文献速递|北京大学韩鹏/童美萍教授WR:磁性MoS2@Fe3O4高效激活过硫酸盐，快速降解游离DNA碱基和抗生素抗性基因

在这项工作中，MoS2@Fe3O4（MF）是通过将Fe（III）和Fe（II）共同沉淀到MoS2球体表面而合成的。所制备的样品被很好地表征了出来。请注意，ARG主要由DNA碱基、脱氧核糖和磷酸盐组成。自由基引起的ARG损伤主要是由DNA碱基的攻击引起的。因此，DNA碱基的降解过程对ARGs的降解非常关键。由于其最低的还原电位（1.29V），鸟嘌呤（G）被发现比其他碱基如胸腺嘧啶（T）、腺嘌呤（A）和胞嘧啶（C）最容易被氧化和损坏。然而，单纯的G损伤不能导致ARG的完全断裂。此外，由于鸟苷自由基（1.29V）的还原电位高于烷基过氧自由基（1.05V），DNA被组蛋白修复是可行的。因此，为了证明PMS通过MF激活是否能完全降解ARG，本研究对其对所有DNA碱基包括T、A、C和G的降解性能进行了研究。DNA碱基的降解机制和它们的降解途径被确定。此外，还考察了DNA碱基在复杂水基中的降解性能，如在不同的溶液pH值下，在阴离子和天然有机物共同存在的情况下，以及在实际水样（1L的大工作容积）中。此外，还确定了在四个重复使用的循环中以及在连续运行14天的连续流动反应器中的降解性能。此外，还研究了MF/PMS系统对两种模型ARG（染色体kanR和质粒gmrA）和从ARB中提取的DNA的降解，以及对两种模型ARB（大肠杆菌K-12 MG 1655和大肠杆菌S17-1）的消毒。

Fig. 1. Degradation performances of different systems towards 10 μM of four DNA bases (a) T, (b) A, (c) C, and (d) G. Reaction condition: [catalyst] = 200 mg/L, [PMS] = 200 mg/L, volume = 50 mL, T = 25 °C.Fig. 2. Effects of different scavengers on the removal of four DNA bases (a) T, (b) A, (c) C, and (d) G in MF/PMS system. Reaction condition: [L-histidine] = 1 mM, [MeOH] = 100 mM, [TBA] = 100 mM, [pBQ] = 5 mM, [MF] = 200 mg/L, [PMS] = 200 mg/L, volume = 50 mL, T = 25 °C.Fig. 3. EPR spectra of (a) 1O2, (b) ·OH and SO4·−, (c) O2·−; schematic of adsorption processes (d) between PMS and Fe3O4, and (e) between MF and PMS; (f) adsorption energy and charge transfer of Fe3O4/PMS and MF/PMS system.Fig. 4. The degradation pathways of four DNA bases and the chemical structure of four DNA bases. (a) degradation pathway of T; (b) chemical structure of T; (c) degradation pathway of A; (d) chemical structure of A; (e) degradation pathway of C; (f) chemical structure of C; (g) degradation pathway of G; (h) chemical structure of G.Fig. 5. The effects of (a) pH; and different anions, including (b) Cl−, (c) NO3−, (d) SO42−, (e) CO32−, and (f) HCO3−, on catalytic performances of MF/PMS system. Reaction condition: [MF] = 200 mg/L, [PMS] = 200 mg/L, volume = 50 mL, T = 25 °C.Fig. 6. (a) The effects of humic acid (HA) on catalytic performance of MF/PMS system (volume = 50 mL); (b) degradation performances of MF/PMS system towards T in real water samples (volume = 1 L). Reaction condition: [MF] = 200 mg/L, [PMS] = 200 mg/L, T = 25 °C.Fig. 7. The degradation performances of MF/PMS system towards (a) kanR and (b) gmrA as well as total DNA extracted from (c) E. coli K−12 MG1655 and (d) E. coli S17−1.Fig. 8. The inactivation performance of MF/PMS system towards (a) E. coli K−12 MG1655 with kanamycin resistance genes; the degradation performances of MF/PMS system towards (b) intracellular kanR and extracellular kanR as well as (c) intracellular DNA and extracellular DNA of E. coli K−12 MG1655 during the disinfection process. The inactivation performance of MF/PMS system towards (d) E. coli S17−1 with gentamycin resistance genes; the degradation performances of MF/PMS system towards (e) intracellular gmrA and extracellular gmrA as well as (f) intracellular DNA and extracellular DNA of E. coli S17−1 during the disinfection process.Fig. 9. (a) Reusability of MF/PMS system. Reaction condition: [MF] = 200 mg/L, [PMS] = 200 mg/L, volume = 50 mL, T = 25 °C; (b) schematic of the continuous flow reactor; (c) setup of the continuous flow experiment; (d) the degradation performance of MF/PMS system in the continuous flow reactor for long-term experiments.