【作者】 张华；

【导师】 戚栋明； 孙阳艺；

【作者基本信息】 浙江理工大学 ， 工程硕士（纺织工程领域）（专业学位）， 2021， 硕士

【摘要】 胶体分子,是指类分子结构的复合胶体粒子,由于其在形貌上可模拟多种分子结构,在组成上可进行多功能组合,已在药物传递、稳定乳液、成像、催化、油水分离等领域表现出巨大的应用前景,吸引了研究者们的广泛关注。胶体分子的性能受形貌和组成的影响,决定着胶体分子的应用领域,其中胶体分子的形貌控制是当前严重制约这类胶体分子发展的瓶颈问题。在种子粒子溶液中,通过控制生长物质在种子粒子上异质成核和生长,是制备形貌可调的胶体分子的有效方法。但对于生长物质为无定形的化合物,由于其分子结构的柔性特征,合成生长物质为无定形的化合物胶体分子更具挑战性。因此,如何设计和制备形貌可调的无定形胶体分子,并掌握不同形貌的形成机制,以实现无定形胶体分子的可控制备和实际应用,是该领域普遍关心的课题。本论文以磁性四氧化三铁粒子作为种子粒子,以无定形的硅烷偶联剂作为生长物质,以十六烷基三甲基溴化铵（CTAB）为连接剂和致孔剂,通过调控硅源前驱体与种子粒子之间的润湿性以及反应动力学,可控的制备了共价键数目可调的AXn型Fe₃O₄-介孔氧化硅（mo Si O₂）胶体分子,并对不同共价键数目n的胶体分子的形成机理进行了深入研究,考察了经十八烷基三甲氧基硅烷改性后的胶体分子在油水分离中潜在应用价值;进一步选用比表面积高的花瓣状（AXn型,n=6）Fe₃O₄@mo Si O₂胶体分子,经扩孔后合成了孔径和比表面积差异显著的花瓣状Fe₃O₄@mo Si O₂胶体分子,经氨基功能化后,考察了功能化前后和不同孔径下的花瓣状Fe₃O₄@mo Si O₂胶体分子吸附剂对常见的重金属离子的吸附行为。主要研究内容和结果如下:（1）AXn型Fe₃O₄-介孔氧化硅胶体分子的可控制备以Fe₃O₄纳米粒子为种子,在碱性水体系中,吸附十六烷基三甲基溴化铵（CTAB）后,加入硅烷偶联剂硅酸四乙酯（TEOS）和1,2-双（三乙氧基硅基）乙烷（BTEE）作为硅源前驱体,其经水解-缩合反应,在Fe₃O₄种子粒子上异相成核和生长,制备了共价键数目n可调的AXn型Fe₃O₄@mo Si O₂胶体分子,经除表面活性剂CTAB后,得到介孔结构的AXn型Fe₃O₄@mo Si O₂。研究了TEOS/BTEE的体积比、TEOS/BTTE的整体用量、CTAB的用量以及硅烷偶联剂的滴加速度,对AXn型Fe₃O₄@mo Si O₂胶体分子的共价键数目n和粒径的调控,深入探讨了AXn型Fe₃O₄@mo Si O₂胶体分子的形成机制。经十八烷基三甲氧基硅烷（OTMS）修饰后,胶体分子颗粒膜水接触角可达150°以上,在油水分离中显示出良好的潜在应用价值。（2）AXn型Fe₃O₄-介孔氧化硅胶体分子对重金属Cu²⁺的吸附行为研究在合成花瓣状（AXn型,n=6）Fe₃O₄-介孔氧化硅胶体分子的基础上,通过硼氢化钠水溶液对花瓣状Fe₃O₄@mo Si O₂胶体分子进行蚀刻,制备了不同孔径大小和比表面积的花瓣状Fe₃O₄@mo Si O₂胶体分子,接枝3-氨基丙基三乙氧基硅烷（APTES）后,制备了花瓣状Fe₃O₄@mo Si O₂胶体分子吸附剂。研究了花瓣状Fe₃O₄@mo Si O₂胶体分子吸附剂对重金属Cu²⁺的吸附行为。研究表明:在p H=6.0下,Cu²⁺吸附效果最佳,其最大吸附量为38.8 mg/g,胶体分子对Cu²⁺的吸附等温线和吸附动力学分别符合Langmuir模型和准二级动力学模型,表明吸附属于单分子层上的化学吸附过程;进一步通过分子内扩散模型说明,其吸附速率由表面吸附及内扩散作用共同控制,且孔径越大,孔隙率互联程度越高吸附平衡时间越短。该吸附剂吸附Cu²⁺后易于磁性分离回收,经酸溶液脱洗后,脱除率高达93%,重复使用4次后,对Cu²⁺的吸附效率仍然保持在76%,说明该吸附剂具有良好的重复利用性。更多还原

