摘要/Abstract

氧化石墨烯（GO）由于具有优异的物理化学性质，被广泛应用于能源化工、环境修复、纳米材料、液相催化等领域.与此同时，GO在应用的过程中不可避免会排放到自然界中，释放到环境中的毒性可能导致生物系统的不稳定性.因此，本文系统研究了几种常见阳离子（Na⁺、K⁺、Ca²⁺、Mg²⁺），阴离子（PO₄^3-、SO₄^2-、CO₃^2-、HCO₃^-、Cl^-）和粘土矿物（蒙脱石、高岭土、膨润土、纳米氧化铝）在不同浓度下对GO聚沉的影响，并以FTIR表征聚沉GO前后的粘土矿物.实验结果表明，阳离子具有较强的GO聚沉能力，且不同价态阳离子的聚沉能力有着较大差异.经分析，GO在水溶液中的电性为负，阳离子作为反离子，聚沉行为符合Schulze-Hardy规则，同价态阳离子间聚沉能力存在差异的主要原因是电负性和离子的水合作用.阴离子则起到增加GO水溶液稳定性的作用，且阳离子的聚沉作用高于阴离子的稳定作用.具有相同价态阴离子的钠盐聚沉GO的能力也存在差异，主要原因是HCO₃^-和CO₃^2-的水解作用使得其负电荷数降低，稳定GO的能力下降.粘土矿物含有羟基和金属氧键，可与GO发生相互作用.根据粘土矿物最大聚沉效率的不同，聚沉能力为：纳米氧化铝>高岭土>膨润土>蒙脱土，主要影响因素为粘土矿物在水中的电性.本文有助于了解GO在不同水环境中的聚沉行为，对未来石墨烯工程应用于污染治理具有重要意义.
关键词: 氧化石墨烯, 聚沉, 阳离子, 阴离子, 粘土矿物
Graphene oxide (GO) is widely used in energy chemical, environmental restoration, nanomaterials, liquid phase catalysis, etc. due to its excellent physical and chemical properties. At the same time, GO is inevitably discharged into nature during the application process, and the toxicity released into the environment may lead to instability of the biological system. Therefore, this paper systematically studied several common cations (Na⁺, K⁺, Ca²⁺, Mg²⁺), anions (PO₄^3-, SO₄^2-, CO₃^2-, HCO₃^-, Cl^-) and clay minerals (montmorillonite, kaolin, bentonite, nano-alumina) on GO coagulation at different concentrations. And FTIR is used to characterize the clay minerals before and after the precipitation of GO. The experimental results show that the cations have strong GO coagulation ability, and the coagulation ability of different valence cations has a large difference. After analysis, the electrical properties of GO in aqueous solution are negative, the cation acts as a counter ion, and the coagulation behavior conforms to the Schulze-Hardy rule. The main reason for the difference in coagulation ability between isovalent cations is electronegativity and ionic hydration. The anion acts to increase the stability of GO, and the coagulation ability of the cation is more effective than the stabilization ability of the anion. The ability of sodium salts with the same valence anion to coagulate GO also differs, mainly because the hydrolysis of HCO₃^- and CO₃^2- causes a decrease in the negative charges, resulting in a decrease in the ability to stabilize GO. The clay minerals contain hydroxyl and metal-oxygen bonds that interact with GO. According to the maximum removal rate, the clay minerals have the coagulation ability:nano-alumina > kaolin > bentonite > montmorillonite. The main influencing factors are the electrical properties of clay minerals in aqueous solution. This paper is helpful to understand the coagulation behavior of GO in different water environments, and it is of great significance for the future application of graphene engineering in pollution control.
Key words: graphene oxide, coagulation, cation, anion, clay mineral


PDF全文下载地址:

点我下载PDF