The Effect of Surface Modification on Removal of Ammonia by using Ice Formation

Ammonia-nitrogen is the predominant pollutant in the main drinking water sources, which is also, can cause failure in water treatment process due to the inhibition effect. Our study confirmed that the freeze separation process seems to have potential for ammonia removal from water. The effect of different operational factors including initial concentration of ammonia and ion species were also investigated, wherein the inhibition is ordered as follows: Mg2+>Ca2+>Na+>K+. Experimental data have shown that the surface modification of the nucleating agent plays a very crucial role in ice nucleation and the process obtained a ammonia removal efficiency as high as 93, 89 and 85% for the S-a, S and S-b spiked with 450 mg/L ammonia, respectively. In addition, the results also show that those four solutions have different ammonium removal speed and the ordered are as follows: S-a>S>S-b> only water aqueous solution. Moreover, the date also shows that this method reveals highly effective to remove ammonia in the real ground water. The mechanism study reveals that hydrophilic material became nucleation centers and promoted the freezing process. The hydrophobic material solution needs more time to freezing due to decreased of the freezing temperature.