Box–Behnken design in optimizing heavy metal removal from wastewater using selenium hybridized graphitic carbon nitride nanocomposites

Abstract

In this study Box–Behnken designs and response surface methodology (BBD-RSM) was used for optimizing heavy metal adsorption. The hazardous effect of wastewater on agriculture, animals and human as well makes its remediation is being considered a global challenge. Herein, a novel visible-light-responsive selenium-doped graphitic carbon nitride composites via the exfoliation of g-C3N4 polymer with different concentrations of selenium precursor (1 w%, 2.5 w%, 5 w%, with respect to the weight of g-C3N4) under ultrasound irradiation condition to produce the hybridized the corresponding polymeric nanocomposites (5%Se/g-C3N4), (10%Se/g-C3N4) and (25%Se/g-C3N4) denoted names C1, C2, C3; respectively. Full chracterization for the nanocomposites was performed using scanning electron microscope (SEM), X-ray diffraction (XRD), UV–Vis diffuse reflection spectroscopy. The as-prepared nanocomposites compared to pure g-C3N4 were applied in wastewater treatment for a real sample collected from Siwa Lake that suffered from increasing the heavy metal ions due to industrial drainage. Testing the catalytic activity of the prepared composites in treatment of wastewater sample collected from Siwa Lake in Egypt affected by the industrial drainage that was analyzed to determine the occurred polluted heavy metal ions. It was indicated that this sample contained Ca(II), Zn(II), Fe(II), Cu(II), Mn(II) and Cd(II) ions. The metal adsorption measurements were developed using atomic absorption spectroscopy (AAS) to show the removal efficiency of metal ions.