Surfactant properties and tetrachloroethene (PCE) solubilisation ability of humic acid-like substances extracted from maize plant and from organic wastes: A comparative study

Maize-HA-like substance solubilised PCE at the rate of 0.05 g of PCE for each gram of maize-HA-like substance, which was 3.6-9.6 times lower than the data obtained in our earlier work using HA extracted from organic wastes, but was higher than that obtained with commercial HA from leonardite. Taking into consideration the two-site model of solubilisation of PCE in surfactant (i.e., solute partitioning into the micellar hydrophobic core and dissolution and/or binding into the hydrophilic non-ionic shell) and macromolecular composition of HA-like substance, the non-ionic hydrophile-alkyl lipophile balance was expected to control PCE solubilisation as the good multiple linear regression indicated: log Kdom = −1.37 + 0.062 alkyl-C +0.055 O-alkyl-C (R2 = 0.93, P < 0.05, n = 6), where log Kdom represents the micelle-water partitioning of PCE (mL g−1) and alkyl-C and O-alkyl-C represent the content of these two kinds of C detected by CP MAS 13C NMR (as % of the total C).