Performance on the forward osmosis membrane with polyethersulfone supported layer modified by sulfonated carbon nanotubes for dyeing wastewater treatment

Forward osmosis (FO) attracted more attentions to alleviate water crisis and energy shortage because of high water recovery, mild operating conditions and high anti-fouling performance. In this paper, poly(sodium- p -styrenesulfonate) (PSS) was adopted to prepare sulfonated carbon nanotubes (SCNTs) through an in-situ polymerization method to enhance its hydrophilicity. And SCNTs were then incorporated into a polyethersulfone (PES) solution to fabricate SCNTs-FO membranes which were subsequently applied to the treatment of simulated dye wastewater. The results indicated that the hydrophilicity of the SCNTs-FO membrane was significantly increased. The 0.06 wt%SCNTs-FO membrane had the lowest water contact angle that was 56.14°, showing a 56.6 % reduction compared with the pristine membrane. Meanwhile, more coherent nanochannels were formed inside the support layer, which facilitated the rapid passage of water molecules. In the active layer facing draw solution mode, with 1 mol/L NaCl as the draw solution, the water flux of the 0.06 wt%SCNTs-FO membrane reached 6.54 LMH, which was approximately three times higher than that of the pristine membrane. In addition, the J s / J w ratio decreased to 0.003 g/L which was lower than that of the relevant literature. It demonstrated that the selectivity of the SCNTs-FO membrane was obviously enhanced. After 9 hours anti-fouling test in methylene blue solution, the flux recovery rate of the membrane after the first cleaning with C 2 H 5 OH was the highest. And the water flux recovery of the 0.06 wt%SCNTs-FO membrane after cleaning was stable, which predicted that it had good anti-fouling stability and showed great application potential in the treatment of dyeing wastewater.