Removal of Heavy Metals from Water by the Direct Addition of Chitosan Prepared from Prawn and Squilla Shells

Abstract

Chitosan was prepared from prawn shell (Fenneropenaeus indicus) and squilla (Oratosquilla nepa) and quality characteristics such as moisture, ash, viscosity and degree of deacetylation were determined. The efficacy of the prepared chitosan to remove heavy metals when directly added to water samples at 1% level was assessed. Water samples with the addition of known quantities of lead, zinc, cadmium, copper and iron and water samples collected from different locations in Vembanad Lake were used in this study. Significant reduction in the concentration of heavy metals was observed after treatment with chitosan. Chitosan from prawn shell was found to be more effective in the removal of heavy metals from water. Treatment with prawn chitosan removed 68% cadmium from spiked samples, whereas squilla chitosan removed 37%. In the case of water samples collected from Vembanad Lake, treatment with chitosan from prawn shell removed approximately 50% of cadmium and the same treatment resulted in removal of lead to non-detectable levels in all the samples.