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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 13 C 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); R 2 ) 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).

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 13 C 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); R 2 ) 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).

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