Novel Amine Modified Nanoporous SBA-15 Sorbent for the Removal of H2S fromGas Streams in the Presence of CH4

A new sorbent has been developed by grafting Hexamethylenetetramine on a mesoporous molecular sieve(SBA-15) by wet impregnation method. This sorbent (Hexamine/SBA-15) has been characterized usingN2 physisorption, X-ray diffraction (XRD) at low angles (2θ°) and FT-IR. To investigate the H2S removalcapacity of this adsorbent from 9000 ppm H2S balance CH4-containing gas mixtures, the breakthroughtests have been performed on a fixed-bed flow system. SBA-15 without amine loading showed a very lowH2S adsorption capacity (0.015 mmol-Sulfur/g-sorbent) and saturation capacity (0.032 mmol-Sulfur/gsorbent).The results show that after the amine loading, hexamine is dispersed inside the mesochannels ofmesoporous SBA-15. Effects of the amine loading and sorption temperature on the sorption behavior ofthis developed sorbent have also been studied. Increase of amine loading enhances the H2S sorption onthis sorbent, When Hexamine was 50wt%, the removal performance was optimum(qb= 0.9 mmol/gsorbent).With increase in temperature, both the breakthrough capacity (qb) and the saturation capacity (qs)decrease. High sorption capacity is observed at low temperature (T=22℃, qs= 1.9 mmol/g-sorbent) whichprovides a promoting effect in removal of H2S from gas mixtures streams on the developedHexamine/SBA-15 sorbent. This developed sorbent is regenerated easily at 100°C, and shows very goodstability. The breakthrough capacity decreased from 0.9 mmol. g-1 for the first cycle to 0.75 mmol g-1 forthe second cycle and 0.74 mmol g-1 for the third cycle. Although the breakthrough capacity decreasedabout 83 % of the first breakthrough tim, H2S can be recovered