Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
Environ Pollut. 2024 May 1;348:123884. doi: 10.1016/j.envpol.2024.123884. Epub 2024 Mar 26.
The most recent structural study of graphene oxide (GO) indicates that the oxidized debris (ODs) adhered to as-prepared GO will strip in certain aquatic settings. The impact of ODs stripping on the characteristics of GO has been widely reported, but its effects on GO aggregation have received less attention. Here, the influence of OD stripping on the GO aggregation property was identified, and the aggregation of as-prepared GO and GO upon OD stripping was compared. Upon ODs stripping, the pKa values of GO shifted from 3.91, 6.25, and 9.84 to 4.54, 6.65, and 10.21, respectively. Further analysis indicated the removal of ODs reduced the net negative charge and improved the hydrophobicity of GO, hence promoting the aggregation of GO. The acceleration of GO-Ca-OD aggregate formation was facilitated by the collective effects of ODs stripping, functional group deprotonation, double layer compression, OD bridging, and charge neutralization. The metal ions and stripped ODs attach to GO edges and link GO, which perform like bridges and contribute to further aggregation. In general, the existence of ODs adds complexity to the constructions and characteristics of GO, and it is important to take this into account while evaluating the aggregation characteristic of GO-based materials.
最近对氧化石墨烯（GO）的结构研究表明，在某些水基环境中，附着在制备好的 GO 上的氧化碎片（ODs）会剥落。ODs 剥落对 GO 特性的影响已被广泛报道，但对 GO 聚集的影响却较少受到关注。在这里，确定了 ODs 剥落对 GO 聚集特性的影响，并比较了制备好的 GO 和 GO 在 ODs 剥落时的聚集情况。ODs 剥落后，GO 的 pKa 值分别从 3.91、6.25 和 9.84 变为 4.54、6.65 和 10.21。进一步的分析表明，ODs 的去除减少了 GO 的净负电荷并提高了其疏水性，从而促进了 GO 的聚集。ODs 剥落、官能团去质子化、双层压缩、OD 桥接和电荷中和的共同作用促进了 GO-Ca-OD 聚集体的形成。金属离子和剥落的 ODs 附着在 GO 边缘并连接 GO，它们像桥一样发挥作用，有助于进一步聚集。总的来说，ODs 的存在增加了 GO 的结构和特性的复杂性，在评估基于 GO 的材料的聚集特性时，考虑到这一点很重要。
