Estimation of the Break Point

When the constant pattern of the adsorption zone holds and the amount of an adsorbed is much larger than its concentration in the feed solution, then the velocity of movement of the adsorption zone is given as follows  

Under the constant pattern, the term d /dC should be constant. The integration of dq/dC = constant with the boundary conditions 

The time required from the start of feeding to the break point can be estimated with the assumption of the constant pattern stated above. Thus, substitution of Equation 11.10 into Equation 11.6 gives the following equation for the rate of adsorption  

Integration of this equation between the break point and exhaustion point, where the ratio of the adsorbate concentration in the effluent to that in the feed becomes a value of (1 - the ratio at the break point), gives 

An adsorbate A is adsorbed in a fixed-bed adsorber that is of 25 cm height and packed with active charcoal particles of 0.6 mm diameter. The concentration of A in a feed solution is 1.1 mol m , and the feed is supplied to the adsorber at an interstitial velocity of 1.6 m h L The adsorption equilibrium of A is given by the following Freundlich-type isotherm. 

---