Green synthesis of tannic acid functionalized graphene hydrogel to efficiently adsorb methylene blue
Green synthesis of tannic acid functionalized graphene hydrogel to efficiently adsorb methylene blue
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DOI：
10.1016/j.colsurfa.2021.126972
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发表时间：
2021-09
期刊：
影响因子：
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通讯作者：
Guohong Yao;Xinkai Liu;Guangyang Zhang;Z. Han;Hui Liu
中科院分区：
文献类型：
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作者：
Guohong Yao;Xinkai Liu;Guangyang Zhang;Z. Han;Hui Liu
以单宁酸（TA）为还原剂和封端剂，采用一种简单、绿色的方法合成了TA功能化石墨烯（TA-rGO），避免了化学稳定剂的使用。然后在TA-rGO存在下，通过2-丙烯酰胺基-2-甲基-1-丙磺酸（AMPSA）和丙烯酸（AA）的无规共聚反应合成pH响应性TA功能化石墨烯水凝胶（TRGAA）。通过FTIR、XPS、拉曼光谱、TGA和SEM等手段对水凝胶的化学组成和分子结构进行了表征。系统研究了吸附剂种类、pH值、染料初始浓度、吸附时间、吸附温度对吸附过程的影响。结果表明，AMPSA和AA的引入显著提高了水凝胶的吸附能力。该水凝胶的吸附行为符合Langmuir等温吸附模型和准二级吸附模型。TRGAA水凝胶对亚甲基蓝的吸附能力显著，最大吸附量为1000 mg/g。此外，以乙醇为解吸剂考察了TRGAA水凝胶的重复使用效率，TRGAA水凝胶在6次吸附-解吸循环后仍能保持良好的吸附效果。TRGAA水凝胶是一种理想的阳离子染料吸附剂，这是由于独特的化学组成和多孔层状结构的协同作用。本工作基于TRGAA水凝胶的绿色合成和高吸附能力，对石墨烯基复合材料在环境保护领域的应用具有重要的理论意义和实用价值。
Tannic acid (TA) functionalized graphene (TA-rGO) was synthesized by a simple and green method using TA as both reducing agent and capping agent, avoiding the use of additional chemical stabilizers. pH-responsive TA functionalized graphene hydrogel (TRGAA) was then synthesized by random copolymerization of 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPSA) and acrylic acid (AA) in the presence of TA-rGO. The chemical composition and molecular structure of the resulting hydrogel were characterized by means of FTIR, XPS, Raman spectra, TGA, and SEM. The effects of adsorbent category, pH value, initial dye concentration, adsorption time, and adsorption temperature on the adsorption process were systematically studied. The results indicated that the introduction of AMPSA and AA had significantly improved the adsorption capacity of the hydrogel. The adsorption behaviors of the hydrogel conformed to Langmuir isothermal model and pseudo-second-order model. The adsorption capacity of TRGAA hydrogel to methylene blue was significant, with the maximum adsorption capacity of 1000 mg/g. In addition, ethanol was used as the desorbent to investigate the reuse efficiency, and TRGAA hydrogel could still maintain a good adsorption effect even after 6 adsorption-desorption cycles. TRGAA hydrogel was an ideal adsorbent for cationic dyes, which was owing to the synergistic effect of distinctive chemical composition and porous layered structure. This work based on the green synthesis and high adsorption capacity of TRGAA hydrogel might has important theoretical significance and practical value for developing the application of graphene-matrix composite materials in the field of environmental protection.