As a Master student at Federal University of Santa Catarina, Brazil, I worked with membrane filtration in order to remove cyanotoxin from drinking water. The filtration device was a dead-end stirred cell made of stainless steel and useful volume of 200 mL. The cell holds the membrane support, the membrane (diameter of 4.1 cm), the stir bar support and the stir bar. The pressure for the filtration was supplied by a nitrogen cylinder connected direct to it. This filtration device had no automatically flux measurement/recorder system, then samples were taken each 10 minutes to determine the permeate mass and to calculate the flux.
Stainless steel dead-end cell and the membrane support.
Here, at the Membrane Science & Technology Laboratory, to work with microfiltration membranes and super fine activated carbon (S-PAC), aiming to remove atrazine from water, a dead-end membrane system known as “Amicon cell” is being used.
The Amicon cell system is a lab-scale setup consist of a pressure vessel (Milipore), an Amicon cell (Milipore) per se and a balance connected to a computer. The 800 mL capacity pressure vessel hold the feed solution and the pressure is also supplied by a nitrogen tank. The Amicon cell consist of a cap with the pressure relief, a 10 mL capacity cell body (made of Polysulfone), a membrane support (diameter of 2.5 cm) and the inlet and permeate outlet.
Pressure vessel and Amicon Cell.
The permeate is collected in the glassware placed over the balance, and the membrane flux is determined automactilly by recording the mass of permeate collected over time using a data acquisition software Labview (National Instruments).
Data acquisition software Labview (National Instruments).
Comparing the two systems, the Amicon cell system hold a higher volume enabling longer filtration time. For the filtration system used in Brazil, the stir bar support placed over the membrane reduces the membrane area available for filtration to about 1/6 of the total membrane area, speeding the membrane fouling process. Collecting the volume direct over the scale and the automatic recording and calculation of permeate flux by the data acquisition software Labview improve the quantity and accuracy of the data, and facilitates working with membrane filtration system as a whole.