theoretical investigation into the effect of surface tension component ratios between the polar and dispersion components of applied solvents and 2D materials (Figure 3b). [523] The results indicated that a solvent suited for certain 2D materials LPE should have surface tension component ratios similar to the 2D materials. [523] However, direct exfoliation using sonication and Figure 3. Top-down approaches in 2D materials preparation. a) Schematically illustration of ultrasonic-assisted exfoliation. Reproduced with permission. [524] Copyright 2013, American Association for the Advancement of Science. b) Top and middle rows: dispersibility of graphene and MoS 2 as a function of total surface tension and polar to dispersive ratio. Bottom row showing the thickness histogram of graphene and MoS 2 exfoliated using solvents with the optimal surface tension and polar to dispersive component ratio. Reproduced with permission. [523] Copyright 2015, American Chemical Society. c) Detailed schematic of cathodic exfoliation (top) and anodic exfoliation (bottom) of graphene from graphite. Reproduced with permission. [1184] Copyright 2015, Elsevier. d) DFT calculation results of ion-intercalation exfoliation of graphite into graphene using SO 4 2− ion (bottom left), Li ion (top right) and K ion (bottom right). Reproduced under terms of the CC-BY license. [565] Copyright 2017, The Authors, published by the Royal Society of Chemistry. e) Left: SEM image (top) and AFM image (bottom) of a typical graphene obtained by ion-intercalated exfoliation. Right: Lateral size (top) and thickness (bottom) distribution of graphene through ion-intercalation exfoliation. Reproduced with permission.

In this work, novel magnetic nanocomposites, Fe 3 O 4 @Ba 3 (PO 4) 2 (denominated FBP) nanoflakes loaded with Ag nanoparticles (NPs) (denominated FBPA), were reported for cleaning E. coli from water. FBPA with 1 wt% Ag (denominated FBPA1) showed a higher adsorption efficiency (94%) than FBPA with 10 wt% Ag (denominated FBPA10), for water heavily contaminated with E. coli (5 Â 10 8 CFU/mL), both at a dosage of 1 g/L within 10 min. Importantly, the loaded Ag NPs can greatly improve the disinfection effect of FBP due to the great antimicrobial activity of Ag NPs via the released Ag þ. Confocal fluorescent images and dilution plating results showed that~100% of E. coli could be inactivated by FBPA1 within 10 min. The calculated disinfection capacity was higher than some other materials. Three co-existed salts in solutions decreased the disinfection efficiency of FBPA1 to be~67% (NaCl),~59% (CaCl 2), and~41% (MgCl 2). Furthermore, FBPA1 can be reclaimed via a magnet to be reused. FBPA1 maintained an adsorption efficiency of 86%, disinfection effect of 70%, and~90% of loaded Ag NPs after the fifth recover and reuse cycle.

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