In this study, phosphorylated polyacrylonitrile hollow fiber membrane was synthesized by reacting aminated polyacrylonitrile hollow fiber membrane with phosphinic acid in a Mannich reaction. The batch single-factor measurements revealed that the phosphorylated polyacrylonitrile (PPAN) membrane had an outstanding ability for Hg2+ adsorption. Thermodynamic investigations indicated that the adsorption process was homogenous, and the theoretical maximum adsorption capacity predicted by the Langmuir model was 371.75 mg·g-1. The PPAN membrane was able to successfully chelate Hg2+ ions and attain saturation in 4 h, demonstrating that the reaction was chemically controlled by the adsorption kinetics. Based on the FT-IR and XPS spectral characterization data, successful phosphinic acid group grafting was proven, and a plausible mechanism for Hg2+ adsorption by PPAN membranes was presented. Furthermore, the five adsorption-desorption cycle experiments revealed that PPAN hollow fiber membranes had outstanding reusability, indicating a possible use for removing heavy metal ions from wastewater.
Keywords: Adsorption; Hollow fiber membrane; Modification; Polyacrylonitrile; Recyclability; Selectivity.
© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.