Experimental and modeling study on room-temperature removal of hydrogen sulfide using a low-cost extruded Fe₂O₃-based adsorbent

In order to prevent corrosion and catalyst deactivation, commercial adsorption processes for hydrogen sulfide (H₂S) removal operate at relatively high temperature (350–450 °C) by ZnO adsorption. This paper reports firstly data from experimental and modeling studies of the dynamic performance of a low-cost extruded Fe₂O₃ -based adsorbent for H₂S removal at room temperature. The H₂S adsorbent containing iron (III) oxide (Fe₂O₃) and bentonite was prepared by hydrothermal-precipitation method and the material has been characterized by several techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), and low temperature N₂ physical adsorption. The Fe₂O₃-based extruded adsorbent was used in a continuous fixed-bed column experiments to evaluate the efficiency for removal of H₂S under the effect of various process parameters including the bed depth, the flow rate and the initial H₂S concentration. The results showed that the total H₂S uptake slightly increased with increasing the bed depth and the initial H₂S concentration, and decreased with increasing the flow rate. In the modeling part, the dynamics of the adsorption process was modeled by two adsorption models namely, Thomas model and BDST (bed depth service time) model. The kinetic parameters obtained from the models were used to predict the breakthrough time for a larger column which contained the adsorbent about 40 times more than that in the mini column experiments. The Thomas model was the suitable model for prediction of 10 % C₀ breakthrough time with an error about 4 %.