Preparation of a Cross‐Linked Al(OH) ₃ /PVA/PVP Composite and Its Study on the Removal Ability of Fluoride Ion From Wastewater

ABSTRACT With the development of fluorinated waste treatment and the extraction of metals such as rare earths, high‐density F − wastewater becomes a potential threat. Compared to inorganic adsorbents for F − removal with high cost due to agglomeration, this paper firstly utilizes maleic anhydride to control pH and achieves cross‐linked PVA/PVP as polymer matrix and in situ synthesized Al(OH) 3 (ATH) as inorganic particles simultaneously, and obtains cross‐linked ATH/PVA/PVP composite films with good mechanical property and excellent F − removal capability. With the increasing ATH contents of ATH/PVA/PVP composites, the initial decomposition temperature improves from 253°C to 262°C. The SEM shows that the in situ synthesized ATH can be relatively evenly distributed on the surface and inside the ATH/PVA/PVP composite with a diameter of 8–30 μm. For the ATH/PVA/PVP composite, the most suitable pH for F − adsorption is 5, and the adsorption capacity can reach 34.9 mg/g, and the F − removal efficiency can reach 98.07%. The F − removal of ATH/PVA/PVP composite can still remain 79.8% after five times regeneration, and interfering ions such as Cl − , NO 3 − have little effect on the F − removal. The Young's modulus and tensile strength of the ATH/PVA/PVP composite can remain 6.2 GPa and 10.1 MPa even at 25 wt% ATH contents.