A waste derived biosurfactant for preparation of templated silica powders

As previous work indicated potential of compost isolated humic acid-like substances as chemical auxiliaries, three samples (cHALi) were obtained from green wastes composted for 0-60 days to assess source aging effects on product properties. These substances were compared for surface activity, disperse red 1 dye solubility enhancement, and chemical nature. No performance differences were established among cHALi. They lower water surface tension to 38 mN•m-1 at 0.7-0.8 g•L-1 critical micellar concentration and enhance the dye solubility upon increasing their concentration. However the soluble dye/added cHALi ratio is higher in the premicellar than in postmicellar concentration region. Structural investigation indicated cHALi as amphiphiles with 1-3×105 g•mol-1 MW. Dynamic light scattering at pH 5-13 and 25-60 °C indicated particles with 72-218 nm size in the premicellar region increasing to 145-373 nm in the presence of dye. In the postmicellar region the particle size was 90-117 nm, much less sensitive to pH and temperature, regardless of the dye presence. For properties and/or chemical structure cHALi were compared to sodium dodecylbenzenesulfonate, polyacrylic acid, soil and water humic substances. The results encourage exploitation of compost as source of low cost biosurfactants.