Bioinspired Self-Propelled Micromotors with Improved Transport Efficiency in the Subsurface Environment for Soil Decontamination

Limited transport efficiency of remediation reagents in the subsurface environment is regarded as a key challenge facing in situ soil remediation. Herein, taking advantage of natural hollow fibers, tubular micromotors capable of autonomous movement to facilitate the migration of remediation reagents and achieve efficient degradation of organic pollutants in soil are developed. Widely-used nanocatalysts in soil treatment, Fe3O4 and MnO2, are integrated on the fiber surface to enable self-propulsion via recoil of micro/nanobubbles and activation of hydrogen peroxide (H2O2) and peroxymonosulfate. Featured with tiny sizes and wireless motion, the micromotors navigate in microchannels and microenvironments with complex terrain. The dependence of transport efficiency in heterogeneous and porous environments on H2O2 concentration is revealed based on column studies. With fluorescent g-C3N4 decorated on the surface to enable visualization, the horizontal/vertical migration of prepared micromotors in soil is proved to be greatly enhanced due to self-propulsion and bubble generation. The micromotors exhibit excellent catalytic performances toward the degradation of a wide spectrum of water-soluble antibiotics and water-insoluble polycyclic aromatic hydrocarbons. Overall, the bioinspired micromotors unveil a new strategy to improve the transport of remediation reagents in the subsurface environment, which holds great potential for efficient in situ soil treatment. Bioinspired self-propelled micromotors based on natural fibers demonstrate enhanced horizontal and vertical migration in the subsurface environment, which promotes the transport efficiency of remediation reagents in soil for in situ remediation. The micromotors exhibit excellent catalytic performances toward the degradation of a wide spectrum of water-soluble antibiotics and water-insoluble polycyclic aromatic hydrocarbons.image