Gao Feng, Zhang Lei, Yang Libin, Zhou Xuefei, Zhang Yalei
State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Key Laboratory of Yangtze Water Environment for Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Nanomaterials (Basel). 2023 Jan 9;13(2):279. doi: 10.3390/nano13020279.
Herein, three types of graphene oxides (GOs, GO-M1, GO-M2 and GO-M3) have been successfully prepared from graphite by three different methods and utilized for the removal of Cr(VI) from aqueous solutions. Further, the effects of initial concentration and pH, adsorbent dosage, contact time and temperature on the adsorption performance of GOs were investigated by batch adsorption experiments. Furthermore, the adsorption mechanisms for Cr(VI) adsorption by GOs are mainly the redox reaction and electrostatic attraction, while there are also pore filling, ion exchange and complexation involved in these adsorption processes. The adsorption kinetic and isotherm data indicate that these adsorption processes of GOs on Cr(VI) are dominantly monolayer chemisorption and equilibrium can be reached in 30 min. The saturation adsorption capacities (Q, 298.15 K) of GO-M1, GO-M2 and GO-M3 for Cr(VI) are estimated to be 3.5412 mg⋅g, 2.3631 mg⋅g and 7.0358 mg⋅g, respectively. Moreover, the adsorption thermodynamic study showed that these adsorption processes of Cr(VI) by the three types of GOs at 298.15 K to 323.15 K are endothermic, entropy-driven and thermodynamically spontaneous and feasible. Overall, these findings provided vital insights into the mechanism and application of Cr(VI) removal by GOs.
在此，通过三种不同方法成功地从石墨制备了三种类型的氧化石墨烯（GOs、GO-M1、GO-M2和GO-M3），并将其用于从水溶液中去除Cr(VI)。此外，通过批量吸附实验研究了初始浓度、pH值、吸附剂用量、接触时间和温度对GOs吸附性能的影响。此外，GOs对Cr(VI)的吸附机制主要是氧化还原反应和静电吸引，同时这些吸附过程中还涉及孔隙填充、离子交换和络合作用。吸附动力学和等温线数据表明，GOs对Cr(VI)的这些吸附过程主要是单层化学吸附，30分钟内可达到平衡。GO-M1、GO-M2和GO-M3对Cr(VI)的饱和吸附容量（Q，298.15 K）估计分别为3.5412 mg⋅g、2.3631 mg⋅g和7.0358 mg⋅g。此外，吸附热力学研究表明，三种类型的GOs在298.15 K至323.15 K下对Cr(VI)的这些吸附过程是吸热的、熵驱动的，并且在热力学上是自发的和可行的。总体而言，这些发现为GOs去除Cr(VI)的机制和应用提供了重要的见解。
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