Abstract: To evaluate the effectiveness of zeolite as a filling medium for permeable reactive barriers (PRB) in remediating NH4+ contaminated groundwater and the applicability of in-situ regeneration processes. Achieve the sustainable use of zeolites in removing NH4+ contamination from groundwater. This study combines the adsorption and ion exchange functions of zeolite with in-situ chlorination regeneration technology, based on the mechanism of NH4+ breakpoint chlorination removal, it was carried out through batch adsorption and ion exchange experiments, dynamic simulation tests, combined with mechanism analysis. The results indicate that when the zeolite dosage is 40 g/L, the initial pH is 7, and the adsorption time is 180 min, the removal efficiency is 92.47%, and the maximum adsorption capacity is 6.22 mg/g. Dynamic simulation experiments show that the chloride regeneration technology can remove 99% of the NH4+ adsorbed on zeolite, and there is almost no NH4+left in the regenerant. The NH4+ on the surface of the zeolite is first replaced by Na+ and then oxidized into N2. Both natural zeolite and modified zeolite adsorption columns showed good dynamic removal of NH4+, and the proposed in-situ zeolite regeneration process proved to be stable during continuous cycle tests, making it suitable for the treatment of NH4+ contaminated groundwater.

Key words: NH4+')">

NH4+, zeolites, permeable reactive barrier, regeneration, groundwater