Adsorption Mechanism and Regeneration Performance of Calcined Zeolites for Hydrogen Sulfide and Its Application

Abstract

Hydrogen sulfide (H2S) is a very toxic, acidic, and odorous gas. In this study, a calcined zeolite was used to investigate the adsorption performance of H2S. Among particle size, calcination temperature and time calcination temperature and time had significant effects on the adsorption capacity of H2S on the zeolite. The optimal calcination conditions for the zeolite were 332 °C, 1.8 h, and 10–20 mm size, and the maximum adsorption capacity of H2S was approximately 6219 mg kg–1. Calcination could broaden the channels, remove the adsorbed gases and impurities on the surface of zeolites, and increase the average pore size and point of zero net charge. As the zeolite adsorbed to saturation, it could be regenerated at the temperatures between 200 and 350 °C for 0.5 h. Compared with the natural zeolite, the adsorption capacities of dimethyl disulfide, dimethyl sulfide, toluene, CH3SH, CS2, CO2, and H2S were significantly higher on the calcined zeolite, while the adsorption capacity of CH4 was lower on the calcined zeolite. A gas treatment system by a temperature swing adsorption–regeneration process on honeycomb rotors with calcined zeolites was proposed. These findings are helpful for developing techniques for removing gas pollutants such as volatile sulfur compounds and volatile organic compounds to purify biogas and to limited toxic concentrations in the working environment.

Formaldehyde dissipation mechanism of active alginate gel and its application in deep air purification

“…There was also a linear negative correlation between the removal capacity of ACA-cactus formaldehyde from air ow and working time, with correlation coe cients greater than 0.91 (Table 1). It is well known that air ow rate and pollutant concentration are two important factors to control membrane diffusion, and effective working time is another key material performance index (Zha et al, 2024). In the orthogonal experiment, the formaldehyde concentration (Factor 1) was set at three levels as 0.081, 0.162 and 0.326 mg•m − 3 ;the air ow rate (Factor 2) was set at three levels as 0.5, 1.0 and 2.0 L•min − 1 while the working time (Factor 2) were set at three levels as 5, 10 and 30 h. Results showed that the rapid and highly e cient formaldehyde dissipation of plant active components in ACA-cactus made the air ow rate become the key factor on the removal rate with the sequence of Factor 2 > Factor 3 Factor 1.…”