Highly-selective and well-effective removal of cesium ions by segregative titanium-ferrocyanide/chitosan melamine...

Selectively and efficiently removing Cs is of great urgency and challenge for the treatment of radioactive wastewater. In this work, titanium-ferrocyanide/chitosan melamine sponge composite (TFCM) was synthesized by cross-linking and titanium-doping strategy, and employed to remove Cs⁺ from water. The obtained TFCM exhibited excellent adsorption performance for Cs⁺, due to its porous and 3D skeleton structure. The TFCM demonstrated a broad range of pH (pH = 3-11) suitability and high removal ratio of Cs⁺. The adsorption behavior of TFCM on Cs⁺ conformed to the Langmuir adsorption process and pseudo-second-order kinetics model. Remarkably, TFCM displayed a high selectivity in Cs⁺ adsorption with the presence of other cationic (K⁺, Na⁺, Ca²⁺, Mg²⁺). TFCM could easily be separated from water because of loading on the melamine sponges. Besides, the TFCM could maintain more than 78.1 % removal ratio of Cs⁺ after five adsorption-desorption cycles. Furthermore, the concentration of Cs⁺ could decrease to 10 μg/L from 20 mg/L with a prominent removal ratio of 99.95 %. Characterization results revealed that the adsorption process of Cs⁺ by TFCM was dominated by ion-exchange. In summary, the TFCM is a high selectivity, efficiently and easily separable adsorbent with excellent application prospects for removing Cs from radioactive wastewater.