Abstract:

We measured the stability of crude oil droplets formed by chemical dispersants with the addition of a hydrophobically modified chitosan. Emulsions of crude oil in saline water were prepared using a combination of the biopolymer hydrophobically modified chitosan and the chemical dispersant Corexit 9500A. This dataset reports zeta potential, interfacial tension, percent transmittance, viscosity, elastic and viscous modulus for several ratios of Corexit to crude oil and biopolymer to Corexit. This dataset includes images and videos of the oil-in-water behavior when exposed to dispersants. Dataset supporting the publication Venkataraman et al. 2013 Attachment of Hydrophobically Modified Biopolymer at the Oil-Water Interface in the Treatment of Oil Spills, ACS Appl. Mater. Interfaces, 5 (9), 3572-3580, DOI: 10.1021/am303000v.

Suggested Citation:

John, Vijay. 2016. Dataset for: Attachment of a Hydrophobically Modified Biopolymer at the Oil–Water Interface in the Treatment of Oil Spills. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7J67DWQ

Publications:

Venkataraman, P., Tang, J., Frenkel, E., McPherson, G. L., He, J., Raghavan, S. R., … John, V. T. (2013). Attachment of a Hydrophobically Modified Biopolymer at the Oil–Water Interface in the Treatment of Oil Spills. ACS Applied Materials & Interfaces, 5(9), 3572–3580. doi:10.1021/am303000v

Purpose:

Our objective in the current study is to attach natural additives such as polysaccharides to oil droplets to enhance the stability of the droplets and potentially reduce the amount of dispersant required for effective dispersion of crude oil.

Data Parameters and Units:

Data.xlsx - Mass ratio (HMC:Corexit where HMC = hydrophobically modified chitosan), Zeta potential (mV), NaCl Conc. (0.6M, 0M), pH (4); DOR = dispersant to oil ratio (v/v), IFT = interfacial tension (mN/m), Std. Dev = standard deviation, LHMC/Corexit = mass ratio of low molecular weight hydrophobically modified chitosan to Corexit ratio (w/w), Corexit/Oil (0.01, 0.05); Time (minutes), % Transmittance, Corexit/Oil (v/v) (0., 0.001, 0.01, 0.02, 0.1), LHMC/Corexit (0, 0.125, 0.25, 0.5), Unmodified = unmodified chitosan, shear rate (1/s), viscosity (Pa.s), 1:50, 1:10, saline water, LHMC elastic modulus (Gi, Pa), LHMC viscous modulus (Gii, Pa), HHMC elastic modulus (Gi, Pa), HHMC viscous modulus (Gii, Pa), angular frequency (rad/s). HHMC Tethers Oil Slick.wmv-- Oil is pipetted into a water flask. A high molecular weight hydrophobically modified chitosan is added. It coalesces the oil to the air-water interface away from the flask edges, and it is lifted out of the water with a net. LHMC-COREXIT.wmv-- Two flasks of oil dispersed into emulsion droplets are compared over a few seconds: the first flask shows the oil without addition, the second flask shows the addition of low molecular weight hydrophobically modified chitosan. Figure 3a bottom 0 min.tif, Figure 3a bottom 10 min.tif, Figure 3 a bottom 30 min.tif - photographic images of emulsion in vials mass ratio LHMC:Corexit 0.5 (w/w) after 0, 10 and 30 minutes. Figure 3a top 0 min.tif, Figure 3a top 10 min.tif, Figure 3a top 30 min.tif - photographic images of emulsion in vials LHMC/Corexit 0 (w/w) (Corexit only) after 0, 10, and 30 minutes. Figure 6A.tif, Figure 6b.tif, Figure 6C.tif - high resolution cryogenic scanning electron microscope images of oil droplet dispersed by Corexit (dispersant to oil volume ratio 0.01). Figure 6D.tif, Figure 6E.tif, Figure 6F.tif - high resolution cryogenic scanning electron microscope images of oil droplet dispersed by Corexit after sequential addition of lower molecular weight hydrophobically modified chitosan (dispersant to oil volume ratio 0.01 and LHMC:Corexit = unity). Figure 7c-A.tif - photographic image of a layer of crude oil on the surface of saline water, Figure 7c-B.tif - photographic image of a layer of crude oil on surface water after the application of Corexit, Figure 7c-C.tif, Figure 7c-D.tif, Figure 7c-E.tif - photographic images of crude oil in saline water with Corexit after the application of high molecular weight hydrophobically modified chitosan, Figure S4 bottom 0 min.tif, Figure S4 bottom 10 min.tif, Figure S4 bottom 30 min.tif - photographic images of crude oil droplets in seawater (pH = 7.9, conductivity = 85 mS/cm) upon addition of LHMC (LHMC:Corexit 0.5 (w/w)) after 0, 10 and 30 minutes with Corexit:oil 0.01 (v/v). Figure S4 top 0 min.tif, Figure S4 top 10 min.tif, Figure S4 top 30 min.tif - photographic images of crude oil droplets in seawater (pH = 7.9, conductivity = 85 mS/cm) with Corexit (Corexit:crude oil 0.01 (v/v)).

Methods:

Interfacial tension between crude oil and saline water was measured using the pendant drop method on a standard goniometer (Ramé-Hart Model 250) and DROPimage advanced software. For extremely low interfacial tensions of the dispersant-oil mixtures not accessible by the pendant drop method, the interfacial tension was measured using the spinning drop tensiometer (Grace Instruments model M6500). Droplet radii were measured using an optical microscope. Turbidity of emulsion the transmittance of light (λ=400 nm) through the emulsion was measured as function of time using a UV–vis Spectrophotometer (Shimadzu UV-1700) and UV Probe software (version 2.32). Compositions and microstructures examined with a 3 kV Cryo-Scanning Electron Microscopy (Hitachi S-4800 SEM) at approx. 9 mm distance. Steady-shear rheological measurements (TA Instruments AR 2000 rheometer) using cone and plate geometry of 40 mm diameter with 1 degree cone angle. Zeta potential using Laser Doppler Velocimetry (Zetasizer Nano, Malvern Instruments).

Instruments:

Gonionmeter (Ramé-Hart Model 250), UV-Vis Spectrophotometer (Shimadzu UV-1700), Cryo-Scanning Electron Microscope (Hitachi S-4800) operated at 3 kV and working at distance of ~9 mm, TA Instruments AR 2000 rheometer using cone and plate geometry of 40 mm diameter with 1 degree cone angle, Laser Doppler Velocimetry (Zetasizer Nano, Malvern Instruments)

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