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Li X, Ding G, Song G, Zhuang Y, Wang C, Li R, Liu Q. Aggregation behavior of aqu/nC 60 produced via extended mixing: Influence of sunlight and agitation intensity. Ecotoxicol Environ Saf 2020; 193:110332. [PMID: 32088550 DOI: 10.1016/j.ecoenv.2020.110332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 06/10/2023]
Abstract
Aggregation of C60, as an important process governing its mobility and toxicity, has been quantitatively investigated. However, effects of sunlight and agitation intensity on the aggregation behavior of aqu/nC60 produced via extended mixing, have not been clarified. Therefore, in the present study, the aggregation behavior of aqu/nC60 produced at 500 and 800 rpm in the absence and presence of sunlight was investigated. Aggregation with increasing concentrations could be accelerated, while changes of Zave and zeta potential were not obvious. Critical coagulation concentrations (CCCs) of aqu/nC60 obtained at 800 rpm in the absence/presence of sunlight and that at 500 rpm under sunlight were 330, 205 and 170 mM NaCl, and 10.0, 2.6 and 3.1 mM CaCl2, respectively. These CCCs indicated that the aqu/nC60 prepared by the extended mixing were more stable than those produced by other methods. Salt-induced aggregation occurred more easily for aqu/nC60 formed under sunlight than that formed in the dark. Extra surface oxidation induced by high agitation intensity remarkably increased the stability of aqu/nC60 in NaCl solutions. In contrast, in CaCl2 solutions, aqu/nC60 formed at high agitation intensity had similar stability or even inadequate stability to that obtained at low agitation intensity due to the charge neutralization and cross-link bridging.
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Affiliation(s)
- Xueyao Li
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
| | - Guanghui Ding
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China.
| | - Guobin Song
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
| | - Yuting Zhuang
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
| | - Chunchao Wang
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
| | - Ruijuan Li
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
| | - Quanbin Liu
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
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Li X, Ding G, Zhang J, Wang Y, Li W, Wang C, Li R, Yang Z. Generation and properties of aqu/nC 60: the combined effects of humic acid, sunlight, and agitation intensity. Environ Sci Pollut Res Int 2020; 27:12527-12538. [PMID: 32002835 DOI: 10.1007/s11356-020-07811-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/21/2020] [Indexed: 06/10/2023]
Abstract
Once released into natural water, the environmental behavior and fate of C60 could inevitably been affected by humic acid (HA), sunlight, and hydrodynamic conditions. However, the combined effects of these factors are not so clear. Therefore, in the present study, effects of HA, sunlight, and agitation intensity on generation and properties of aqu/nC60 were investigated. The results indicated that HA could increase the concentration of aqu/nC60 mainly through the steric hindrance effect. The higher agitation intensity led to higher concentrations of aqu/nC60 and more efficient steric stabilization was formed by HA. Sunlight irradiation promoted the surface oxidization and consequently enhanced the dispersion of C60. The relative order of the influence on the UV/vis concentration was sunlight > agitation intensity > HA. In addition, HA might not always enhance the dispersion of aqu/nC60 due to light screening/ROS scavenging, over-coating, or chain-like bridging mechanism. Therefore, evaluating the environmental behavior and fate of C60 should take these factors into account together.
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Affiliation(s)
- Xueyao Li
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
| | - Guanghui Ding
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China.
| | - Jing Zhang
- College of Environment and Chemical Technology, Dalian University, Dalian, 116622, China.
| | - Yingying Wang
- College of Environment and Chemical Technology, Dalian University, Dalian, 116622, China
| | - Wanran Li
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
| | - Chunchao Wang
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
| | - Ruijuan Li
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
| | - Zhanning Yang
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian, 116026, China
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