Daiqiang Li , Xueli Guo , Lian Wang , Hua Deng , Zhilin Zhang , Jinzhu Ma , Hong He
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引用次数: 0
Abstract
The physical and chemical properties of VOCs and zeolite materials generally affect adsorption efficacy for VOCs removal. Here, toluene and methanol were chosen as typical VOCs with different polarities and molecular diameters to investigate the performance and mechanism of their adsorption on Beta zeolites with various Si/Al ratios. It was found that high-silica Beta exhibited superior toluene adsorption capacity, while low-silica Beta showed higher methanol adsorption capacity. Compared with single-component adsorption, in the case of co-adsorption of toluene and methanol, the saturation adsorption capacities for toluene and methanol only changed slightly even with the existence of competitive adsorption and weakened adsorption strength. Importantly, there was almost no decrease in absorption capacity after 10 repeated adsorption-regeneration cycles, showing the excellent reusability of Beta zeolites for toluene and methanol removal. Whether on low-silica or high-silica Beta, physical adsorption of toluene and methanol was dominant, along with a small proportion of chemical adsorption on low-silica Beta based on acid sites. Similar size between the diameters of toluene and the pore channels of Beta zeolites was responsible for strong adsorption force, increase of adsorption capacity, and minor effect on absorption performance in the process of competitive adsorption. Strong interaction between acid sites and polar methanol through H-bond or non-polar toluene by electrostatic attraction promoted chemical adsorption. Furthermore, toluene and methanol both tended to absorb in the twelve-membered-ring of Beta zeolites on Si-OH-Al, Al-OH, and Si-OH sites. This study provides insight into the factors influencing the adsorption performance and mechanism of toluene and methanol on zeolites, which gives potential guidance for the selection of adsorbents for high-efficiency VOCs removal.
期刊介绍:
Microporous and Mesoporous Materials covers novel and significant aspects of porous solids classified as either microporous (pore size up to 2 nm) or mesoporous (pore size 2 to 50 nm). The porosity should have a specific impact on the material properties or application. Typical examples are zeolites and zeolite-like materials, pillared materials, clathrasils and clathrates, carbon molecular sieves, ordered mesoporous materials, organic/inorganic porous hybrid materials, or porous metal oxides. Both natural and synthetic porous materials are within the scope of the journal.
Topics which are particularly of interest include:
All aspects of natural microporous and mesoporous solids
The synthesis of crystalline or amorphous porous materials
The physico-chemical characterization of microporous and mesoporous solids, especially spectroscopic and microscopic
The modification of microporous and mesoporous solids, for example by ion exchange or solid-state reactions
All topics related to diffusion of mobile species in the pores of microporous and mesoporous materials
Adsorption (and other separation techniques) using microporous or mesoporous adsorbents
Catalysis by microporous and mesoporous materials
Host/guest interactions
Theoretical chemistry and modelling of host/guest interactions
All topics related to the application of microporous and mesoporous materials in industrial catalysis, separation technology, environmental protection, electrochemistry, membranes, sensors, optical devices, etc.