Calcium alginate and chitosan as potential sorbents for strontium radionuclide

Assessment of the suitability of activated carbon with a modified surface for the adsorptive removal of radionuclide ions from aqueous solutions

Commercial granular activated carbon, commonly applied in water purification, was used in this work for the adsorptive removal of radioactive metal ions. Relatively cheap methods were used to modify the commercial activated carbon: soluble components of ash were removed from part of it by washing with hot distilled water and another part was subjected to surface oxidation with 30% hydrogen peroxide. The carbon samples were characterized using different techniques. The specific surface area and micro-/mesopore volumes for the samples were calculated on the basis of determined nitrogen adsorption isotherms, and the chemical nature of the surface of the activated carbon samples was also studied. All three samples were used to study the sorption of radioactive metal ions of Cs(I), Sr(II), Co(II) and Am(III). These metal ions have been selected for testing as potential reactive water contaminants that may appear in water as a result of a nuclear power plant accident (Tan et al. 2024). The adsorption process has been identified and studied under different conditions and found to be dependent on solution pH as well as adsorbent mass. The sorption capacity of the activated carbon samples was determined as removal efficiency (R) and distribution coefficients (Kd). On the basis of the results obtained, the modification process of the activated carbon had a slight influence on its adsorption efficiency towards the radioactive metals.

The Incorporation of Strontium in a Sodium Alginate Coating on Titanium Surfaces for Improved Biological Properties

Orthopedic implant failure is mainly attributed to the poor bonding of the implant to bone tissue. An effective approach to minimize the implant failure would be modifying the surface of the implant. Strontium (Sr) can stimulate the proliferation and differentiation of osteoblasts and reduce the activity of osteoclasts. In this study, a titanium (Ti) surface was successively functionalized by covalently grafting dopamine, sodium alginate (SA), and Sr²⁺ via the electrostatic immobilization method. The as-prepared coatings on the Ti surface were characterized by using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and contact angle. The results indicated that the Sr-incorporated coatings were successfully prepared and that Sr distributed uniformly on the surface. A long-lasting and sustained Sr release had been observed in Sr²⁺ release studies. The Ti/DOPA/SA/Sr exhibited little cytotoxicity and a robust effect of Sr incorporation on the adhesion and spreading of MG63 cells. The proliferation and alkaline phosphatase (ALP) activity of MG63 cells were enhanced by immobilizing Sr²⁺ on the SA-grafted Ti. The Sr-containing coatings, which displayed excellent biocompatibility and osteogenic activity, may provide a promising solution for promoting the tissue integration of implants.