Abstract: Adsorption is one of the attractive approaches of phosphorus removal in waste effluents. In this study， the autoclaved aerate concrete （AAC） from urban construction and demolition debris was selected as the research object， and the static adsorption experimental method was adopted to study the AAC adsorption performance of phosphorus from wastewater. And the adsorption mechanism of AAC was explored by using Langmiur and Freundlich adsorption model fitting. The results showed that with the increased of AAC concentration， the removal rate of phosphorus in the water was also increased. When the concentration of the adsorbent was 10 g/L， the removal rate of phosphorus by AAC had reached 93.61%. At the same dose of the adsorbent， the removal percentage of phosphate by AAC was rapidly increased over time， and reached equilibrium after 8 hours. The removal rate of phosphorus was all above 95%. The maximum phosphorus adsorption amount was positively correlated with the initial concentration of phosphorus. Under different pH， the order of phosphorus adsorption capacity was pH =9＞pH= 5＞pH =7. The isothermal adsorption fitting results of Langmuir and Freundlich showed that the removal of phosphorus by AAC was mainly caused by electrostatic adsorption and chemical adsorption on the surface.

Key words: autoclaved aerate concrete, phosphorus, electrostatic adsorption, chemisorption