Influence of sintering temperature on orthophosphate and pyrophosphate removal behaviors of red mud granular adsorbents (RMGA)

► Increase of sintering temperature (ST) leads to two opposite effects on RMGA. ► Influence of ST on RMGA for phosphate removal varies with initial pH in solution. ► Precipitation affects orthophosphate removal greatly for RMGA of lower ST. ► Pyrophosphate is relatively easily adsorbed on RMGA than orthophosphate. ► Some effective sites on RMGA are selective for orthophosphate or pyrophosphate.