Surface modification of biogenic hydroxyapatite particles with 2-thiophenecarboxaldehydeAuthor(s): Bayram Kizilkaya, Nail Ucyol and A. Adem Tekinay
In present study, it was investigated whether biogenic hydroxyapatite is suitable to chemical modification. The chemical modification on the surfaces of bone particles was made on two step using silanization and shiff base reaction. Fish Bones were used as biogenic hydroxyapatite and it were cleaned in order to make them ready for chemical proceeding. Chemical modifications were performed on the surface of fish bone particles. Firstly, free amine (-NH2) group was obtained in molecule by silanization of the surfaces of fish bones with 3-amminopropyl-triethoksisilane (S1). Afterwards, amine groups that exist on the surface of bones were reacted with 2-thiophenecarboxaldehyde (B4) that includes aldehyde groups. The materials were analyzed with FT-IR, SEM-EDS, TGA and Zeta potential. In SEM-EDS analysis, the band of silisium (Si) and sulfur (S) elements of molecules for S1 and B4 can be clearly seen. The point of zero charge (Pzc) of unmodified bone apatite (H), modified bone 3-amminopropyl-triethoksisilane (HS1) and 2-thiophenecarboxaldehyde (HS1B4) was investigated and determined as 7.25, 7.72 and 7.57, respectively. Additionally, nitrogen for H, HS1 and sulfur for HS1B4 was detected as 8.031, 8.291 and 0.916 %, respectively. 2-thiophenecarboxaldehyde bonded on the surface of bone was calculated as 143.4 μmol g-1. The results showed that surface modification was performed successfully. BET surface area of the unprocessed apatite is 5.65 m2g-1 and the surface area of modified apatite HS1B4 is 2.95 m2 g-1. This study was shown that waste fish bones occurring waste and non-economic value as industrial is to be suitable for chemical modifications and it could be effectively converted to different materials.