Adsorption of Heavy Metals in an Aqueous Solution Using Starfish (Asterina Pectinifera) Biochar

Abstract

Objectives:Heavy metals caused by industrialization have affected human society for several decades. Because of their toxicity for humans, lots of heavy metal treatments have been developed. However, many of those treatments have economic considerations and environmental disadvantages. This work explored an experimental assessment of adsorption of heavy metals using starfish (SF) biochar through quantitative and qualitative characterization and batch-tests.Methods:Biochar (NACSF) was produced at 300℃ for 2 h in anaerobic conditions. The NACSF was characterized with XRD, XRF, FT-IR, SEM-EDX and elemental analyses. Moreover, batch-tests for each heavy metal using NACSF were conducted with ICP-OES analyses in order to evaluate the adsorption characteristics.Results and Discussion:Based on the characterization results, the NACSF consisted of carbon and CaCO₃ mainly. The adsorption rates of Pb, Cu, Zn and Cd decreased in the following order: Pb≫Cu>Zn≥Cd. Moreover, the Langmuir equation fit all adsorption data better than the Freundlich equation. Also, due to the alkalinity of NACSF, the measured pH values of all experimental groups were approximately 7~8.Conclusions:The NACSF treatment was the most effective for Pb removal and it was determined that precipitation and surface adsorption were the most likely mechanisms for Pb removal. Thus, NACSF derived from starfish could be an cost-effective and eco-friendly treatment for heavy metal contaminated wastewater.