Efficient adsorption behavior of Fe-based ternary magnetic LDHs for naphthalene acetic acid: Role of Fe element

Naphthalene acetic acid (NAA) is an auxin plant growth regulator (PGR) and widely used to regulate the growth process of plants. As excessive NAA enter the environment, it damages the ecological environment and endangers human life and health. Layered bimetallic hydroxides (LDHs) are widely used for the adsorption of pollutants due to their large surface area and excellent structural properties. Based on the classical Fe₃O₄@MgAl-LDH material, Fe₃O₄@FeMgAl-LDHs were synthesized by adding different contents of Fe element to adsorb NAA in water. The morphology and properties of Fe₃O₄@FeMgAl-LDHs and the effect of Fe on adsorption efficiency were studied. The adsorption process and adsorption mechanism of NAA were analyzed. The results indicated that the content of Fe element will affect the adsorption effect of NAA by influencing the specific surface area and adsorption sites of Fe₃O₄@FeMgAl-LDHs. The maximum adsorption capacity for NAA can reach 330.1 mg/g when the proportion of Fe is 0.50. Exploring the adsorption mechanism, Fe₃O₄@FeMgAl-LDHs achieved efficient removal of NAA through hydrogen bonding, van der Waals forces, anion exchange, and electrostatic interactions. The adsorption efficiency of various PGRs were deeply explored. Fe₃O₄@FeMgAl-LDH (Fe-0.50) has good adsorption and regeneration ability for various PGRs. Therefore, by exploring the influence of different Fe ratios on the adsorption efficiency of the Fe₃O₄@FeMgAl-LDH, the adsorption performance of the material can be improved, making it have greater application advantages in wastewater treatment containing drugs.