Ying Tian,Changqing He,Xincheng Zhang,Lin He,Zhenghe Xu,Hong Sui,Xingang Li
Separating water-in-heavy oil (W/HO) emulsions at low (room) temperature is challenging when exploiting heavy oil. We propose an adaptable strategy for constructing Si/O-doped demulsifiers. A nonionic demulsifier (APBMP) has been synthesized based on polysiloxane modified by allyl polyether and butyl acrylate. APBMP achieves 95.97% dehydration within 5 min for W/HO emulsions at 288.15 K and complete dehydration in 15 min at 323.15 K. Mechanistic studies found that doping Si/O into the demulsifier molecules increases the number of hydrogen bond sites, which enables the demulsifiers to quickly disperse natural stabilizers (e.g., asphaltenes) and replace them at the oil–water interfacial film. The demulsifiers prefer to occupy the interfacial sites rather than dissolve into the bulk oil or water phases. Driven by hydrogen-bond-dominated noncovalent interactions, the oil–water interfacial film is softened, reconstructed, and broken. These findings provide insights into developing novel materials for oil–water separations in a low-carbon way.
Carbon-driven advanced oxidations show great potential in water purification , but regulating structures and properties of carbon-based catalysts to achieve ultrafast Fenton-like reactions remains challenging. Herein, a biomorphic diatomite-based catalyst (BD-C) with Si–O doping was prepared using natural diatomite as silicon source and porous template. The results showed that the metal-free BD-C catalyst exhibited ultrafast oxidation performances (0.95–2.58 min −1 ) towards a variety of pollutants in PMS-based Fenton-like reaction, with the Fenton-like activity of metal-free catalyst comparable to metal-based catalysts or even single-atom catalysts. Pollutants (e.g., CP, BPA, TC, and PCM) with electron-donating groups exhibited extremely low PMS decomposition with overwhelmed electron transfer process (ETP), while high PMS consumption was induced by the addition of electron-withdrawing pollutants (e.g., MNZ and ATZ), which was dominated by radical oxidation. The BD-C/PMS system also showed a high ability to resist the environmental interference. In-depth theoretical investigations demonstrated that the coordination of Si–O can lower the potential barrier of PMS activation for accelerating the generation of radicals, and also promote the electron transfer from pollutants to the BD-C/PMS complexes. In addition, BD-C was deposited onto a polytetrafluoroethylene membrane (PTFEM) with 100% of pollutants removal over 10 h, thereby revealing the promising prospects of utilizing BD-C for practical applications.
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