Macromolecular grafting of carboxyl polymers on the surface of non-woven fabrics and their adsorption behavior on metal cations

In order to address the issues of the time-consuming, the low density of functional groups and the instability of mussel-inspired adsorbents, an efficient in situ cross-linked mussel-inspired coating-assisted macromolecular grafting strategy was proposed to prepare a polyacrylic acid (PAA) grafted polypropylene nonwoven (PP-g-PAA) for the efficient removal of heavy metal ions. The mussel-inspired coating was formed by rapid deposition in the presence of oxidizing agents and polyamines, and then thiol-terminated polyacrylic acid (PAA-SH) prepared by thiol-ene click reaction and glutaraldehyde were added in situ, and then PAA brushes were introduced on the surface of the polypropylene nonwoven via the Michael addition Schiff base reaction between the thiol and o-benzoquinone, and the improvement of the stability of the adsorbent was achieved through in situ formation of the three-dimensional cross-linked structure. A high density carboxyl group functionalized adsorbent with a grafting rate up to 38.98% was obtained, which also exhibited unprecedented tolerance to strong acid, alkali and polar organic solvents. Meanwhile, grafting on polyester nonwovens, sponges and PVDF membrane substrates confirmed the versatility of the proposed method. The PP-g-PAA was characterized by SEM, IR and XPS, and the adsorption behaviors of the adsorbent for Pb2+, Cu2+ and Cd2+ were systematically investigated. The results showed that the adsorption capacity of PP-g-PAA was nearly twice as high as that of the mussel-inspired adsorbent. The adsorption mechanism was also well investigated.