Technological Parameters for Preparation and Granulation of Ammonium Ion-Exchange Material

As a raw material, kaolin was modified to prepare a high-performance ammonium ion-exchange material.According to cation-exchange capacity (CEC) measurement, the prepared ammonium ion-exchange material has an ammonium ion-exchange capacity greater than 75 mg/g and can be used to remove ammonia nitrogen in water treatment. A pharmaceutical extruder-rounder was used to study the effects of granulation process. Polyethylene glycol6000 (PEG-6000) was used as the pore-forming agent and calcining temperature of 650 ℃ was used as the optimal condition. NMR data indicate that 27Al is mainly converted from hexa-coordinated Al to tetra-coordinated Al during the modification. Compared with 29Si in the original kaolin, 29Si in the modified kaolin does not have an obvious change. A comparison of the data with Langmuir and Freundlich isotherm models shows a good correlation. The Freundlich model describes the process more accurately, and the adsorption process of ammonia nitrogen in water with the ammonium ion-exchange material closely matches the pseudo-second-order reaction.