湿法冶金清洁生产技术国家工程实验室知识库

Nitrite is an important pollutant appearing in the large amount of wastewater from flue gas denitrification process. Its removal is essential for wastewater discharge or reuse. In this paper, we made an attempt to remove nitrite using ion exchange resin (IXR) by conducting batch experiments first, in which adsorption equilibrium and kinetics were determined. Fixed bed experiments were then carried out to investigate bed breakthrough and elution behavior. Isotherm data showed that nitrite adsorption on IXR fitted Freundlich model better than Langmuir model. Kinetic data from batch experiments were well correlated with second-order reversible kinetics model. From bed experiments, it was found that increase in flow rate and inlet concentration decreased breakthrough time, but the capacity of saturated adsorption stayed almost the same. It was also found that the capacity of adsorption decreased in the presence of other anions. Breakthrough curves under various operating conditions were well predicted by the Thomas model, and nitrite ions adsorbed in the bed could be completely eluted by using 3.0 wt% NaCl solution at flow rate of 3.0 L center dot h(-1).