Perfluoroalkyl
substances (PFASs) are highly toxic synthetic chemicals,
which are considered the most persistent organic contaminants in the
environment. Previous studies have demonstrated that hydrated electron
based techniques could completely destruct these compounds. However,
in the reactions, alkaline and anaerobic conditions are generally
required or surfactants are involved. Herein, we developed a simple
binary composite, only including PFAS and hydrated electron source
chemical. The system exhibited high efficiency for the utilization
of hydrated electrons to decompose PFASs. By comparing the degradation
processes of perfluorooctanoic acid (PFOA) in the presence of seven
indole derivatives with different chemical properties, we could conclude
that the reaction efficiency was dependent on not only the yield of
hydrated electrons but also the interaction between PFOA and indole
derivative. Among these derivatives, indole showed the highest degradation
performance due to its relatively high ability to generate hydrated
electrons, and more importantly, indole could form a hydrogen bonding
with PFOA to accelerate the electron transfer. Moreover, the novel
composite demonstrated high reaction efficiency even with coexisting
humic substance and in a wide pH range (4–10). This study would
deepen our understanding of the design of hydrated electron based
techniques to treat PFAS-containing wastewater.
The spin state change of Fe3+ ions induced the paramagnetic Fe0.5Ni0.5OOH shell on the ferromagnetic Cu0.5NFe3Ni0.5 core via superexchange interaction, facilitating charge transfer and oxygen species ad(de)sorption for boosted OER performance.
The detailed hydrogen bond (HB) behavior
of ethylammonium nitrate
(EAN) ionic liquid (IL)–water mixtures with different water
concentrations has been investigated at a molecular level by using
classical molecular dynamics simulations. The simulation results demonstrate
that the increasing water concentration can weaken considerably all
cation–anion, cation–water, anion–water, and
water–water HBs in EAN–water mixtures, and the corresponding
HB networks around cations, anions, and water molecules also change
significantly with the addition of water. Meanwhile, both the translational
and the rotational motions of anions, cations, and water molecules
are found to be much faster as the water concentration increases.
On the other hand, the order of their HB strength is found to be cation–anion
> anion–water > cation–water > water–water
at
low water mole fractions (<38%), while the corresponding order
is cation–anion > cation–water > anion–water
> water–water at high water mole fractions (>38%). The
opposite
orders of anion–water and cation–water HBs at low and
high water concentrations, as well as the different changes of HB
networks around cations and anions, should be responsible for the
increasing deviation in diffusion coefficient between cations and
anions with the water concentration, which is favorable to the cation–anion
dissociation. In addition, the competing effect between ionic mobility
and ionic concentration leads to that the ionic conductivity of EAN–water
mixtures initially increases with the water mole fraction and follows
a sharp decrease beyond 90%. Our simulation results provide a molecular-level
concentration-dependent HB networks and dynamics, as well as their
relationship with unique structures and dynamics in protic IL–water
mixtures.
Solar water splitting is an eco-friendly technology to produce clean energy, but the water oxidation half reaction hinders the overall water splitting due to four electron transfer processes. Z-Scheme photocatalytic...
The loading-dependent diffusion behavior of CH, CO, SO, and their binary mixtures in ZIF-10 has been investigated in detail by using classical molecular dynamics simulations. Our simulation results demonstrate that the self-diffusion coefficient D of CH molecules decreases sharply and monotonically with the loading while those of both CO and SO molecules initially display a slight increase at low uptakes and follow a slow decrease at high uptakes. Accordingly, the interaction energies between CH molecules and ZIF-10 remain nearly constant regardless of the loading due to the absence of hydrogen bonds (HBs), while the interaction energies between CO (or SO) and ZIF-10 decease rapidly with the loading, especially at small amounts of gas molecules. Such different loading-dependent diffusion and interaction mechanisms can be attributed to the relevant HB behavior between gas molecules and ZIF-10. At low loadings, both the number and strength of HBs between CO (or SO) molecules and ZIF-10 decrease obviously as the loading increases, which is responsible for the slight increase of their diffusion coefficients. However, at high loadings, their HB strength increases with the loading. Similar loading-dependent phenomena of diffusion, interaction, and HB behavior can be observed for CH CO, and SO binary mixtures in ZIF-10, only associated with some HB competition between CO and SO molecules in the case of the CO/SO mixture.
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