Optimization of Pb Adsorption from Seawater from Former Bauxite Mines Using Crab Shell Waste

Abstract

Crab shell waste can cause pollution to the surrounding environment, but has the potential to be used as a biosorbent in the absorption of heavy metals, especially Pb because crab shells contain CaCO3 and chitin. Methods: Several variables that play a role in the biosorption process, among others: initial metal concentration, biosorbent mass, and contact time. Pb metal was determined by the Atomic Absorption Spectroscopy (AAS) method. Results: The results showed that the crab shell biosorbent contained Pb 0.019 mg/g. The concentration of Pb in the shell was used as a correction factor. Optimal result for parameter of initial concentration of Pb is 100 mg/L with efficiency percentage (99.11 ± 0.02)% and adsorption capacity (620.15 ± 0.3) ug/g. The optimal result of contact time is 120 minutes with efficiency percentage (91.22 ± 0.13)%. The optimal yield of biosorbent mass based on the percentage efficiency (98.01 ± 0.2)% is 2 grams. Conclusion: This study can show that crab shell waste can be used as an effective biosorbent for Pb metal adsorption. The results of the optimization of the best factors to be used in the biosorption process of Pb metal were the initial concentration of 100 mg/L, the mass of the biosorbent was 3 grams and the contact time was 110 minutes. The optimum conditions for Pb adsorption were successfully applied to seawater from the former bauxite mine.