Removal of thiocyanate ions from aqueous solutions using polypyrrole and polyaniline conducting electroactive polymers

Polypyrrole (PPy/Cl) and polyaniline (PAni/Cl) synthesized chemically onto sawdust (SD) was used for removal of thiocyanate (SCN-) ions from aqueous solutions. The effect of some important parameters such as pH, initial concentration, sorbent dosage, and contact time on uptake of SCN- was investigated. PPy/SD was found to be much more effective sorbent than PAni/SD for uptake SCN- from aqueous solutions. Removal of SCN- ions using PPy/Cl is supposed to be occurred mostly via ion exchange process at the surface of polymer coated onto sawdust as a very thin film. Desorption studies were also carried out for figuring out the possibility of the regeneration and reuse of the exhausted adsorbent. A proposed mechanism based on interesting anion exchange properties of the PPy/Cl has been discussed. It was found that polypyrrole conducting polymers doped with releasable counterions can be used for used to remove some anions via ion exchange process under simple open circuit conditions. The finding in this paper shows the promising application of polypyrrole conducting polymers in future water or wastewater purification technology.