Tailoring nanofiltration membrane performance for highly-efficient antibiotics removal by mussel-inspired modification

• A mussel-inspired coating was successfully built on PEG NF membranes.
• The tough mussel-inspired coating can obviously enhance the antibiotics rejection.
• Optimizing conditions efficiently enhanced practical separation performance.

For efficiently sieving active molecules to concentrate/purify antibiotics, the pores of novel hydrophilic polyethylene glycol (PEG) based nanofiltration (NF) membrane should be finely tailored. Herein, an effective coating layer is successfully built on the PEG based NF membrane through self-polymerization of mussel-inspired dopamine (DA) which is confirmed by various physicochemical characterizations. Interestingly, with smaller pores, the hydrophilic PEG based membranes after coating with mussel-inspired polydopamine can significantly increase the rejections to salts and other active molecules with only little sacrifice of dual resistance to fouling and chlorine. Importantly, the best comprehensive antibiotics separation performance of NF membrane can be achieved by mussel-inspired dopamine modification around 6 h. Such an advanced membrane shows the highly stable tobramycin solution flux over 46 L m−2 h−1 alongside tobramycin (TOB), clindamycin phosphate (CP) and cephalexin (CA) rejections up to 99%, 94% and 93% with 50 ppm feed concentration under 8.0 bar, respectively. Interestingly, when the feed concentration increases up to 800 ppm, the membrane still exhibits the high rejections to all of antibiotics up to 90%. Therefore, coating with mussel-inspired dopamine is a highly effective way to tailor the pores of hydrophilic PEG based NF membranes toward the excellent separation performance for expanding membrane applications in separating negative and amphiprotic charged antibiotics.

A hydrophilic PEG based NF membrane with dual resistance to chlorine and fouling has been synthesized through interfacial polymerization (IP) of amino functional polyethylene glycol (PEG) and trimesoyl chloride (TMC), prolonging the service life of the NF membranes significantly and promoting it application in waste water treatment, pharmaceutical and fine chemicals industries. Herein, an effective coating layer is synthesized successfully through self-polymerization of dopamine in mild conditions. Being exploited to separate antibiotics, the dopamine-6 h modified membrane owns best comprehensive separation performance with highly stable tobramycin solution flux over 46 L m−2 h−1 alongside TOB, CP and CA rejections up to 99%, 94% and 93% with 50 ppm feed concentration under 8.0 bar. As a promising “green” technique featuring nearly zero emission and less energy consumption, our NF processes owning highly efficient antibiotic concentration ability in substituting conventional separation techniques for concentration and purification of active molecules in pharmaceutical and fine chemicals industries.Figure optionsDownload high-quality image (306 K)Download as PowerPoint slide