Autonomous self-propelled reduced graphene oxide hydrogel-CuO@rGO micromotors for high-efficiency removal of organic dye pollutant

Zengze Liu; Ziwei Zheng; Yanlin Liu; Xiaoqiu Yang; Yangwei Chen; Fang Tan

doi:10.1016/j.jconhyd.2025.104650

Autonomous self-propelled reduced graphene oxide hydrogel-CuO@rGO micromotors for high-efficiency removal of organic dye pollutant

J Contam Hydrol. 2025 Jun 13:274:104650. doi: 10.1016/j.jconhyd.2025.104650. Online ahead of print.

Authors

Zengze Liu¹, Ziwei Zheng², Yanlin Liu², Xiaoqiu Yang², Yangwei Chen², Fang Tan³

Affiliations

¹ School of Optoelectronic Materials & Technology, Jianghan University, Wuhan, Hubei 430056, PR China; School of Environment and Health, Jianghan University, Wuhan, Hubei 430056, PR China.
² School of Optoelectronic Materials & Technology, Jianghan University, Wuhan, Hubei 430056, PR China.
³ School of Optoelectronic Materials & Technology, Jianghan University, Wuhan, Hubei 430056, PR China; Division of Pure and Applied Biochemistry, Department of Chemistry, Lund University, Box 124, 22100 Lund, Sweden. Electronic address: yanxizaof@sina.com.

PMID: 40532439
DOI: 10.1016/j.jconhyd.2025.104650

Abstract

This study featured about the synthesis of graphene oxide hydrogel-CuO@reduced graphene oxide (rGH-CuO@rGO) micromotors with core-shell structure via an ultrasonication-assisted chemical precipitation method and their application for catalytic dye degradation. The micromotors were comprehensively characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), spectroscopic techniques (Fourier transform infrared (FTIR), Raman), surface area measurement (BET), and X-ray photoelectron spectroscopy (XPS) to determine their microstructure, composition, and chemical states. Degradation performance for methylene blue (MB) was evaluated under varying conditions: reaction time (0-120 min), peroxymonosulfate (PMS) concentration (0-5 g·L^-1), pH (3-8), quantity of micromotors (12-24), and MB concentration (5-100 mg·L^-1). The removal rate of MB was achieved over 90 % within 120 min at pH 8. The micromotors demonstrated excellent catalytic efficiency, reusability and stability over four cycles. In the dual oxidant system (H₂O₂/PMS) the micromotors exhibited effective self-propulsion and stable MB removal. The generation of hydroxyl (•OH) and sulfate (•SO₄^-) free radicals in the system was confirmed by electron paramagnetic resonance spectrometer (EPR). Ultra High Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (UHPLC-QTOF/MS) was used to identify the degradation intermediates, and the possible MB degradation pathways were proposed. Moreover, the micromotors showed satisfactory performance in removing mixed dye wastewater and phenolic compound. Additionally, the low ecotoxicity of the micromotors was demonstrated by cytotoxicity assessment. This study provided a novel and valuable route to synthesizing self-driving micromotors with potential extensive applications in environmental remediation.

Keywords: Core-shell; CuO; Micromotor; Organic dyes; Oxidative degradation; Self-propulsion; rGO.