Adsorptive removal of oil spill from oil-in-fresh water emulsions by hydrophobic alumina nanoparticles functionalized with petroleum vacuum residue

• Nano-alumina functionalized with VR can be used for oil spill removal from o/w emulsions.
• Adsorption mechanism, kinetics and isotherms were studied in detailed.
• Adsorption isotherms were described by the Polanyi theory-based Dubinin–Ashtakhov (DA) model.
• Nano-alumina functionalized with VR could be employed as an alternate adsorbent for oil spill remediation.

Oil spills on fresh water can cause serious environmental and economic impacts onshore activities affecting those who exploit freshwater resources and grassland. Alumina nanoparticles functionalized with vacuum residue (VR) were used as a low-cost and high hydrophobic nanosorbents. The nanomaterial resulting showed high adsorption affinity and capacity of oil from oil-in-freshwater emulsion. The effects of the following variables on oil removal were investigated, namely: contact times, solution pH, initial oil concentrations, temperature, VR loadings and salinity. Kinetic studies showed that adsorption was fast and equilibrium was achieved in less than 30 min. The amount adsorbed of oil was higher for neutral system compared to acidic or basic medium. Increasing the VR loading on nanoparticle surface favored the adsorption. Results of this study showed that oil removal for all systems evaluated had better performance at pH value of 7 using nano-alumina functionalized with 4 wt% VR. Adsorption equilibrium and kinetics were evaluated using the Polanyi theory-based Dubinin–Ashtakhov (DA) model, and pseudo-first and pseudo-second order-models, respectively.

Effect of pH on oil adsorption onto (a) virgin alumina, (b) Al/2VR and (c) Al/4VR nanoparticles at pH values 4 (□), 7 (○) and 10 (□). Other experimental conditions: Adsorbent dose, 2.5 g/L; shaking rate, 600 rpm; Temperature, 298 K. The symbols are experimental data, and the dashed lines are from the Polanyi theory-based DA model (Eq. (4)).Figure optionsDownload high-quality image (30 K)Download as PowerPoint slide