Comparison of the Effectiveness of Solid and Solubilized Dioctyl Sodium Sulfosuccinate (DOSS) on Oil Dispersion Using the Baffled Flask Test, for Crude Oil Spill Applications

Abstract

The accidental release of natural crude oil into our marine waters and its subsequent effect on the environment is one of the major problems that the environmental protection agencies and coast guards of most countries worldwide have to deal with. In this study, the effectiveness on oil dispersions of a composite particle made of paraffin wax and the surfactant dioctyl sodium sulfosuccinate (DOSS) was compared to that of the same DOSS dissolved in a liquid solvent using the U.S. EPA’s baffled flask procedure. Solid dispersant composite particles were prepared by ultrasonically spray freezing paraffin wax and DOSS molten solution while varying the mass ratio. The amount of DOSS in the composite particle was determined by the methylene blue complexation procedure. Liquid delivery of DOSS was accomplished by dissolving the surfactant in propylene glycol (PG). The results from the study showed that the dispersion effectiveness of the DOSS–paraffin wax composite particles were dependent on particle size, the solubility of the matrix material (paraffin wax) in the crude oil, and the DOSS-to-oil ratio (DOR, mg/g). This is because the paraffin wax would have to dissolve in the crude oil to release DOSS, which is then used for the dispersion of the crude oil. At 23 mg/g DOR, which was the maximum DOR used in the study, the dispersion effectiveness of the dispersant composite particles was 60 vol % and 62.6 vol % in the heavy Texas crude (TC) and the light crude (LC) oils, respectively. The dispersion effectiveness of the solubilized DOSS on TC was significantly higher than that of the dispersant composite particles; however, at DOR of 23 mg/g, the effectiveness of the dispersant composite particles on LC was just 1.8 vol % below that of the solubilized DOSS. There was a significant increase in the dispersion effectiveness when the mixing energy was increased from 150 to 200 rpm (rpm); nevertheless, the effectiveness was almost the same at 200 and 250 rpm. Dispersion effectiveness was analyzed at different salinity environments, that is, in brackish water (1.6 and 2.8 wt % salt concentration) and saline water (3.5 wt % salt concentration). The dispersant composite particles performed better at low salinities; however, the dispersion effectiveness almost leveled off at 2.8 and 3.5 wt % salt concentrations. The results of this study show the potential of dispersant composite particles to replace solubilized dispersants in oil spill remediation in the near future and, as a result, eliminate the environmental complications associated with the use of solvents in formulating traditional liquid dispersants.

Targeted and Stimulus-Responsive Delivery of Surfactant to the Oil–Water Interface for Applications in Oil Spill Remediation

“…The design of this system utilizes HNTs as the main surfactant carrier and small amounts of paraffin wax as a thin coating to encapsulate the surfactants in the lumen of the HNTs. This work is complementary to earlier interesting and important results by Nyankson and co-workers who showed the concept of encapsulating oil-soluble surfactant in large paraffin wax microspheres that dissolve in crude oil and thus release the surfactant. Thus, the water-soluble polyoxyethylene(20) sorbitan monooleate (Tween 80) nonionic surfactant, an intrinsic component of COREXIT 9500EC (the industry dispersant standard), is used as a model surfactant.…”

“…Additionally, paraffinic compounds are biodegraded efficiently through ubiquitous marine organisms such as Alcanivorax borkumensis. We also note that multiple surfactants can be loaded into halloysite nanotubes and is distinct from methods directly encapsulating surfactants in large particles of wax through spray drying …”

“…31 We also note that multiple surfactants can be loaded into halloysite nanotubes 12 and is distinct from methods directly encapsulating surfactants in large particles of wax through spray drying. 23 The concept of stimulus-responsive delivery of surfactant has other significant potential applications that are being studied in our laboratory. Of particular importance is the application of these concepts to enhanced oil recovery whereby the delivery of surfactants in wax coated halloysite nanotubes triggers release of surfactant only on contact with oil in the reservoir and thus prevents loss of surfactant in surfactant flooding operations in oil recovery.…”

A Decade of GoMRI Dispersant Science: Lessons Learned and Recommendations for the Future

“…A major challenge to the use of liquid dispersants is the drift of the dispersant spray when aerially applied. Also, liquid dispersants can be washed off when applied to heavy or weathered oils (Nedwed et al, 2008;Nyankson et al, 2014;Owoseni et al, 2014). The use of gel-like dispersants has been proposed to overcome such limitations (Nedwed et al, 2008).…”

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“…So, AS probably sorbed onto suspended solid and transported in an undissolved form to the deeper part of the offshore stations. In addition, study needs more sampling at different depths but, another type of methylene blue active surfactant could be exist in the bottom water such as alkyl sulfate, dioctyl sodium sulfosuccinate (DOSS) (Nyankson et al, 2014) which might be used as an oil spill dispersant to transfer the oil from the surface in the Mediterranean waters (EMSA, 2010). Because, after application of DOSS for deepwater horizon oil spiil, Kujawinski et al, (2011) found that DOSS was sequestered in deepwater hydrocarbon plume and had not been biodegraded in two mouths at distances of nearly 300 km from the well.…”