UTILIZATION OF SOME STARCH DERIVATIVES IN HEAVY-METAL IONS REMOVAL

Three types of starch derivatives containing amide groups were used in removal of heavy metal ions from their solutions. These starch deriva tives were poly(acrylamide)-starch graft copolymer, carbamoylethylated starch, and starch carba mate. The different factors affecting metal ion adsorption on these substrates, such as pH, metal ion concentratio n, type of starch derivatives, treatment time, and temperature, were s tudied. Results obtained indicate that the poly(acrylamide)-starch gra ft copolymer was a selective adsorbant for Hg2+ at pH 0.5-1. The adsor ption values of different metal ions on these starch derivatives follo w the order of Hg2+ > Cu2+ > Zn2+ > Ni2+ > Co2+ > Cd2+ > Ph2+. The ads orption values depend upon pH, type of starch derivative, treatment du ration, and temperature. The adsorption efficiency percentage of metal ions on the three substrates follows the order of carbamoylethylated starch > poly(acrylamide) - starch graft copolymer > starch carbamate. (C) 1998 John Wiley & Sons, Inc.