Application of central composite design for the simultaneous removal of tetracycline and cefixime using nanoscale zero-valent iron modified by montmorillonite and graphene oxide

Abstract

In the current study, montmorillonite and graphene oxide supported nanoscale zero-valent iron (Mt–nZVI–GO) composite was synthesized for the simultaneous elimination of tetracycline (TC) and cefixime (CFX) from aqueous environments. The fabricated adsorbent was characterized using different techniques, including scanning electron microscopy, energy dispersive X-ray, Fourier transform infrared spectroscopy, X-ray diffraction analysis, vibrating sample magnetometer, and Brunauer–Emmett–Teller analysis. The central composite design based on response surface methodology was applied to assay the effects of experimental variables, including pH (4–8), the adsorbent dosage (0.2–0.4 g/L), and contact time (10–30 min) for efficient simultaneous removal of TC/CFX. The optimal conditions at a pH of 4, adsorbent dosage of 0.4 g/L, and the contact time of 30 min resulted in 92.34% (actual) and 91.23% (predicted) removal. Eventually, the Mt–nZVI–GO nanocomposite can be an effective, inexpensive, and promising adsorbent for removing TC/CFX from wastewater of the hospital and pharmaceutical industry.