Composite nanofiltration membrane prepared by depositing barium alginate interlayer on electrospun polyacrylonitrile substrate

Interlayer-regulated thin-film nanofibrous composite (TFNC) membranes were fabricated extensively for seawater purification, but the mechanical and stability performance of the composite membranes continually existed a tremendous challenge. In this work, a composite nanofiltration (NF) membrane was prepared by interfacial polymerization (IP) method of piperazine (PIP) and trimesoyl chloride (TMC) combined through coating barium alginate (BaAlg) on the polyacrylonitrile substrate obtained by the electrospun technology. With the deposition of the BaAlg hydrogel interlayer, the diffusion rate of PIP depressed and a homogeneous polyamide (PA) selective layer could be realized. The TFNC membranes of BaAlg interlayer modified via cross-linking sodium alginate (SA) with barium ions had higher stability, hydrophilicity and separation performance. The impact of SA content, operating pressure and time on the NF membrane desalination performance was explored. The mechanical properties of composite NF membranes were greatly improved and the tensile strength could be as high as 8.17 MPa. The preferred TFNC membranes could display a permeation flux of 112.5 ± 1.8 L·m−2·h−1, and the Na2SO4 retention rate was up to 98.7 ± 0.5 %. The prepared NF membranes are of great importance in seawater purification, which is conducive to obtaining high performance with excellent development potential.