•The laminated nanofiber support showed high hydrophilicity and mechanical strength.•The nanofiber-supported TFC has high permselectivity and low structural parameter.•A high water flux of 57 LMH was obtained against 2 M NaCl solution.•The TFC was used in a FO–MD process for TC wastewater treatment.•TC rejection was over 99.9% and wastewater can be reclaimed in a FO–MD process.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°, 13 ± 0.77 MPa and 68 ± 0.28%, respectively. Polyamide composited membrane formed thereon demonstrated a low structural parameter (S = 168 µm), 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.

Novel Fe3O4/polyacrylonitrile (PAN) composite nanofibers (NFs) were prepared by a simple two-step process, an electrospinning and solvothermal method. Characterization by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) demonstrated formation of a uniform nanoparticles coating (about 20 nm in thickness) on the PAN nanofiber backbone. The coating was constructed by well-crystallized cubic phase Fe3O4 nanoparticles as examined by X-ray diffraction spectroscopy (XRD). The coating doubled the specific surface area of NFs, from 8.4 to 17.8 m2 g–1, as confirmed by nitrogen sorption isotherm analysis. To evaluate the feasibility of Fe3O4/PAN composite NFs as a potential adsorbent for antibiotic removal, batch adsorption experiments were conducted using tetracycline (TC) as the model antibiotic molecule. The results showed that Fe3O4/PAN composite NFs were effective in removing TC with no impactful loss of Fe in the pH regime of environmental interest (5–8). The adsorption of TC onto Fe3O4/PAN composite NFs better fitted the pseudo-second-order kinetics model, and the maximum adsorption capacity calculated from Langmuir isotherm model was 257.07 mg g–1 at pH 6. The composite NFs also exhibited good regenerability over repeated adsorption/desorption cycles. Surface complexation between TC and the composite NFs contributed most to the adsorption as elucidated by X-ray photoelectron spectroscopy (XPS). This highly effective and novel adsorbent can be easily modularized and separated, promising its huge potential in drinking and wastewater treatment for antibiotic removal.Keywords: adsorption; antibiotic; electrospinning; nanofiber; solvothermal;

•FO is effective for tetracycline recoverable separation from antibiotic wastewater.•Membrane orientation affects fouling & ICP, playing an important role in FO.•Increasing feed velocity raises shear stress & k value, reducing membrane fouling.•Solution pH significantly influences the tetracycline separation.•TC rejection and water flux could be maintained with hydraulic cleaning in FO mode.To minimize the risk of antibiotic wastewater generated by the pharmaceutical industries, the potential separation efficacy of tetracycline (TC) from aqueous solution using forward osmosis (FO) process with thin film composite membrane was systematically studied. First, the microstructure and transport properties of TFC membrane were characterized. Then, the effects of membrane orientation, feed velocity and solution pH on the behavior of the FO process for TC separation were studied. Finally, the performance of TFC membrane for TC separation in a long-term FO mode operation was investigated. The results showed that the membrane performance in FO mode (active layer facing the feed solution) and PRO mode (active layer facing the draw solution) was highly affected by solute resistivity (K) value. The water flux and TC rejection achieved over 20 LMH and 99.0% in FO mode, respectively. High TC concentration factor (CF) of 2.6 was obtained in FO mode, indicating the concentrated TC solution could be harnessed to recover the TC by conventional crystallization. However, severe water flux decline accompanied with low tetracycline CF was found in PRO mode, which was mainly attributed to serious fouling and high K value occurred in the porous support. With the flow velocity rising, the shear stress and mass transfer coefficient (k) on the membrane surface increased, alleviating the membrane fouling. Acidic environment would favor the separation due to the change of TC speciation and TFC membrane properties. A long-term testing demonstrated that more than 97% TC rejection and 74% water flux recovery were well maintained with simple hydraulic cleaning after 5 cycles FO mode operation. This work implied that the FO based technology could be developed as an effective alternative for the treatment of tetracycline antibiotic wastewater as well as the recovery of antibiotics from the wastewater.

We report a simple and rapid method for fabricating a surface-enhanced Raman scattering (SERS) substrate, which offers good flexibility, excellent optical transparency, and high SERS activity. Specifically, the SERS substrate (AuNPs/PMMA film) was obtained through self-assembly of gold nanoparticles (AuNPs) on newborn poly(methyl methacrylate) (PMMA) template. The UV–vis spectroscopy analysis and scanning electron microscopy observation revealed that the gold nanoparticles were closely assembled on the flexible and transparent PMMA template. The fabricated AuNPs/PMMA film SERS substrate allowed detection of model molecule, malachite green isothiocyanate, at a concentration as low as 0.1 nM, and exhibited good reproducibility in the SERS measurement. The Raman enhancement factor (EF) of the AuNPs/PMMA film was found to be as high as (2.4 ± 0.3) × 107. In addition, measure of residual malachite green on fish surface was carried out, and the result indicated that the AuNPs/PMMA film had great potential in the in situ ultrasensitive detection of analyte on irregular objects.