Adsorption characteristics of nitrite on Friedel’s salt under the landfill circumstance

• The adsorption capacity of the nitrite on Friedel’ salt is 3.817 mg g−1.
• The adsorption can be well described by the Lagergren-first-order kinetics.
• The adsorption agrees well to the Langmuir–Freundlich model.
• The adsorption can be affected by the variation of the landfill circumstance.
• The migration of nitrite in the landfill can be affected by Friedel’s salt.

Landfill sites contain abundance of Friedel’s salt. In this study, Friedel’s salt was prepared by a coprecipitation method and characterized by the X-ray diffraction (XRD) pattern and Fourier transform infrared (FTIR) spectroscopy. The adsorption characteristics of nitrite on Friedel’s salt were investigated to reveal the effect of Friedel’s salt on the migration of nitrite in the landfill. The adsorption was an exothermic process and could be well described by Lagergren-first-order kinetics and Langmuir–Freundlich model, with a maximum adsorption capacity of 3.817 mg g−1. Low pH was beneficial to the adsorption process. However, the Cl−, SO42−, PO43− and organic matter in the leachate could restrict the adsorption to a low level. The results suggested that Friedel’s salt could affect the migration of nitrite in the landfill, which was related with the variation of the landfill circumstance.

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