Vapor mercury uptake performance of laboratory-made sulphur impregnated active carbons (SIACs) was investigated using a fixed bed reactor in a temperature range of 25 to 200°C. Effects of the initial concentration, the flow rate, the loading amount of SIACs, temperature, and the sulphur impregnation on the mercury uptake performance were studied. Mercury uptake capacity is greatly enhanced by sulphur impregnation with SO_2. Mercury uptake capacity depends on sulphur content and specific surface area (SSA) to lesser extent. The true capacity is difficult to measure since the adsorbed mercury undergoes a diffusive process in deeper and smaller pores that is extremely slow. There seems to be a dependence of capacity on inlet concentrations. The enhanced uptake observed with higher flow rate suggests the role of external diffusion in controlling the rate of uptake under certain conditions. The strong negative temperature dependence of sulphur-free CS in adsorbing mercury confirms the physical nature of the adsorption with conventional activated carbons (AC). SIACs produced with SO_2 showed a more complicated behavior when temperature was varied, suggesting a mixed adsorption mechanism. The positive temperature effect observed with FCSS indicates the roles of sulphur form and sulphur impregnation methods in determining mercury uptake performance at high temperatures.
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