Hollow Fiber Nanofiltration membranes, also called direct Nanofiltration (dNF), are the next generation polymer membranes. Polymer membranes have got better and better over the last 50 years. Nevertheless, we are facing major challenges. Our water increasingly contains micro-pollutants, including the residues from hormones, pesticides and medicines, which are difficult to remove. With our next generation Nanofiltration membranes we are able to provide the solution.
The principle of these membranes is that they can block all kinds of micro-pollutants and above all that they are easier to clean. Nanofiltration combines the advantages of a low fouling hollow fiber configuration with the ability to remove organics and salinity in one simple step. The Nanofiltration membranes are manufactured using the so called “layer-by-layer” process, where multiple nano-scale layers are deposited on a membrane support. The number of nano layers determines the rejection and flux properties of the membrane. A unique solution for troubled water.
Removal of micro-pollutants
The primary focus of the dNF membranes is on the removal of micro-pollutants and organics from water. These micro-pollutants, such as pesticides, pharmaceuticals and personal care products are a growing threat to the quality of our drinking water supplies. Our technology is ideally suited for waste water re-use applications and for polishing of surface water to drinking water standards. In addition, the mineral balance of the water is not affected by our membranes.
Other applications for our Nanofiltration membranes include color removal, softening, recovery of cleaning solutions (NaOH recycling) and partial desalination for industrial, process and municipal applications.
Reduction in capital and operating cost
The hollow fiber configuration provides an open, low fouling construction as the flow is not obstructed by spacers used in spiral wound elements. In addition, hollow fibers can be backwashed and the PES chemistry allows for continuous operation and cleaning with chlorine and cleaning at very high and low pH. Direct Nanofiltration replaces UF/NF, and for selected applications, UF/RO, with a one step process. This results in a significant reduction in capital and operating cost, while reducing the foot print of the installation.
Two types of Nanofiltration membranes are available with molecular weight cut-offs (MWCO) ranging from 400 to 800 Dalton. The Nanofiltration MexFil™ modules are available with a 110 mm (4”) and 200 mm (8”) diameter. The WMC confirguration modules are available for easy rack assembly in a vertical position. The dNF modules are supplied with robust end caps to ensure reliable operation at higher pressure.