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Carbon nitride compounds (CN) complexed with the in-situ-produced Cu(II) on the surface of CuAlO2 substrate (CN-Cu(II)-CuAlO2) is prepared via a surface growth process for the first time and exhibits exceptionally high activity and efficiency for the degradation of the refractory pollutants in water through a Fenton-like process in a wide pH range. The reaction rate for bisphenol A removal is ∼25 times higher than that of the CuAlO2. According to the characterization, Cu(II) generation on the surface of CuAlO2 during the surface growth process results in the marked decrease of the surface oxygen vacancies and the formation of the C–O–Cu bridges between CN and Cu(II)-CuAlO2 in the catalyst. The electron paramagnetic resonance (EPR) analysis and density functional theory (DFT) calculations demonstrate that the dual reaction centers are produced around the Cu and C sites due to the cation−π interactions through the C–O–Cu bridges in CN-Cu(II)-CuAlO2. During the Fenton-like reactions, the electron-rich center...

Efficient cycling of Fe3+/Fe2+ is a key step for the Fenton reaction. In this exploration, from microalgae, we have prepared a novel Fe-N-graphene wrapped Al2O3/pentlandite composite which showed high Fenton catalytic ability through accelerating of Fe3+ reduction. The catalyst exhibits high activity, good reusability along with stability, and wide adaptation for the organics degradation under neutral pH. High TON and H2O2 utilization efficiency have also reached by this catalyst. Characterization results disclose a unique structure that the layered Fe-N-graphene structure tightly covers on Al2O3/pentlandite particles. Mechanistic evidence suggests that the accelerated Fe3+/Fe2+ redox cycle originates from the enhanced electron transfer by the synergistic effect of Fe, Ni and Al in the catalyst, and it causes the low H2O2 consumption and high •OH generation rate. Moreover, organic radicals formed in the Fenton process also participate in the Fe3+ reduction, and this process may be accelerated by the N dop...

Mesoporous Cu-doped γ-Al2O3 (γ-Cu–Al2O3) was prepared via an evaporation-induced self-assembly process, in which Cu+/2+ was co-incorporated into mesoporous γ-Al2O3 by chemical bonding of Al–O–Cu. The catalyst was found to be highly effective and stable for the degradation and mineralization of aromatic pollutants, as demonstrated with bisphenol A, 2,4-dichlorophenoxyacetic acid, ibuprofen, diphenhydramine, and phenytoin in the presence of H2O2 under neutral pH conditions. In addition, the high utilization efficiency of H2O2 was maintained at approximately 90% prior to the disappearance of the initial aromatic pollutants. On the basis of all of the characterization results, the pollutant degradation processes predominantly occurred on the surface of the catalyst due to the formation of σ-Cu–ligand complexes between the phenolic OH group and the surface Cu. In the reaction system, in addition to the unselective oxidation by •OH, H2O2 directly attacked the σ-Cu2+-complexes aromatic ring with the phenolic OH ...

Fe2O3 and/or Al2O3 were supported on mesoporous SBA-15 by wet impregnation and calcinations with AlC(l)3 and FeCl3 as the metal precursor and were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectra (FTIR) of adsorbed pyridine. Fe2O3/Al2O3@SBA-15 was found to be highly effective for the mineralization of ibuprofen aqueous solution with ozone. The characterization studies showed that Al-O-Si was formed by the substitution of Al3+ for the hydrogen of surface Si-OH groups, not only resulting in high dispersion of Al2O3 and Fe2O3 on SBA-15, but also inducing the greatest amount of surface Lewis acid sites. By studies of in situ attenuated total reflection FTIR (ATR-FTIR), in situ Raman, and electron spin resonance (ESR) spectra, the chemisorbed ozone was decomposed into surface atomic oxygen species at the Lewis acid sites of Al3+ while it was converted into surface adsorbed (OHads)-O-center dot and O-2(-) radicals at the Lewis acid sites of Fe3+. The combination of both Lewis acid sites of iron and aluminum onto Fe2O3/Al2O3@SBA-15 enhanced the formation of (OHads)-O-center dot and O-2(-) radicals, leading to highest reactivity. Mechanisms of catalytic ozonation were proposed for the tested catalysts on the basis of all the experimental information.

Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr-Ag-Bi(2)WO(6) nanojunction system as a catalyst under visible light (lambda >or= 400 nm) irradiation. The visible-light-driven (VLD) AgBr-Ag-Bi(2)WO(6) nanojunction could completely inactivate 5 x 10(7) cfu mL(-1) E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi(2)WO(6) superstructure, Ag-Bi(2)WO(6) and AgBr-Ag-TiO(2) composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr-Ag-Bi(2)WO(6) nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr-Ag-Bi(2)WO(6) nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K(+)) leakage from the killed bacteria. This work provides a potential effective VLD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection.

