Design and optimization of a novel Y-Fe-GO magnetic adsorbent for simultaneous removal of tetracycline and arsenic and adsorption mechanisms

Composite pollution containing antibiotics and heavy metals is still a challenge for the field of wastewater treatment. In this study, a novel magnetic Y-Fe modified GO adsorbent (YMGO) was designed and prepared for the simultaneous and effective removal of tetracycline (TC) and arsenic with superior separation ability. The adsorbents were optimized by varying the ratios of Y(III):Fe(III):Fe(II), of which the adsorption of both TC and As(V) by YMGO-2 was higher than many other reported adsorbents. The scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) results verified that the Y-Fe based particles were successfully and homogenously in-situ generated on GO matrix. More importantly, the presence of TC or As(V) showed significantly adverse effect on the adsorption of As(V) or TC in the composite system, compared with the adsorption in single TC/As(V) system. 2D Fourier transform infrared correlation spectroscopy (2D-FTIR-COS) and XPS analyses indicated that the hydrogen bond (HB), π-π electron-donor–acceptor (EDA), n-π, and cation bonding bridge interactions were involved in the adsorption of TC, while ion-exchange between As(V) and Y/Fe-OH groups played important roles in the uptake of As(V). Notably, in combined system, the interaction of As(V) with Y/Fe cations outperformed the anion-π interaction formed between As(V) and TC, leading to a significant suppression of TC adsorption. Whereas the competition for Y/Fe cations by TC caused a reduction in As(V) adsorption. Furthermore, the YMGO-2 exhibited excellent magnetic separation performance and reusability for both TC and As(V). This study can provide a powerful material for the simultaneous treatment of TC and As(V) containing wastewater and a mechanistic insight into the co-removal of combined pollutants.