doi:10.1038/nindia.2013.139 Published online 21 October 2013
Researchers have developed new organic fluorescent beads that can scavenge heavy-metal ions. They produced the beads using organic compounds from the cellulose of a salt-tolerant plant . The beads could be used to remove toxic ions from industrial wastewater.
Existing techniques for heavy-metal ions removal are ineffective and expensive. To devise a simple and cost-effective way to remove such ions, the researchers synthesized water-soluble monoamide and diamide organic compounds by oxidizing cellulose isolated from a salt-tolerant plant and subjecting these compounds to microwave radiation in the presence of ethylenediamine. They then made monoamide and diamide beads by smearing the compound on sodium alginate in the presence of calcium chloride.
To test the ability of the beads to adsorb lead and mercury ions, they were separately exposed to lead- and mercury-containing solutions. The monoamide beads showed a higher metal-ion-adsorbing capacity than the diamide beads. The monoamide beads have more amine and carboxyl groups, which bind to metal ions. This makes the monoamide beads more efficient metal-ion scavengers than the diamide beads.
"Besides being metal-ion scavengers, these beads could be used for designing metal-ion sensors due to their fluorescent properties," says A. K. Siddhanta, a co-author of the study.