Aggregation of graphene oxide upon the stripping of oxidized debris: An experimental and molecular dynamics simulation study.

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-Ca2+-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. Copyright © 2024 Elsevier Ltd. All rights reserved.

Citation

Jiahai Yu, Wenli Li, Dan Zhang, Tinglin Huang, Huan Tang. Aggregation of graphene oxide upon the stripping of oxidized debris: An experimental and molecular dynamics simulation study. Environmental pollution (Barking, Essex : 1987). 2024 May 01;348:123884

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PMID: 38548155

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