Adsorption of methylene blue from aqueous solution by periodic mesoporous titanium phosphonate materials

Abstract

Periodic mesoporous titanium phosphonate (PMTP-1) materials were synthesized and used as an adsorbent for the removal of a cationic dye, methylene blue (MB), from aqueous solutions. The PMTP-1 powder has a uniform mesopore size of 2.9 nm with high surface area of 606 m2/g. The batchdye adsorption experiments were performed under various conditions including contact time, adsorbent dose, initial MB concentration, solution pH and temperature. The adsorption equilibrium was achieved after 30 minutes of contact time, and the adsorption of MB on PMTP-1 was best fitted to the Langmuir isotherm model with the maximum monolayer adsorption capacity of 617.28 mg/g. Thermodynamic parameters such as ΔG, ΔH and ΔS were calculated. Results of kinetic studies indicated that the adsorption process followed the pseudo-second-order model, which suggests that the process might be a chemisorption. The study results indicate that the PMTP-1 powder could be used as an efficient adsorbent for the removal of textile dyes from effluents.