Novel adsorbent hydrous bismuth oxide for the removal of nitrate from aqueous solutions

Abstract

Hydrous bismuth oxides (HBOs) have the sorptive property to remove nitrate from water. HBOs are also efficient in removing other competitive anions like bicarbonates and sulfates from water. To use HBOs as sorptive filtration media, their characteristics in terms of crystallinity and particle size are important. The objective of this study was to explore the kinetic and equilibria study of HBOs for the removal of nitrate from water. For the present study, three hydrous bismuth oxides, HBO1, HBO2, and HBO3, were prepared under increasing volumetric presence of hydroxide. Both HBO2 and HBO3 were found to be almost equally efficient for nitrate removal from aqueous solutions. Because HBO2 is a superior bismuth oxide, kinetic and equilibrium studies were performed with HBO2. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) techniques were used to characterize the adsorbents. The pH of point of zero charge (pHPZC) of the HBOs also supported the results of the removal of nitrate. © 2014 American Society of Civil Engineers.