Self-sustained hydrophilic nanofiber thin film composite forward osmosis membranes: Preparation, characterization and application for simulated antibiotic wastewater treatment

Forward osmosis (FO) is an emerging membrane separation process. However, the lack of high performance FO membrane hinders its wide application. In this study, self-sustained electrospun polyacrylonitrile (PAN) nanofiber supported polyamide (PA) thin film composite (PA/PAN-eTFC) membrane was developed, and evaluated for simulated tetracycline (TC) wastewater treatment. Specifically, a PAN nanofiber support was fabricated by electrospinning without any backing layer. The PAN nanofiber support was then laminated by a paper laminator. The laminated nanofiber support possessed good hydrophilicity and mechanical properties with water contact angle, stress and strain of 32.3 +/- 1.3 degrees, 13 +/- 0.77 MPa and 68 +/- 0.28%, respectively. Polyamide composited membrane formed thereon demonstrated a low structural parameter (S = 168 mu m), high permselectivity (A = 1.47 LMH bar-1, B = 0.278 LMH), and achieved over 57 LMH water flux using 2 M NaCl as draw solution. The PA/PAN-eTFC was successfully applied in a forward osmosis-membrane distillation (FO-MD) hybrid process for treatment of simulated TC wastewater and water production for the first time. TC rejection was higher than 99.9%, and 15-22% water recovery was obtained after 7 h running in the FO-MD hybrid process. Meanwhile, the PA/PAN-eTFC membrane exhibited a relatively long-term stable performance in the hybrid system. These results indicate the PA/PAN-eTFC is a promising FO membrane for wastewater treatment.