State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; School of Environmental and Safety Engineering, Changzhou University, Changzhou 213164, China.
Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, School of Resources & Environment, Nanchang University, Nanchang 330031, China.
Sci Total Environ. 2023 Feb 20;860:160318. doi: 10.1016/j.scitotenv.2022.160318. Epub 2022 Nov 19.
Fulvic acid (FA) can affect the dispersion of graphene oxide (GO) in aquatic environments, however, the possible mechanisms remain unclear. Dynamic light scattering techniques combined with a multiple regression model were applied to explore the influence of FA sub-fractions (FA - FA) on the aggregation kinetics of GO in aqueous environments. The ratios of critical coagulation concentration (CCC) values were CCC: CCC: CCC: CCC = 1:2:3:3, which were consistent with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and Schulze-Hardy rules. The GO remained stable at pH 3-10 and aggregated at pH < 3 or pH > 10, and its critical coagulation pH values were 1.44 and 12.25 with 10 mM NaCl as background. The CCC values of GO in the presence of FA - FA were greater than those in the absence of FA sub-fractions. The ratios of CCC values of GO (r) increased in the presence of FA sub-fractions in the order of FA > FA > FA > FA > FA and ranged from 1.01 to 2.15 for certain metal ions including Na, Mg, La, and Ce. The CCC values of GO were significantly related to C, H, O, N, S, H/C, O/C, carboxylic C, and carbonyl C of FA sub-fractions (P < 0.05), respectively, and could be predicted using the multiple linear regression eq. CCC = Z (98.959- 60.911 ∗ O/C + 4.799 ∗ O-alkyl C - 0.845 ∗ aromatic C - 6.237 ∗ carbonyl C). The predicted CCC values for GO were within 90 % prediction intervals, and the average error of the CCC values was 3.3 % and R = 0.986. This investigation is expected to provide a scientific basis for the transport and ecotoxicity of GO in environments.
富里酸（FA）会影响氧化石墨烯（GO）在水相环境中的分散性，但其可能的作用机制尚不清楚。本研究采用动态光散射技术并结合多元逐步回归模型，研究了 FA 各亚组分（FA- FA）对 GO 在水相环境中聚集动力学的影响。结果表明，GO 在 pH 3-10 条件下保持稳定，在 pH < 3 或 pH > 10 条件下发生聚集，临界聚沉 pH 值分别为 1.44 和 12.25，此时背景电解质为 10 mM NaCl。GO 在 FA- FA 存在时的 CCC 值大于不存在 FA 亚组分时的 CCC 值。在 FA 亚组分存在的情况下，GO 的 CCC 值与 FA 亚组分的组成顺序呈正相关，依次为 FA > FA > FA > FA > FA，在某些金属离子（Na、Mg、La 和 Ce）存在时，r 的范围为 1.01-2.15。GO 的 CCC 值与 FA 亚组分的 C、H、O、N、S、H/C、O/C、羧酸 C 和羰基 C 显著相关（P < 0.05），并可以使用多元线性回归方程进行预测：CCC = Z（98.959-60.911 ∗ O/C+4.799 ∗ O-alkyl C-0.845 ∗ aromatic C-6.237 ∗ carbonyl C）。GO 的预测 CCC 值在 90%预测区间内，平均误差为 3.3%，R = 0.986。该研究为 GO 在环境中的迁移和生态毒性提供了科学依据。
