Borrás Alejandro, Henriques Bruno, Gonçalves Gil, Fraile Julio, Pereira Eduarda, López-Periago Ana M, Domingo Concepción
Materials Science Institute of Barcelona (ICMAB-CSIC), Campus UAB, 08193 Barcelona, Spain.
LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
Gels. 2022 Jul 19;8(7):452. doi: 10.3390/gels8070452.
This article reports the synthesis of an aerogel involving reduced graphene oxide (rGO) and polyethylenimine (PEI), and describes its potential application as an effective sorbent to treat Hg(II) contaminated water. The rGO/PEI sorbent was synthetized using a supercritical CO method. N physisorption, electron microscopy, and elemental mapping were applied to visualize the meso/macroporous morphology formed by the supercritical drying. The advantages of the synthetized materials are highlighted with respect to the larger exposed GO surface for the PEI grafting of aerogels vs. cryogels, homogeneous distribution of the nitrogenated amino groups in the former and, finally, high Hg(II) sorption capacities. Sorption tests were performed starting from water solutions involving traces of Hg(II). Even though, the designed sorbent was able to eliminate almost all of the metal from the water phase, attaining in very short periods of time residual Hg(II) values as low as 3.5 µg L, which is close to the legal limits of drinking water of 1-2 µg L. rGO/PEI exhibited a remarkably high value for the maximum sorption capacity of Hg(II), in the order of 219 mg g. All of these factors indicate that the designed rGO/PEI aerogel can be considered as a promising candidate to treat Hg(II) contaminated wastewater.
本文报道了一种包含还原氧化石墨烯（rGO）和聚乙烯亚胺（PEI）的气凝胶的合成，并描述了其作为有效吸附剂处理汞（II）污染水的潜在应用。rGO/PEI吸附剂采用超临界CO₂方法合成。通过N₂物理吸附、电子显微镜和元素映射来观察超临界干燥形成的介孔/大孔形态。合成材料的优点在于，与冷冻凝胶相比，气凝胶的GO表面更易于PEI接枝，前者中含氮氨基分布均匀，最终汞（II）吸附容量高。从含有痕量汞（II）的水溶液开始进行吸附测试。尽管如此，所设计的吸附剂能够在极短时间内从水相中去除几乎所有的金属，使残余汞（II）值低至3.5 μg/L，接近饮用水1-2 μg/L的法定限值。rGO/PEI对汞（II）的最大吸附容量表现出非常高的值，约为219 mg/g。所有这些因素表明，所设计的rGO/PEI气凝胶可被视为处理汞（II）污染废水的有前景的候选材料。
