Nanoconfinement regulation of La-Mg LDH/Ti3C2TX (T = O, OH) for effective removal of fluoride: Membrane fabrication and mechanism revelation

Abstract

The present study utilized a nanoconfinement-regulated La-Mg LDH/Ti₃C₂T_X (T = O, OH) adsorbent to achieve efficient fluoride removal. The modified adsorbent effectively increased the surface area and active sites of the material through controlled intercalation of La-Mg LDH into the Ti₃C₂T_X gaps. The La-Mg LDH/Ti₃C₂T_X composite was found to exhibit superior suitability for pseudo-second-order kinetics and conformed well to the Langmuir model. Under initial conditions of a fluoride ion concentration of 200 mg/L, pH 7, and a temperature of 298 K, the adsorption capacity was determined to be 139.860 mg/g. The adsorption of fluoride was primarily governed by electrostatic interactions and anion exchange processes. The La-Mg LDH/Ti₃C₂T_X adsorbent with nanoconfinement regulation had the best adsorption effect on fluoride ions, and fluoride ions were more inclined to be adsorbed at the interface of La-Mg LDH/Ti₃C₂T_X. Furthermore, facile fabrication of La-Mg LDH/Ti₃C₂T_X membrane was achievable. Membrane filtration experiments demonstrated that the defluorination efficiency was significantly influenced by the thickness of membrane, water velocity, and solution pH. The membrane processing capacity was 11526 L/m³ when the membrane thickness was 9 mm and the flow rate was 10 mL/min. The present study offers novel insights into the development of defluorinated materials.