Regeneration of the exhausted mesoporous Cu/SBA-15-[N] for simultaneous adsorption–oxidation of hydrogen sulfide and phosphine

Effect of Cu/HZSM-5 sorbents with different Si/Al ratios on the adsorption and oxidation performance of H2S

This study employed a wet impregnation method to synthesize five types of Cu/HZSM-5 adsorbents with Si/Al ratios of 25, 50, 85, 200, and 300, used for the removal of H2S in low-temperature, low-oxygen environments. The impact of different Si/Al ratios on the adsorption oxidative performance of Cu30/HZSM-5-85 adsorbents was investigated. According to the performance test results, Cu30/HZSM-5-85 exhibited the highest breakthrough capacity, reaching 231.75 mg H2S/gsorbent. Cu/HZSM-5 sorbent maintains a strong ability to remove H2S even under humid conditions and shows excellent water resistance. XRD, BET, and XPS results revealed that CuO is the primary active species, with Cu30/HZSM-5-85 having the largest surface area and highest CuO content, providing more active sites for H2S adsorption. H2-TPR and O2-TPD results confirmed that Cu30/HZSM-5-85 sorbent exhibits outstanding redox properties and oxygen storage capacity, contributing to excellent oxygen transferability in the molecular sieve adsorption-oxidation process. With notable characteristics such as a large surface area, high desulfurization efficiency, and water resistance, Cu30/HZSM-5-85 sorbents hold significant importance for industrial applications.

Two Birds with One Stone: Copper-Based Adsorbents Used for Photocatalytic Oxidation of Hg0 (Gas) after Removal of PH3

Cu_X/TiO₂ adsorbents with CuO as the active component were prepared via a simple impregnation method for efficient purification of phosphine (PH₃) under the conditions of low temperatures (90 °C) and low oxygen concentration (1%). The PH₃ breakthrough capacity of optimal adsorbent (Cu₃₀/TiO₂) is 136.2 mg(PH₃)·g_sorbent^-1, and the excellent dephosphorization performance is mainly attributed to its abundant sur face-active oxygen and alkaline sites, large specific surface area, and strong interaction between CuO and the support TiO₂. Surprisingly, CuO is converted to Cu₃P after the dephosphorization by Cu_X/TiO₂. Since Cu₃P is a P-type semiconductor with high added value, the deactivated adsorbent (Cu₃P/TiO₂) is an efficient heterostructure photocatalyst for photocatalytic removal of Hg⁰ (gas) with the Hg⁰ removal performance of 92.64% under visible light. This study provides a feasible strategy for the efficient removal and resource conversion of PH₃ under low-temperature conditions and the alleviation of the environmental risk of secondary pollution.

Cu/HZSM-5 Sorbent Treated by NH3 Plasma for Low-Temperature Simultaneous Adsorption-Oxidation of H2S and PH3

In this study, an NH₃ plasma-treated Cu/HZSM-5 sorbent was introduced to simultaneously remove H₂S and PH₃ in low-temperature and low-oxygen environments. The effects of the Cu loading amounts, modification methods, and plasma-treatment conditions on the adsorption-oxidation performance of the sorbents were investigated. From the performance test results, the sorbent treated by NH₃ plasma with the specific energy input (SEI, electrical input energy to the unit volume of gas) value of 1 J·mL^-1 (Cu/HZSM-5-[S1]) was identified as having the highest breakthrough capacities of 108.9 mg S·g^-1 and 150.9 mg P·g^-1 among all of the materials tested. After three times of regeneration, the sorbent can still maintain the ideal performance. The results of Fourier transform infrared (FT-IR) spectroscopy and CO₂ temperature-programmed desorption (CO₂-TPD) indicated that the NH₃ plasma treatment can introduce amino groups (functional groups) onto the sorbent surface, which greatly increases the number and strength of the basic sites on the sorbent surface. Results of N₂ adsorption/desorption isotherms and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) showed that the morphology of the sorbent changed after the plasma treatment, which exposed more active sites (copper species). In situ IR spectra showed that the amino groups are continuously consumed during the reaction process, indicating that these amino groups can help sorbents to capture gas molecules. Moreover, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses indicated that CuO is the main active species and the consumption of CuO and accumulation of the reaction products on the surface and inner pores of the sorbent are the primary reasons for the deactivation of the sorbent.