Preparation of AC/KOH and AC/Fe3O4/ZnO nanocomposite from waste rice straw for the removal of cyclophosphamide from aqueous solutions

Abstract

Abstract In this study, rice straw was used for synthesizing AC/KOH and AC/Fe3O4/ZnO as fresh adsorbents for the elimination of Cyclophosphamide (CP) from water samples. In so doing, the crystalline form, the chemical compound and the morphology of the adsorbents were characterized utilizing scanning electron microscopy (SEM), X-ray diffraction (XRD) spectrometry, Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), pHpzc, and Brunauer, Emmett, and Teller (BET) methods. Then, the optimum conditions for removal efficiency of CP onto AC/Fe3O4/ZnO nanocomposite were obtained at CP concentration of 20 mg L−1, AC/Fe3O4/ZnO nanocomposite dose of 0.01 g, solution pH of 7, equilibrium time of 45 min, and temperature of 25 °C. The CP adsorption data was modeled by isotherm models (Langmuir, Freundlich, and Temkin) and kinetic models (pseudo-first-order, pseudo-second-order, and intraparticle diffusion) using the origin nonlinear software version 6.1. Based on the results obtained, the maximum adsorption capacities of CP on AC/KOH and AC/Fe3O4/ZnO were 185.6 and 224.3 mg g−1, respectively. In addition, the results of the desorption tests showed that AC/KOH and AC/Fe3O4/ZnO were comfortably regenerated using methanol and sodium hydroxide.