The zeta potentials of g-C3N4 nanoparticles: Effect of electrolyte, ionic strength, pH, and humic acid

  • Shunan DongEmail author
  • Zhuo Zeng
  • Wangwei Cai
  • Zhiyue Zhou
  • Chuanbin Dou
  • Han Liu
  • Jihong XiaEmail author
Research Paper


In this study, zeta potentials of graphitic carbon nitride (g-C3N4) nanoparticles were detailedly investigated under various electrolytes, solution pH, and humic acid (HA) concentration conditions. The hydrodynamic radius of g-C3N4 nanoparticles was measured to be 388.9 ± 24 nm, and the specific surface area of the g-C3N4 nanoparticles was measured to be 46.2 m2 g−1. The absolute values of g-C3N4 zeta potentials significantly decreased with the increasing ionic strength (IS) due to the charge screening. Compared to the monovalent cation, the zeta potentials of g-C3N4 were less negative with the presence of divalent cations. In addition, K+ was more effective than Na+ in decreasing the absolute values of g-C3N4 zeta potentials, and Ca2+ was more effective than Mg2+ in decreasing the absolute values of g-C3N4 zeta potentials. When NaCl and CaCl2 were used as the electrolytes, the zeta potentials of g-C3N4 became less negative with the decreasing pH conditions. When FeCl3 and AlCl3 were used as the electrolytes, the zeta potentials of g-C3N4 became more positive with increasing solution pH due to the changing species of Fe3+ and Al3+. The zeta potentials of g-C3N4 were significantly more negative with the presence of HA. The results from this work indicated electrolytes, solution pH, and HA concentration conditions play a complex role in zeta potentials of g-C3N4 nanoparticles in aqueous environment.


Zeta potentials g-C3N4 nanoparticles Aqueous environment Electrolyte pH Humic acid Colloids 


Funding information

This work was supported by the National Key R&D Program of China (2018YFD0900805), the National Natural Science Foundation of China (41907160), and the Fundamental Research Funds for the Central Universities (2019B01914).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.College of Agricultural EngineeringHohai UniversityNanjingChina

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