Removal and adsorption mechanism of tetracycline and cefotaxime contaminants in water by NiFe2O4-COF-chitosan-terephthalaldehyde nanocomposites film

Adsorption of tetracycline (TC) and cefotaxime (CTX) by novel NiFe2O4-COF-chitosan-terephthalaldehyde nanocomposites film (NCCT) was explored. To assess the feasibility of NCCT as a potential adsorbent for TC and CTX removal, a series of adsorption experiments were conducted. These results showed that the chemical crosslink of chitosan with terephthalaldehyde (TPA) restricted NCCT degradation of acid. In addition, NCCT as a film adsorbent could be separated completely in only 2 s without mass loss, much faster than any other magnetic materials. The abundant functional groups of chitosan, COF and TPA could significantly improve the adsorption capacity of NCCT on antibiotics. The pseudo-second-order kinetics model better illustrated the adsorption of TC and CTX onto NCCT, and the maximum adsorption capacity are 388.52 mg g−1 and 309.26 mg g−1, respectively. The nanocomposites film NCCT also exhibit excellent reproducibility after six adsorption cycles. In addition, various analysis results implied the adsorption mechanism of TC on NCCT was mainly through complexation, cation exchange, electrostatic attraction, hydrogen bonding and the π–π interaction. For CTX, the mechanism of adsorption included condensation reaction, electrostatic attraction, hydrogen bonding and π–π interaction. This kind of high-efficiency and novel nanocomposites film adsorbents can be ultrafastly separated from water, verifying NCCT has huge potential in water treatment for antibiotic contaminants removal.