The removal of hardness of water using sulfonated waste plastic

The possibility of using waste polystyrene to remove the hardness of water has been investigated. Waste of polystyrene is consisting of white coffee cups and they were converted into adsorbent by heterogeneous sulfonation. Infra red technique has been used to confirm the sulfonation. Degree of sulfonation and cation exhange capacity have been determined by titration. Hard water has been prepared by dissolving Mg or Ca salts in distilled water. The modified polymer provides high purification of hard water comparable to conventional adsorbent.

This paper gives a technique to recycle waste polystyrene which have been mass produced and hence is very beneficial for the protection of global environment. It allows the preparation of cation exchanger resin from waste and its application in the softening of hard water. The application sulfonated waste plastics for the softening of water with a hardness of about 150 mg/L in ion calcium or magnesium has been tested. For calcium ions, the capacity of exchange varies from 0.22 for sample treated at one hour for 60°C to 0.93 for that treated for 4 h at 40°C while for magnesium ions, it reaches its maximum for waste polystyrene sulfonated for 2 h at 60°C (0.78 mmol/g). It is important to note that the exchange capacity of resins show the same trend of the variation of sulfonation. Finally, we intend to study in further research the possibility of regenerating the resin after exchange.