Bio-inspired loose nanofiltration membranes with optimized separation performance for antibiotics removals

The organic contaminants including pesticides, dyes and antibiotics imperilled both environment and creatures, thus hampering the sustainable and healthy development of human society. Loose nanofiltration (NF) is a highly efficient separation process aiming at removing organic contaminates from water. Previously, we developed a kind of cost-effective multi-functional bio-coatings. Herein, we investigated the effects of fabrication conditions on separation performance of the loose membranes with the bio-coating as the effective selective layer. Operation conditions including flow-rate of feed solutions, temperature, operating pressure to obtain optimum separation performance were examined in detail for imitating the industrial separation conditions. The membrane fabricated by 9.0 h coating in 100 ml pH = 8.5 solutions containing 0.2 g of gallic acid (GA) and 0.3 g of branched polyethyleneimine (PEI) demonstrates high rejections to both dyes (97% for CV and 100% for RB) and antibiotics (96.7% for AH) under 5.0 bar operation pressure with flow rate of feed solution at 70 L h−1 at 25 °C. Interestingly, the membrane demonstrates stable solution flux as high as 35 L m−2 h−1 under 5.0 bar operation pressure in continuous operation mode for separations of three typical antibiotics, and shows intriguing promise in recovery of antibiotics and dyes and waste water treatment containing organic contaminants.