【作者】 王靖煖；

【导师】 于静；

【作者基本信息】 哈尔滨工程大学 ， 化学工程与技术， 2022， 硕士

【摘要】 近年来,全球对能源的需求量持续增长,能源不合理使用导致的环境污染,高效开发和利用新能源已成为首要问题。核能是最具希望的新能源之一,铀是核燃料的主要成分,海洋中含有较大的铀资源储量,是未来获取铀的主要开发目标。木质素（L）被广泛用作水处理等方面的吸附材料,但其本身为粉末状,不利于操作和回收,应用的过程中也可能对环境造成污染,不能满足对材料实用性的要求。因此,本文以自由基聚合法将粉末状的木质素制成多网络交联的木质素基水凝胶。本文具体包括三个方面的内容:通过将氨基化改性的木质素（AL）与N-异丙基丙烯酰胺（PNIPAM）进行自由基聚合反应,制备了一种三维网络结构的温敏型AL-PNIPAM水凝胶。溶胀性能研究表明,该水凝胶的体积随温度变化而产生相应的变化。通过研究热力学和动力学实验数据,可知水凝胶对铀酰离子的吸附是多分子层吸附过程。当温度为298.15 K、p H=6和铀酰离子浓度为50 mg·L^-1的溶液中,测得AL-PNIPAM材料的吸附容量可达85.5 mg·g^-1。同时,XPS分析结果表明,AL-PNIPAM水凝胶分子链中的酰胺基与氨基和铀发生配位作用,从而达到吸附的效果。利用蒙脱土（MMT）粉末的微观片层结构,将氨化后的木质素（AL）与海藻酸钠（SA）结合成的线性共聚物插层在MMT的片层中,形成第一层网络。SA与Ca²⁺相互交联,形成第二层网络,构建新型双网络结构的AL-MMT/SA水凝胶球。当温度为298.15K时,处于最佳p H值（p H=5）以及浓度为50 mg·L^-1的铀酰离子溶液中,吸附剂达到饱和吸附后,AL-MMT/SA水凝胶的吸附容量为115.8 mg·g^-1。结合动力学和热力学拟合模型分析,可知该水凝胶是多分子层吸附过程。XPS分析结果表明,水凝胶的氨基和羧基中O和N元素参与对铀酰离子的配位作用中。为了进一步提高吸附速率,通过高温法将多乙烯多胺（PP）接枝到琼脂（ag）分子中,使得氨基和羟基进行羟胺基化的脱水缩合反应,制得具有高吸附效率的AL-ag-PP水凝胶。在温度为298.15 K、p H=8和浓度为50 mg·g^-1的条件下,水凝胶的最大吸附容量为105 mg·g^-1。根据实验的吸附动力学数据可知,吸附剂能够进行高效吸附,达到平衡所需时间为40 min,属于单分子层吸附过程。XPS分析结果表明,水凝胶中的氨基与铀发生配位作用。更多还原

【Abstract】 The global demand for energy has grown continuously in recent years.Environmental pollution is caused by irrational use of energy continue to deteriorate,which gradually threatens human security and social development.Nuclear energy is one of the most promising new energy sources.Uranium is the basic raw material of nuclear fuel.Ocean would become the staple developing objective for uranium resources because of larger reserves.Lignin（L）is widely used as an adsorption material in water treatment and other aspects.But the powder type of lignin would make it hard to operate,recycle,and leads to environmental pollution during application,which cannot meet the requirements for material practicability.Herein,powdered lignin was made into the multi-network cross-linked lignin-based hydrogel through free radical polymerization.This article includes the following three aspects:The temperature-sensitive AL-PNIPAM hydrogel with three-dimensional network structure was fabricated by the free radical polymerization of aminated lignin（AL）and N-isopropyl acrylamide（PNIPAM）.The swelling test indicates,the volume of AL-PNIPAM hydrogel changed with temperature variation.The adsorption kinetics and isothermal data suggest that the adsorption of uranyl ion by hydrogel is a multi-molecular layer adsorption process.The theoretical adsorption capacity reaches 85.5 mg·g^-1 at 298.15 K and p H=6 in the uranium solution with initial concentration of 50 mg·L^-1.Meanwhile,according to the results of XPS analysis,uranyl ion coordinated with the amino and amide groups in the molecular chain of AL-PNIPAM hydrogel.A novel AL-MMT/SA hydrogel sphered with double network structure were constructed,where the first layer of network was formed by the intercalation of the linear copolymer of aminated lignin（AL）and sodium alginate（SA）into the microscopic lamellar structure of montmorillonite（MMT）powder,and the second layer network was formed by the crossing-linking between SA and Ca²⁺.When the temperature is 298.15 K,the adsorbent reaches a saturated adsorption capacity and the maximum adsorption capacity is 115.8 mg·g^-1 in uranyl ion solution with an optimal p H of 5 and a concentration of 50 mg·L^-1.The analysis of adsorption model show that the adsorption process of the hydrogel is multi-molecular layer adsorption.XPS analysis reveals uranyl ion coordinated with the O and N elements in the amino and carboxyl groups.In order to improve the adsorption rate,polyvinyl polyamine（PP）was grafted into agar（ag）molecules through the dehydration condensation reaction of amino and hydroxyl amination to construct AL-ag-PP hydrogel with high adsorption efficiency.The maximum adsorption capacity of AL-ag-PP hydrogel is 105 mg·g^-1 at 298.15 K and the p H of seawater in the uranium solution with initial concentration of 50 mg·L^-1.The experimental adsorption kinetic data shows that the adsorbent could carry out high-efficiency adsorption and reaches equilibrium within 40min,which is a monolayer adsorption process.According to the results of XPS analysis,uranyl ion coordinated with amino in the hydrogel.更多还原