Study On Adsorption Of U(?) And Its Adsorption Mechanism On Bundle Hydroxyapatite And Its Magnetic Composite Material

With the rapid development of the nuclear industry,more and more nuclear industries have provided convenience to human life,but the effects on human life after a nuclear accident are unpredictable.So it is imminent to develop emergency materials with an ultra-fast adsorption rate,powerful adsorption capacity and convenienced to recycle for uranium ions.Hydroxyapatite has attracted people's attention because it does not cause secondary pollution to the environment,its morphology is controllable,and its structure facilitates adsorption.In this paper,calcium nitrate,diamine hydrogen phosphate,citric acid,cobalt chloride,ferrous chloride hexahydrate,ethylene glycol,ethanol,and ammonia were used to prepare bundle-like hydroxyapatite?B-HAP?and its magnetic composite materials by hydrothermal synthesis and chemical precipitation method.And their adsorption behaviors for uranyl ions were investigated.We can find B-HAP has great potential as an emergency material to solve the uranium containing wastewater because of its fast adsorption efficiency,large adsorption capacity by batch experiments.Based on the advantages of fast adsorption efficiency,large adsorption capacity,and easy recovery,B-HAP@CoFe₂O₄ is expected to become a recyclable emergency material for processing uranium-containing radioactive wastewater generated in a nuclear accident.We conducted researches mainly from the following points:?1?The present work successfully fabricated bundle-like hydroxyapatite?B-HAP?microstructures which composed of numerous nanorods by employing a facile and green method.The B-HAP was applied to treat the U?VI?containing wastewater.The abatement of U?VI?by B-HAP was very rapid and the saturated adsorption capacity was superior;over 96.7%of U?VI?was abated within 5 min,and the maximum adsorption capacity was as high as to 1305 mg/g,signifying the feasibility and effectiveness of this B-HAP in the treatment of uranium-contaminated wastewater due to nuclear accidents.It is worthy to note that other ions in solution exhibited relatively low interference on its performance,indicating that B-HAP has great application potential to capture U?VI?from radioactive-contaminated wastewater as well.The U?VI?removal mechanism by B-HAP was confirmed with results from XRD,FT-IR and XPS.Chernikovite[H₂?UO₂?₂?PO₄?₂·8H₂O]was newly formed after U?VI?abatement by B-HAP.Economic assessment suggested B-HAP and its application on U?VI?abatement was cost-effective.With characteristics of high adsorption rate,large capacity,and some common anions and cations almost have no effect on adsorption,B-HAP has great application potential as an emergency treatment material for nuclear accidents.?2?We have successfully prepared the B-HAP@CoFe₂O₄ magnetic composite material by hydrothermal synthesis and applied it to radioactive wastewater containing UO₂²⁺.We found that B-HAP@CoFe₂O₄ had a quick removal rate and high adsorption capacity for UO₂²⁺by batch experiments?93.7%of the uranium ions in the solution were eliminated within 10 minutes,and the maximum adsorption capacity met 338 mg/g?.It is worth noting that B-HAP@CoFe₂O₄ can eliminate uranyl ions under a wide pH condition,indicating that B-HAP@CoFe₂O₄ has the potential to be a recyclable emergency material to deal with the radioactive wastewater containing UO₂²⁺.To confirm the mechanism of B-HAP@CoFe₂O₄removal of uranyl ions,we conducted the analysis of XRD and FT-IR,it was discovered that B-HAP@CoFe₂O₄ interacted with U?VI?to newly form a compound,meta-autunite[Ca?UO₂?₂?PO₄?₂?H₂O?₆].Based on the advantages of fast adsorption efficiency and large adsorption capacity,B-HAP@CoFe₂O₄ is expected to become a recyclable emergency material for the treatment of uranium-containing radioactive wastewater generated in a nuclear accident.