Anions environmental pollution problem

Acid rain caused by SO2 and NOx in air is a major environmental pollution problem in many parts of the world. The major cationic components of acid rain are H", Na", NHt, K, Mg and Ca the major anionic components are Cl", NO3" and S04 . The ionic balance between the total positive charge and negative charge of these ions is almost 100 %, so the simultaneous determination of these ions is important. 

Environmentally, anions pose a considerable pollution problem. In particular, the nitrate anion (used in fertilizers on agricultural land) often pollutes river water to unacceptable levels. This pollution leads to eutrophocation and consequent disruption of aquatic life cycles (16). Radioactive per-technetate anions also cause a pollution problem in the nuclear fuel cycle. Selective binding and sensing of environmentally sensitive anions is, therefore, an important goal. 

The photolytic removal of chlorine from chlorobenzene, chlorophenols and chlorinated biphenyls and dioxins continues to be examined as a potential solution to the problem of the destruction of these compounds when present as environmental pollutants. Guillet has reported that aqueous solutions of the copolymer of vinyl-naphthalene and styrene sulphonate will solubilize to a small degree 2,2, 3,3, 6,6 -hexachlorobiphenyl, and that illumination of the solution with simulated sunlight leads to the formation of biphenyls with fewer chlorine substituents. It is suggested that the process involves the absorption of light by the naphthalene and exciplex formation with the biphenyl followed by electron transfer to the biphenyl. The chlorinated biphenyl anion radical would then be expected to expel chloride ion. The dechlorination of mixtures of variously chlorinated biphenyls (such as those typically used as... 

Generally, UV detection is used for the determination of most environmental pollutants. However, the use of UV detectors in CE for metal ion and anion analysis is not suitable due to the poor absorbance of UV radiation by metal ions and anions. The most common method to solve this problem is indirect UV detection. The main advantage of the indirect UV detection method is its universal applicability. The complexation of metal ions with Ugands also increases the sensitivity of their detection. The complex-ing agent is either added to the electrolyte (in situ, online complexation) or to the sample before the introduction... 

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