Preparation of Oil-in-Seawater Emulsions Based on Environmentally Benign Nanoparticles and Biosurfactant for Oil Spill Remediation

Abstract

One remediation technique of oil spills is the application of dispersants to oil slicks, which is essentially a process of emulsification. Tetradecane and crude oil-inseawater emulsions formed with silica nanoparticles modified in situ with rhamnolipid produced a longer stability and smaller droplet size. The interactions of silica particles with rhamnolipid were characterized by contact angle, interfacial tension, TEM, and SEM measurements. The images of confocal fluorescence microscopy and SEM showed the oil droplet microstructure and the morphology of nanoparticles at the oil droplet−water interface. The average emulsion droplet size and emulsion index were investigated. These results indicated a synergistic stabilization upon rhamnolipid addition. The synergy was even more efficient in the case of seawater with a high salinity. Here, because of the strong flocculation caused by high salinity, silica nanoparticles alone were not an effective emulsifier in seawater. The modification of silica nanoparticles by rhamnolipid changed the contact angle and promoted their adsorption at the oil−seawater interface, which provided an efficient barrier to droplet coalescence. The emulsification of rhamnolipid-modified silica nanoparticles worked well in crude oil−seawater system. So, this could be a new method to deal with the issue of the marine oil spill by environmentally benign silica particles and rhamnolipid.

Influence of Rhamnolipids and Ionic Cross-Linking Conditions on the Mechanical Properties of Alginate Hydrogels as a Model Bacterial Biofilm

“…Based on the obtained diagram, the CMC of rhamnolipids in water at room temperature (22 • C) was determined and it was 43.21 mg/dm 3 . This corresponds to the values in the literature, where the CMC of rhamnolipids under the same conditions is reported between 10 and 200 mg/dm 3 , depending on the source of origin [46][47][48][49]. The differences in CMC values occur due to the variation in the length of the lipid chain and the presence of one or two rhamnose residues in rhamnolipids produced by various microorganisms [50].…”

Eco-Friendly Pickering Emulsion Stabilized by Silica Nanoparticles Dispersed with High-Molecular-Weight Amphiphilic Alginate Derivatives

“…Emulsions are applied in various fields such as foods, paints, cosmetics, pesticides and coal treatment. , In industrial applications, the long-term stability of emulsions required is generally achieved by a proper use of organic materials, such as surfactant-like molecules, surface active polymers, or low-molecular-weight surfactants. , Emulsions stabilized by solid particles in place of surfactants are known as Pickering emulsions. Compared to traditional emulsions, Pickering emulsion exhibits higher physical/chemical stabilities .…”

Formation and stabilization of nanoemulsions using biosurfactants: Rhamnolipids

“…Influence of thermal processing (30-90 °C, 30 min) on (a) the mean particle diameter (d32 ) and (b) the ζ-potential of oil-in-water nanoemulsions (1 rhamnolipid, 10% MCT) produced using standardized homogenization conditions (13 kpsi, three cycles) and stored at room temperature for 24 h before analysis. The photograph of the nanoemulsions in (a) was taken after 24 h storage.…”