Membrane separation processes 2013/2014 Assignment 1 Submission Date: 26/02/2014 - 4 PM 1) The rejection of an ultrafiltration membrane formed by a barrier layer and a support layer has been measured for several particle sizes. The data are reported in Fig. 1.

Fig. 1 a) Calculate the radius of the pores assuming cylindrical geometry. b) What is the Molecular Weight Cut Off of the membrane? c) Calculate the water flux through the membrane at 25°C when it is operated at an applied pressure of 2.A bar. The porosity of the barrier layer is 0.1, its thickness is 2 µm. It is assumed that the tortuosity factor is 1 and the hydrodynamic resistance in the support layer of the membrane is negligible compared to the barrier layer resistance. d) A measurement of the water flux in the same conditions on a different layered membrane gives you a flux that is 0.B times the previous. The barrier layer has the same characteristic than before. You attribute the change to the support layer. Calculate the resistance of the support layer. 2) A pharmaceutical company that manufacturer sulfamethoxazole has an effluent of 5 g/L that needs to be treated to drinking water quality levels and not directly discharged into a river due to possible implication on fish and mammal reproduction. The effluent is treated with a Nanofiltration membrane NF-270. Data of permeate volume taken at different pressure are available (Table 1). The module has an area of 3 m2 and the feed flow rate is 12 L/min. The membrane retains 98% of the chemical at steady state conditions. a) Calculate the hydraulic permeability of the membrane. b) Calculate the recovery at 5.A bar. c) Calculate the permeate concentration assuming ideal conditions for the separation (no concentration polarisation).

d) The maximum concentration of sulfamethoxazole according to the regulation is 0.15 g/L. To meet the requirements (with an applied pressure of 5.A bar), would you have 2 modules in series or parallel?

P (bar) Permeate Volume (mL) Time (s)

3 2103 60 5 3759 60 7 5152 60 10 7245 60

Table 1 Legend: A: Last digit of your UUN B: Second to last digit of your UUN

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ASSESSMENT FEEDBACK

Course: Membrane separation processes Assignment 1 Student’s Name: ..........................................................................................................

Matric No: S OVERALL ASSESSMENT INDICATORS MAX MARK MARK COMMENTS

1 Units handling and conversions 1

2 Calculations 2

3 Ex 1: Correct applications of equations.

1.5

4 Ex 1: Ability to correlate characterisation data available to transport.

1.5

5 Ex 2: Mass balances setup 4

Lessons to be taken forward to your next assignment (which may not be in the same course).

OVERALL MARK

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