Fluoride sorption by nano-hydroxyapatite/chitin composite

In this study the fluoride adsorption potential of novel nano-hydroxyapatite/chitin (n-HApCh) composite was explored. The sorbent was characterized using FTIR studies. The effects of pH, interfering anions and contact time were studied. The sorption data obtained under optimized conditions were subjected to Langmuir and Freundlich isotherms. Kinetic studies indicate that the rate of sorption of fluoride on n-HApCh composite follows pseudo-second-order and pore diffusion patterns. n-HApCh composite possesses higher defluoridation capacity (DC) of 2840 mgF− kg−1 than nano-hydroxyapatite (n-HAp) which showed a DC of 1296 mgF− kg−1. Field trials were conducted with the sample collected from a nearby fluoride endemic area.