Modified carbon nitride as an efficient adsorbent for ammonia nitrogen with low concentration

The adverse effects of excessive ammonia on aquatic ecosystem have provoked the development of efficient methods for its removal. Here, we present a thermal copolymerization of melamine and sodium hydrogen carbonate and successfully introduce oxygen groups into the structure of g-C3N4, which is applied to low-concentration ammonia removal. Oxygen groups are introduced into g-C3N4 and increase its surface electron negativity. When the initial concentration of ammonia nitrogen is 18.74 mg L-1, the lowest concentration of it after adsorption is 1.43 mg L-1, and the ammonia nitrogen removal efficiency is 92.3%. The main reason for our material high performance on adsorption ammonium may be ascribed to deprotonated carboxylic acid, which has the ability to adsorb positively charged ammonium ions.