Core Shell Nanostructure: Impregnated Activated Carbon as Adsorbent for Hydrogen Sulfide Adsorption

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Hydrogen sulfide (H2S) is a toxic gas requiring efficient capture methods.
• Activated carbon is a common adsorbent, but its performance can be enhanced.
• Nanostructure materials offer improved adsorption properties.

Purpose of the Study:

• To synthesize and characterize core-shell nanostructure adsorbents for H2S capture.
• To evaluate the H2S adsorption performance of modified coconut shell activated carbon (CAC).
• To investigate the effect of different core and shell materials on adsorbent performance and stability.

Main Methods:

• Modification of commercial CAC using impregnation with zinc acetate (ZnAc2), zinc oxide (ZnO), titanium dioxide (TiO2), and potassium hydroxide (KOH).
• Synthesis of core-shell structures with various combinations of core and shell materials.
• Characterization using scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) analysis.
• Performance evaluation in an adsorber column under ambient temperature and 1.5 bar pressure with 5000 ppm H2S.

Main Results:

• The ZnAc2/ZnO/CAC_WOS adsorbent exhibited the highest adsorption capacity (1.17 mg H2S/g), a 53% improvement over raw CAC.
• Adsorbent degradation was observed, with ZnAc2/ZnO/CAC_OS and ZnAc2/ZnO/CAC_WS showing better stability than ZnAc2/ZnO/CAC_WOS.
• The incorporation of silica as a shell potentially enhanced adsorbent stability across multiple adsorption-desorption cycles.

Conclusions:

• Core-shell nanostructure adsorbents, particularly those incorporating ZnO and silica, show promise for efficient H2S capture.
• Material modification significantly enhances adsorption capacity compared to unmodified activated carbon.
• Further research is needed to optimize stability for practical, long-term H2S removal applications.