Effect of agitation mode (mechanical, ultrasound and microwave) on uranium sorption using amine- and dithizone-functionalized magnetic chitosan hybrid materials

Magnetic chitosan nanoparticles, activated by glycidyl methacrylate, can be functionalized grafting diethylenetriamine (DETA) and dithizone for improving U(VI) sorption at pH around 5. The physicochemical properties of the materials have been characterized a wide variety analytical techniques. Uranyl increases with (progressive deprotonation amine sulfur groups). Uptake kinetics are controlled agitation mode: equilibrium time is reduced while using ultrasonic treatment (especially highest frequency: 80 kHz): cavitation effect improves accessibility to internal reactive groups (sorption capacity increased). diffusivity coefficient increased 4–5 times. In case microwave, significantly R-Dithizone, down 0.8 mmol U g−1) because temperature increase, which limits (exothermic mechanism). Mass transfer tremendously enhanced: less than 60 s (30 min 120 mechanical agitation). Sorption monolayer saturation (Langmuir) decreases increasing from 2.20 1.74 g−1 R-Amine (from 1.77 1.22 R-Dithizone). enthalpy close −19.7 kJ mol−1 (with positive entropy change, ΔS°) −34.2 R-Dithizone (negative ΔS°). Metal desorption highly efficient 0.3 M Na2CO3 /0.1 H2O2 solution. instantaneous (less 1 min) complete when microwave treatment. allows efficiency decreasing concentration eluent compared agitation. process successfully applied uranyl separation leachates marine sediments, especially in presence Complexon III (masking agent).