A garment to protect the wearer from toxic agents may be made of a fabric that contains an adsorbent, such as activated carbon. In a test of such a fabric, a gas stream containing 7.76 mg/L of carbon tetrachloride (CCl₄) was passed through a 7.71-g sample of the fabric at a rate of 1.0 L/min, and the concentration of CCl₄ in the gas leaving the fabric was monitored. The run was continued for 15.5 min with no CCl₄ being detected, after which the CCl₄ concentration began to rise.

(a) How much CCl₄ was fed to the system during the first 15.5 min of the run? How much was adsorbed? Using this information as a guide, sketch the expected concentration of CCl₄ in the exit gas as a function of time, showing the curve from t = 0 to t 15.5 min.

(b) Assuming a linear relationship between amount of CCl₄ adsorbed and mass of fabric, what fabric mass would be required if the feed concentration is 5 mg/L, the feed rate 1.4 L/min, and it is desired that no CCl₄ leave the fabric earlier than 30 min?