Structure Characteristics and Hot-Coal-Gas Desulfurization Properties of Zn-Based Sorbents Supported on Mesoporous Silica with Different Pore-Arrangement Patterns: A Comparison Study

Abstract

Ordered mesoporous MCM-41 (two-dimensional (2D) hexagonal pore arrangement) and MCM-48 (threedimensional (3D) cubic channel arrangement) with similar pore sizes and surface areas were selected for comparison when used as support for Zn-based sorbents for hot coal gas desulfurization. Compared to that of Zn/M48 (MCM-48-supported desulfurizer), the adsorption capacity of Zn/M41 (MCM-41-supported sorbent) increases by 24.4−56.3%. The initial reaction rate constants of Zn/ M41 are 1−13 times greater than those of Zn/M48. These are correlated to the structural features of sorbents. Zn/M41 has a large wall thickness of the framework, suggesting higher thermal stability. Furthermore, the sorbent particles and ZnO grains in Zn/M41 are both smaller in size, which facilitates contact between H 2 S and ZnO. Additionally, Zn/M41 possesses a large surface area and pore volume, beneficial for the diffusion of H 2 S through sorbents. The analysis of the atmospheric effects reveals that there is a stronger synergistic effect of CO and H 2 on desulfurization over Zn/M41.

Review on Template Removal Techniques for Synthesis of Mesoporous Silica Materials

“…Mesoporous silica materials, for instance, the SBA (Santa Barbara Amorphous) series, MCM (Mobil Composition of Matter) series, and KIT (Korean Advanced Institute of Science and Technology) series have gained extensive attention over the last decades due to their highly tunable textural and chemical characteristics and are therefore used in different fields: biomedical and pharmaceutical applications, − adsorption of pollutants from wastewater, , catalysis, − aromatization, biogas purification and upgrading, sensing, desulfurization, − for CO 2 capture, − Li-ion battery application, upgrading microalgal biocrude, hydrodenitrogenation, and hydrogen production. , Figure (a) displays the number of publications for mesoporous silica materials, and Figure (b) shows their applications in different research areas from 2000 to 2021 (Web of Science). Poly­(ethylene glycol)- block -poly­(propylene glycol)- block -poly­(ethylene glycol) (P123 copolymer), poly­(ethylene oxide)-poly­(propylene oxide)-poly­(ethylene oxide) (pluronic F-127) as nonionic surfactants, cetyltrimethylammonium bromide (CTABr), and cetyltriethylammonium bromide (CTEABr) as cationic surfactants, and anionic surfactants such as sodium dodecyl benzenesulfonate (SDBS) and sodium dodecyl sulfate (SDS) as well as ionic liquid (IL) are the common organic templates used for the synthesis of mesoporous silica materials.…”

Bimetallic-MOF-Derived ZnxCo3–xO4/Carbon Nanofiber Composited Sorbents for High-Temperature Coal Gas Desulfurization

“…To date, multiple sorbents composed of metal oxides for high-temperature desulfurization have been developed . By thermodynamic modeling, researchers have examined 28 metal oxides and identified 11 possible oxides with thermodynamic feasibility as desulfurization materials, including Fe, Zn, Mo, Mn, V, Ca, Sr, Ba, Co, Cu, and W. − Among them, the ZnO-based sorbents have attracted great interest due to the high uptake of sulfur compounds (H 2 S and COS). , The removal of H 2 S by ZnO-based sorbents can be realized through the following equation Specifically, ZnO is considered one of the best metal oxide sorbents, as it shows the most favorable desulfurization thermodynamics . Although ZnO has a high H 2 S sorption capacity, the reduction of zinc oxide in the highly reducing atmosphere followed by vaporization of elemental zinc can be a severe problem when the temperature is higher than 600 °C.…”

“…9,10 The removal of H 2 S by ZnObased sorbents can be realized through the following equation Specifically, ZnO is considered one of the best metal oxide sorbents, as it shows the most favorable desulfurization thermodynamics. 11 Although ZnO has a high H 2 S sorption capacity, the reduction of zinc oxide in the highly reducing atmosphere followed by vaporization of elemental zinc can be a severe problem when the temperature is higher than 600 °C.…”

Porous Carbon Nanofibers Supported Zn@MnOx Sorbents with High Dispersion and Loading for Hot Coal Gas Desulfurization

“…7,8 In order to solve this problem, porous supporters such as activated carbon, zeolites, γ-Al 2 O 3 and molecular sieve have been introduced into the preparation of sorbent. [9][10][11] Liu et al synthesized desulfurization sorbent with highly dispersion of active components by combining porous MAS-9 and Ca-based oxides. 12 It was found that the sorbent exhibited a sulfur capacity of 17.16 g S 100 g -1 sorbent.…”