Effects of ordered mesoporous silica on the performances of composite nanofiltration membrane

• Mesoporous silica SBA-15 was firstly utilized on the NF-membrane fabrication.
• Influences of mesoporous silica on the membrane performances were deeply analyzed.
• We investigated the changes on microstructures of the SBA-15 modified NF membrane.
• The influential mechanisms on NF-membrane performances were carefully proposed.

Surface modified composite nanofiltration (MCNF) membrane was prepared by traditional interfacial polymerization approach using trimesoyl chloride and piperazine as reacting monomers, mesoporous silica SBA-15 as a surface modification additive, for investigating the influences of mesoporous-silica introduction on the membrane performances. Its surface properties and microstructures were carefully characterized by various analyzing instruments. Furthermore, the rejection performance was tested using 2000 ppm of MgSO4 aqueous solution under 1 MPa working pressure. Its fouling-resistance performance was also evaluated by using bovine serum albumin as an organic pollutant model, based on the changes of permeate flux in the running process. The experimental results show that the introduction of SBA-15 material can obviously enable the permeate flux of the NF membrane to be increased from 32.4 to 45.6 L/h·m2, accompanied with slight decrease of MgSO4 rejection from 97.88 to 85.23%. The SBA-15 modified MCNF membrane exhibits excellent fouling-resistance performance, with the permeate flux still retaining 72.53% of the initial flux value, after the anti-fouling test running for 270 min. The introduction of SBA-15 significantly improves the hydrophilicity, effective surface area and pore size of the membrane separation layer, which is favorable for the enhancement of permeate flux and fouling-resistance performances.