The photodegradation of the widely used amine drugs including primary amine (mexiletine), secondary amine (propranolol, phenytoin), and tertiary amine (diphenhydramine, antipyrine) were investigated in the presence of nitrate and humic substances under simulated sunlight. All of the amine drugs were photodegraded by nitrate due to the attack of hydroxyl radicals (*OH). The bimolecular rate constants for the reaction between each amine drug and *OH ranged from (2.1 +/- 0.2) x 10(9) to (8.7 +/- 0.3) x 10(9) M(-1) s(-1). In contrast, only mexiletine, propranolol, and diphenhydramine were selectively photodegraded in the presence of humic substances (HS). Fulvic acid was a more efficient sensitizer than humic acid throughout. The HS triplet states were verified to be main reactive species in the photochemical reaction. Furthermore, an electron transfer mechanism for the reaction with the HS triplet states was proposed on the basis of all information obtained under a series of experiments. The electron transfer from the nonbonding electrons on nitrogen (N-electrons) of the amine drugs to the excited ketone of the HS occurred. The availability of N-electrons and presence of hydrogen on carbon alpha of amine (alpha-hydrogen) were two key factors for the electron-transfer interaction. Moreover, the photoproducts were identified by GC-MS and the degradation pathways were proposed. The results strongly suggest the impact of humic substances on the photochemical fate of amine drugs in the natural waters.

Manganese oxide was supported on mesoporous zirconia (MnO(x)/ MZIW) by wet impregnation, drying, water washing, and calcinations with manganese acetate tetrahydrate as the metal precursor for the first time and was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectra (FTIR), temperature-programmed reduction (TPR), temperature-programmed oxygen desorption (O2-TPD), and UV-vis diffuse reflectance spectra (UV-vis DRS) measurements. The catalyst was found to be highly effective for the mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) aqueous solution with ozone. The characterization studies showed that nonstoichiometrically MnO(x) was highly dispersed on mesoporous zirconia by the strong interaction of the [Mn(H2O)6]2+ complex with surface hydroxyls of the support. Moreover, the multivalence oxidation states of MnO(x) enhanced the electron transfer, causing the higher catalytic reactivity. On the basis of all information obtained under different experimental conditions, MnO(x)/MZIW enhanced the mineralization of 2,4-D by the formation of *OH radicals resulting from the catalytic decomposition of ozone.

Triazine-containing azo dyes, anionic reactive brilliant red K-2G, reactive brilliant Red X-3B, and reactive yellow KD-3G were degraded in the electrooxidation, photocatalysis and combined electrooxidation and phtocatalysis process at the gamma-Bi2MoO6 film electrode under visible light irradiation. Furthermore, in the combined process, synergetic degradation of the dyes was observed by the analysis of degradation kinetics and total organic carbon variation. The synergetic mechanism was studied using X-ray photoelectron spectra and electrochemical impedance spectra as well as analysis of variation of current vs time in various processes. It is suggested that application of bias potential with a lower value than the redox potential of the targeted dyes efficiently increases the photocatalysis rate of the dyes by prohibiting recombination of electrons and holes. At the bias greater than the redox potential of the dyes, the degradation of the dyes was efficiently improved bythe combined electrooxidation and photocatalysis process. The main active oxygen species involved in the dyes degradation was hydroxyl radicals as confirmed via DMPO spin-trapping electron spin resonance measurements and the effect of radical scavengers. Intermediates mainly including organic aromatic and aliphatic carboxylic acids were detected.

In this present study, nanoporous silica SBA-15 supported palladium catalysts are prepared through two different methods. The catalysts are employed for catalytic deep oxidation reaction of benzene at a high gas hourly space velocity of 100,000 h(-1). It is found that the traditional aqueous impregnation method has some difficulties and disadvantages in obtaining highly dispersed palladium active phases. Whereas, when a grafting procedure is employed, palladium tends to be highly dispersed as nanoparticles due to the confinement of the nanosized pore channels of the support materials. The catalysts prepared via the grafting procedure catalyze the benzene oxidation far more effectively than those prepared via aqueous impregnation method, and complete conversion of benzene can be achieved below 190 degrees C over the most active catalyst. The nanoporous silica-supported palladium catalysts are promising materials for the control of some types of VOCs such as benzene.