改性氧化石墨烯/壳聚糖功能材料对刚果红的吸附研究

A modified graphene oxide/chitosan composite used as an adsorbent for Congo red in aqueous solutions

以氧化石墨烯(GO)和壳聚糖(CS)为前体物,以乙二胺四乙酸二钠(EDTA-2Na)为表面改性剂,制备了一种新型改性氧化石墨烯/壳聚糖功能材料(GEC),并将此材料作为吸附剂用于水中刚果红的吸附去除,探讨了时间、pH值、吸附剂投加量、温度及初始浓度对GEC吸附去除刚果红的影响.结果表明,GEC对水中刚果红具备良好的吸附能力,且在pH=2~12的范围内都具有较佳的吸附效果.GEC对刚果红的吸附动力学可以较好地用伪二级动力学模型进行描述,其吸附数据可应用Langmuir吸附等温模型进行拟合,其吸附过程是自发的吸热反应过程.根据Langmuir模型计算得到GEC室温条件下最大吸附量为175.43 mg·g^(-1).用2 mol·L^(-1)NaOH溶液在60℃水浴条件下对GEC进行脱附再生实验,在重复循环利用6次后,GEC对刚果红的吸附量仅下降了5.89%,刚果红的去除率仍保持在88%以上.以上结果表明,GEC适合作为一种有效的吸附剂去除水中刚果红.

A novel adsorbent for Congo red from aqueous solutions has been successfully prepared by modifying graphene oxide/chitosan composite with disodium ethylenediaminetetraacetate（ EDTA-2Na）（ GEC）. Batch adsorption experiments were carried out to evaluate the adsorption of Congo red by GEC under different conditions. The results indicate that GEC have good ability for adsorption of Congo red in a large range of pH（ 2 ~ 12）. The kinetics of adsorption exhibited pseudo-second-order behavior. The adsorption performance were well described by the Langmuir isotherm model. The adsorption capacity increased with increasing temperature. The calculated thermodynamic parameters indicate that the adsorption is a spontaneous,endothermic and feasible process. The maximum adsorption capacity of GEC was 175. 43 mg·g^（-1）at 298 K. The further regeneration experiments show the adsorption capacity of GEC for Congo red decreased 5. 89% after 6 times reuse,indicating the potential material for practical application.