The Features of Membrane

Membrane qualities are the significant information that is needed to be concerned by the users when selecting the right membrane for the right application. To select the proper membrane, specific reactant and production condition is one of the factors to optimize the effective membrane utilization technologically. Normally, the manufacturer must supply the purchaser with the sufficient information regarding the membrane’s features. Some of the manufacturers even provide the customers with the reactant specified for each type of membrane. In today’s world, these information can be easily found on the public relations and company’s websites.

The size of the filter holes and their capabilities in filtering salt is the very first membrane feature the users should know. Generally, the size of the filter holes indicates the characteristic of the MF type membrane but as for UF type membrane, the filter holes size is measured in MWCO (molecular weight cut off) which is the measurement unit indicating the capability to filter substances according to molecule mass, membrane’s holes and the MWCO of the membrane which has large size. On the other hand, the capability to filter salt shows the feature of RO and NF type membrane and other qualities which are all important as factors for selection and application

The density of the filter holes and their dispersing are also the feature of membrane affecting to the ‘flux’, filtering capability, fouling and the pressure. All the membranes have the dispersing distance between each hole. A good membrane with filter holes is supposed to be a tube with dispersing holes along with width but in reality, the filter holes of the membrane have no fixed positions. Instead they come in a crooked line with low density below 10%, resulting in a low ‘flux’ which requires higher pressure. As a result, the reactant would be dissolved making it clogged or fouled easily, lowering the flux even more and the capability to separate the substances when filtering. A regular development of the membrane’s filter holes as well as the density is obviously one of the most challenging task to be performed by the scientists.
The Hydrophilicity and Hydrophobicity are other 2 qualities that users should know when selecting the right membrane for food ingredient substances which most of the time include protein components. The Hydrophilicity membrane can reduce fouling that arises from Protein absorption from the membrane’s filter holes’ surface. If utilizing the Hydrophobicity, this would result in protein absorbing membrane affects the flux, the capability to separate and cleansing.

The membrane’s is also another important quality the user should know. Some of the reactants may have suspended matter particles with charges. Should the charges are different from the membrane; the pulling effect will happen between the membrane itself and the particles inducing fouling. Generally, each membrane’s surface is designed to possess negative charge while other membrane type may have changing charge according to the changing pH.

Each membrane is designed to be Acid-Base tolerated on different temperature. Basically, the manufacturers must provide these essential details to customers. The materials made of ceramic possess greater Acid-Base and temperature tolerance than the Polymer-made membranes (Figure 2-2). Therefore, the microbes can be killed with the steam which is appropriate for the quarantine process. Besides, the Acid-Base tolerance is also an important factor when cleansing membrane with Base-solutions. Though the Ceramic membrane is more tolerated to Acid-Base conditions but this does not imply to Phosphoric acid. Likewise, some other membrane types  are not resistant to Chlorine (ppm level) namely Cellulose Acetate and Polysulfone.

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