Effective Removal of Nitrates from the Drinking Water by Chemical and Electrochemical Methods
Abstract
In the present study, the effective removal of nitrates from the water was investigated using the Nano alumina adsorbent and then the electrochemical method for the removal of nitrates using Pt anode and brass cathode were studied. Nano alumina has been used as an adsorbent to remove nitrates from aqueous solutions. The effects of contact time, adsorbent dosage and initial nitrate concentrations on the adsorption process have been investigated. The effects of pH and temperature on adsorption have been studied inorder to optimize the range. Furthermore, the electrochemical method for the removal of nitrates using a pt anode and a brass cathode has been observed to produce excellent results. The nitrate removal efficiency increases with electrolysis time in the current density range from 1 to 2 A dm-2. Maximum nitrate (NO3-) ions removal was achieved for nitrate (NO3-) ions concentrations of 200 mg/L after 90 minutes of electrolysis at a current density of 2 A dm-2. Direct nitrate reduction is possible at all nitrate concentrations and begins at a potential below 300mV vs. SCE in the cyclic voltammetry (CV) studies. From the CV and DPSV studies, we have known that electrocatalytic reduction has a direct relationship between current and electrode potential. In CV, the electrode potential was found to be below 300mV and DPSV showed that an electro-catalytic reduction occurred at a potential of 300mV. From these studies, we infer that NO3- ions are adsorbed on platinum electrode surfaces and desorbed from the surface. The adsorbed NO3- ion is converted into NO2- (Nitrite) ions on the electrode surface (this is the rate-determining step) and the NO2- ion is converted into NO, N2O, and finally into N2 gas.
