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

Sugarcane bagasse ash (SCBA) was utilized as an alternative silica source to synthesize a ZSM-5 support (SC-ZSM5), 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 degrees C, 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.