Removal of ciprofloxacin and cephalexin antibiotics in water environment by magnetic graphene oxide nanocomposites; optimization using response surface methodology

Abstract

This study investigates the efficient removal of ciprofloxacin (Cip) and cephalexin (Cep) using magnetic graphene oxide (Fe3O4/GO) as an adsorbent. To this end, the magnetic nanocomposite was synthesized via a co-precipitation method. The surface and properties of the adsorbent were characterized using pHpzc, XRD, FE-SEM, FT-IR, VSM, and TEM techniques. The XRD and FT-IR results were consistent with those of previous results. The FE-SEM and TEM results of the synthesized nanoparticles were less than 30 nm in size and showed a spherical shape. The maximum saturation magnetization of the Fe3O4/GO nanocomposite was 45.97 emu g−1. Also, the pHpzc of the nanocomposite was 6.2. The optimal conditions for independent variables were found to be an antibiotic concentration of 15 mg L−1, pH of 7, a contact time of 33 min, and a nanocomposite amount of 0.55 g. Furthermore, under these optimal conditions, Fe3O4/GO magnetic nanocomposite removed 96.39 % of Cip and 97.69 % of Cep from the water samples. Among different eluents (i.e., acetonitrile, chloroform, methanol, and ammonia), significant desorption of Cip and Cep antibiotics was achieved using methanol. Furthermore, applying the Fe3O4/GO magnetic nanocomposite on real water samples revealed that nanocomposite could remove Cip and Cep antibiotics in the range of 89.96–95.83 %. Considering the high potential of Fe3O4/GO magnetic nanocomposite in removing Cip and Cep antibiotics, it can be considered a suitable candidate for removing antibiotics from contaminated water sources.

Keywords

• Antibiotics
• Removal
• Magnetic graphene oxide
• Central composite design