Copper Exchanged Nanotitanate for High Temperature H₂S Adsorption

Abstract

The H2S breakthrough capacity of copper-exchanged Engelhard Titanosilicate-2 (ETS-2) was measured at temperatures up to 950 °C and it was found that the adsorbent efficiency remains unchanged across the entire temperature range. Below 750 °C, the adsorption capacity at breakthrough is 0.7 mol of H2S per mole of copper while above 750 °C the capacity of the adsorbent is halved. The change in H2S capacity is due to Cu2+ reduction by the H2 which is formed through the thermal dissociation of H2S. The adsorbent shows good potential for use over a wide range of operating temperatures in H2S scrubbing processes.

Breakthrough performances of metal-exchanged nanotitanate ETS-2 adsorbents for room temperature desulfurization

“…2 shows the XRD patterns of the native and the different metal exchanged forms of ETS-2. The native form is cryptocrystalline as evidenced by low broad peaks in the XRD profile, which are characteristic of nano particles of anatase (Yazdanbakhsh et al, 2014). It can be seen that no significant crystalline peaks are visible for the rest of the samples, indicating that Na-ETS-2 structure is able to accommodate Ag, Ca, Cu and Zn during the ion exchange process without having any significant effect on its nano structure.…”

“…In the presence of H 2 S, structural changes start to occur from 350 1C. However, the removal capacity still shows promising values up to 650 1C after which sintering progresses leading to loss of copper adsorption sites (Yazdanbakhsh et al, 2014).…”

Use of zeolites for the removal of H 2 S: A mini-review

“…As well as other zeolites, surface area matters for the adsorption characteristics, increasing the surface area which allows active ions to be highly dispersed and accessible to gas molecules. This material defined as an effective support for metals and an outstanding adsorbent for H 2 S [39] was used by Rezai et all. [40] in order to remove hydrogen sulfide even below the levels of 0.5 ppm at ambient temperatures.…”

“…However, if both copper uptake and distribution of copper on the structure properties were required to combine, Cu-ETS-2 was the one having the highest H 2 S breakthrough capacity. Following these experiments, the group has also studied [39] Cu-ETS-2 for the adsorption of H 2 S between the temperatures of 250°C and 950°C to examine the temperature changes on the performance and crystal structure of copper sulfide crystals. With the measurements between 250°C and 950°C by intervals of 100°C, H 2 S adsorption remained stable between 250°C and 650°C, but then it decreased till half of the capacity (from 0.7 mol H 2 S per Cu to 0.35 mol H 2 S per Cu) due to the oxidation state change of Cu +2 .…”

Towards practical application of gasification: a critical review from syngas and biochar perspectives

“…But lime had to be added as a separating agent to prevent sintering of the CaBa sorbent and maintain stable gasification conditions in the gasifier. To enhance the adsorptive capacity of the sorbents, high surface area materials such as Al2O3, TiO2, and zeolites were often used to support the metal oxides by increasing surface areas and cation exchange capacity (Rezaei et al, 2015;Yazdanbakhsh et al, 2014).…”