3D Hierarchical Layered Double Hydroxide‐Based Micromotors for Motion‐Based Adsorption and Efficient Removal of Tetracycline Hydrochloride and p ‐Nitrophenol

Abstract This paper reports a novel bioinspired 3D hierarchical sodium citrate (SC)–functionalized layered double hydroxides (LDHs)‐based magnetic micromotor as an active self‐propelled micromachine for the adsorption and removal of TCH or PNP from water. This micromotor was composed of MgAl‐based layered double hydroxides intercalated with citrate anions (CA) and MgFe 2 O 4 fiber/Mn 3 O 4 . The outer SC‐functionalized MgAl‐LDH layer functioned as a functional unit for TCH or PNP adsorption, MgFe 2 O 4 fibers acted as a buffer layer, facilitating the nucleation and growth of MgAl‐LDH. MgFe 2 O 4 nanoparticles provided magnetism for recycling. Mn 3 O 4 served as a catalyst in decomposing H 2 O 2 for self‐propulsion of the micromotor. The obtained micromotor exhibited a circle motion form with an average speed of 147.50 µm s −1 in 5 wt% H 2 O 2 . Due to the cooperation of self‐propelled movement with interlayer water repellency after SC intercalation, these micromotors exhibited a rapid removal rate of antibiotics or organic pollutants from water. The maximum adsorption capacities of SC‐MgAl‐LDH/MgFe 2 O 4 /Mn 3 O 4 toward tetracycline hydrochloride (TCH) and p ‐nitrophenol (PNP) were 146.20 and 127.39 mg g −1 in the presence of 5 wt% H 2 O 2 . Therefore, this study provides an efficient option for wastewater treatment.