| With the gradual depletion of traditional fossil fuels and the damage to the environment,human beings have to focus on the development of new energy.Nuclear energy,as a clean and efficient low-carbon energy,has been widely used in all walks of life.In order to ensure the sustainable development of nuclear energy,it is urgent to solve the current shortage of uranium resources.There are 4.5 billion tons of uranium in seawater,about 1000 times of that of land uranium mines.The development of uranium extraction from seawater is expected to solve the energy shortage and other problems.In recent years,many countries and organizations have carried out a lot of research on uranium extraction from seawater.However,because the extraction of uranium from seawater is a long-term engineering research,the biological pollution such as bacteria and other organisms in seawater has a great impact on the materials due to the long-term immersion of seawater.Therefore,it is imperative to develop the preparation of antibacterial materials for uranium extraction from seawater.In this study,a new antibacterial group hyperbranched poly(amido amine)(h-PAMAM)was introduced into the materials for uranium extraction from seawater for the first time,and two kinds of hyperbranched antibacterial materials were successfully prepared by simple hydrothermal grafting method(PAN-h-PAMAM and PAO-h-PAMAM).The materials were characterized in detail,and their adsorption and antibacterial properties were tested.The results show that both materials have good antibacterial properties,and the materials modified by hyperbranched poly(amido amine)(h-PAMAM)and amidoxime groups shows higher uranium adsorption properties.This paper proved that h-PAMAM has effective antibacterial activity and uranium adsorption property.The h-PAMAM was grafted to the surface of the PAN fiber for the first time by simple hydrothermal method.After alkali treatment,a new type of hyperbranched antibacterial uranium extraction material was obtained,named as PANh-PAMAM.The saturated adsorption capacity of the material to uranium was 296.43 ± 4.88 mg/g under p H = 8.The material showed excellent antibacterial ability against marine bacteria,and the antibacterial rate was 94.00 ± 0.25%.The optimum p H of the material is 6 and the adsorption capacity is 106.88 ± 5.60 mg/g in uranium solution containing 0.44 M Na Cl.The experiment shows that h-PAMAM has the ability of antimarine bacteria and uranium adsorption,and has a certain potential of uranium extraction from seawater.This paper obtained the material which has the highest adsorption capacity for uranium among amino-functionalized adsorbents,named as PAO-h-PAMAM,and applied it to the real seawater of laboratory for uranium extraction for the first time.By further improving the hyperbranched antibacterial material for uranium extraction,the amidoxime group was introduced into the material to obtain PAO-h-PAMAM.The introduction of amidoxime group effectively improves the properties of the material by the synergistic effect of the hyperbranched poly(amido amine)and amidoxime groups,including the successful change of the optimal p H to neutral;the improvement of the salt resistance,and the adsorption capacity of the PAO-h-PAMAM in uranium solution containing 0.44 M Na Cl is 411.95 ± 2.39 mg/g;the improvement of the selective adsorption capacity,and the PAO-h-PAMAM shows excellent selective adsorption ability in uranium solution with multiple competing ions.At p H=8,it takes 72 h for the material to saturate,and the saturated adsorption capacity is 441.00 ± 5.69 mg/g.After five adsorption and elution cycles,the adsorption rate and elution rate of uranium can maintain very high levels(97.20 ± 0.21% and 97.10 ± 0.19%).More importantly,the material showed excellent antibacterial activity on five common bacteria and marine bacteria,and the existence of bacteria would not affect the adsorption capacity.Finally,after 42 days of adsorption in real seawater,the adsorption capacity of the material to uranium was 5.82 mg/g.The results show that the synergistic effect between amidoxime and hyperbranched poly(amide amine)can improve the properties of the materials and it has a good application prospect to improve the comprehensive properties of materials by the synergism between functional groups.In summary,the novel antibacterial polymer h-PAMAM was introduced into the field of uranium extraction from seawater in this paper.The two kinds of hyperbranched antibacterial materials showed high antibacterial activity against marine bacteria,and the synergistic effect between amidoxime and hyperbranched poly(amido amine)makes the material show excellent marine applicability,including very high adsorption capacity,excellent selectivity,salt resistance and recyclability.Therefore,the materials introduced in this paper have high practicability,and are expected to be used in extracting uranium from real seawater.In addition,the research results of this paper have reference value for the problems of antibacterial performance and adsorption performance of materials for uranium extraction from seawater. |
PDF Full Text Request