Cellulose and Paper Department, National Research Centre, 33 El Bohouth Str., P.O. 12622, Dokki, Giza, Egypt.
Sci Rep. 2023 Jul 12;13(1):11306. doi: 10.1038/s41598-023-37894-4.
The chromium adsorption behavior from aqueous solution by the amphoteric Janus nitrogen-doped carbon quantum dots (AJ-N-CQDs) was investigated. The pseudo-first-order and the second-order adsorption kinetics models were employed to analyze the experimental data; the second-order adsorption kinetics model presented a better correlation to the experimental data, suggesting a chemisorptions process. The values obtained in the pseudo-first-order are still suitable for describing the Kinetics of Cr(VI) sorption. These values elucidate the surface processes involving chemisorption and physisorption in the adsorption of Cr(VI) by AJ-N-CQDs. The R of the Boyd model gave a better fit to the adsorption data of AJ-N-CQDs (i.e., external diffusion), which means the surface processes involving external Cr(VI) adsorption by AJ-N-CQDs. The higher value of α may be due to the greater surface area of the AJ-N-CQDs for the immediate adsorption of Cr(VI) from the aqueous solution. AJ-N-CQDs have fluorescence spectra before and after Cr(VI) adsorption, indicating they are promising for chemical sensor applications.
研究了两性 Janus 氮掺杂碳量子点（AJ-N-CQDs）从水溶液中吸附铬的行为。采用伪一级和二级吸附动力学模型对实验数据进行分析；二阶吸附动力学模型与实验数据相关性更好，表明这是一个化学吸附过程。从伪一级动力学模型中得到的值仍然适用于描述 Cr(VI)的吸附动力学。这些值阐明了在 AJ-N-CQDs 吸附 Cr(VI)过程中涉及化学吸附和物理吸附的表面过程。Boyd 模型的 R 值更适合 AJ-N-CQDs 的吸附数据（即外部扩散），这意味着涉及 AJ-N-CQDs 外部 Cr(VI)吸附的表面过程。α 值较高可能是由于 AJ-N-CQDs 的更大表面积，使其能够立即从水溶液中吸附 Cr(VI)。AJ-N-CQDs 在吸附 Cr(VI)前后具有荧光光谱，表明它们有望用于化学传感器应用。
