Facile synthesis of layer-by-layer decorated graphene oxide based magnetic nanocomposites for β-agonists/dyes adsorption removal and bacterial inactivation in wastewater

Abstract

Abstract The escaped β-agonists and dyes during conventional wastewater treatment processes pose a non-negligible threat to humans and environment. In this study, a novel method based on the thiol modified chitosan magnetic graphene oxide nanocomposite (Fe3O4@SiO2/GO/CS/MPTS) was reported for the effective removal of β-agonists and dyes as well as the disinfection of microorganisms in complex wastewater. The surface and textural properties of the nanocomposites were characterized through Fourier transform infrared spectrums (FT-IR), scanning electron micrographs (SEM), X-ray photoelectron spectra (XPS), vibrating sample magnetometry (VSM) and zeta-potential measurements analysis. And the influence of several parameters (pH, contact time, pollutants concentration and adsorbent dose) on the adsorptive performances of nanoparticles was carefully estimated by the batch adsorption studies. According to Langmuir isotherm, the maximum adsorption capacities of Fe3O4@SiO2/GO/CS/MPTS were 215.52, 263.85, 184.16, 558.66 and 613.50\xa0mg\xa0g−1 for dopamine (DA), clenbuterol (CLE), orciprenaline (ORC), methylene blue (MB) and crystal violet (CV), respectively. The data of the adsorption kinetic and adsorption isotherm fitted well with pseudo-second order kinetic and Langmuir isotherm models, which indicating the existence of chemical adsorption and monolayer adsorption process. The adsorption mechanisms of β-agonists and dyes were ascribe to electrostatic interaction, π–π interaction and cation−\xa0π interaction. Moreover, the nanocomposite could be reused for four cycles for β-agonists and five cycles for dyes with minor loss of adsorption capacity. In addition to its excellent adsorption capacity, the as-prepared nanocomposite exhibited the highest antibacterial activity of 88.94% and 100% against E. coli and S. aureus at the nanomaterial concentration of 75\xa0μg\xa0mL−1, as compared to GO showing 31.67% and 26.87% antibacterial activity for E. coli and S. aureus, respectively. Predictably, this magnetic nanomaterial with high adsorption efficiency and excellent antibacterial activity provided a potential method for the removal of pollutants and inactivation of bacterial in wastewater.