1. If adsorption of pure gases A and B follow the Langmuir isotherm equations, calculate the total loading of the adsorbates per gram of the solid in equilibrium with an equimolar mixture of A and B at a total pressure of 1 bar. Assume that the Langmuir isotherm is obeyed by the mixture as well.
QA = 1.72*pA /(1+0.92* pA) and QB = 0.33 * pB /(1+0.18 *pB)
2. Calculate the adsorption separation factor αAB in the above question if a mixture of A and B (60% A, total pressure = 1 bar ) is in equilibrium with the adsorbent.
3. The velocity of the mass transfer zone for adsorption of a solute in a packed bed is 5 cm/min. The length of the bed is 120 cm. The equilibrium time is 26 min. What is the thickness of the mass transfer zone ?
4. What percentage of the bed remains unused in above question at breakthrough?
5. Adsorption equilibrium data for the decolorization of a sample of waste oil using a special type of clay collected from a set of laboratory experiments could be fitted by a Henry's law type relation – Y = 4.2 * 10-4 X*, where Y= number of color units per kg oil, and X* = number of color units per kg clay in equilibrium. 1000 Kg of a waste oil having an initial color concentration of 50 units has to be treated to reduce the concentration to 1 color unit . The adsorbent has an effective surface area of 25 m*m/g, and the surface mass transfer coefficient is KL =5.2 * 10-6 m/s (on the solid phase concentration basis). The density of the oil is 950 kg/m3.
a) Calculate the minimum quantity of adsorbent required.
b) What is the required contact time if 1.2 times the minimum amount of adsorbent Is used?