Wang, ShaobinDuan, XiaoguangYang, Yangyang2023-05-152023-05-152022https://hdl.handle.net/2440/138377The aim of this PhD research is to study the environmental application by Mn-based systems including micro/nano-motors. Artificial micro/nano-motors with autonomous motion are miniaturized robots that can convert chemical reactions into mechanical motion, which have been applied in diverse applications arranging from environmental purification to biomedical therapy. Due to the low price, high activity, and flexibility of structure, MnO2 efficiently induces decomposition of H2O2 and generates O2 bubbles, endowing the asymmetric micromotors with powerful driving force. This PhD thesis is presented in “Thesis by publication” and contains two review papers (published) and four research papers (published: Paper One and Paper Two; under review: Paper Three; unsubmitted: Paper Four). In this thesis, the Review Paper One highlighted the recent advances of Mn-based micro/nano-motors in the environmental and biomedical applications, systematically deepening the understandings upon the design and synthesis of Mn-based active materials. Initially, Mn-based micro/nano-motors in the dual-oxidation system of H2O2/peroxymonosulfate (H2O2/PMS) was proposed to degrade organic contaminants via advanced oxidation processes (AOPs) at the early doctoral stage. Yet lack of knowledge in the PMS activation inhibited the progress of Paper Three. Thus, the system of MnO2 + PMS in the phenol degradation was investigated in Paper One. Specifically, Cu-doped amorphous MnO2 was prepared via a facile one-step chemical deposition at room temperature and was applied to activate PMS to remove phenol. In this paper, the direct oxidation by high-valence Mn sites (from Mn(Ⅳ)(s) to Mn(III)(s) and Mn(Ⅱ)(s)) and PMS-based electron-transfer pathway (from Mn(III)(s) to Mn(Ⅳ)(s)) was intensified. Then deeper mechanism of PMS activation by various MnOx materials was clarified in Paper Two. PMS-based electron-transfer pathway was extended from Mn(Ⅱ)(s) to Mn(III)(s) and Mn(Ⅳ)(s). Paper One and Paper Two revealed that Mn(Ⅱ)(s) and Mn(III)(s) would bond with PMS (HSO5−) to form confined Mn(Ⅱ, Ⅲ)(s)−(HO)OSO3− complexes via an inter-sphere interaction to induce the direct electron transfer in the phenol oxidation. Afterwards, FeOx@MnO2@SiO2 flask micromotors were fabricated and applied to degrade antibiotics in the H2O2/PMS system with a long-lasting motion, and the results are reported in Paper Three. PMS adjusted the local environment to control over-violent O2 formation from H2O2 decomposition by occupying the Mn sites and enhanced organic removal due to the strengthened contacts and Fenton-like reactions between inner FeOx and peroxides within the microreactor. Intriguingly, the polymerization of phenol was found and the phenolic polymers with particle-like structures were attached onto MnO2 surfaces in the MnO2/PMS system in Paper Two. Thus, the Pespective Review Two proposed that PMS-based AOPs could be used to synthesize materials during the toxic organic removal. In Paper Four, dual-asymmetric MnO2 nanotubes were selectively etched by hydrochloric acid from a single-asymmetric MnO2 nanorod through a hydrothermal method. Then the tubular MnO2 surfaces were coated by a polymeric layer assembled by phenolic particles in the system of (phenol + PMS + MnO2). The partially coated polymeric layer on the MnO2 surfaces could regulate the H2O2 decomposition via the varied exposure of Mn active sites. This work verified the potential application of conventional PMS-AOPs in novel material synthesis, endowing this technique with a new path to promoting the development of Fenton/Fenton-like AOPs. In summary, this thesis accelerated the environmental remediation by Mn-based micro/nano-motors and provided a new thought of the application of PMS-AOPs technique.enMn-based micro/nano-motorspollutants degradationThesis