Activated carbon-polyethyleneimine-alginate composite fiber for scavenging pharmaceuticals with different charges from aqueous solutions

Activated carbon (AC) is a potential adsorbent for water purification, though it is difficult to separate after use. To solve this problem, for the first time, the ternary composite fiber (ACPEIA) of AC, polyethyleneimine (PEI), and alginate (A) was fabricated as a multifunctional adsorbent for scavenging pharmaceuticals with different charges from the aqueous environment. The hydroxyl functional group of AC was bonded with the aldehyde group of glutaraldehyde through nucleophilic addition resulting in adduct containing free aldehyde moiety for the action of cross-linker. The aldehyde functionalized AC was crosslinked with the amino group of PEI and the hydroxyl group of A resulting in ACPEIA. The carboxyl group of ACPEIA was further crosslinked with calcium ion through ionotropic gelation to give a stable fiber. The fiber demonstrated as a scavenger for removal of model contaminants with different charges such as 1-naphthol (NPT) as neutral, diclofenac (DCF) as anionic, and amitriptyline (AMT) as cationic pharmaceuticals at pH 6.5. The fiber revealed a maximum adsorption capacity of 814 µmol ¬¬g-1 for NPT, 450 µmol g-1 for DCF, and 410 µmol g-1 for AMT. FTIR and XPS spectra of the fiber before and after sorption supported the adsorption mechanism like electrostatic interaction.