Fluoride Removal from Wastewater by Natural and Modified Gibbsite

Abstract

A low-cost adsorbent produced from natural and modified gibbsite was evaluated for defluoridation. Batch experiments were used to explore the best fluorine removal conditions. The experimental results showed the best conditions of removing fluorine as follows: reaction temperature was controlled at 298 K, the dosage of gibbsite added was 40 g/L, and the contact reaction time was 120 min. The concentration of fluorine ions in the wastewater treated by natural gibbsite decreased from 30 to 9.29 mg/L, and when treated by La 3+ -modified gibbsite, it reduced from 30 to 3.08 mg/L. The performances of natural and modified gibbsite were examined with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray analysis (EDX), and scanning electron microscopy (SEM) analyses. The pseudo-second-order kinetic model can well describe the process of defluorination of natural and modified gibbsite.

Removal of phosphorus and fluorine from wastewater containing PF6−via accelerated decomposition by Al3+ and chemical precipitation for hydrometallurgical recycling of lithium-ion batteries

“…The coprecipitation of PO 4 3− and F − in this study was expected to proceed by surface adsorption on formed Al(OH) 3 , as these anions are reported to precipitate by surface adsorption on Al(OH) 3 . 38–40…”