Simultaneous removal of mixed contaminants by organoclays - Amoxicillin and Cu(II) from aqueous solution

The treatment of mixed contaminants in wastewater faces a significant challenge because of the distinct fate and transport mechanism of metals and organic contaminants. The present study explored the possibility of organoclays used to simultaneously remove amoxicillin (AMX) and Cu(II) from wastewater. The adsorption of AMX onto organobentonite (DK1) was 6 times higher than that using bentonite (control), while adsorption of Cu(II) on DK1 showed comparable results as that using bentonite. Adsorption isotherms indicated that AMX was well described by Langmuir isotherms, while Cu(II) adsorption data fitted well with Freundlich isotherms, and adsorption kinetics of both could be explained by the first-order and pseudo-second-order kinetic models. The exothermic nature of simultaneous adsorption of AMX and Cu(II) onto DK1 was disclosed by the thermodynamic study. Furthermore, DK1 was characterized using EDS and XRD, which confirmed the simultaneous adsorption of AMX and Cu(II) onto DK1 by evaluation of their morphologies and chemical compositions. Finally, the simultaneous adsorption of AMX and Cu(II) onto DK1 occurred through partition for AMX and ion-exchange for Cu(II). DK1 was further used to remove AMX and Cu(II) from industrial wastewater. More than 34.8% AMX and 43.6% Cu(II) were removed, indicating its great potential removal of mixed organic and metal contaminants.