HAs solubilized PCE at the rate of 0.18-0.47 g PCE/g aqueous biosurfactant. These results were much higher than those reported in the literature for a commercial HA (0.026 g/g), but they were in line with those measured in this work for nonionic surfactants such as Tween-80 (0.69 g/g) and Triton X-100 (1.08 g/g).
authors.affiliation: Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Via Celoria 2, 20133 Milano, Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Quadri
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Chen
authors.forename: James W
authors.initials: JW
authors.lastname: Jawitz
authors.forename: Fulvia
authors.initials: F
authors.lastname: Tambone
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Genevini
authors.forename: Franco
authors.initials: F
authors.lastname: Faoro
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Adani
mesh_terms: D046529:Microscopy, Electron, Transmission; D012987:Soil; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry*; D013750:Tetrachloroethylene / Q000737:chemistry*
chemical_list: D012987:Soil; D013501:Surface-Active Agents; D013750:Tetrachloroethylene