Influence of surface properties of RO membrane on membrane fouling for treating textile secondary effluent

Influence of surface properties of RO membrane on membrane fouling for treating textile secondary effluent

2017

Reverse osmosis (RO) is a promising technology for treating and reusing textile secondary effluent (SE). To better understand the effect of membrane surface properties on membrane fouling, the performances of three commercial polyamide thin-film composite RO membranes (BW30-4040, CPA2-4040, and RE-4040-FEN) with different roughness and hydrophilicity were investigated for treating textile SE. The RO membranes were characterized by ATR-FTIR, SEM, AFM, and contact angle, respectively. The results showed that the flux increased with an increase in the surface hydrophilicity of membrane. CPA2-4040 had the highest hydrophilic surface and thus the largest initial flux. There was a strong correlation between the membrane fouling and the surface roughness; the fouling increased with an increase in the surface roughness. The roughest surface of CPA2-4040 led to the most significantly flux decline. However, the fouling reversibility was not related directly to surface roughness. BW30-4040 with the secondary roughness and the most hydrophobic surface had the highest fouling reversibility. This was mainly due to the primary hydrophilicity of textile SE in nature. Fluorescence excitation-emission matrix (EEM) showed that hydrophilic neutral protein-like matters and soluble microbial products (SMP) were the main foulants, thus stronger affinity with hydrophilic surface of membrane. Graphical abstract ᅟ

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