Effect of Co and Fe substitution on catalytic VOCs removal on zinc aluminate

Recycling of a spent alkaline battery as a catalyst for the total oxidation of hydrocarbons

A spent alkaline battery-based (SB) catalyst was prepared from the black mass of a spent alkaline battery to determine the potential of recycling spent alkaline batteries as catalysts for the total oxidation of hydrocarbons. Five different acids (H₂SO₄, HNO₃, C₂H₂O₄, HCl, and H₃PO₄) were used to examine the effect of acid treatment on catalytic activity during catalyst preparation. Hexane, benzene, toluene, and o-xylene (HBTX) were adopted as the VOCs for experiments. The properties of the prepared catalysts were studied using ICP/OES, BET, XRD, ATR/FTIR, TGA, SEM, and H₂-TPR analyses. The results showed that acid treatment significantly influenced the activity of the SB (400) catalyst, with the type of acid also found to greatly influence the activity of the catalyst. The order of activity according to the type of acid was H₂SO₄ > HNO₃ > C₂H₂O₄ > HCl > H₃PO₄ > none. Good performance of an acid-treated SB catalyst was associated with high concentrations of manganese and iron and a large BET surface area. In addition, the sequence in which the TPR peaks appeared at low temperatures according to each acid treatment was consistent with that of catalyst activity.

Catalytic oxidation of toluene, ethyl acetate and chlorobenzene over Ag/MnO2-cordierite molded catalyst

Multi-structured Ag/MnO₂-cordierite molded catalysts were prepared by hydrothermal method and applied to the catalytic oxidation of VOCs. Catalytic activities of Ag/MnO₂-cordierite were evaluated by 1000 ppm of toluene, ethyl acetate and chlorobenzene degradation respectively at the air atmosphere, and their physicochemical properties were characterized through multiple techniques containing XRD, SEM, TEM, H₂-TPR and XPS. It is found that nanorod Ag/MnO₂-cordierite molded catalyst showed prominent catalytic activity for VOCs decomposition and the T₉₀ for toluene, ethyl acetate and chlorobenzene are 275 °C, 217 °C and 385 °C respectively under the space velocity of 10,000 h⁻¹. High valence manganese oxide, more active lattice oxygen proportion and superior low-temperature reducibility were the great contributors to the high activity of the catalyst with nanorod morphology. Studies of space velocity and catalytic stability over nanorod Ag/MnO₂-cordierite molded catalyst have confirmed the good catalytic performance, excellent mechanical strength and satisfied anti-toxicity to Cl at higher space velocity, which indicates that this molded catalyst have promise for industrial application.