负载双金属离子的多糖微球材料及其氟铀共吸附特性研究

发布时间：2018-03-06 18:26

本文选题：海藻酸钠/羧甲基纤维素　切入点：魔芋葡甘聚糖　出处：《西南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：在核燃料铀纯化转化过程中将产生大量含铀、氟废水,废水的排放会造成水体环境中氟、铀污染,对人和动植物产生危害,因此,废水中的铀、氟离子的去除是十分必要的。吸附法,由于其具有对低浓度放射性废水效果好,灵活性高,吸附剂可再生,且吸附剂价格低等优势,而备受关注。但现有吸附剂只对氟离子,铀离子中的一种具有吸附功能,而不能同时去除此两种离子。因此,研发具有高效低成本特点的新型双功能吸附剂成为关键。本研究制备了两种吸附剂,羧甲基魔芋葡甘聚糖负载镧铝(CMKGM-La-Al)球形吸附剂,以及海藻酸钠/羧甲基纤维素负载钙铝(S A/CMC-C a-Al)球形吸附剂。并系统的研究了吸附剂对铀、氟离子的吸附特性,吸附机理,再生特性,后处理技术等。具体内容如下:1、采用溶胶-凝胶法,利用电喷装置,制备出CMKGM-La-Al微球吸附剂。对不同La/Al质量比及不同质量浓度的CMKGM对微球凝胶强度的影响进行了研究,并探讨了 C MK GM-La-Al吸附剂对铀酰根离子、氟离子的吸附特性。得出制备微球凝胶强度较大的CMKGM-La-Al微球吸附剂的最佳条件:La/Al质量比为2:1,CMKGM的质量浓度为4%。吸附优化条件为:pH 5.0,浓度40 mg L-1,反应时间15 h时,CMKGM-La-Al微球吸附剂对铀酰根离子的吸附量最大为 45.45 mg g-1;pH 2.0,温度 25℃,浓度 40 mg L-1,反应时间 4 h时,CMKGM-La-Al微球吸附剂对氟离子的吸附量最大为20.37 mg g-1。研究了 CMKGM-La-Al微球对铀酰根离子、氟离子的等温吸附模型,动力学模型及热力学模型,结果表明:吸附均符合Langmiur等温模型和准二级动力学模型,CMKGM-La-Al微球对铀酰根离子、氟离子的吸附过程均为自发的。溶液中存在的如HCO3-,NO3-,SiO32-,Cl-等不同阴离子,对CMKGM-La-Al吸附剂除氟除铀效果的影响并不显著。吸附铀后的CMKGM-La-Al吸附剂再生5次后,再生率在80%以上;吸附氟后的吸附剂,经4次再生后,再生率在72%以上。焚烧后的烧失率均在90%以上。对吸附剂进行了 SEM,FT-IR,EDX,pHpzc及XPS等表征,推测CMKGM-La-Al微球对氟离子和铀离子的吸附机理,CMKGM-La-Al微球吸附剂可以高效去除溶液中的氟离子和铀离子,是一种具有应用前景的吸附剂。2、采用溶胶共混、溶胶-凝胶法,利用电喷装置,制备了SA/CMC-Ca-Al复合微球吸附剂。研究了 S A/CMC质量比、钙离子(Ca2+)及铝离子(Al3+)质量浓度对SA/CMC-Ca-Al微球凝胶强度的影响,在SA/CMC质量比为9:1,且溶液浓度为2.5 wt%,Ca2+浓度为3 wt%,Al3+浓度为7.5 wt%的条件下,制备出凝胶强度最大的微球吸附剂。探讨了 S A/CMC-Ca-Al微球吸附剂对铀、氟离子的吸附特性,优化条件为:pH 4.0,温度25℃,浓度100 mg L-1,吸附时间15h,SA/CMC-Ca-Al对铀酰根离子的最大吸附量为101.76 mgg-1;pH 2.0,温度25℃,浓度1000mg L-1,吸附时间4h,SA/CMC-Ca-Al对氟离子的最大吸附量为35.98 mg g-1。研究了 SA/CMC-Ca-Al微球吸附剂对铀、氟离子的等温模型,动力学模型和热力学模型,结果表明:SA/CMC-Ca-Al吸附剂对铀离子,氟离子的吸附均符合Langmiur等温模型;对铀离子符合准一级动力学模型,对氟离子符合准二级动力学模型。溶液中存在的如 Zn2+,Mg2+,Co2+,Pb2 +,Ni2 +,HCO3-,NO3-,SiO32-,SO42-,Cl-等不同阴阳离子对SA/CMC-Ca-Al吸附剂除氟铀效果的影响并不显著。吸附氟,铀后的SA/CMC-Ca-Al吸附剂经5次再生后,再生率分别在75%和98%以上。焚烧后吸附剂的烧失率均在89%以上。对吸附剂进行了 SEM、FT-IR、EDX和XPS表征,研究SA/CMC 的改性和 SA/CMC-Ca-Al 吸附机理。SA/CMC-Ca-Al 是一种很有前景的吸附剂。3、研究了在不同柱高、初始离子浓度、填料高度时SA/CMC-Ca-Al吸附剂的柱动态吸附实验。柱动态吸附研究结果表明:SA/CMC-Ca-Al柱的穿透时间和耗竭时间随填料高度的增加而延长,随流速和初始浓度的增加而提前;吸附量随流速和初始浓度的增加而增加,随填料高度的增加而减小。
[Abstract]:In the nuclear fuel uranium purification process will produce large amounts of uranium, fluoride wastewater, wastewater emissions will cause water fluoride in environment, uranium pollution, harm to human and plants, therefore, uranium in wastewater, removal of fluoride ion is necessary. Adsorption method, because it has the effect of low concentration of radioactive waste water is good, high flexibility, adsorbent adsorbent and renewable, low price advantage, attracting more and more attention. But the existing adsorbents only for fluoride ion, a uranium ion adsorption function, and can not remove these two ions. Therefore, a new bifunctional adsorbent with high efficiency and low cost characteristic research become the key. This study has prepared two kinds of adsorbent, carboxymethyl konjac glucomannan with lanthanum aluminum (CMKGM-La-Al) spherical adsorbent, carboxymethyl cellulose and sodium alginate / calcium aluminum (S A/CMC-C load a-Al) spherical adsorbent. And systematically study Adsorption of uranium, adsorption, fluoride ion adsorption mechanism, regeneration characteristics, postprocessing techniques. The specific contents are as follows: 1 by sol-gel method, using electronic device, the preparation of CMKGM-La-Al microsphere adsorbent. Influence of different La/Al ratio and different concentrations of CMKGM on the strength of Gel Microspheres study and discuss the C MK GM-La-Al adsorbent for uranyl ions, the adsorption characteristics of fluoride ion. The optimum conditions of preparation of microspheres with high gel strength CMKGM-La-Al microsphere adsorbent: La/Al mass ratio was 2:1, the mass concentration of CMKGM adsorption optimum conditions for 4%.: pH 5, Mg concentration of 40 L-1, 15 when the reaction time is h, CMKGM-La-Al microspheres adsorption capacities of uranyl