Comparative Analysis on Nitrate Removal from Aqueous Solution by Adsorption onto Various Materials

Elevated concentration of nitrate results in eutrophication of natural water bodies affecting the aquatic environment and reduces the quality of drinking water. This in turn causes harm to people’s health, especially that of infants and livestock. Adsorption is promising process due to being economical and less production of sludge and fewer disposal problems in removal of nitrate from water. The main objective of this article is to review the mechanism of removal of nitrate from water by adsorption process, using activated carbon, clay, chitosan, agricultural, and industrial wastes as adsorbents. This paper compares the enhanced nitrate adsorption capacities achieved by the modifications, and the mechanisms of adsorption, and presents advantages and drawbacks of the techniques. Modified chitosan shows higher uptake of NO۳- compared to other conventional adsorbents. Agricultural wastes, after surface modification, have also been explored for NO۳- removal and, in some cases, these wastes show an appreciable potential for NO۳- removal. For an adsorbent to be effective in a plant-scale water treatment system, it should have the following characteristics: large nitrate adsorption capacity, high nitrate selectivity in the presence of other ions, low cost, capable of efficient regeneration for multiple re-use of the adsorbent, and good hydraulic conductivity when used in fixed-bed columns.

Keywords:

Water treatment , Nitrate removal , Adsorption , Activated carbon