Adsorption of fluoride from aqueous solutions by polyacrylic acid modified with aluminium

A novel and efficient PAA-Al-250 adsorbent was successfully synthesized and used for fluoride removal. PAA-Al-250 was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, N2 adsorption–desorption surface area and pore size analyzer. PAA-Al-250 had good fluoride adsorption capability. The optimum pH was 2.0 and more than 90% fluoride removal was achieved from 10 mg L−1 aqueous solution after 5 h at room temperature. Fluoride adsorption on PAA-Al-250 followed the Freundlich model and the maximum adsorption capacity of the adsorbent was 283.48 mg g−1. Kinetic study indicated that the adsorption followed pseudo-second-order model.