Oxidizing emulsifiers: Gelators for water in hydrocarbon reactive emulsions

Abstract Oxidizing emulsifiers were produced using calcium peroxide and polysaccharides extracted from edible mushrooms. The polysacchardes were mainly glucans, as indicated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Our study investigates the potential application of these oxidizing emulsifiers to remediate and immobilize spills of a model hydrocarbon (toluene) in groundwater. Interfacial tension measurements showed that the oxidizing emulsifiers adsorbed at toluene-water interfaces, producing rigid interfacial films (as demonstrated through Langmuir trough experiments). The oxidizing emulsifiers were particle-like, as observed with scanning electron microscopy (SEM). Emulsification tests and optical microscopy observations showed that the oxidizing emulsifiers stabilized water in toluene emulsions, hence promoting contact between the emulsifying oxidizers and toluene. Therefore, toluene degradation was greater with the oxidizing emulsifiers than with calcium peroxide (used at the same concentrations), as demonstrated through gas chromatography-mass spectroscopy (GC-MS) experiments. Shear rheology tests showed that the water in toluene emulsions stabilized by the oxidizing emulsifiers were gel-like. The gelation of hydrocarbon spills would be useful to immobilize hydrocarbon spills during their remediation, thereby impeding their unwanted migration. Our study describes for the first-time emulsifying oxidizers, which have the potential to enhance the remediation of hydrocarbon spills (compared to traditional oxidizers), while safely immobilizing them.