Blog

Factors that have a profound influence on the structure or morphology of a particular membrane are the nature of the process by which it is manufactured and the form of the raw material used. The main manufacturing processes are:

● sintering of fine graded particles
● solvent casting or phase inversion, involving the stage-wise evaporation of a solution of polymer in a mixture of solvents
● irradiation and etching of an impervious film, and
● stretching an impervious film to cause multiple ruptures.

To be effective for separation, membranes should exhibit appropriate characteristics, such as good chemical resistance (to both feed and cleaning fluids), mechanical stability, thermal stability, high permeability, high selectivity and general
stability in operation. Originally, all membranes were based on natural materials or derivatives of natural cellulose. Whilst cellulosic media continue to play an important role in certain areas of application, the major source of membranes is now synthetic polymers. There is an immense variety of polymeric materials available as membrane media, including grades with specially developed properties (hydrophobic or hydrophilic, anionic or cationic) for specific filtration applications.

During the last twenty years or so, inorganic materials such as ceramics and metals have become of increasing significance as membrane materials. The introduction of these, despite their being nearly an order of magnitude more expensive than their organic counterparts, has occurred because of their much-improved operating lifetimes, their robustness, their greater tolerance to extreme conditions of operation, such as higher temperature and aggressive chemicals, and the subsequent overall saving in lifetime costs.

Ask for free sample, please click here.