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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.
Bisphenol F (BPF) has been frequently detected in various environmental compartments, and previous studies found that BPF exhibits similar estrogenic and anti-androgenic effects on the mammalian ...endocrine system to those of bisphenol A (BPA). However, the potential disrupting effects of BPF on aquatic organisms and the underling disrupting mechanisms have not been investigated. In this study, the potential disrupting mechanisms of BPF on the hypothalamic–pituitary–gonadal (HPG) axis and liver were probed by employing the OECD 21-day short-term fecundity assay in zebrafish. The results show that BPF exposure (1 mg/L) impaired the reproductive function of zebrafish, as exemplified by alterations to testicular and ovarian histology of the treated zebrafish. Homogenate testosterone (T) levels in male zebrafish decreased in a concentration-dependent manner, and 17β-estradiol (E2) levels increased significantly when fish were exposed to 0.1 and 1 mg/L BPF. The real-time polymerase chain reaction was performed to examine gene expression in the HPG axis and liver. Hepatic vitellogenin expression was significantly upregulated in males, suggesting that BPF possesses estrogenic activity. The disturbed hormone balance was enhanced by the significant changes in gene expression along the HPG axis. These alterations suggest that BPF leads to adverse effects on the endocrine system of teleost fish, and that these effects were more prominent in males than in females.
In this study, the manganese cobalt composite (Mn-Co)-loaded SiO
2
, MgO, TiO
2
, γ-Al
2
O
3
and silicalite-1 were prepared by ultrasonic complexation method. The catalysts were characterized by XRD, ...BET, SEM, TEM, H
2
-TPR and XPS, and the activity of catalytic oxidation of toluene was evaluated. It was found that Mn-Co loaded γ-Al
2
O
3
(Mn
2
CoO
x
/γ-Al
2
O
3
) exhibited excellent catalytic activity. When the gas hour space velocity (GHSV) was 45,000 h
−1
, the removal rate of toluene reached 91.2% within 5.5 h, and the selectivity of CO
2
was 71.10% at ambient temperature. The operation of Mn
2
CoO
x
/γ-Al
2
O
3
at different temperatures was investigated, and the better toluene removal efficiency more than 80% after reacting 9h was obtained at 50 °C. The characterization results showed that better catalytic activity is related to smaller grain size, higher Mn
3+
/Mn
4+
values and the relative content of active oxygen species (O
II
+ O
III
). Increased amounts of low state species easily led to the imbalance of the catalyst surface charge and promoted the formation of more oxygen vacancies.
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.
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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.
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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%.
N, N-Dimethylformamide (DMF) is a widely used organic solvent whose wastewater is difficult to biodegrade directly. In this paper, a novel chemical/biological combined technique consisting of ...alkaline hydrolysis stripping, activated sludge and a bio-trickling filter (BTF) was developed for DMF wastewater treatment. The main pollutant, DMF, was decomposed to dimethylamine and formate under alkaline conditions, and the dimethylamine was stripped out by the BTF. The pretreated wastewater was then degraded in an activated sludge process. The operation performances of alkaline hydrolysis, activated sludge and BTF processes were investigated separately. At the optimal conditions of an alkali dosage of 40 g/L, an air/liquid ratio of 3000:1 and 5 h in the air-stripping process, the removal of total organic carbon and DMF was found to be 58% and 96%, respectively. A chemical oxygen demand removal efficiency of 80–90% was obtained in the activated sludge process. The performance of BTF was excellent with a dimethylamine removal efficiency close to 90% even at a high loading of 16 g/d.
