Abstract

In this study, a novel chitin based composite hydrogel reinforced by tannic acid modified reduced graphene oxide (TRGO) was prepared via a facile freezing–thawing approach. Epichlorohydrin (ECH) and TRGO sheets were employed as efficient crosslinkers to fabricate dually crosslinked TRGO/chitin composite hydrogels with advanced mechanical and adsorption properties. Results indicated that the TRGO reinforced chitin composites increased the mechanical property remarkably with exhibiting compression strength from 22.7 kPa for neat chitin hydrogel to 72.3 kPa for the hydrogel with loading of 7% TRGO. Multiple interactions such as hydrogen bonding between TRGO and chitin as well as the dually covalent crosslinking bonds were responsible for the extensive improvement in compression strength. Furthermore, the TRGO reinforced hydrogels exhibited an excellent adsorption capacity towards Congo red (CR). The maximum adsorption capacity of CR was 230.5 mg g⁻¹ for chitin hydrogel with loading of 7% TRGO. The adsorption of CR was found following the Langmuir isotherm and pseudo-second-order models. Hence, the prepared TRGO/chitin hydrogels provide an easy and efficient way for the removal of CR dye from wastewater.

中文翻译：

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单宁酸官能化石墨烯增强的高强度几丁质基水凝胶对刚果红的吸附作用

摘要

在这项研究中，通过一种简便的冻融方法，制备了一种由鞣酸修饰的还原氧化石墨烯（TRGO）增强的几丁质基复合水凝胶。表氯醇（ECH）和TRGO片材被用作有效的交联剂，以制备具有先进的机械和吸附性能的双交联TRGO /甲壳质复合水凝胶。结果表明，TRGO增强的几丁质复合材料的机械性能显着提高，压缩强度从纯甲壳质水凝胶的22.7 kPa增至负载7％TRGO的水凝胶的72.3 kPa。TRGO和几丁质之间的氢键以及双重共价交联键等多重相互作用导致了抗压强度的大幅提高。此外，TRGO增强水凝胶对刚果红（CR）表现出出色的吸附能力。CR的最大吸附量为230.5 mg g几丁质水凝胶的^-1为TRGO负载量的7％。遵循Langmuir等温线和拟二阶模型发现了CR的吸附。因此，制备的TRGO /甲壳质水凝胶为从废水中去除CR染料提供了一种简单有效的方法。