ADSORPTION OF HEAVY METALS USING BIO-CALCIUM CARBONATE DERIVED FROM A GOLDEN APPLE SNAIL (GAS) SHELL

Abstract

In this research studied the use of calcium carbonate (CaCO3) from golden apple snail (GAS) shells for application as an absorbent material to remove heavy metals in water sources, which replaces commercial calcium carbonate (CaCO3) to reduce production costs and increase waste value. The adsorption of heavy metal contents (such as lead; Pb and Cadmium; Cd), phase formation, and physical characterization of golden apple snail shells were investigated for use as a calcium source in the production of naturally based biomaterials. The samples were calcined between 700°C and 950°C for 5 hr. TG and DTA analysis of samples demonstrated the decomposition of CaCO3 to CaO. The XRD results demonstrated that natural shell powder has a crystal phase of CaCO3 with an aragonite structure. Furthermore, the CaCO3 (calcite phase) was transformed into calcium oxide (CaO) as a component, which showed that the phase transformation depended on the calcination temperature. The adsorption experiments showed good performance at about 99.6%, 99.7%, and 97% removal efficiency in a shorter time for calcined GAS at 700, 800, and 900°C, respectively. This study suggests that the golden apple snail shell could be an effective biomaterial for heavy removal from contaminated water.