PFAS retentions of direct nanofiltration validated by KWR (the independent Dutch Water Research Institute)
NX Filtration’s hollow fiber nanofiltration membrane technology (or dNF) is very efficient in rejecting PFAS compounds, based on a sustainable process that significantly reduces the need for energy and avoids the use of pre-treatment chemicals.
Our dNF40 membrane has proven to be an effective and sustainable solution to facilitate PFAS removal processes.
PFAS process retention rates from real world validation by KWR
PFAS20 – A group of substances on the EU monitor to be regulated. Average dNF40 process retention for these molecules is 94.7%
PFAS4 – A group of substances that e.g. Sweden will be using in their legislation. Average dNF40 process retention for these molecules is 94.6%
“Especially PFAS requires a robust barrier to reject them from polluted water to obtain high quality and safe permeate or product water with lowest ecological footprint possible. Therefore, we see an increasing interest for our membrane technology” says Erik Roesink, founder and CTO of NX Filtration.
A unique element of the test protocol was that a representative subset of PFAS has been tested under realistic concentrations, regularly seen in practice. “Also, the duration of test plays an important role in getting to realistic and representative results” according to Joris de Grooth, R&D Director at NX Filtration. Long term testing ensures that PFAS removal via adsorption in the systems could be omitted.
The specific research questions to be answered within the experiment were: What is the process retention of a wide range of PFAS substances by applying hollow fiber direct nanofiltration? And what is the influence of the water matrix (surface water and effluent) on this retention? KWR also researched the PFAS adsorption behaviour. The test has been performed with a containerized full scale Mexpert pilot unit of NX Filtration located at the premises of KWR.
Figure 1: dNF40 performance on a variety of PFAS, ordered by size. Both membrane retention (based on retentate concentration) and process retention (based on feed concentration) are provided.
*permeate below the limit of detection (LOD). All PFAS presented are within the PFAS20 group. PFOA, PFOS, PFNA, and PFHxS constitute the PFAS4 group.