Abstract:
Objective To study the application of nitrogen-doped carbon quantum dots (CQDs) in oil and gas development through alkylation modification of CQDs prepared by hydrothermal method.
Methods Carbon quantum dots CQDs and nitrogen-doped carbon quantum dots N-CQDs were synthesized with citric acid as carbon source and diethylenetriamine as nitrogen source under hydrothermal conditions. An amphiphilic surfactant R-(N-CQDs) was obtained by surface modification of the prepared N-CQDs through an alkylation reaction.
Results The particle size distribution of CQDs and N-CQDs was uniform, with the typical particle size characteristics of carbon quantum dots. The fluorescence quantum yields of CQDs and N-CQDs were 10% and 47%, respectively, at the maximum excitation wavelength, and nitrogen doping significantly improved the fluorescence properties of carbon quantum dots. Compared with commonly utilized surfactant SDBS, R-(N-CQDs) could reduce surface tension and improve foam stability and emulsification.
Conclusion The modified carbon quantum dots can reduce water surface tension, have excellent emulsification and foam stabilization performance, and have specific application potential in oil and gas development.