An engineer has been requested to design a portable system of the size of one cubic foot (c.a. 0.03m3 ) to utilize in direct air capture (DAC). You are required to ensure that the outlet CO2 retentate is capable of reaching 150200ppm at all times. It is given that the system is expected to cater to a constant inlet air flow rate of 0.5L/min. You may assume that the concentration of CO2 in the air is 400ppm, with a feed pressure of 760 torr. The membrane properties are given as follows: (i) CO2 permeance = 10,000GPU; (ii) CO2/(O2+N2) selectivity =30; (iii) pressure ratio =0.03, respectively. - Determine whether a single membrane stage can be achieved if the minimum outlet flow rate of the permeate stream is set at 0.1L/min. Justify your answer. - Propose an appropriate membrane cascade with the required area to achieve the desired output, if the approach mentioned above cannot be realized