Aluminium hydroxide impregnated macroreticular aromatic polymeric resin as a sustainable option for defluoridation

• Aluminium hydroxide impregnated macroporous polymeric adsorbent was prepared.
• Characterization of the adsorbent was studied in detail.
• The sorbent has a maximum F− ion adsorption capacity of 36.61 mg g−1 at pH 7.0.
• F− ion adsorption favoured by electrostatic interaction and hydrogen bonding.
• Adsorbent is effectively regenerated with sodium hydroxide.

The purpose of the present study was to explore the potential application of aluminium hydroxide impregnated macroporous polymeric resin as a sustainable option for fluoride removal from aqueous solution. Electrostatic interaction between fluoride and the cationic metal hydroxide as well as hydrogen bonding (metal-OH⋯F) could be inferred through Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) techniques. This macroreticular adsorbent gave a high adsorption capacity (92.39 and 36.61 mg g−1 at pH 3.0 and 7.0) by fitting the experimental data with the nonlinear Langmuir isotherm model. The pseudo-second-order adsorption process could be described using surface and intraparticle diffusion. Thermodynamics of adsorption accounted for the spontaneity and exothermic interaction with a corresponding decrease in entropy. The Al(OH)3 impregnated polymeric resin adsorbent was tested with 5 mg L−1 fluoride and its efficacy was demonstrated in a laboratory scale column study. The resin exhibits good potential towards practical applications for the remediation of fluoride.

Figure optionsDownload as PowerPoint slide