Chitosan extracted from the feather of Dosidicus gigas crosslinked with glutaraldehyde for use as a 99Mo adsorbent

Abstract

The production of Technetium-99 m (99mTc) is important for cancer diagnosis. The solvent extraction is the most widely used method to obtain 99mTc; however, due to the evaporation of the polluting solvent into the environment, a radiochemical separation using a chromatographic column system based on adsorbent materials would be cleaner and more efficient.In this study, squid feather (Dosidicus gigas) chitosan (SFC) polymers have been synthesized and crosslinked with glutaraldehyde solutions at concentrations of 50, 40 and 25 % to study the adsorption of 99Mo with the aim of test a promising material to produce 99mTc in the chromatographic column of the 99Mo/99mTc generator. Likewise, the same methodology of synthesis was performed using a commercial chitosan (CC) as a control. Deacetylation degree was measured obtaining 74.15 % and 77.65 % for the SFC and CC polymers, respectively. The molecular weight obtained was 990.72 kDa for SFC and 722.72 kDa for CC and the characterization of the biopolymers was performed with FTIR, SEM, XRD, TGA y FT Raman techniques. Equilibrium time, adsorbent mass and pH effect were evaluated as factors that influence the adsorption process of 99MoO4-2. The zero load point (pHPZC) analysis confirmed the positive charge of the crosslinked polymers, improving the adsorption capacity of 99MoO4-2 at low pH values between 2 and 4, following a pseudo-first order model. With respect to the adsorption isotherms, they exhibit maximum values of 99MoO42- of 482 mg g−1 SFCG40 and 502 mg g−1 CCG25 with a better fit to the Langmuir theoretical model.

Keywords

• Biopolymer
• Adsorption
• 99MoO42- ion
• Chitosan
• Squid feather