Effects of sonication on co-precipitation synthesis and activity of copper manganese oxide catalyst to remove methane and sulphur dioxide gases

Research status of volatile organic compound (VOC) removal technology and prospect of new strategies: a review

As an important component of air pollution, the efficient removal of volatile organic compounds (VOCs) is one of the most important challenges in the world. VOCs are harmful to the environment and human health. This review systematically introduced the main VOC control technologies and research hotspots in recent years, and expanded the description of electrocatalytic oxidation technology and bimetallic catalytic removal technology. Based on a three-dimensional electrode reactor, the theoretical design of a VOC removal control technology using bimetallic three-dimensional particle electrode electrocatalytic oxidation was proposed for the first time. The future research focus of this method was analyzed, and the importance of in-depth exploration of the catalytic performance of particle electrodes and the system reaction mechanism was emphasized. This review provides a new idea for using clean and efficient methods to remove VOCs.

Ultrasound-assisted sequentially precipitated nickel-silica catalysts and its application in the partial hydrogenation of edible oil

Sequentially precipitated Mg-promoted nickel-silica catalysts with ageing performed under various ultrasonic intensities were employed to study the catalyst performance in the partial hydrogenation of sunflower oil. Results from various characterisation studies showed that increasing ultrasonic intensity caused a higher degree of hydroxycarbonate erosion and suppressed the formation of Ni silicates and silica support, which improved Ni dispersion, BET surface area and catalyst reducibility. Growth of silica clusters on the catalyst aggregates were observed in the absence of ultrasonication, which explained the higher silica and nickel silicate content on the outer surface of the catalyst particle. Application of ultrasound also altered the electron density of the Ni species, which led to higher activity and enhanced product selectivity for sonicated catalysts. The catalyst synthesised with ultrasonic intensity of 20.78 Wcm^-2 achieved 22.6% increase in hydrogenation activity, along with 28.5% decrease in trans-C18:1 yield at IV = 70, thus supporting the feasibility of such technique.

Ultrasound-assisted hydrothermal method for the preparation of the M-Fe2O3-CuO (M: Mn, Ag, Co) mixed oxides nanocatalysts for low-temperature CO oxidation

In this article, M-Fe₂O₃-CuO (M: Mn, Ag and Co) mixed oxides nanocatalysts were synthesized by a novel ultrasound-assisted hydrothermal method and the effect of irradiation power and time on the physicochemical and catalytic properties in oxidation of carbon monoxide at low temperature was investigated. The synthesized samples were studied using XRD, BET, TPR and SEM techniques. The results indicated that the incorporation of Mn into Cu-Fe catalyst had a significant influence on the catalytic properties and the catalyst promoted with 10 wt% Mn exhibited the full conversion of CO at 100 °C. This catalyst possessed a high BET area (145.1 m² g^-1) and a mesoporous texture with a relatively narrow pore size distribution with a mean crystal size of 13 nm.

Mn-CeOx/MeOx(Ti, Al)/cordierite preparation with ultrasound-assisted for non-methane hydrocarbon removal from cooking oil fumes

Cooking oil fumes (COFs) which contains a variety of volatile organic compounds (VOCs) is noxious not only to the environment but also to human health. Among COFs, the Non-methane Hydrocarbon (NMHC) removal rate is an index of the removal rate of COFs in the latest COFs purification standard (DB 11/1488-2018). Ultrasonic treatment can assist the synthesis of catalysts by creating "cavitation", which can improve the surface microtopography of catalysts. The research results in this paper revealed that the NMHC conversion of catalysts with ultrasonic treatment increased significantly. Besides, the samples that coated TiO₂ had a higher conversion of NMHC than that coated Al₂O₃ because TiO₂ has better oxidation performance than Al₂O₃. According to the XPS, SEM, EDS and BET data, because of the enhancement of interaction of the active components of catalysts caused by ultrasonic intervention, T-UU-CTAB exhibited the best catalytic performance, which attributed to the high levels of Mn⁴⁺/Mn³⁺, Ce⁴⁺/Ce³⁺ and O_ads/O_latt, more developed pore structure owing to the smaller particle size, higher dispersion of active components, larger specific surface area and larger total pore volume produced by the ultrasonic treatment. Moreover, the conversion of NMHC over T-UU-CTAB is 93.6% at 400 °C.