A Study of Chelating Polymer Resins of Environmental Importance

Air, water and food are three important natural resources of man. Water is one of the most important and essential requirements of man, without which life cannot exist. Water pollution disturbs the normal uses of water for public water supply, recreation and aesthetics, aquatic life and wild life, agriculture and industry. A wide variety of pollutants viz., organic, inorganic, biological and radiological have been identified in the environment consequent to urbanization, industrialization and new technological developments. The major inorganic pollutants are inorganic salts, mineral acids, finely divided metals, metallo-organics, organometallic compounds, heavy and trace metal ions in aquatic environment. Heavy metal ions, although naturally occurring can be present in some aquatic environment in sufficiently high concentrations and in toxic physico-chemical forms, that might create severe pollution problem. Sources of heavy metal pollution are mainly aquatic releases from industrial operations, fossil fuel burning, domestic sewage and land run-off. These metal ions exhibit a wide range of toxicity to aquatic organisms and man. The background levels of these metal ions vary widely depending upon the location. Removal of heavy metal ions from industrial waste water is an interesting technique not only for pollution control but also to reuse the water. Most of the waste water results from cooling, rinsing, finishing, tanning, plating operations in the industry and is contaminated with heavy metal ions. These metal ions are not biodegradable; hence their concentration continuously increases in the environment. The toxic effects of heavy metal ions are well known. Industrial applications of heavy metal ions in general and chromium (VI) in particular evoked considerable attention. These metal ions besides being carcinogenic, pose serious threat to aquatic biota and environment. Therefore, the removal of toxic metals from waste water still remains as a topic of present research. Increased awareness of the toxicity of metal ions has prompted the implementation of strict regulations for their disposal or removal using traditional methods such as ion-exchange, reverse osmosis, precipitation etc.