Jom FTEKNIK Volume 3 No. 2 Oktober 2016 1 APLIKASI SHRINKING CORE MODEL PADA SINTESIS HIDROKSIAPATIT DARI KULIT KERANG DARAH (Anadara granosa) DENGAN MENGGGUNAKAN METODE HIDROTERMAL SUHU RENDAH Ervina 1 , Ahmad Fadli 2 , Idral Amri 2 1 Mahasiswa Jurusan Teknik Kimia S1, 2 Dosen Jurusan Teknik Kimia, Fakultas Teknik, Universitas Riau Kampus Binawidya Jl. HR Subrantas Km 12,5 Pekanbaru 28293 ervina.hunafa@gmail.com ABSTRACT Hydroxyapatite (HA) is a ceramic material that can be used as bone and dental implants. Hydroxyapatite can be synthesized from the cockle shell (Anadara granosa). The purpose of this study was to determine the effect of time and stirring rate on the characteristics of HA using a low temperature hydrothermal method as well as decide of the kinetics model with the approach of shrinking core models. There are 3 models that are used, namely diffusion through the liquid film control, diffusion through the layer results (HA) control, and chemical reaction control. Research procedures initiated by the reaction of 36.9 g NH 4 H 2 PO 4 dissolved in 600 mL of water were then added as much as 39.37 g CaO at stirring rate of 100 rpm, 200 rpm, 300 rpm and reaction time of 5 minutes to 150 minutes. The mixture was reacted at a temperature of 90˚C to form a paste. The paste was dried in an oven at 120˚C for 12 hours and calcined at a temperature of 900˚C for 1 hour. The results showed that the product formed is 95% fraction massa of HA. Kinetics model that describes the events of the synthesis of HA for belong to model 2, i.e diffusion through the layer results (HA) control with the smallest error percentage of 16.15 % with the formula: Keywords: cockle shell, hydrothermal, hydroxiapatite, kinetics model, shrinking core model 1. Pendahuluan Hidroksiapatit (HA) dapat dibuat dengan cara alami dan sintetik. Senyawa alami tersebut diperoleh dari cangkang telur, kulit kerang, karang, dan lainnya. Harga hidroksiapatit sintetik yang dibuat dari bahan kimia sangat mahal. Hidroksiapatit dapat disintesis dengan berbagai metode, yaitu metode presipitasi, metode mechanochemical, metode solid state reaction, metode sol gel, dan metode hidrotermal suhu rendah. Metode hidrotermal merupakan metode yang paling tepat untuk memperoleh hidroksiapatit dengan kualitas bagus, kemurnian tinggi, bentuk ukuran seragam, kristalinitas tinggi, dan reaktivitas sangat tinggi (Yoshimura dan Byrappa, 2008). Beberapa literatur melaporkan pembentukan hidroksiapatit dari kulit kerang dalam media posfat dengan menggunakan metode hidrotermal. Komposisi mineral