Water photo-oxidized sea

Platinum plates with 1 cm area per side were metallographically polished to a mirror finish, rinsed with distilled water, and flamed just before exposure to sea water for either ellipsometric or contact angle measurements. The platinum plates were wetted with photo-oxidized sea water before immersing into experimental sea water, so that passage of the surface through the air—sea water interface would not cause any film present there to be transferred to the plate. For the same reason plates removed from the experimental sea water were immediately immersed while still visibly wet in photo-oxidized sea water and then rinsed. 

Adsorption on plates used for contact angle measurements was allowed to proceed from a volume of about 40 ml for one week at 3°-4°C. The plates were then rinsed three times with photo-oxidized sea water and five times with triple distilled water to remove residual salts before drying. 

Figure 5. Electrophoretic mobilities of model particles in untreated and photo-oxidized sea water from Cheasapeake Bay (top) and Gulf of Mexico (bottom) and in photo-oxidized, seven-ion water of comparable salinities.

CB, Chesapeake Bay water OC, Atlantic sea water G, Gulf of Mexico sea water UV, photo-oxidized sea water HA, photo-oxidized sea water extract of humic acid. 

If an ellipsometer reading is made on a platinum surface immersed in triple-distilled water and the water is replaced by photo-oxidized sea... 

A further interesting aspect of heterogeneous photochemistry concerns oil spilled at sea near land, which is subjected to environmental effects such as evaporation, dissolution, photo oxidation, dispersion into the water column and biodegradation. The fate of heavy fuel oil stranded on rock was studied under different environmental conditions [87]. Samples exposed to full or reflected sunlight showed depletion of the larger and more alkylated aromatic hydrocarbons and formation of resins, in agreement with reported laboratory studies on thin films of oil. 

Armstrong, F. A. J., Williams, P. M., and Strickland, J. D. H. (1966). Photo-oxidation of organic matter in sea water by ultra-violet radiation, analytical and other applications. Nature 211, 481—483. 

Each of these oxidation methods which have been used for analysis of dissolved organic matter in sea water have advantages and disadvantages which are summarized in Table IV. Oxidation by the persulfate method appears to be incomplete the photo-oxidation method seems to incompletely oxidize particles the dry oxidation method results in loss of volatile fraction during evaporation and drying steps. However, if proper precautions are followed and sample contamination is prevented, any of these oxidation methods can probably be used with confidence to measure organic carbon in sea water and to study the distribution of DOC in sea-water systems (Fig. 9). 

The absorption of solar radiation by abiotic sea water constituents initiates a cascade of reactions leading to the photo-oxidative degradation of organic matter and the concomitant production (or consumption) of a variety of trace gases and LMW... 

Walsh T.W. 1989. Total dissolved nitrogen in sea water a new-high-temperature combustion method and a comparison with photo-oxidation. Mar. Chem. 26 295-311. 

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