Hailu Fu,Jilei Lin,Shuang Cao,Bosheng Chen,Renhua Huang,Hao Chen,Tao Ding,Pengfei Sun,Ligang Luo
A series of cobalt-based catalysts (Co 3 O 4 , Mn/Co 3 O 4 , K-Co 3 O 4, and K-Mn/Co 3 O 4 ) were prepared for toluene catalytic combustion and anti-K poisoning experiments. Co 3 O 4 catalyst has exhibited good performance in toluene oxidation , but it has poor anti-K poisoning performance. The Mn/Co 3 O 4 catalyst has shown excellent low-temperature catalytic activity , good resistance to K poisoning at T 90 of 226 °C, and achieved a complete toluene conversion at about 235 °C; the activity after the addition of K slightly reduced at T 90 of 237 °C. A series of characterizations indicated that adding Mn can effectively promote the Co 2+ ↔Co 3+ cycle, increase the Co 3+ content on the catalyst surface, and enhance the redox performance of the catalyst. On the other hand, MnO x intercepts K species and generates Mn-O-K, blocking most of the poisonous effects of K on cobalt oxide , thereby protecting the active species (Co 3+ and surface-adsorbed oxygen) and acidic sites on the Co 3 O 4 surface. Finally, GC-MS and in-situ infrared characterization were adopted to investigate the reaction mechanism of the catalysts. Two reaction paths of the Co 3 O 4 catalyst may co-occur. Still, the reaction path of the Mn/Co 3 O 4 catalyst is relatively simple; that is, the chemically adsorbed toluene molecules are oxidized through surface-active oxygen, after which various intermediate by-products are formed successively. Finally, they are completely degraded into CO 2 .
Yu Xin Zhang,Xiao Dong Hao,Tian Wang,Yu Xin Meng,Xu Han
MnOx modified ZnAl layered double oxides (M-LDO) nanocomposites were prepared through an intercalation/reduction/calcination process. The morphology and crystal structure of M-LDO were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR) analysis methods. The results confirmed that the manganese oxide nanoparticles were well distributed on the LDO support. Methyl orange (MO) was chosen as a common water-soluble azo dye probe to evaluate the adsorption performance of M-LDO. The effects of MO initial concentration, agitation time, and temperature on MO adsorption were investigated. It was found that adsorption equilibrium data were best represented by the Langmuir and Redlich–Peterson isotherms and the maximum adsorption capacity was 617.28 mg g−1 obtained from the Langmuir isotherm, which was much larger than some reported adsorbents. Besides, the adsorption process was spontaneous and endothermic in nature and followed a pseudo-second-order kinetic model. The mechanism of the adsorption process was elaborated by an intraparticle diffusion model. Moreover, the regeneration test of M-LDO was carried out and it showed that the used M-LDO was feasible for at least five times. In principle, this adsorbent with a high adsorption capacity and great reutilization performance could be a very promising adsorbent for wastewater treatment.
危险品化学品经营许可证（带存储）