Simultaneous nanocatalytic surface activation of pollutants and oxidants for highly efficient water decontamination

Abstract

Removal of organic micropollutants from water through advanced oxidation processes (AOPs) is hampered by the excessive input of energy and/or chemicals as well as the large amounts of residuals resulting from incomplete mineralization. Herein, we report a new water purification paradigm, the direct oxidative transfer process (DOTP), which enables complete, highly efficient decontamination at very low dosage of oxidants. DOTP differs fundamentally from AOPs and adsorption in its pollutant removal behavior and mechanisms. In DOTP, the nanocatalyst can interact with persulfate to activate the pollutants by lowering their reductive potential energy, which triggers a non-decomposing oxidative transfer of pollutants from the bulk solution to the nanocatalyst surface. By leveraging the activation, stabilization, and accumulation functions of the heterogeneous catalyst, the DOTP can occur spontaneously on the nanocatalyst surface to enable complete removal of pollutants. The process is found to occur for diverse pollutants, oxidants, and nanocatalysts, including various low-cost catalysts. Significantly, DOTP requires no external energy input, has low oxidant consumption, produces no residual byproducts, and performs robustly in real environmental matrices. These favorable features render DOTP an extremely promising nanotechnology platform for water purification.

Specific Adsorption and Efficient Degradation of Cylindrospermopsin on Oxygen-Vacancy Sites of BiOBr

“…The G-BiOBr (Figure A) has distinctively different spectra than the H–BiOBr (Figure B), in which an increasing band in ∼2800–3700 cm –1 region arises with prolonged contact time. This characteristic band is ascribed to the C–H or/and = C–H (∼2800–3000 cm –1 ), N–H (∼3300–3500 cm –1 ), and O–H (∼3200–3700 cm –1 ) stretching mode of CYN, affirming that the CYN is adsorbed on G-BiOBr. , Meanwhile, the band at 1645 cm –1 resulting from δ(O–H) is strengthened and red-shifts toward the lower wavenumber (1620 cm –1 ) (Figure A), inferring the formation of hydrogen bonds between the CYN molecule and OH B on the G-BiOBr surface. , Besides, the weak band at 1417 cm –1 is produced by the bending vibration of O–H. The bands observed at 993, 1043, 1220, and 1318 cm –1 belong to the stretching vibration of SO from the sulfate group of CYN (Figure A).…”

“…This characteristic band is ascribed to the C−H or/and = C−H (∼2800−3000 cm −1 ), N−H (∼3300−3500 cm −1 ), and O−H (∼3200−3700 cm −1 ) stretching mode of CYN, affirming that the CYN is adsorbed on G-BiOBr. 53,54 Meanwhile, the band at 1645 cm −1 resulting from δ(O−H) is strengthened and red-shifts toward the lower wavenumber (1620 cm −1 ) (Figure 8A), inferring the formation of hydrogen bonds between the CYN molecule and OH B on the G-BiOBr surface. 53,55 Besides, the weak band at 1417 cm −1 is produced by the bending vibration of O−H.…”

Efficient and Durable Single-Atom Fe Catalyst for Fenton-like Reaction via Mediated Electron-Transfer Mechanism

“…The recycled Fe 1 -M15 shows roughly the same profile to that of fresh Fe 1 -M15, indicating the Fe−N 4 configuration in both the fresh and recycled catalyst (Figures 4a−d and S9 and Table S3); the decreasing catalytic activity could probably be attributed to the passivation of the active center by the polymerization of BPA degradation intermediates. 48 The investigations on the interference of the components in the natural water matrix and the mechanism studies were conducted in the Fe 1 -M9-catalyzed reaction system for the convenience in experimental operation and reaction kinetics comparison. As shown in Figure 5a, the chloride anion, dihydrogen phosphate ion, and nitrate anion show negligible impact on the pollutant degradation reaction rate; while in the presence of carbonate anion, the BPA degradation performance is slightly decreased, which might result from the decreased surface adsorption of BPA on the catalyst (Figures S10 and S11).…”

Remarkably enhanced Fenton-like catalytic activity and recyclability of Fe-based metallic glass by alternating magnetic field: mechanisms and industrial applications

“…1 Effective, affordable and environmentally benign technologies for degrading these pollutants are thus highly desired. 2,3 Fenton and Fenton-like processes, producing highly oxidizing radicals ( e.g. , ˙OH, and ) that can rapidly degrade organic contaminants into harmless small molecules ( e.g.…”