Rapid one-step preparation of a carboxymethyl chitosan gel with a novel crosslinker for efficient adsorption of Sr2+

A novel crosslinker, iminodiacetic acid (IA), was used to fabricate a three-dimensional carboxymethyl chitosan (CMC) hydrogel. The gel was synthesized using a simple one-step method within a short reaction time of 2 min. IA also plays the role of adsorption site provider. Fourier transform infrared spectroscopy (FT-IR) and X-Ray Diffraction (XRD) demonstrated the crosslinking reaction. The swelling ratio and the surface morphology can be modulated by changing the CMC:IA ratio, resulting from the changes on the degree of cross-linking and the number of functional groups, which in turn greatly affect the adsorption capacity for Sr 2+ . The maximum adsorption capacity can reach 144.73 mg/g, depending on the pH value. XPS spectra indicate that the adsorption derives from the ion exchange of Na + to Sr 2+ , mainly interacting with the carboxyl radicals on CMC as well as IA. In addition, the gel shows high mechanical strength , which is helpful to the application and recycle in wastewater treatment . The facile and fast synthesis, high adsorption capacity and strong mechanical strength prove that the gel is a promising material for radioactive wastewater treatment.