The adsorption characteristics were investigated with differently sized agglomerates of zeolite particles for moving-bed applications. As a result, the saturation amount of NO gas adsorbed on the agglomerates was almost the same as that of the primary particles, and thus the negligible influence of binder was confirmed. Relying on the measured adsorption rate for the agglomerates of different sizes, the region of favorable agglomerate size for the moving-bed application was identified as 0.8 to 1.3 x 10(-3) in where the adsorption rate is still appreciable and the agglomerates are large enough to ensure smooth flow inside the apparatus. As an example of the application of the proved adsorption rate equation, the influence of operational parameters was theoretically demonstrated on the performance of a co-current moving-bed adsorber. It was found that, in order to attain the significant gas cleaning efficiency during the treatment of a large volume of gas, the solids velocity should be increased and the adsorbent recycle system should be used to improve the utilization of adsorbent.