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Analysis of copper removal using different seafood wastes by differential pulse voltammetry (DPV)

Current methods of heavy metal removal are shown to have several drawbacks: cost of operation, generation of toxic sludge and complicated procedures in the treatment. In this study, the ability of seafood waste as a sustainable biosorbent was investigated. Three commonly consumed seafood wastes in Malaysia were chosen for this study: crab shells, prawn shells and cockle shells. This study aimed to determine the differences in copper removal between crab, prawn and cockle shells at fixed concentrations and weights of shells. Differential pulse voltammetry using a modified screen-printed electrode was used to determine the concentration of copper for each waste sample. Removal of copper was first observed at different shell weights between 20 and 100 mg and at a fixed copper concentration of 20 ppm. Shell weights with the highest removal, 20 mg and 40 mg, were then used for further observation at concentrations between 1-20 ppm. At a weight of 20 mg, prawn shells showed the highest removal percentage of copper at 34.40% while crab shells and cockle shells showed the highest removal percentage of 31.22% and 12.78%, respectively. This was likely due to the presence of calcium carbonate and chitin as the main component in crab and prawn shells. Cockle shells showed low removal efficiency under these conditions. In conclusion, untreated crab shells and prawn shells were shown to successfully remove copper in water.