Ozonization to Upgrade Waste-Derived Soluble Lignin-Like Substances to Higher Value Products

Soluble biobased lignin-like polymeric substances (SBO) isolatedfrom the alkaline hydrolysates of composted biowastesare promising chemical auxiliaries for multiple uses. They havegood surfactant properties. Their black color spoils their performancein detergency and dyeing. Ozonization of SBO is reportednow to yield bleached biosurfactants with improvedperformance. The work was performed, with SBO obtainedfrom composted gardening residues, alone or mixed with kitchenwastes. They were dissolved in water at 3.3% concentration.Oxygen containing 4 mol/mol % ozone was flown at 60 L/h for 48 h through the SBO solution. The crude ozonized productsin ca. 80% yield were filtered through different molecularcut off membranes and characterized for chemical features,molecular weight, and surface tension in water. The ozonizedfractions with 200–500 kDa molecular weights accounted for12–29% of the total ozonized fractions’s organic matter. Theylowered water surface tension to 48–52 mN/m. The lowermolecular weight ozonized fractions had no surfactant activity,but their molecular features suggest other potentially valuableuses.