ions to a maximum of 45.45 mg g-1; pH 2, 25 degrees Celsius temperature, concentration of 40 mg L-1, 4 h reaction time, CMKGM-La-Al microspheres adsorption capacities of fluoride ion maximum Study of CMKGM-La-Al microspheres for uranyl ions is 20.37 mg g-1., isothermal adsorption model of fluoride ion, the results showed that the dynamic model and thermodynamic model of adsorption conformed to Langmiur isotherm model and pseudo two order kinetics model, CMKGM-La-Al microspheres for uranyl ions, the adsorption process of fluoride ions are present in the solution spontaneously. Such as HCO3-, NO3-, SiO32-, Cl- and other different anions on CMKGM-La-Al adsorption removal effect of fluoride removing uranium effect is not significant. CMKGM-La-Al adsorption of uranium after 5 times of regeneration, the regeneration rate was above 80%; the adsorption of fluoride, after 4 times of regeneration, the regeneration rate was above 72%. After the burning of the burning loss rate was more than 90%. The adsorbents were SEM, FT-IR, EDX, pHpzc and XPS characterization, speculated that the adsorption mechanism of CMKGM-La-Al microspheres for fluoride ion and uranium ions, the adsorption of CMKGM-La-Al microspheres can be removed efficiently in solution The fluorine and uranium ions, is a promising adsorbent.2, sol blend, sol gel method, using EFI device, the preparation of SA/CMC-Ca-Al composite microspheres of S adsorbent. The mass ratio of A/CMC (Ca2+), calcium ion and aluminum ion (Al3+) concentration on gel effect the strength of SA/CMC-Ca-Al microspheres, SA/CMC mass ratio was 9:1, and the concentration of the solution is 2.5 wt%, the concentration of Ca2+ was 3 wt%, the concentration of Al3+ was 7.5 wt% under the conditions of preparation of microsphere gel adsorbent. The maximum intensity of S A/CMC-Ca-Al microsphere adsorbent on adsorption characteristics of uranium, fluoride, optimum conditions for: pH 4, temperature 25, Mg concentration 100 L-1, adsorption time 15h, the maximum adsorption capacity of SA/CMC-Ca-Al on uranyl ion was 101.76 mgg-1; pH 2, 25 degrees Celsius temperature, concentration of 1000mg L-1, adsorption time 4h, the maximum adsorption capacity of SA/CMC-Ca-Al fluoride was 35.98 mg of g-1. SA/CMC-Ca-Al microsphere adsorbent for uranium, isothermal model of fluoride ion, the results showed that the kinetics model and thermodynamic model, SA/CMC-Ca-Al adsorption of uranium ions, the adsorption of fluoride ions were fitted to the Langmiur isotherm model; pseudo first-order kinetic model of uranium ions, with the pseudo two order kinetics model of fluorine ions present in the solution. Such as Zn2+, Mg2+, Co2+, Pb2 +, Ni2 +, HCO3-, NO3-, SiO32-, SO42-, Cl- and other different ions on SA/CMC-Ca-Al adsorption effect of fluoride removal effect of uranium is not significant. The adsorption of fluoride, SA/CMC-Ca-Al adsorbent uranium after 5 times of regeneration, the regeneration rate of more than 75% and 98% respectively in the incineration process. After adsorption the burning loss rate was more than 89%. The adsorbents were SEM, FT-IR, EDX and XPS characterization,.SA/CMC-Ca-Al and adsorption mechanism of SA/CMC-Ca-Al modification of the SA/CMC adsorption is a promising agent.3 was studied at different column height at the beginning Initial ion concentration, column dynamic adsorption experiments of SA/CMC-Ca-Al adsorbent packing height. The results show that the increase of the dynamic adsorption column SA/CMC-Ca-Al column through time and time with the filling height increased, and advance with increasing velocity and initial concentration; adsorption capacity increased with the increase of flow rate and initial concentration, and decreases with the the filler height increases.

【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O647.3

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