Microwave-synthesized hydroxyapatite from paddy field snail (Pila ampullacea) shell for adsorption of bichromate ion

Microwave-assisted synthesis of hydroxyapatite (HAp) from paddy field snail (Pila ampullacea) shell has been conducted. The synthesis was performed by producing CaO from snail shell using calcination method followed by wet preparation method with phosphoric acid. Microwave irradiation procedure was applied for the HAp formation. Physicochemical characterization of material was studied by X-ray diffraction (XRD) measurement, gas sorption analyzer, Fourier-Transform Infra-Red and also scanning electron microscope-energy dispersive X-ray and adsorption study for Cr(VI) in the form of bichromate ion. The XRD pattern shows that crystalline of HAp was obtained by both microwave irradiated method and reflux method with the similar properties as the material obtained from by CaO. Adsorption experiment showed the similar capability of prepared HAp. The kinetics of adsorption obeys pseudo second-order model. The adsorption isotherms are fit with Langmuir adsorption isotherms with the adsorption capacity of 23 and 21 mg g−1 for HAp prepared by reflux and microwave irradiation methods, respectively.