Aggregation kinetics of UV-aged soot nanoparticles in wet environments: Effects of irradiation time and background solution chemistry

Duan, Zhihui; Wang, Ping; Yu, Guangwei; Liang, Miaoting; Dong, Jiawei; Su, Jiana; Huang, Weilin; Li, Yongtao; Zhang, Aiqian; Chen, Chengyu

doi:10.1016/j.watres.2021.117385

Cited by 11 publications

(15 citation statements)

References 51 publications

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“…Irradiation experiments were conducted in a photochemical reactor (NAI-GHY-DSGGY, China) equipped with a mercury lamp (GGZ1000, λ = 365 ± 50 nm) to provide a constant UVA intensity of ∼2 mW/cm 2 . , Suspensions containing NPs were withdrawn after continuous irradiation for 2, 4, 8, 10, 14, 16, 18, 20, 22, and 24 days and stored at 4 °C in the dark before the measurement. These experimental conditions could be equivalent to irradiation for 6–68 days annually under natural conditions in Guangzhou, China (23°9′27.5400″ N, 113°21′27.2988″ E) (Table S1).…”

Section: Materials and Methodsmentioning

confidence: 99%

Differential Photoaging Effects on Colored Nanoplastics in Aquatic Environments: Physicochemical Properties and Aggregation Kinetics

Su,

Ruan,

Luo

et al. 2023

Environ. Sci. Technol.

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Nanoplastics (NPs) have different colors, which could affect their photoaging processes in aquatic environments. This study investigated the effects of irradiation on physicochemical properties and aggregation kinetics of five colored NPs. Photodegradation rates and photooxidation degrees ranked white ≈ yellow > red > blue ≈ black NPs, indicating that NPs with longer color wavelengths photoaged faster. The discoloration process followed color fading (2–14 days, except for white NPs), yellowing (10–16 days), yellow fading (18 days), and turning transparent (20–22 days). White NPs exhibited a different photoaging sequence (C–H → C–OH → CO → O–CO) from others. Photodegradation was mainly controlled by singlet oxygen, producing 13 chemicals that were mostly organic acids. The overall colloidal stability of pristine NPs ranked blue > yellow > red > black > white. Irradiation for 16 days retarded aggregation of white and other NPs in NaCl solution, raising the critical coagulation concentration (CCC) by 82.14 and 0.85–7.90%, respectively. Contrarily, irradiation promoted aggregation in CaCl2 solution by reducing the CCC of white (67.37%) and other (33.33–37.58%) NPs. The findings demonstrate that colored NPs underwent photoaging processes different from white/transparent NPs, which were focused by previous work, highlighting the important role of color in their environmental fate and transport.

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Section: Materials and Methodsmentioning

confidence: 99%

Differential Photoaging Effects on Colored Nanoplastics in Aquatic Environments: Physicochemical Properties and Aggregation Kinetics

Su,

Ruan,

Luo

et al. 2023

Environ. Sci. Technol.

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“…It is consistent with the findings on PSNPs 43 and nC 60 , 19 despite there being also many publications revealing the photoinduced accordant tendency between them. 17,44,63 These discrepancies may result from differences in particle attributes and aging conditions. Larger k fast and lower CCC appeared in the CaCl 2 solution (Figures S12i and Figure 3b), indicating that Ca 2+ had a stronger capacity to destabilize DBioCs.…”

Section: Effects Of Irradiation Time On the Colloidal Stability Of Db...mentioning

confidence: 99%

“…In fact, this hypothesis has been verified in other carbon materials. 43,44 Therefore, the experimentally measured attachment efficiencies (α) for pristine and photoaged DBioCs in NaCl solutions were fitted as a function of electrolyte concentrations grounded in classical DLVO theory (TEXT S9).…”

Section: Effects Of Irradiation Time On the Colloidal Stability Of Db...mentioning

confidence: 99%

“…36,37 Such a drastic evolution inspired us that photoaging may change the DBC structure, thus affecting its Hamaker constant, which has recently been confirmed in soot nanoparticles (SNPs). 44 However, there have been, hitherto, few studies on the Hamaker constants of DBC, let alone the impact of the aging processes on them. Therefore, exploring the photoaging mechanism, establishing the relation between photoaging and colloidal stability, and determining the variation rules on the Hamaker constant under photoaging are imperative to accurately describe and predict the actual environmental behaviors of DBC.…”

Section: Introductionmentioning

confidence: 99%

“…Its value, immune to environmental conditions, is only related to materials’ inherent structure . As reported, sunlight can degrade the chromophores and even mineralize DBC. , Such a drastic evolution inspired us that photoaging may change the DBC structure, thus affecting its Hamaker constant, which has recently been confirmed in soot nanoparticles (SNPs) . However, there have been, hitherto, few studies on the Hamaker constants of DBC, let alone the impact of the aging processes on them.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

New Insights into Aggregation Behaviors of the UV-Irradiated Dissolved Biochars (DBioCs) in Aqueous Environments: Effects of Water Chemistries and Variation in the Hamaker Constant

Tang,

Guo,

Zhu

et al. 2024

Environ. Sci. Technol.

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The aggregation behavior of ubiquitous dissolved black carbon (DBC) largely affects the fate and transport of its own contaminants and the attached contaminants. However, the photoaging processes and resulting effects on its colloidal stability remain yet unknown. Herein, dissolved biochars (DBioCs) were extracted from common wheat straw biochar as a proxy for an anthropogenic DBC. The influences of UV radiation on their aggregation kinetics were systematically investigated under various water chemistries (pH, electrolytes, and protein). The environmental stability of the DBioCs before and after radiation was further verified in two natural water samples. Hamaker constants of pristine and photoaged DBioCs were derived according to Derjaguin−Landau−Verwey−Overbeek (DLVO) prediction, and its attenuation (3.19 ± 0.15 × 10 −21 J to 1.55 ± 0.07 × 10 −21 J after 7 days of radiation) was described with decay kinetic models. Pearson correlation analysis revealed that the surface properties and aggregation behaviors of DBioCs were significantly correlated with radiation time (p < 0.05), indicating its profound effects. Based on characterization and experimental results, we proposed a three-stage mechanism (contended by photodecarboxylation, photooxidation, and mineral exposure) that DBioCs might experience under UV radiation. These findings would provide an important reference for potential phototransformation processes and relevant behavioral changes that DBC may encounter.

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The aggregation of natural inorganic colloids in aqueous environment: A review

Guo

et al. 2023

Chemosphere

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Aggregation kinetics of UV-aged soot nanoparticles in wet environments: Effects of irradiation time and background solution chemistry

Cited by 11 publications

References 51 publications

Differential Photoaging Effects on Colored Nanoplastics in Aquatic Environments: Physicochemical Properties and Aggregation Kinetics

Differential Photoaging Effects on Colored Nanoplastics in Aquatic Environments: Physicochemical Properties and Aggregation Kinetics

New Insights into Aggregation Behaviors of the UV-Irradiated Dissolved Biochars (DBioCs) in Aqueous Environments: Effects of Water Chemistries and Variation in the Hamaker Constant

The aggregation of natural inorganic colloids in aqueous environment: A review

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