A new insight: Investigating calcium silicate hydrate as a potential adsorbent for hydrogen sulfide removal

Hydrogen sulfide (H2S) is a highly toxic and corrosive gas that poses significant environmental and health hazards, necessitating the development of effective adsorption materials. This study investigates the adsorption mechanisms of H2S on the Hydrated calcium silicate crystal, motivated by the critical need to develop efficient and economical H2S adsorption materials for environmental protection and public health. Using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations, the research focuses on the Tobermorite 9 & Aring; (001) surface, identifying the bridge site between the O 20 and O 24 atoms as the most stable adsorption position for H2S. Analysis of the charge density differential reveals electron transfer from the Ca atom to the H atom, suggesting electron loss and gain patterns indicative of chemical interaction dynamics. Partial density of states analysis reveals a weak interaction between the Ca-S due to minimal hybridization of the S-p and Cad orbitals, with a notable Z-direction distortion of the Ca atom (0.0537 & Aring;) among surface atoms. AIMD results indicate that at 1073 K, the H2S molecule transitions from adsorption to desorption, suggesting that the process is predominantly physical adsorption. This discovery is crucial for optimizing the regeneration and recycling of adsorbents, enhancing the economic efficiency and sustainability of treatment systems, and reducing environmental impacts. It holds significant implications for the development of efficient hydrogen sulfide adsorption materials.