Nitrate (NO3-) and bicarbonate (HCO3-) are harmful for the water quality and can potentially create negative impacts to aquatic organisms, crops and humans. This study deals with the removal of… Click to show full abstract
Nitrate (NO3-) and bicarbonate (HCO3-) are harmful for the water quality and can potentially create negative impacts to aquatic organisms, crops and humans. This study deals with the removal of NO3- and HCO3- from contaminated wastewater using Fe-exchanged nano-bentonite and Fe3O4 nanoparticles. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, surface area measurement and particle size analysis revealed that the adsorbents fall under the nano-scale size range with high specific surface area, and Fe was successfully exchanged in the nano-bentonite clay. The kinetics of adsorption was well defined by pseudo-first order and pseudo-second order kinetic models for both NO3- and HCO3-. The Fe-exchanged nano-bentonite was a better performing adsorbent of the oxyanions than Fe3O4 nanoparticles. According to the Sips isothermal model, the Fe-exchanged nano-bentonite exhibited the highest NO3- and HCO3- adsorption potential of 64.76 mg g-1 and 9.73 meq g-1, respectively, while the respective values for Fe3O4 nanoparticles were 49.90 mg g-1 and 3.07 meq g-1. Thus, inexpensiveness and easy preparation process of Fe-exchanged nano-bentonite make it attractive for NO3- and HCO3- removal from contaminated wastewater with significant environmental and economic benefits.
               
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