Study on ammonianitrogen adsorption from low concentration wastewater by modified zeolite and its desorption
改性沸石吸附低浓度氨氮废水及其脱附的研究

Sodium chloride aqueous solution was used to modify the natural zeolite obtained from Zhejiang Province and the properties of low-concentration ammonia-nitrogen (NH3-N) adsorption from wastewater for the zeolites were studied. The adsorption isotherms, adsorption kinetics and dynamic adsorption adsorption were compared between the natural zeolite and the modified zeolite, and dynamic desorption of NH3-N from the modified zeolite was also conducted. The results showed that the equilibrium adsorption quantity increased with increasing equilibrium concentration and Freundlich equation was better to predict the experimental data than Langmuir equation. The modified zeolite had higher adsorption capacity than the natural zeolite. The adsorption kinetic data were fitted well by the pseudo second-order kinetic model. Forty-liter wastewater containing 20 mg/L NH3-N was effectively treated by the adsorption column with 105 g modified zeolite, which was 2.67 times that of the adsorption column with equal mass natural zeolite, and the concentration of NH3-N was less than 5 mg/L in the effluent. The desorption efficiency of NH3-N from the modified zeolite was to 95.2% using the mixture of NaCl and NaOH solution.