NF270, a new membrane having promising characteristics and being suitable for treatment of dilute effluents from the paper industry

A good nanofiltration membrane for the paper mill waters is hydrophilic, having both high retention and high permeability, and it should be resistant to fouling and temperature increase. The membrane should also withstand alkaline and acidic cleaning and mechanical wear. Membranes having all these properties do not exit. Based on laboratory- and pilot-scale experiments one promising membrane is the NF270 from Dow. The membrane is rather hydrophilic and it has fairly high retention and permeability. However, its resistance to temperature is not sufficient for all applications in the paper industry. By using this membrane or other similar NF membranes in the high-shear cross-rotational CR-filter fluxes above 100 L/(m2 h) and retentions over 80% for conductivity and total carbon are obtainable with many rather dilute effluents from the paper industry.