Enhanced oil recovery using hyperbranched polyglycerol polymer-coated silica nanoparticles

Functionalized Fe3O4-SiO2 magnetic nanoparticles (Fe-Si-MNPs) coated with hyperbranched polyglycerol polymer were prepared and tested for oil recovery from oil in water (O/W) emulsions. The structure, chemistry, and surface modifications of the newly developed demulsifier (PSiMNPs) were analyzed, and the percentage demulsification efficiency (%eta(dem)) was tested at differing concentrations of surfactant (C-sur), oil (C-oil), and demulsifier (D-PSiMNPs). The developed PSiMNPs can be separated from the solution by a magnetic field, regenerated using ethanol, and reused several times. The reported %(eta dem) was >= 80% for all the studied C-oil. The %eta(dem) improved as the C-sur and pH decreased, with maximum values of 98.8% and 98.5% achieved at C-sur = 0.05 g/L and a pH = 4, respectively. A D-PSiMNPs = 100 mg/L was sufficient to achieve %eta(dem) of 99.4% for C-oil =100 mg/L and slightly decreased to-93% for C-oil-4000 mg/L. The PSiMNPs can be reused up to 15 times with a steady %eta(dem) of 89.1% for C-oil = 100 mg/L and 88.6% for C-oil = 4000 mg/L. The adsorption of oil on the PSiMNPs follows Freundlich isotherm with maximum adsorption capacity (qmax) of 192.8 g/mg and Langmuir constant (b) of 28.06 mg/L for C-oil = 900 mg/L. The q(max) of the recycled PSiMNPs slightly decreased to 189.08 g/mg. The kinetic of oil recovery follows the PSO with a K-2 of 0.0169 g/mg. min. Surface modification of Fe-Si-MNPs enhanced the oil adsorption, increased the adsorption capacity, and extended the service life resulting in a better cost and process feasibility.