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

Graphical A novel and facile strategy was applied for designing and fabricating a bioinspired 3D hierarchical SC (sodium citrate)-functionalized MgAl-LDHs-based magnetic micromotor as an active self-propelled micromachine for the adsorption and removal of TCH or PNP from water. 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.