Arabic Gum-Grafted-Hydrolyzed Polyacrylonitrile@ZnFe2O4 as a Magnetic Adsorbent for Remediation of Levofloxacin Antibiotic from Aqueous Solutions

Fereshte Hassanzadeh-Afruzi; Farhad Esmailzadeh; Golnaz Heidari; Ali Maleki; Ehsan Nazarzadeh Zare

doi:10.1021/acsomega.2c06555

Arabic Gum-Grafted-Hydrolyzed Polyacrylonitrile@ZnFe₂O₄ as a Magnetic Adsorbent for Remediation of Levofloxacin Antibiotic from Aqueous Solutions

ACS Omega. 2023 Feb 10;8(7):6337-6348. doi: 10.1021/acsomega.2c06555. eCollection 2023 Feb 21.

Authors

Fereshte Hassanzadeh-Afruzi¹, Farhad Esmailzadeh¹, Golnaz Heidari¹, Ali Maleki¹, Ehsan Nazarzadeh Zare²

Affiliations

¹ Catalysts and Organic Synthesis Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Iran.
² School of Chemistry, Damghan University, Damghan 36716-45667, Iran.

Abstract

The Arabic gum-grafted-hydrolyzed polyacrylonitrile/ZnFe₂O₄ (AG-g-HPAN@ZnFe₂O₄) as organic/inorganic adsorbent was obtained in three steps using grafted PAN onto Arabic gum in the presence of ZnFe₂O₄ magnetic nanoparticles and then hydrolysis by alkaline solution. Fourier transform infrared (FT-IR), energy-dispersive X-ray analysis (EDX), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and the Brunauer-Emmett-Teller (BET) analysis analyses were used to characterize the chemical, morphological, thermal, magnetic, and textural properties of the hydrogel nanocomposite. The obtained result demonstrated that the AG-g-HPAN@ZnFe₂O₄ adsorbent showed acceptable thermal stability with 58% char yields and superparamagnetic property with magnetic saturation (Ms) of 24 emu g^-1. The XRD pattern showed that the semicrystalline structure with the presence of ZnFe₂O₄ has distinct peaks which displayed that the addition of zinc ferrite nanospheres to amorphous AG-g-HPAN increased its crystallinity. The AG-g-HPAN@ZnFe₂O₄ surface morphology exhibits uniform dispersion of zinc ferrite nanospheres throughout the smooth surface of the hydrogel matrix, and its BET surface area was measured at 6.86 m²/g, which was higher than that of AG-g-HPAN as a result of zinc ferrite nanosphere incorporation. The adsorption effectiveness of AG-g-HPAN@ZnFe₂O₄ for eliminating a quinolone antibiotic (levofloxacin) from aqueous solutions was investigated. The effectiveness of adsorption was assessed under several experimental conditions, including solution pH (2-10), adsorbent dose (0.0015-0.02 g) contact duration (10-60 min), and initial concentration (50-500 mg/L). The maximum adsorption capacity (Q _max) of the produced adsorbent for levofloxacin was found to be 1428.57 mg/g (at 298 k), and the experimental adsorption data were well explained by the Freundlich isotherm model. The pseudo-second-order model satisfactorily described the adsorption kinetic data. The levofloxacin was mostly adsorbed onto the AG-g-HPAN@ZnFe₂O₄ adsorbent via electrostatic contact and hydrogen bonding. Adsorption-desorption studies demonstrated that the adsorbent could be efficiently recovered and reused after four consecutive runs with no significant loss in adsorption performance.