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•Anaerobic co-metabolism of TBBPA was studied in a bioelectrochemical system.•Two different biodegradation pathways were suggested.•Microbial diversity analysis of biofilm was carried ...out.•Azoarcus was speculated as the major microorganism for the biodegradation of TBBPA.
Tetrabromobisphenol A(TBBPA), a pollutant in industrial wastewaters, needs to be removed due to its high toxicity and persistence. The main biodegradation pathway for TBBPA has been studied, and bisphenol A(BPA), which is toxic to the environment, is recognized as the general terminal product. In this study, we explored a new approach for the anaerobic biodegradation of TBBPA in a bioelectrochemical system (BES) through co-metabolic degradation of TBBPA with glucose. The half-life of TBBPA was significantly reduced to 13.5h−1 at 25μg/l of TBBPA. With an increase in the concentration of TBBPA, the removal rates of TBBPA rose to more than eighty percent. Based on the analysis of the products, we found that the degradation products of TBBPA were 2,6-dibromo-4-(1-methyl-1-phenylethyl) phenol, (double-benzenes product) and 2,6-dibromo-4-(prop-1-en-2-yl) phenol (single-benzene product), rather than BPA. Simultaneously, we proposed two degradation pathways for TBBPA in a BES system. According to the microbial diversity analysis of the anode biofilm, we speculated that the microorganism responsible for the biodegradation of TBBPA was Azoarcus. Additionally, we briefly analyzed the effect of TBBPA on the performance of BES system to pave the way for the further analysis of the interaction between the TBBPA and the BES system.
Zr-doped-TiO2 loaded glass fiber（ZT/GF） composite photocatalysts with different Zr/Ti ratios were prepared with a sol–gel process. Zr4＋can replace Ti4＋in the TiO2 lattice, which is conducive to ...forming the anatase phase and reducing the calcination temperature. The glass fiber carrier was responsible for better dispersion and loading of Zr-doped-TiO2 particles, improving the applicability of the Zr-doped-TiO2. The ZT/GF photocatalysts were characterized by X-ray diffraction（XRD）, scanning electron microscope（SEM）, Fourier transform infrared spectroscopy（FT-IR）, ultraviolet–visible spectroscopy（UV–vis） and Barrett–Joyner–Halenda（BJH）. The performance of photocatalysts with different loading was evaluated in formaldehyde degradation under visible light at room temperature. ZT/GF0.2exhibited the highest activity, with a formaldehyde removal rate as high as 95.14% being observed, which is better than that of the photocatalyst particles alone. The stability of the catalyst was also tested, and ZT/GF exhibited excellent catalytic performance with 94.38%removal efficiency, even after seven uses.
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•The cobalt doped Mn-Ce solid solution catalyst possessed the excellent low-temperature oxidation activity on benzene catalytic oxidation.•The incorporation of Co resulted in a change ...of Mn and Ce charge on the catalyst surface compared to the Mn-Ce-O solid solution.•The Co-doped Mn-Ce-O solid solution catalysts presented the excellent water-resistant, stability and CO2 selectivity.•The doping of Co into the lattice of a Mn-Ce-O solid solution lowers the energy of oxygen vacancy and promotes the formation of more oxygen vacancies.
In this paper, CoxMn1−xCeOδ mixed oxides were synthesized using a co-precipitation method. The catalyst’s performance for the benzene combustion reaction was evaluated, and Co0.25Mn0.75CeOδ (CMC-0.25) exhibited good catalytic activity, stability and CO2 selectivity. The prepared catalysts were characterized and analyzed completely by XRD, BET, Raman, TEM and HRTEM, XPS, H2-TPR, and O2-TPD. The results demonstrated that a solid solution was formed with more active oxygen induced by Co doping. Strong interaction effects among Co-Mn-Ce-O were speculated as the main mechanisms underlying the high-efficiency catalytic capacity. The prepared Co-doped Mn-Ce mixed oxides catalyst may be a potential low-cost catalyst alternative to replace industrial noble metal catalysts.
A series of CeO2/Al2O3 catalysts was modified with praseodymium oxide using an extrusion method. The cata- lytic activities of the obtained catalysts were measured for the selective catalytic ...reduction of NO with NH3 to screen suitable addition of praseodymium oxide. These samples were characterized by XRD, N2-BET, NH3-TPD, NO-TPD, Py-IR, H2-TPR, Raman spectra and XPS, respectively. Results showed the optimal catalyst with the Pr/Ce molar ratio of 0.10 exhibited more than 90% NO conversion in a wide temperature range of 290-425℃ under GHSV of 5000 h i. The number of Lewis acid sites and the chemisorbed oxygen concentration of the catalysts would increase with the Pr incorporation, which was favorable for the excellent catalytic performance. In addition, the Pr incorporation inhibited growth of the Al2O3 crystal particles and led to the lattice expansion of CeO2, which increased catalytic activity. The results implied that the higher chemisorbed oxygen concentrations and the more Lewis acid sites were conductive to obtain the excellent SCR activity.
