[Preparation and NH₄⁺-N Removal Performance of a Novel Filter Substrate Made from Sludges]

A novel absorbent was prepared by high-temperature calcination using waterworks terminal aluminum coagulation sludge as a raw material. This study discussed ammonia nitrogen adsorption performance of the adsorbent by static adsorption test, mainly investigated the influences of different initial pH, contact time and temperatures on the ammonia adsorption effect, and also analyzed the adsorption isotherms, kinetic and thermodynamic properties of adsorbent on the ammonia nitrogen. Experimental results showed that the adsorbent had a better effect for ammonia removal under neutral conditions; the adsorption process was basically balanced within 6 h, and it followed the pseudo second-order model. Langmuir adsorption model could be better fitted for the adsorption of ammonia adsorbent; the thermodynamic parameters indicated that the adsorption process of ceramic adsorbents on NH₄⁺-N was a kind of spontaneous, endothermic reaction (ΔG^θ <0, ΔH^θ >0), and it was found to be a physical adsorption based on the average adsorption energy. Thus, treating ammonia wastewater by coagulation sludge has a good prospect.