Efficient and selective extraction of uranium from seawater based on a novel pulsed liquid chromatography radionuclide separation method

The novel pulsed liquid chromatography radionuclide separation method presented here provides a new and promising strategy for the extraction of uranium from seawater.In this study,a new chromatographic separation method was proposed,and a pulsed nuclide automated separation device was developed,alongside a new chromatographic column.The length of this chromatographic column was 10 m,with an internal warp of 3 mm and a packing size of 1 mm,while the total separation units of the column reached 12,250.The most favorable conditions for the separation of nuclides were then obtained through optimizing the separation conditions of the device:Sample pH in the column=2,sample injection flow rate=5.698 mL/min,chromatographic column heating temperature=60℃.Separation experiments were also carried out for uranium,europium,and sodium ions in mixed solutions;uranium and sodium ions in water samples from the Ganjiang River;and uranium,sodium,and magnesium ions from seawater samples.The separation factors between the different nuclei were then calculated based on the experimental data,and a formula for the separation level was derived.The experimental results showed that the separation factor in the mixed solution of uranium and europium(1:1)was 1.088,while achieving the initial separation of uranium and europium theoretically required a 47-stage separation.Considering the separation factor of 1.50for the uranium and sodium ions in water samples from the Ganjiang River,achieving the initial separation of uranium and sodium ions would have theoretically required at least a 21-stage separation.Furthermore,for the seawater sample separation experiments,the separation factor of uranium and sodium ions was 1.2885;therefore,more than 28 stages of sample separation would be required to achieve uranium extraction from seawater.The novel pulsed liquid chromatography method proposed in this study was innovative in terms of uranium separation and enrichment,while expanding the possibilities of extracting uranium from seawater through chromatography.

Branched fibrous amidoxime adsorbent with ultrafast adsorption rate and high amidoxime utilization for uranium extraction from seawater

Direct collection of uranium from low uranium systems via adsorption remains challenging.Fibrous sorbent materials with amidoxime(AO)groups are promising adsorbents for uranium extraction from seawater.However,low AO adsorption group utilization remains an issue.We herein fabricated a branched structure containing AO groups on polypropylene/polyethylene spun-laced nonwoven(PP/PE SNW)fibers using grafting polymerization induced by radiation(RIGP)to improve AO utilization.The chemical structures,thermal properties,and surface morphologies of the raw and treated PP/PE SNW fibers were studied.The results show that an adsorptive functional layer with a branching structure was successfully anchored to the fiber surface.The adsorption properties were investigated using batch adsorption experiments in simulated seawater with an initial uranium concentration of 500μg·L^(−1)(pH 4,25℃).The maximum adsorption capacity of the adsorbent material was 137.3 mg·g^(−1)within 24 h;moreover,the uranyl removal reached 96%within 240 min.The adsorbent had an AO utilization rate of 1/3.5 and was stable over a pH range of 4–10,with good selectivity and reusability,demonstrating its potential for seawater uranium extraction.

Assembly of a core–shell MOF with stability into polyacrylamide hydrogel for boosting extraction of uranium from seawater

Efficient and selective extraction of uranium(U(VI))from seawater is essential for sustainable nuclear power production.This study reports a novel adsorbent zeolitic imidazolate framework(ZIF)-67@SiO_(2)-A/polyacrylamide(PAM)which was synthesized by grafting the core–shell metal–organic frameworks(MOFs)-based nanostructures coated with the 3-aminopropyl triethoxysilane(APTES)functionalized SiO_(2)(SiO_(2)-A)onto PAM hydrogel.The SiO_(2) shell was grown on the surface of MOF,which improved the acid-base resistance of MOF.The introduction of ZIF-67@SiO_(2)-A enhances the specific surface area and adsorption efficiency of the PAM.The ZIF-67@SiO_(2)-A/PAM shows remarkable adsorption capacity,fast adsorption kinetics,and good reusability for uranium.It has excellent adsorption property(6.33 mg·g^(-1),30 d)in natural seawater.The X-ray photoelectron spectroscopy(XPS),Fourier transform infrared(FTIR),energy dispersive spectroscopy(EDS)mappings,and density functional theory reveal that the coordination by N and O in ZIF-67@SiO_(2)-A/PAM with uranium is the main mechanism of uranium adsorption.Thus,ZIF-67@SiO_(2)-A/PAM has great potential to capture uranium from natural seawater.

Study on the surface of hydrous titanium oxide adsorbent for extracting uranium from seawater-Ⅱ. The surface of HTO

This is second paper summarizing the study on the hydrous titanium oxide absorbent for extracting uranium fromseawater. The investigation is performed by means of X- ray photoelectronic energy spectroscopy for chemical analysis ( ESC A ) , determination of surface hydroxy radical, Fourier-transfer infrared spectrophotometry (FT-IR ) , electron paramagnetic resonance (EPR), inductively coupled Plasma torch (ICP), etc. The emphasis is laid upon the exploration of HTO surface and a discussion about the adsorption micromechanism.