Study on the performance of alginate hydrogel filtration membrane crosslinked by different metal ions

Four kinds of hydrogel filtration membranes were prepared from sodium alginate (NaAlg) by cross-linking sodium alginate with Ca2+, Cu2+, Ba2+, and Zn2+ solutions. The four membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TG). The mechanical properties of the four membranes, the swelling properties in saline and the retention properties of four inorganic salts and five dyes were studied. The pore size distribution and retention mechanism were analyzed by molecular dynamics simulation. The results showed that copper alginate (CuAlg) and barium alginate (BaAlg) hydrogel filtration membranes had better mechanical properties, anti-swelling properties and dye/salt separation properties. The alginate hydrogel filtration membrane has the advantages of simple production method, green and renewable raw materials, and no use organic solvents, and has good application prospects in the fields of dye desalination and other fields.