Desalination of dye and protein by Ba2+/Ca2+ co-crosslinked alginate filtration membrane loaded on polypropylene non-woven

Calcium alginate hydrogel filtration membranes show excellent fouling resistance, but the poor mechanical properties and instability limit the use of the membranes. In this paper, sodium alginate was co-crosslinked with Ba2+ and Ca2+ to prepare barium alginate/calcium alginate composite hydrogel membrane loaded on polypropylene non-woven (Ba/CaAlg-PP). The morphology, structure, and swelling rate of the composite filtration membrane were characterized. The fracture strength of the Ba/CaAlg membrane reached a maximum value of 2.47 MPa. The rejection rates of Ba/CaAlg-PP membrane for Methyl blue and NaCl were close to 100 % and <8.0 %, respectively. Meanwhile, the flux of the Ba/CaAlg-PP membrane in dye/NaCl mixture was 43.2 L·m−2·h−1 and the selectivity coefficient of dye/NaCl reached 154.6. Ba/CaAlg-PP membranes exhibited excellent permeability, rejection and long-term stability in protein desalination. The results of simultaneous fluorescence spectroscopy and molecular dynamics simulations showed that the Ba2+ in the Ba/CaAlg-PP membrane did not disrupt the helical structure of BSA. The Ba/CaAlg-PP membrane has a wide range of applications prospect in proteins and dyes desalination.