High-efficiency hydrogen sulfide removal using copper (II) nitrate-impregnated ZSM-5 derived from sugarcane bagasse ash

Abstract

Sugarcane bagasse ash (SCBA) was utilized as an alternative silica source to synthesize a ZSM-5 support (SC-ZSM-5), which was subsequently impregnated with copper (II) nitrate (CuN) to create an alternative adsorbent for hydrogen sulfide (H₂S) removal. We investigated the effects of varying CuN loading levels, inlet gas components (CO₂ and moisture), and H₂S adsorption temperatures on the adsorption capacity. Our findings revealed that copper (II) nitrate and copper (II) hydroxy nitrate were the primary phases present in the CuN/SC-ZSM-5 samples. After H₂S removal, the CuN/SC-ZSM-5 sample was primarily composed of the presence of copper (I) disulfide, copper (II) sulfide, and copper (II) sulfate phases, with NOx released as a by-product. Higher adsorption temperatures enhanced the H₂S breakthrough capacity and NOₓ emissions, which can negatively impact air quality. Additionally, presence of CO₂ and moisture levels influenced H₂S removal performance. Upon regeneration at 600 ºC, the material decomposed into copper oxides, which remained active for further H₂S removal, demonstrating dual functionality in both adsorption and regeneration. This research not only transforms sugar industry waste into a valuable material but also enhances adsorption capacity, cost-effectiveness, eco-friendliness, and reusability for industrial gas purification, contributing to cleaner air and greener technologies.