Sites For Peroxymonosulfate Activation Research Articles

A comparison study of photocatalytic performance of g-C3N4 prepared from different precursors for the activation of different peroxides

In this study, g-C3N4 catalysts were prepared from six different precursors including urea, melamine and its hydrochloride, dicyandiamide, thiourea, trithiocyanuric acid to compare their photocatalytic performance and the activation of three commonly seen peroxides, i.e., H2O2, peroxymonosulfate (PMS), and peroxydisulfate (PDS) under visible light irradiation. The structural and photoelectric properties were analyzed systematically. Results showed that the g-C3N4 synthesized from trithiocyanuric acid (TCA-CN) showed the largest SSA (56.59 m2/g), the narrowest band gap (2.621 eV), and lowest carriers’ recombination rate, which correspondingly exhibited the best photocatalytic performance for the degradation of bisphenol A (BPA). Moreover, the g-C3N4 synthesized by urea (U-CN) demonstrating the strongest photoelectron density, widest band gap (2.790 eV) and the most positive VB potential showed the highest activating efficiencies of all three oxidants. In general, persulfates were more competent to enhance the degradation of BPA than H2O2, and PMS showed the highest activity. The dominant reactive oxidation species (ROS) depended more on the type of peroxides than on the catalyst precursors. The effective activation of PDS by U-CN was primarily resulting from the photoelectrons to produce extra •OH to enhance compounds degradation, and high yield of 1O2 could be achieved by PMS activation through h+ oxidation, leading to the most significant enhancement of BPA removal. The N–C3 and NHx of U-CN were likely the sites for PMS activation. Moreover, the U-CN/LED/PMS process showed the strong adaptability to the complex water environment. This work may provide new insights into selecting highly efficient g-C3N4-based advanced oxidation processes for water remediation.

Enhanced Interfacial Electron Transfer by Asymmetric Cu-Ov -In Sites on In2 O3 for Efficient Peroxymonosulfate Activation.

Enhancing the peroxymonosulfate (PMS) activation efficiency to generate more radicals is vital to promote the Fenton-like reaction activity, however, how to promote the PMS adsorption and accelerate the interfacial electron transfer to boost its activation kinetics remains a great challenge. Herein, we prepared Cu-doped defect-rich In2 O3 (Cu-In2 O3 /Ov ) catalysts containing asymmetric Cu-Ov -In sites for PMS activation in water purification. The intrinsic catalytic activity is that the side-on adsorption configuration of the O-O bond (Cu-O-O-In) at the Cu-Ov -In sites significantly stretches the O-O bond length. Meanwhile, the Cu-Ov -In sites increase the electron density near the Fermi energy level, promoting more and faster electron transfer to the O-O bond for generating more SO4 ⋅- and ⋅OH. The degradation rate constant of tetracycline achieved by Cu-In2 O3 /Ov is 31.8 times faster than In2 O3 /Ov , and it shows the possibility of membrane reactor for practical wastewater treatment.

Enhanced Interfacial Electron Transfer by Asymmetric Cu‐Ov‐In Sites on In2O3 for Efficient Peroxymonosulfate Activation

AbstractEnhancing the peroxymonosulfate (PMS) activation efficiency to generate more radicals is vital to promote the Fenton‐like reaction activity, however, how to promote the PMS adsorption and accelerate the interfacial electron transfer to boost its activation kinetics remains a great challenge. Herein, we prepared Cu‐doped defect‐rich In2O3 (Cu‐In2O3/Ov) catalysts containing asymmetric Cu−Ov−In sites for PMS activation in water purification. The intrinsic catalytic activity is that the side‐on adsorption configuration of the O−O bond (Cu−O−O−In) at the Cu‐Ov‐In sites significantly stretches the O−O bond length. Meanwhile, the Cu‐Ov‐In sites increase the electron density near the Fermi energy level, promoting more and faster electron transfer to the O−O bond for generating more SO4⋅− and ⋅OH. The degradation rate constant of tetracycline achieved by Cu‐In2O3/Ov is 31.8 times faster than In2O3/Ov, and it shows the possibility of membrane reactor for practical wastewater treatment.

Covalent organic frameworks derived carbon supported cobalt ultra-small particles: C[dbnd]O and Co-Nx complex sites activated peroxymonosulfate synergistically for efficient degradation of levofloxacin

Recently, the carbon materials with metal-Nx sites or carbonyl (CO) have attracted extensive attention in the degradation of organic pollutants for peroxymonosulfate (PMS) activation. However, the synergistic mechanism of different sites for PMS activation is not clear. In this study, covalent organic frameworks (COF) derived carbon materials (Co–C500COF) with abundant CO and ultra-small Co particles were synthesized by simple hydrothermal and calcination. Theoretical and experimental results revealed that the introduction of cobalt species formed the Co-Nx site, which was beneficial to the release of CO which originally blocked by N group in COF. The results indicated that Co–C500COF showed excellent catalytic activity, which resulted in 94.3% of levofloxacin (LVX) removal within 2h for PMS activation, and good stability, 80% degradation efficiency after five cycles. The Co–C500COF/PMS system also maintained the incredible degradation effects in a wide pH range (3–9) and complex water environment with ion interference, which made it more potential for industrial application. The mechanism exploration revealed that CO and cobalt and nitrogen coordination (Co-Nx) sites were related to the production of singlet oxygen (1O2) in the main active reactive species. The degradation intermediates and toxicity of LVX were also evaluated, possible degradation pathways were proposed, and most intermediates were more environmentally friendly than LVX. Our catalyst is an ideal catalyst for the removal of organic pollutants from actual wastewater.