【Abstract】 Colloidal molecules（CMs）,refer to composite colloidal particles with molecular-like structures.It can not only simulate a variety of molecular structures in morphology and structure,but also combin a variety of functions in composition.It has shown extraordinary potential applications in drug delivery,emulsions stabilization,imaging,catalysis,oil-water separation,etc.The performance of colloidal molecules is affected by their morphology and composition,which determines the application fields of colloidal molecules.However,the morphological control of colloidal molecules is currently a bottleneck that seriously limits the development of this colloidal molecules.It is an effective method to prepare colloidal molecules with adjustable morphology by controlling the heterogeneous nucleation and growth of the grown material on the seed particle in the seed solution.However,it is more challenging to synthesize colloidal molecules with amorphous growth material because of the flexible characteristics of its molecular structure.Therefore,how to design and prepare amorphous colloidal molecules with adjustable morphology,master the formation mechanisms of different morphology,and realize the controllable preparation and practical application of amorphous colloidal molecules,is a topic of general concern in this field.In this paper,magnetic Fe₃O₄particles were used as seed particles,amorphous silane coupling agent was used as the grown material,cetyltrimethylammonium bromide（CTAB）was used as the linker and poreforming agent.By regulating the wettability and reaction kinetics between the silicon source precursor and the seed particles,AXn-type Fe₃O₄-mesoporous silica colloidal molecules with adjustable number of covalent bonds were prepared in a controllable manner.In addition,the formation mechanism of colloidal molecules with different number of covalent bond n was deeply studied,and the potential application of octadecyltrimethoxysilane modified colloidal molecules in oil-water separation was investigated.Furthermore,petal-like（AXn type,n=6）Fe₃O₄@mo Si O₂colloidal molecules with high specific surface area were selected,and after further expansion,this petal-like Fe₃O₄@mo Si O₂colloidal molecules with significant differences in pore size and specific surface area were synthesized.After amino functionalization,the adsorption behavior of petal-like Fe₃O₄@mo Si O₂colloidal molecules adsorbents for common heavy metal ions were investigated before and after functionalization and at different pore sizes.The main research contents and results are as follows:（1）Controllable Preparation of AXn-type Fe₃O₄-mesoporous silica colloidal moleculesUsing Fe₃O₄nanoparticles as seeds,under an alkaline water system,after adsorbing cetyltrimethylammonium bromide（CTAB）,the silane coupling agent tetraethyl silicate（TEOS）and 1,2-bis（triethoxysilyl）ethane（BTEE）as the silicon source precursor were added.After the hydrolysis and condensation reactions of silicon source precursors,these silicon precursors nucleated and grown on the Fe₃O₄NPs,AXn-type Fe₃O₄@mo Si O₂colloidal molecules with adjustable covalent bond number of n were prepared.The mesoporous AXn-type Fe₃O₄@mo Si O₂was obtained by removing the surfactant CTAB.The volume ratio of TEOS/BTEE,the total amount of TEOS/BTTE,the amount of CTAB,and the drop acceleration of silane coupling agent were studied to regulate the number of covalent bonds n and particle size of AXn-type Fe₃O₄@mo Si O₂colloidal molecules.The formation mechanism of AXn-type Fe₃O₄@mo Si O₂was discussed in detail.After being modified by octadecyltrimethoxysilane（OTMS）,the water contact angle of the colloidal molecular particle membrane can reach over 150°,which shows good potential application value in oil-water separation.（2）Adsorption behavior of heavy metal Cu²⁺by AXn-type Fe₃O₄-mesoporous silica colloidal moleculesBased on the synthesis of petal-like（AXn type,n=6）Fe₃O₄-mesoporous silica colloidal molecules,which were further etched by sodium borohydride aqueous solution to prepare petal-like colloidal molecules with different pore size and specific surface area.The petal-like Fe₃O₄@mo Si O₂colloidal molecules adsorbents were prepared by grafting 3-aminopropyltriethoxysilane（APTES）.The adsorption behavior of heavy metal Cu²⁺by petal-like Fe₃O₄@mo Si O₂colloid molecules was studied.The results show that the adsorption effect of Cu²⁺is the best at p H=6.0,and the maximum adsorption capacity is 38.8 mg/g.The adsorption isotherms and adsorption kinetics of Cu²⁺on colloidal molecules are in accordance with the Langmuir model and the Quasi-second-order kinetic model,respectively,indicating that the adsorption process is a chemical adsorption process on a monolayer.It is further illustrated by the intramolecular diffusion model that the adsorption rate is jointly controlled by surface adsorption and internal diffusion,and the larger the pore size,the higher the degree of porosity interconnection,the shorter the adsorption equilibrium time.After adsorbing Cu²⁺,the adsorbent is easy to be magnetically separated and recovered.After dewashing with acidic solution,the removal rate of Cu²⁺is as high as 93%.And the adsorption efficiency of the adsorbent is maintained at 76%and after repeated use for4 times,indicating that the adsorbent has good reusability.更多还原