Abstract:
A nitrogen removal granular material (MZ) was prepared from modified zeolite with the addition of polyvinyl alcohol (PVA) and sodium bicarbonate (NaHCO
3), and the effects of factors such as the dosage and pH on the adsorption performance of ammonia nitrogen (NH
4+-N) were investigated. The results showed that the removal rate of NH
4+-N by MZ was 94.0% under the conditions of MZ dosage of 5 g/L and initial pH of 7. The adsorption process of NH
4+-N by MZ was in accordance with the quasi-secondary kinetic model and Freundlich adsorption isotherm model, and this process was jointly affected by liquid film diffusion and intra-particle diffusion, and the saturated adsorption amount of NH
4+-N was 8.47 mg/g. The four common cations showed inhibitory effects on the adsorption of NH
4+-N by MZ in the order of K
+ > Na
+ > Ca
2+ > Mg
2+. After five cycles of regeneration, the MZ could still maintain more than 80% of NH
4+-N removal. Combined with the analytical results of material characterization, the adsorption of NH
4+-N by MZ is mainly due to chemical adsorption based on ion exchange, while physical adsorption contributes less.