Modified bentonites as adsorbents of hydrogen sulfide gases

Carbonate-rich bentonite was modified by iron and copper chlorides in order to synthesize effective and cheap adsorbents for neutralization of H2S in low-concentrated exhaust gases. Bentonite and modified bentonite were analysed using atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and BET surface area analysis. In addition, bentonite and modified bentonite were tested as hydrogen sulfide adsorbents. Iron-containing material showed a significant improvement in the capacity for H2S removal. The longest time of effective protective action (before H2S appears on the outlet of the column) was obtained for the bentonite modified with copper hydroxide. The results indicated that on the surface of modified samples hydrogen sulfide reacts with metal hydroxide forming sulfides. Sulfided iron-containing sample could be regenerated by exposing it to the air.