Abstract:
The purpose of this research is to study
the change in wettability of clays due to the influence of mesophilic soil microorganisms' activity when
adding model contaminants: water-in-oil emulsion, glycerol and oleic acid. During the experiments, the
objectives of this study were to specify peculiarities of wetting contact angle hysteresis of clays with
substrates of different mineral composition and microbial activity. Hydrophilicity/hydrophobicity of the
stimulator for microbial activity does not have a clear effect on clay properties. The surface heterogeneity
mostly increases with time, perhaps, due to biofilm exudates whatever was a type of microbial stimulator.
Chemical and geometric heterogeneities played comparable roles in the surface hydrophilic-hydrophobic
balance. Results obtained prove that microbial communities and/or the Fe chemical state alteration (pyrite,
hematite or goethite) were responsible for both hydrophilization and hydrophobization of the surface. The
equation for the drop spreading rate was presented and verified by well comparison of experimental results
with simulations.
