The heteroaggregation behavior of nanoplastics on goethite: Effects of surface functionalization and solution chemistry

Jiayan Wu; Quanyun Ye; Peiran Li; Leiye Sun; Minye Huang; Jieyu Liu; Zubair Ahmed; Pingxiao Wu

doi:10.1016/j.scitotenv.2023.161787

The heteroaggregation behavior of nanoplastics on goethite: Effects of surface functionalization and solution chemistry

Sci Total Environ. 2023 Apr 20:870:161787. doi: 10.1016/j.scitotenv.2023.161787. Epub 2023 Jan 24.

Authors

Jiayan Wu¹, Quanyun Ye², Peiran Li², Leiye Sun¹, Minye Huang¹, Jieyu Liu¹, Zubair Ahmed¹, Pingxiao Wu³

Affiliations

¹ School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
² Guangdong Engineering & Technology Research Center for System Control of Livestock and Poultry Breeding Pollution, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China.
³ School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou 510006, PR China; Guangdong Engineering and Technology Research Center for Environmental Nanomaterials, Guangzhou 510006, PR China. Electronic address: pppxwu@scut.edu.cn.

PMID: 36706999
DOI: 10.1016/j.scitotenv.2023.161787

Abstract

Nanoplastics have attracted extensive attention in recent years. However, little is known about the heteroaggregation behavior of nanoplastics on goethite (FeOOH), especially the contribution of surface functional groups. In this study, the heteroaggregation behavior between polystyrene nanoplastics (PSNPs) and FeOOH was systematically investigated under different reaction conditions. Moreover, the effect of different functional groups (-NH₂, -COOH, and bare) of PSNPs and solution chemistry was evaluated. The results showed that PSNPs could heteroaggregate with FeOOH, and the heteroaggregation rate of PSNPs with surface functionalization was significantly faster. The removal of suspended PSNPs was enhanced with increasing NaCl or CaCl₂ concentration. However, heteroaggregation was significantly inhibited with the increase of solution pH. The zeta potentials analysis, time-resolved dynamic light scattering (DLS) and heteroaggregation experiments suggested that the electrostatic force affected the heteroaggregation process significantly. Fourier transform infrared (FTIR) spectra proved that the adsorption affinity between PSNPs and FeOOH was stronger after surface functionalization, especially for CH, O-C=O, and -CH₂- groups, indicating that chemical bonding also made a contribution during the heteroaggregation process. This work is expected to provide a theoretical basis for predicting the environmental behavior between PSNPs and FeOOH.

Keywords: Functional groups; Goethite; Heteroaggregation; Polystyrene nanoplastics.