Cellulose nanocrystals/graphene oxide composite for the adsorption and removal of levofloxacin hydrochloride antibiotic from aqueous solution

<p><span><span><a name="_Hlk33498008">Residual antibiotics in water are often persistent organic pollutants. </a><a name="_Hlk32994933">The purpose of this study was </a>to prepare a <a name="_Hlk32132836">cellulose nanocrystals/graphene oxide composite</a> (CNCs-GO) with a three-dimensional structure for the removal of the antibiotic levofloxacin hydrochloride (Levo-HCl) in water by adsorption. The Scanning Electron Microscope (SEM), Fourier Transform Infrared (FT-IR), Energy dispersive spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and other characterization methods were used to study the physical structure and chemical properties of the CNCs-GO. The three-dimensional structure of the composite material rendered a high <a name="_Hlk32994964">surface area and electrostatic </a>attraction, resulting in an increased adsorption capacity of the CNCs-GO for Levo-HCl. Based on the Box–Behnken design, the effects of different factors on the removal of Levo-HCl by the CNCs-GO were explored. The composite material exhibited good antibiotic adsorption capacity, with a removal percentage exceeding 80.1% at an optimal pH of 4, adsorbent dosage of 1.0 g L⁻¹, initial pollutant concentration of 10.0 mg L⁻¹, and contact time of 4 h. The adsorption isotherm was well fitted by the Sips model, and kinetics studies demonstrated that the adsorption process conformed to a quasi-second-order kinetics model. Consequently, the as-synthesized CNCs-GO demonstrate good potential for the effective removal of antibiotics such as levofloxacin hydrochloride from aqueous media.</span></span></p>