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The molecular structure of the interphase between plasma-polymerized acetylene films and steel substrates was determined using in situ reflection-absorption infrared spectroscopy (RAIR) and X-ray photoelectron spectroscopy (XPS). Plasma-polymerized acetylene films were deposited onto polished steel substrates using argon as a carrier gas and inductively coupled, radio frequency (RF)-powered plasma reactors that were interfaced directly to the XPS and Fourier transform infrared (FTIR) spectrometers. RAIR showed that the plasma polymerized films contained large numbers of methyl and methylene groups but only a small number of mono substituted acetylene groups, indicating that there was substantial rearrangement of the monomer molecules during plasma polymerization. Bands were observed near 1020 and 855 cm À1 in the RAIR spectra that were attributed to skeletal stretching vibrations in CÀCÀOÀFe groups, indicating that the plasma-polymerized films interacted with the substrate through formation of alkoxide bonds. Another band was observed near 1565 cm À1 and attributed to carboxylate groups in the interphase between the films and the oxidized surface of the substrate. Results obtained from XPS showed that the surface of the iron substrate consisted mostly of a mixture of Fe 2 O 3 and FeOOH and that iron was mostly present in the Fe(III) oxidation state. However, during plasma polymerization of acetylene, there was a tendency for the concentration of FeOOH groups to decrease and for the concentration of Fe(II) to increase, due to the reducing nature of argon=acetylene plasmas. Results from XPS also confirmed the formation of alkoxide and carboxylate groups in the interphase during plasma polymerization of acetylene.

A laboratory investigation was conducted to test the effectiveness of solidifiers with fresh water and artificial seawater using Prudhoe Bay Crude oil. Experiments were designed to study the effects of salinity, solidifier type, solidifier-to-oil mass ratio (SOR), mixing energy and beaker size using five solidifiers. The U.S. Environmental Protection Agency is developing a protocol for testing the effectiveness of solidifiers in a laboratory setting. This involves measuring the amount of free oil remaining in the water after the solidified product is removed using an ultraviolet–visible spectrophotometer. For these experiments, 0.25 mL of oil was added to salinized beaker containing 80 mL of water. Milli-Q water and sterile GP2 seawater were used as the exposure media. The mass of the solidifier was changed depending on the SOR. Each of the solidifier was added to a slick of crude oil on water. After stirring the mixture for 30 minutes, the solidifier was removed. The water with the remaining oil was transferred from the beaker to 250 mL separatory funnel. The solution in the funnel was extracted three times with 20 mL of dichloromethane and the final volume adjusted to 60 mL. The extracted samples were analyzed for oil content with an Agilent 8452 ultraviolet–visible spectrophotometer. All experiments were carried out in triplicate. An analysis of variance (ANOVA) was performed on the data collected, which helped quantify the main and interactive effects of the variables. Salinity of the water was mostly found to be an insignificant factor. Results indicated that SOR and solidifier type are the most important variables affecting removal efficiency.

Chemical countermeasures for oil spill remediation have to be evaluated and approved by the U.S. Environmental Protection Agency before they may be used to remove or control oil discharges. Solidifiers are chemical agents that change oil from a liquid to a solid by immobilizing the oil and bonding the liquid into a solid carpetlike mass with minimal volume increase. Currently, they are listed as Miscellaneous Oil Spill Control Agent in the National Contingency Plan and there is no protocol for evaluating their effectiveness. An investigation was conducted to test the oil removal efficiency of solidifiers using three newly developed testing protocols. The protocols were qualitatively and quantitatively evaluated to determine if they can satisfactorily differentiate effective and mediocre products while still accounting for experimental error. The repeatability of the three protocols was 15.9, 5.1, and 2.7 %. The protocol with the best performance involved measuring the amount of free oil remaining in the water after the solidified product was removed using an ultraviolet-visible spectrophotometer and it was adopted to study the effect of solidifier-to-oil mass ratio, mixing energy, salinity, and beaker size (i.e., area affected by the spill) on solidifier efficiency. Analysis of Variances were performed on the data collected and results indicated that the beaker size increased spreading, which reduced removal efficiency. Mixing speed appears to impart a ceiling effect with no additional benefit provided by the highest level over the middle level. Salinity was found to be mostly an insignificant factor on performance.