Abstract
Pharmaceuticals play a significant role in contemporary medicine. However, their overconsumption has raised national concerns due to their prevalence in water systems, thereby contributing to water pollution. First-generation cephalosporin antibiotics, including cephalexin monohydrate and cefadroxil, are typically prescribed for severe bacterial infections; however, their widespread use and improper disposal contribute to environmental contamination, particularly in aquatic ecosystems. The primary routes through which these pharmaceuticals enter aquatic ecosystems are pharmaceutical waste and hospital effluents, where they persist due to incomplete degradation. Exposure of non-target organisms to these antibiotics results in susceptibility to antimicrobial resistance, posing a significant threat to ecological stability. This project aimed to synthesize a novel nanoadsorbent involving a magnetic porous-porphyrin organic polymer (MP-POP). This synthesis integrates magnetite with a porous porphyrin organic polymer to enhance the efficiency of the nano adsorbent. Characterization techniques were utilized for a comprehensive understanding of the nanoadsorbent include Fourier Transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmet-Teller (BET) analysis, X-ray diffraction, and Zeta potential measurement. Under optimal conditions of pH 4.1, mass of adsorbent of 46 mg, and a temperature condition of 27 ℃, recovery efficiency rates of 93% for cephalexin monohydrate and 95% for cefadroxil were achieved. Equilibrium data acquisition involves the analysis of both linear and nonlinear adsorption isotherms, including the Langmuir, Freundlich, Dubinin-Radushkevich (D-R), Temkin, Sips, and Rendlic-Peterson (R-P) models. The data align closely with the Langmuir adsorption isotherm, yielding R² values of 0.9818 for cephalexin and 0.9804 for cefadroxil. Kinetic studies utilized pseudo-first-order and second-order models, as well as Elovich and intraparticle diffusion models, to identify the rate-determining step. The film diffusion or surface adsorption was identified as the rate-controlling step. Kinetic studies indicated that the adsorption mechanism is described by the pseudo-second-order model, with RSE values of 0.9996 for cephalexin and 0.9959 for cefadroxil. The thermodynamic investigation revealed that the adsorption of cephalexin and cefadroxil onto the MP-POP took place spontaneously, marked by an exothermic characteristic and a lower degree of randomness. In summary, the regeneration and reusability of MP-POP demonstrated a recovery efficiency rate exceeding 75%, thereby affirming the capability of MP-POP to be efficiently recovered and reused.