Controllable growth of Na2CO3 fibers for mesoporous activated alumina ball modification towards the high-efficiency adsorption of HCl gas at low temperature

Abstract

To fundamentally solve the problem of chlorine corrosion in blast furnace gas (BFG) systems, a supported adsorbent is used for HCl removal at low temperature. In this paper, three alkaline substances, Ca(OH)₂, NaOH, and Na₂CO₃, were separately coated on the surface of activated alumina balls (AABs) by wetness impregnation method, using the as-active components. These materials were measured by XRF, XRD, SEM, TEM, and N₂ adsorption to characterize textural properties. The modification experiments indicated that Na₂CO₃ fibers can be obtained on the surface of AABs by adjusting the loading amounts, impregnation time, and drying conditions. The fibers' structure contributes to the gas phase diffusion in the product layer, greatly improving the conversion of Na₂CO₃ (>0.98). The highest value of HCl adsorption capacity reaches 3.56 mmol g⁻¹ when the Na₂CO₃ loading amount is 20 wt%, five times the adsorption capacity of pure AABs. The kinetics of HCl removal by the Na₂CO₃ fiber-modified AABs is controlled by the interfacial chemical reaction.