Catalytic activity and mechanism of fluorinated MgO film supported on 3D nickel mesh for ozonation of gaseous toluene

2020 ◽  
Vol 7 (9) ◽  
pp. 2723-2734
Author(s):  
Jinzhu Zhu ◽  
Jingxiang Sun ◽  
Shuanghong Tian ◽  
Juan Yang ◽  
Jinxi Feng ◽  
...  

The fluorination of a MgO catalyst could suppress acid-caused catalytic deactivation and promote toluene degradation efficiency during catalytic ozonation.

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 934
Author(s):  
Yong Cheng ◽  
Xiuxiu Wang ◽  
Yu Mei ◽  
Dan Wang ◽  
Changchun Ji

Considering the photocatalytic performance of CDs, ZnO, and the unique porous nanostructure and stability of ZIF-8, we prepared ZnCDs/ZnO@ZIF-8 zeolite composites. The resultant material represented an enhanced ability for the photodegradation of TC compared with that of ZnCDs and ZnO. The photocatalytic degradation efficiency reached over 85%. The catalytic activity of the composites was maintained after four cycles. The experimental result indicated that ×O2 radical was the active species in the reaction.


2021 ◽  
Vol 288 ◽  
pp. 120004
Author(s):  
Junxian Gao ◽  
Lingling Tang ◽  
Zhizhang Shen ◽  
Yuming Dong ◽  
Zhenyu Wang ◽  
...  

2014 ◽  
Vol 955-959 ◽  
pp. 2162-2168 ◽  
Author(s):  
Yue Liu ◽  
Lei Liu ◽  
Wei Jin Gong

Iron silicate, a stable and efficient catalyst prepared in the laboratory has been successfully used as a catalyst combined with ozonation in the degradation of p-Chloronitrobenzene (pCNB). The catalytic ozonation removal effectiveness of pCNB was investigated under various physicochemical conditions. Both the adsorption and the single ozonation were not effective for the degradation of pCNB, but the presence of iron silicate in ozonation process could substantially enhance the pCNB removal efficiency. The hydroxyl radical scavenger experiment confirmed that iron silicate catalytic ozonation followed a radical-type mechanism. The increasing of both the iron silicate dosage and the ozone dosage could enhance the removal effectiveness of pCNB. The iron silicate catalyst could be recycled easily without decreasing any ozone catalytic activity after four successive reuses. It is concluded that the iron silicate was an efficient green catalyst for pCNB degradation in drinking water.


2015 ◽  
Vol 5 (2) ◽  
pp. 1143-1152 ◽  
Author(s):  
L. Ciccotti ◽  
L. A. S. do Vale ◽  
T. L. R. Hewer ◽  
R. S. Freire

Systematic evaluation of experimental variables in magnetic nanoparticle preparation and hybrid catalyst application in the heterogeneous catalytic ozonation process.


Author(s):  
S. Psaltou ◽  
E. Kaprara ◽  
M. Mitrakas ◽  
A. Zouboulis

Abstract Catalytic ozonation was applied for the removal of small concentrations (4 μM) of micropollutants benzotriazole, carbamazepine, p-CBA from aqueous solutions at pH 7. These compounds present different physicochemical characteristics and different kinetic rate constants, when reacting with ozone or hydroxyl radicals in range of <0.15–3 × 105, 5.2 × 109, and 8.8 × 109 M−1s−1, respectively. Calcite was used as heterogeneous catalyst and its catalytic activity evaluated, by applying (and optimized) different experimental conditions (i.e., pH, temperature, ozone concentration), concerning the removal efficiency of p-CBA. Study of micropollutants' removal showed all examined organic compounds can be sufficiently removed by application of catalytic ozonation either by use of calcite, or by presence of Co(II) or Fe(II) (applied as homogeneous catalysts), while the optimum catalyst between them was found to be calcite. Carbamazepine with kO3 = 3 × 105 M−1s−1 can be easily removed, even by application of single ozonation, while benzotriazole and p-CBA resulted in 50% and 68.2% higher removal after application of catalytic ozonation within 3 min of oxidation reaction, due to acceleration of hydroxyl radicals' production by presence of calcite in the ozonation system. The contribution of hydroxyl radicals in removal of all three micropollutants was evaluated by extraction of Rct and f•OH parameters.


2021 ◽  
Vol 21 (3) ◽  
pp. 1517-1525
Author(s):  
Yongping Cui ◽  
Yaru Shang ◽  
Xiaohu Cheng ◽  
Ruixia Shi ◽  
Ping Yang

One dimensional Zn doped CuFe2O4 spinel ferrite nanofibers were successfully prepared via a facile electrospinning method followed by two different calcination routes. The results showed that the as-prepared nanofibers through two-step calcination exhibited more uniform size distribution in diameter compared with those calcined by one-step method. X-ray diffraction (XRD) results indicated that with the increase of Zn content the position of diffraction peaks of Zn doped CuFe2O4 slightly shift towards lower 2θ angle because the ionic sizes of the Zn2+ (0.74 Å) is larger than that of Cu2+ (0.69 Å). Fourier transform infrared spectroscopy (FTIR) results showed that with increasing Zn content the position of vibrational band (590 cm−1) shifted towards the smaller wavenumber. Generally, photo-generated carriers increased with the increasing of Zn content. The photo Fenton-like catalytic results revealed that the doping of Zn facilitated the enhancement of degradation efficiency of catalysts. Additionally, 10 at.% Zn doped CuFe2O4 exhibited the best photo Fenton-like catalytic activity and the degradation efficiency of Rhodamine B (RhB) could reach 100% in 40 min. Finally, the enhancement of photo Fenton-like catalytic mechanism of the Zn doped CuFe2O4 nanofibers was mainly attributed to actived spinel structure lattice by Zn doping, which allows more Cu2+ and Fe3+ ions are involved in the photo Fenton-like catalytic reaction.


2012 ◽  
Vol 66 (3) ◽  
pp. 479-486 ◽  
Author(s):  
Miaomiao Ye ◽  
Zhonglin Chen ◽  
Tuqiao Zhang ◽  
Weiyun Shao

Nanosized titanium dioxides were synthesized by hydrolysis of TiCl4 followed by calcination at different temperatures ranging from 300 to 1,000 °C. The as-prepared samples were characterized by X-ray diffraction, N2 adsorption–desorption, and zeta potential analysis. The catalytic activities of the TiO2 nanoparticles were tested by catalytic ozonation of trace 4-chloronitrobenzene (4-CNB) in water. Moreover, the catalytic ozonation activity of a sample calcined at 400 °C (denoted as T400) was tested in aqueous solution using electron paramagnetic resonance (EPR) spin trapping technique with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) spin trap. It was found that with increasing calcination temperatures, the average crystallite size and average pore size increased, in contrast the BET surface areas decreased. However, the isoelectric point (IEP) first increased, and then decreased. The ozone adsorption on the catalyst surface played an important role in determining their catalytic activity. Sample T400 with the IEP of 7.0, farthest away from the 4-CNB solution pH value (pH = 5.3), showed the best catalytic activity. The EPR experiments further confirmed that the hydroxyl radicals TiO2-catalyzed ozonation followed a radical-type mechanism.


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