Environmental degradation processes

As discussed in section 2, the alkyltin component of organotin compounds is relatively stable to environmental degradation processes such as hydrolysis, compared with the association with the relative ligand (such as an isooctyl mercaptoacetate group). Thus, in water, most of the derivatives are reported to dissociate to the constituent alkyltin (usually as the chloride or the oxide) and the relevant anion (KemI, 2000). 

This study has shown that typical coating biocides can be encapsulated within modified silica frameworks. These porous frameworks offer a means to inhibit the aqueous extraction of the biocide. In such combinations the biocides retain their anti-microbial properties, while controlled delivery facilitates a dynamic equilibrium to maintain a minimum inhibitory concentration at the coating interface, over an extended time period. There is evidence that biocide housed in such frameworks has a longer effective activity for a given initial concentration, since it is to some extent protected from the usual environmental degradation processes. 

Photolysis by sunlight Is an Important environmental degradation process for many pollutants In aquatic systems. Photolytlc reactions In complex organic mixtures such as those found In natural waters, wastewaters, and other surface waters are likely to be enhanced by "sensitizers" or retarded by "quenchers" that may be present In complex organic matrices. 

Figure 3. Environmental degradation processes for addition and condensation...

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