Investigation of the capability of regenerated rice husk silica to remove hydrogen sulfide pollution

  Introduction: The main goal of this study was to investigate the capability of regenerated rice husk silica after saturation to remove Hydrogen sulfide (H2S). For this purpose, rice husk silica and regenerated rice husk silica were used as adsorbents bed in filter.   Material and Methods: A poly vinyl chloride filter with one liter of prepared bed was tested. Rice husk silica was prepared in a furnace at temperature of 800 ºC for Four hours, after acid leaching. Saturated rice husk silica was regenerated in a furnace at temperature of 800 ºC for Four hours too. Removal efficiency, elimination capacity, and pressure drop were the three parameters to evaluate the filters bed. System were operated with empty bed residence time of 60 s and different inlet concentration of H2S from 10 to 300 part per million (ppm).   Results: More than 98% of removal efficiency was observed for both packed filters at inlet concentrations of H2S. The maximum elimination capacity was 7.02 gm-3h-1 with H2S mass loading rate of 9.0 gm-3h-1 in the both beds. This study showed that at a 1.0 lmin-1 flow rate and different concentration of inlet H2S. There is no significant difference between the rice husk silica and the regenerated rice husk silica beds in the amount of removal efficiency (p< 0.01). Also, there is no significant difference between these two beds in the amount of elimination capacity at the same condition (p< 0.01). Moreover, this study showed that the amount of pressure drop was undetectable (zero) in both filter’s bed.   Conclusion: The results of this study showed the regenerated rice husk silica has the same performance of the primary rice husk silica, Therefore it can be considered as a suitable and inexpensive bed to remove H2S at low concentration.