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Highly crosslinked organic–inorganic hybrid polymer poly(cyclotriphosphazene-co-melamine) microspheres (PZM) were synthesized by a simple method. The microspheres was characterized by FTIR, SEM and EDX. It was applied to eliminate thorium(IV) from aqueous solution under various conditions, i.e., pH, initial concentration, dosage and contact time. The experimental data were well-imitated via the pseudo-second-order kinetic model and its adsorption processes comply with the Langmuir isotherm model. Adsorption thermodynamic studies demonstrated that the adsorption process, in essence, was spontaneous and endothermic. Furthermore, the maximum experimental adsorption capacity was 98.6 mg g−1 for initial thorium(IV) concentration 50 mg L−1. When pH = 0.0, the thorium(IV) removal efficiency reached at 76.9%, which indicates that the adsorbent can also was used in a peracid environment. Adsorption behavior of thorium(IV) onto the microspheres were weakly affected via temperature, implying that adsorption would be done at room temperature. [ABSTRACT FROM AUTHOR]

Poly (cyclotriphosphazene-co-4,4′-diaminodiphenyl sulfone) (PZD) microspheres were prepared by precipitation polymerization with simple scheme and convenient operation, and used as a special effect adsorbent for adsorbing cationic dye, which is methylene blue (MB) in water. The synthesized PZD microspheres were characterized by SEM, TEM and XPS techniques. The influences of temperature, adsorption time, pH initial MB solution concentration and adsorbent dosage on MB adsorption were studied. The experimental results show that the adsorption of MB dye by PZD microspheres is more in line with the pseudo-second-order kinetics model than the pseudo-first-order kinetic model. In addition, the adsorption process was further resolved using Weber's intraparticle diffusion model. Thermodynamic experiments show that the adsorption process is spontaneously carried out by endotherm. The mechanism of adsorption of MB dye by PZD microspheres may be related to the existence of a lot of electron-rich atoms N, P, S in the adsorbent, the electrostatic attraction and π–π stacking effect between PZD microspheres and MB dye. [ABSTRACT FROM AUTHOR]