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A novel, high temperature solid absorbent based on lithium orthosilicate (Li(4)SiO(4)) has shown promise for postcombustion CO(2) capture. Previous studies utilizing a clean, synthetic flue gas have shown that the absorbent has a high CO(2) capacity, >25 wt %, along with high absorption rates, lower heat of absorption and lower regeneration temperature than other solids such as calcium oxide. The current effort was aimed at evaluating the Li(4)SiO(4) based absorbent in the presence of contaminants found in typical flue gas, specifically SO(2), by cyclic exposure to gas mixtures containing CO(2), H(2)O (up to 25 vol. %), and SO(2) (up to 0.95 vol. %). In the absence of SO(2), a stable CO(2) capacity of ∼ 25 wt % over 25 cycles at 550 °C was achieved. The presence of SO(2), even at concentrations as low as 0.002 vol. %, resulted in an irreversible reaction with the absorbent and a decrease in CO(2) capacity. Analysis of SO(2)-exposed samples revealed that the absorbent reacted chemically and irreversibly with SO(2) at 550 °C forming Li(2)SO(4). Thus, industrial application would require desulfurization of flue gas prior to contacting the absorbent. Reactivity with SO(2) is not unique to the lithium orthosilicate material, so similar steps would be required for other absorbents that chemically react with SO(2).

The present study has identified some SDFs from durum-type wheat grains as suitable prebiotic substrates for the selective proliferation of B. pseudocatenulatum B7003 and L. plantarum L12 in vitro. The results provide the basis for the potential utilisation of wheat-based prebiotics as a component of synbiotic formulations.

A variety of supported metal and metal oxide adsorbents were evaluated for removal of arsine (AsH 3 ) from synthesis gas (syngas), a mixture primarily of carbon monoxide and hydrogen. A copper(II) oxide (CuO)/ carbon adsorbent was judged to be most promising and examined more thoroughly. Exposure of the CuO/ carbon adsorbent to syngas at 750 psig resulted in only a modest increase in bed temperature. No evidence that the adsorbent acted as a methanol synthesis catalyst or promoted other syngas chemistry was observed. It was found, however, that even at modest temperatures (30-40 °C) some reduction to metallic copper (Cu) occurred. The exothermic reduction of CuO presented a significant operational concern, and use of the adsorbent required a controlled reduction to Cu/carbon prior to exposure to syngas. The arsine affinity of CuO/carbon was very high with a minimum capacity of 3.0 wt % arsenic for a syngas feed containing 420 ppbv. The reduced adsorbent, Cu/carbon, was less effective for AsH 3 removal, and at 30 °C its capacity was 1.74 wt %. Operation at 140 °C resulted in more effective AsH 3 removal with a minimum arsenic capacity of 4.31 wt % for a feed gas containing 737 ppbv AsH 3 . The kinetic limitation for AsH 3 adsorption at near ambient temperature is likely the result of slow migration of arsenic from the copper surface. At 140 °C arsenic migration is fast enough to provide a clean copper surface for adsorption. The Cu/carbon adsorbent was slightly less effective for phosphine removal than for AsH 3 . The sulfur-containing contaminants thiophene, carbonyl sulfide, and carbon disulfide were only partially removed from a syngas feed, and the adsorbent had almost no affinity for methyl chloride.

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