Chitosan/polyvinylpyrrolidone/polyvinyl alcohol/carbon nanotubes dual layers nanofibrous membrane constructed by electrospinning-electrospray for water purification

Nanofibrous membrane have great potential in the field of water purification due to the high porosity and large specific surface area. Herein, a dual layers nanofibrous membrane was prepared by combining an active layer containing carbon nanotubes (CNTs) with a porous chitosan (CS)/polyvinylpyrrolidone (PVP)/polyvinyl alcohol (PVA) nanofibrous support layer via electrospinning-electrospray technique for highly efficient heavy metal and organic pollutants removal. Incorporating CNTs into the active layer offered additional nanochannels which significantly enhanced pure water permeate flux (1533.26 L·m^-2·h^-1) and heavy metal ions/dyes rejection (Cu²⁺ 95.68 %, Ni²⁺ 93.86 %, Cd²⁺ 88.52 %, Pb²⁺ 80.41 %, malachite green 87.20 %, methylene blue 76.33 %, and crystal violet 63.39 %). The optimal membranes were formed with a thickness of 20 μm and a roughness of 142 nm while still showing good perm-selectivity compared with commercial PVDF membrane. Moreover, the constructed membrane exhibited good antifouling property and long-term stability during filtration process. This work provides a new strategy to fabricate advanced separation membranes for water treatment.