Dari, Sri Wulan2021-08-312021-08-312020-12wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/10197Composite is a material that is formed from two or more combination materials with the result that it is resulted a composite material that has different mechanical and characteristic properties from the forming material. The purpose of this research is to conduct hydroxyapatite synthesis from lokan shells (Geloina coaxans) using the method of microwave with Diammonium hydrogen phosphate (NH4)2HPO4 precursor and Ca(OH)2 and for adsorption of hydroxyapatite/chitosan as adsorben toward methylene blue. Hydroxyapatite/chitosan (HAp-C) synthesis result of is characterized X-Ray Floresence (XRF) contain is CaO 98,759 %, used to adsorb methylene blue with an adsorption ability of 71,1296 %enCompositemicrowavehydroxyapatiteDiammonium hydrogen phosphate (NH4)2HPO4 precursor and Ca(OH)2Article