Facile one-pot hydrothermal synthesis of reticulated porous tobermorite for fast phosphorus recovery

Abstract

Phosphorus, a depletable resource in nature, has been constantly consumed. Its recovery still remains difficult to be solved. Tobermorite (Ca5Si6O16(OH)2) with chemical stability is an efficient adsorbent for phosphorus. Herein, the reticulated porous tobermorite (CSH) was successfully synthesized through a facile one-step hydrothermal process and its adsorption performance for phosphorus was evaluated. The adsorption reached the equilibrium within 5 min. The kinetic study demonstrated that the adsorption followed the pseudo-second-order model, indicating the adsorption involved the chemisorption. The adsorption perfectly fitted the Langmuir isotherm. The calculated maximum adsorption capacity is 152.46 mg·g−1 at room temperature. Its excellent adsorption performance for phosphorus is attributed to its reticulated porous structure and larger specific surface area. The adsorption is mainly affected by the electrostatic interaction and the releasing ability of OH- and Ca2+ from the CSH. Reticulated porous CSH is a potential efficient adsorbent for phosphorus recovery owing to its facile synthesis, fast adsorption rate, high adsorption capacity and excellent reusability, which provide a feasible alternative for phosphorus recovery.