Desulfurization is necessary for the clean utilization of blast furnace gas. Currently, BFG desulfurization generally follows a process route in which COS is first hydrolyzed into H₂S, followed by H₂S removal. Among different sorbents used, FAU zeolites are attractive due to the regeneration behavior. However, their adsorption performance is limited by mass transfer resistance and insufficient accessibility of active sites; moreover, under conventional synthesis conditions, the Na⁺/K⁺ distribution within the framework is difficult to control, resulting in limited deep desulfurization capacity. This study aims to develop a NaY-seeded strategy for synthesizing FAU zeolites and to elucidate the underlying mechanism of enhanced H₂S adsorption.
A series of FAU zeolite sorbents were prepared using NaY as the seed and NaOH and KOH as the alkali sources. The desulfurization performance of the adsorbents was evaluated in a fixed-bed reactor under simulated BFG conditions. The sorbents were characterized by XRD, N₂ adsorption–desorption, XRF, CO₂-TPD, and in situ FT-IR.
With the seed content increased from 0 to 20%, the breakthrough sulfur capacity initially increased and then decreased, reaching a maximum of 6.20 gS/100 g sorbent at a 15% addition level. Structurally, the introduction of seed crystals induced the formation of a hierarchical pore structure consisting of interconnected micro- and mesopores, with an optimal specific surface area of 824 m²/g, which significantly promoted H₂S diffusion. More importantly, XRD analysis revealed a reversal in the intensity of the (220) and (331) crystal plane diffraction peaks (from I₂₂₀＞I₃₃₁ to I₃₃₁＞I₂₂₀). The seed crystals could induce a redistribution of Na⁺ and K⁺ within the framework, and this redistribution was identified as the dominant factor driving the increase in H₂S adsorption capacity.
This redistribution of Na⁺ and K⁺ alters the local electron density, exposing more accessible active sites within the supercages and thereby accounting for the enhanced H₂S removal capacity.

H2S,Desulfurization,FAU zeolite,Na+/K+ distribution,Blast Furnace Gas