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► Photocatalytic oxidation of gaseous HCHO by ZrxTi1−xO2 samples under visible-light irradiation was discussed. ► With increasing the hydroxyl groups, the activity of samples of ...ZrxTi1−xO2 was increased. ► The result shows that L–H model is valid at the beginning of catalytic oxidation. ► The photocatalytic activitie of Zr0.08Ti0.92O2 samples was affected by the humidity of air.
TiO2, a widely used, inexpensive white powder, has been considered the most promising photocatalyst for the degradation of formaldehyde in air. However, the application of TiO2 without other metal and nonmetal doping is limited because it requires UV activation with a high-energy band gap, and <5% of the solar radiation reaching the earth's surface can be used. To improve the photocatalytic performance of TiO2, sol–gel nano TiO2 with Zr doping can be activated by the UV–vis radiation available in sunlight to perform solar photocatalysis. The properties of the ZrxTi1−xO2 catalysts were fully characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), UV–vis diffuse reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). Our results demonstrate that the optical response of TiO2 was shifted from UV to the visible light region with the introduction of zirconium. The photocatalytic tests indicated that the ZrxTi1−xO2 catalyst demonstrated higher activity for the degradation of formaldehyde compared with P25 and TiO2 under UV–vis light irradiation with an energy-saving lamp.
A series of praseodymium added CeO2(ZrO2)/TiO2 catalysts separately prepared by methods of sol-gel and impregnation were tested for selective catalytic reduction of NO, and characterized by X-ray ...diffraction (XRD), N2-brumauer-emmett-teller (N2-BET), NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), PL spectra, Raman spectra, electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS), respectively. Influence of preparation method on catalytic performance was studied. Results showed that the influence of Pr addition on catalytic performance of the CeO2(ZrO2)/TiO2 catalysts was different between the sol-gel method and the impregnation method. The Pr addition tended to interact with TiO2 and formed the structure of Ti-O-Pr in the sol-gel method while it was more likely to interact with CeO2 forming the structure of Ce-O-Pr in the impregnation method. The total acid amount and redox properties of the catalysts prepared by sol-gel method decreased with the addition of Pr element, which resulted in decrease of catalytic activity. In contrast, the Pr-added catalyst prepared by impregnation method was found to possess easier reducibility, more total acid amount and higher proportion of Ce3+ species, which was favourable for higher catalytic activity.
Pr addition increased the concentrations of Ce3+ and Ti3+, which improved the catalytic activity of CeO2(ZrO2)/TiO2 for selective catalytic reduction of NO by NH3
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•Removal characteristics of nitrogen oxide and particulates had been studied.•The NO removal efficiency of catalytic filter reached 95.3% at 200°C.•The dust removal efficiency of ...catalytic filter reached 99.98%.•The PTFE coating could fix catalyst firmly and improve dust removal efficiency.
A novel Mn-Ce-Nb-Ox/P84 catalytic filter for synergetic removal of particulates and NO was designed and prepared by a new method using functional foaming coating. Removal characteristics of nitrogen oxides (including catalyst loading amount, O2 concentration, NH3/NO molar ratio, H2O and SO2) and particulates, were systematically studied. Results showed that the NO removal efficiency of catalytic filter reached 95.3% at 200°C, as the catalyst loading amount, filtration velocity and mole ratio of NH3/NO were set to be 450g/m2, 1m/min and 1, respectively. The removal characteristic of particulates of Mn-Ce-Nb-Ox/P84 catalytic filter belonged surface filtration and the PM2.5 removal efficiency reached 99.98%.
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Series of CeSn0.8W0.6Ox/TiO2 catalysts were tested for selective catalytic reduction of NO and for synergistic catalytic removals of CO and C3H8 from diesel engine exhaust. Results ...revealed that catalyst 12%-CeSn0.8W0.6Ox/TiO2 calcined at 500°C exhibited the optimal catalytic performance for NH3-SCR of NO. The catalyst obtained more than 90% NO conversion at a wide temperature range of 252–456°C. Both CO and C3H8 could be oxidized into CO2 by the optimized catalyst. Moreover, excellent redox property, rich surface acidity and big specific surface area were the promotional factors for good catalytic performance in catalytic removals of NO, CO and C3H8.
