Preparation of low-cost functionalized diatomite and its effective removal of ammonia nitrogen from wastewater

A low-cost functionalization method was used to treat diatomite, and an efficient adsorbent for ammonia nitrogen was prepared by optimizing the functionalization conditions. The functionalized diatomite (DTC_A-Na) was characterized by SEM, EDS, BET, XRD, FT-IR, and TG. The results demonstrate that DTC_A-Na has excellent adsorption performance after being modified with H₂SO₄ (60.00 wt.%), NaCl (5.00 wt.%), and calcination at 400 °C for 2 h. While studying the effect of adsorption factors on the removal of ammonia nitrogen, the kinetic and thermodynamic behaviors in the adsorption process were discussed. The removal efficiency of the simulated wastewater with the initial ammonia nitrogen concentration of 10.00 mg L^-1 by the DTC_A-Na was more than 80% when the contact time was 60 min, pH was 6-10, the dosage of adsorbent was 1.00 g, and the temperature was 25 °C. The adsorption process of ammonia nitrogen was conformed to the pseudo-first-order and Langmuir isothermal model. The removal efficiency of ammonia nitrogen was still above 80% after 5 times adsorption-desorption experiments. The DTC_A-Na has a brighter prospect of application in the field of ammonia nitrogen wastewater treatment due to its excellent adsorption performance and low-cost advantage.