Which substances a membrane retains depends on the membrane technology used. With membrane processes ranging from microfiltration (MF) to reverse osmosis (RO), theoretically almost the entire spectrum of impurities – from coarse particles to dissolved salts – can be removed.

However, in the field of industrial process bath maintenance, Atec primarily uses microfiltration and ultrafiltration, or in some applications, coarse nanofiltration.

Microfiltration (MF)

Microfiltration is particularly suitable for removing:

• Oils and fat droplets
• Solid particles
• Abrasion and dirt
• Metal hydroxides and other precipitates
• Bacteria

Dissolved bath chemicals such as cleaners, alkalinity, and surfactants pass through the membrane and remain in the process bath. This allows impurities to be removed without significantly altering the bath chemistry.

Ultrafiltration (UF) and coarse Nanofiltration (NF)

In rinse bath maintenance, tighter membranes are often used. In addition to the impurities mentioned above (oil, particles,…), these can additionally retain:

• Macromolecular organic compounds
• Surfactants
• Other larger dissolved molecules

This often allows rinse baths to be used significantly longer and, if necessary, combined with further treatment processes, for example, to reduce conductivity.

The selection of the appropriate membrane is always based on the composition of the process medium and the desired treatment goal.