Construction of Zinc Oxide/Nickel Ferric-Layered Double Hydroxide Composite for Efficient Adsorption of Erythromycin: Kinetic and Thermodynamic Investigation

Abstract

Erythromycin, a persistent antibiotic pollutant, poses challenges for wastewater treatment due to its stability and resistance to biodegradation. The current paper was designed to synthesize three solid adsorbents: nickel ferric-layered double hydroxide (NF), zinc oxide nanoparticles (Z), and zinc oxide/nickel ferric-layered double hydroxide composite (ZNF) for the effective removal of erythromycin (Ery). The features of the fabricated solid materials were fully investigated by employing X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR), thermogravimetric analysis (TGA), and textural characterization via nitrogen gas adsorption/desorption studies. The obtained results presented that the prepared ZNF has a nano-size (123 nm), surface area of 157.161 m²/g with pore radius of 2.67 nm, and rich with different surface chemical function groups. The batch adsorption tests revealed that ZNF achieved the maximum adsorption capacity of 273.51 mg/g at pH 7, 15 °C, 1.7 g/L as adsorbent dosage, and after 6 h of shaking time. The application of various nonlinear isothermal and kinetic models shows good consistency with the Langmuir and pseudo-second-order models. The thermodynamic studies illustrated that the adsorption was endothermic, favorable, and spontaneous. Moreover, all the samples had better reusability and stability after ten adsorption–desorption cycles ZNF loss only 3.1% of its removal efficiency. An interesting and attractive subject of study is the unique structure of ZNF as a pollutant adsorbent with a high adsorption capacity.