皮胶原基吸附剂对高盐度体系铀的选择性吸附基础研究

发布时间：2018-03-06 14:17

本文选题：废弃皮革　切入点：铀　出处：《西南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：针对陆地铀资源不足且从海水中提铀难度较大的关键技术问题,本论文以盐湖铀资源开发为目标,选择富含胶原纤维且价格低廉的制革废弃边角料为原料,分别采用了水解、水热以及固化鞣酸等方法制备了三种吸附材料,系统研究了皮胶原基吸附剂对U(VI)的静态吸附特性和吸附机理,并模拟研究了盐湖高盐度环境对吸附性能的影响及脱附再生性能。结果表明:1、碱活化水解皮革(AALW)的最佳制备条件为:皮革大小(0.25cm的正方颗粒);NaOH浓度(0.075mol/L);水解温度(50oC);水解时间(4h)。AALW对U(VI)的最佳吸附pH为5。AALW吸附U(VI)的等温线与Langmuir方程更加吻合,拟合得到最大吸附量为163.67mg/g。其动力学更切合准二级动力学模型,吸附达到平衡所需时间为240min。吸附过程中一部分U(VI)与碱活化负载的Na+进行离子交换;另一部分U(VI)则与皮革上的活性官能团发生配位络合。2、皮革水热炭(HLW)对U(VI)的吸附受pH影响显著,在pH为5时可达最佳。HLW对U(VI)的吸附等温线更切合Freundlich方程,其动力学更符合准二级动力学模型,吸附达到平衡所需时间为240min。在吸附过程中,水热过程生成的含氧官能团等通过配位络合和静电吸引将UO22+成功吸附到HLW上。3、海绵皮(SLW)的最佳制备条件为:鞣酸质量分数(2%)、水解皮革投料量(1.25g)、水热温度(140oC)、水热时间(1.5h)。海绵皮吸附U(VI)受溶液pH影响显著,在pH为5时达到最优吸附性能。海绵皮对U(VI)的吸附等温线更切合Freundlich方程,其动力学更符合准二级动力学模型,吸附达平衡所需时间为1080min。在吸附过程中,改性皮革表面富含的酚羟基以及皮革本身含有的氨基、羧基等活性官能团对U(VI)都具有很高的的吸附亲和力,能通过配位络合实现对U(VI)的吸附。4、在模拟盐湖高盐度、极低浓度U(VI)(其中铀浓度为800ug/L)的环境下,三种吸附剂中均对铀体现出较高吸附率,其中AALW对U(VI)的吸附性能随着HCO3-浓度的升高而有所减弱。在七元共存金属离子溶液的吸附实验中,AALW、HLW及SLW对U(VI)的都具有较高的选择性,其对U(VI)的吸附率分别为55%、45%及85%,远高于其它金属离子。5、当AALW循环到第四次吸附时,其吸附率降到52%;而AALW的解析率均可达90%,具有良好的脱附性能。酸性洗脱剂由于酸改性作用,在多次循环吸附过程中,HLW吸附率没有下降反而有所上升。SLW经五次吸附-脱附循环后,其吸附率仍可达90%以上。综上所述,改性皮胶原生物质吸附材料对U(VI)具有较好的吸附效果,且三种改性方法简单易行,对从盐湖中铀的富集提取具有一定的参考作用。
[Abstract]:Aiming at the key technical problems of the shortage of terrestrial uranium resources and the difficulty of extracting uranium from sea water, this paper aims at the exploitation of uranium resources in salt lakes, and selects the leathery scrap which is rich in collagen fiber and low price as raw material, which is hydrolyzed respectively. Three kinds of adsorption materials were prepared by hydrothermal method and curing tannic acid method. The static adsorption characteristics and adsorption mechanism of collagen based adsorbent for UVI were systematically studied. The effects of high salinity environment on adsorption and desorption regeneration were simulated. The results showed that the optimum preparation conditions were as follows: the concentration of NaOH was 0.075 mol 路L ~ (-1), the hydrolysis temperature was 50oC ~ (-1), the concentration of NaOH was 0.075 mol / L ~ (-1), the concentration of NaOH was 0.075 mol / L ~ (-1), the concentration of NaOH was 0.075 mol / L ~ (-1), the temperature of hydrolysis was 50oC ~ (-1). The isotherm of the best adsorption pH of 5. AALW for the adsorption of UVI is more consistent with the Langmuir equation, the hydrolysis time is 4 h ~ (-1) 路AALW and the optimum pH is 5.AALW for the adsorption of U ~ (2 +) V _ (I). The maximum adsorption capacity is 163.67 mg / g. The kinetic model is more suitable for the quasi-second-order kinetic model, and the adsorption time is 240 min. During the adsorption process, some of the UGV I) are exchanged with Na supported by alkali activation. On the other hand, there is a coordination complexation. 2 with the active functional groups on leather. The adsorption of UVI on leather is affected significantly by pH, and the adsorption isotherm of UVI can reach the best at 5:00. The adsorption isotherm of UVI is more suitable for Freundlich equation. The kinetics is more in line with the quasi-second-order kinetic model, and the adsorption equilibrium time is 240 min. during the adsorption process, The optimum conditions for the preparation of oxygen containing functional groups formed by hydrothermal process such as coordination complexation and electrostatic attraction to adsorb UO22 onto HLW. 3, Sponge skin were as follows: tannic acid mass fraction 2, hydrolyzed leather feed quantity 1. 25 g / g, hydrothermal temperature 140 oC, hydrothermal time. The adsorption of UVI by sponge skin was significantly affected by the pH of the solution. The adsorption isotherm of the sponge skin on the UVI is more suitable for the Freundlich equation, the kinetics is more in line with the quasi-second-order kinetic model, and the adsorption equilibrium time is 1080 min. during the adsorption process, the adsorption isotherm of the sponge skin is more suitable to the Freundlich equation, and the kinetics of the adsorption isotherm is more consistent with the quasi-second-order kinetic model. The surface of modified leather is rich in phenolic hydroxyl groups and the active functional groups such as amino and carboxyl groups contained in leather have high adsorption affinity to UVI. In very low concentrations of UGV (with a uranium concentration of 800ugr / L), all three adsorbents exhibit high adsorption rates for uranium. The adsorption performance of AALW on UVI decreased with the increase of HCO 3- concentration. In the adsorption experiments of seven component metal ion solutions, both AALWN HLW and SLW have high selectivity for UVI. The adsorption rates of AALW are 55% and 85% respectively, which is much higher than that of other metal ions. When AALW cycles to 4th times of adsorption, the adsorption rate decreases to 52%, while the resolution rate of AALW can reach 90%, which has good desorption performance. The adsorption rate of HL-W increased after five cycles of adsorption and desorption. In conclusion, the adsorption rate of modified collagen biomaterials on UVI was better than that of the modified collagen, and the adsorption rate of the modified collagen was higher than that of the modified collagen after five cycles of adsorption and desorption, and the adsorption rate of the modified collagen was better than that of the modified collagen. The three modification methods are simple and feasible, which is useful for the enrichment and extraction of uranium from salt lakes.
【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;TL212.5

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