Influence of fulvic acid sub-fractions on aggregation kinetics of graphene oxide in aqueous environments

Peng Xia; Weibo Zhang; Qi Jin; Jingyi Si; Fei Guo; Zhongyu Li; Yingchen Bai

doi:10.1016/j.scitotenv.2022.160318

Influence of fulvic acid sub-fractions on aggregation kinetics of graphene oxide in aqueous environments

Sci Total Environ. 2023 Feb 20:860:160318. doi: 10.1016/j.scitotenv.2022.160318. Epub 2022 Nov 19.

Authors

Peng Xia¹, Weibo Zhang², Qi Jin³, Jingyi Si³, Fei Guo³, Zhongyu Li⁴, Yingchen Bai⁵

Affiliations

¹ 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.
² Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, School of Resources & Environment, Nanchang University, Nanchang 330031, China.
³ State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
⁴ School of Environmental and Safety Engineering, Changzhou University, Changzhou 213164, China.
⁵ 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. Electronic address: baiyc@craes.org.cn.

PMID: 36414062
DOI: 10.1016/j.scitotenv.2022.160318

Abstract

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_pH3 - FA_pH13) on the aggregation kinetics of GO in aqueous environments. The ratios of critical coagulation concentration (CCC) values were CCC_Na: CCC_Mg: CCC_La: CCC_Ce = 1:2^-5.15:3^-7.31:3^-7.35, 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_pH3 - FA_pH13 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_pH13 > FA_pH9 > FA_pH7 > FA_pH5 > FA_pH3 and ranged from 1.01 to 2.15 for certain metal ions including Na⁺, Mg²⁺, La³⁺, and Ce³⁺. 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^-n (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 R² = 0.986. This investigation is expected to provide a scientific basis for the transport and ecotoxicity of GO in environments.

Keywords: Aggregation kinetics; Fulvic acid sub-fractions; Graphene oxide; Model prediction.

MeSH terms

Graphite*
Kinetics
Water*

Substances

graphene oxide
fulvic acid
Water
Graphite