The effects of water vapor on binary vapor adsorption of toluene and methylene chloride by activated carbon were investigated on a bench-scale experimental system. Three levels of relative humidity (15,65 and 90 percent) in conjunction with different concentrations of individual adsorbates (from 400 to 1200 ppmv) were tested by tracing the breakthrough curves of each adsorbate eluted from a fixed-bed adsorber. The adsorption capacities of the activated carbon tested for each adsorbate under the various conditions were obtained from calculations based on area integration of the breakthrough curves. It was found that with increasing relative humidity, the shape of breakthrough curves was asymmetrically distorted and the width of the breakthrough curves was broadened for toluene and steepened for methylene chloride. The adsorption capacities for both toluene and methylene chloride were decreased with the increase of relative humidity. The magnitude of the effect of water vapor is greater at the lower toluene concentration and at the higher concentration of methylene chloride. The mechanisms of water vapor influence on the process of multicomponent vapor adsorption are discussed.
A study is under way to investigate the heavy metal binding mechanisms in solidified/stabilized high sulfur coal fly ash and flue gas desulfurization (FGD) sludges. Fly ash and sludge from a typical wet FGD process and dry flue gas desulfurization by-product from a demonstration lime injection multistage burner (LIMB) process are being evaluated. The latter material contains substantial portions of available lime and may prove amenable as a solidifying agent with the fly ash. This paper describes initial results on the waste characterization, solidified/stabilized waste form formulation, and influence of liquid/solid ratio on metal leaching from the waste forms.
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