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Zhang Y, Yin G, Sheng GD, Yu Z, Yin D. Distribution and spatial variation of volatile methylsiloxanes in surface water and wastewater from the Yangtze River Basin, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 929:172541. [PMID: 38642747 DOI: 10.1016/j.scitotenv.2024.172541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 04/08/2024] [Accepted: 04/15/2024] [Indexed: 04/22/2024]
Abstract
Volatile methylsiloxanes (VMSs) earned serious concerns due to their detection and toxicities after their release to the environments. They were also detected in rivers around the globe, but their distribution remained to be explored in larger rivers with longer length, higher water volume and wider watershed. In the present study, 8 cyclic VMSs (cVMSs) and 7 linear ones (lVMSs) were investigated in 42 water samples (27 surface water (including 7 drinking source water) and 15 wastewater) from the Yangtze River Basin, China. Results showed that VMSs were detected in all sampling sites. In surface water, the concentrations of total cVMSs ranged from 17.3 to 4.57 × 103 ng/L, while those of lVMSs ranged from 1.72 to 81.6 ng/L. In wastewater, the total concentrations of cVMSs and lVMSs showed ranges of 17.6-1.66 × 103 ng/L and 2.59-252 ng/L, respectively. Apparently, cVMSs showed significantly higher concentrations than lVMSs. The concentrations of cVMSs followed an order of lower > upper > middle reaches, while those of lVMSs did not show clear distribution patterns. Among cVMSs, those with less Si numbers were dominant, while those with more Si numbers were dominant in lVMSs. Notably, the VMSs were also detected in 7 surface waters that served as drinking source waters, which earned them further concerns. In addition, the VMSs in surface water showed positive correlation with those in wastewater, which led to necessity in management on industrial emissions in the future.
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Affiliation(s)
- Yimeng Zhang
- State Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Ge Yin
- Shimadzu (China) Co., LTD, Shanghai 200233, China
| | - G Daniel Sheng
- State Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Zhenyang Yu
- State Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Daqiang Yin
- State Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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Wang WL, Zhang Y, Sun DM, Chen ZY, Qian M, Zhou Y, Feng XS, Zhang XY. Volatile Methylsiloxanes in Complex Samples: Recent Updates on Pretreatment and Analysis Methods. Crit Rev Anal Chem 2023:1-21. [PMID: 37603425 DOI: 10.1080/10408347.2023.2245050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Volatile methylsiloxanes (VMSs) are massively produced chemicals having applications in industry and home because of their physical and chemical characteristics. They are used in personal care products such as cosmetics, household coatings, cleaners, skin care products, and others. Resultantly, large number of VMSs are discharged into air where they can be subjected to atmospheric migrations over long distances causing toxic and estrogenic effects, persistence, and bioaccumulations. Many institutions have taken measures to control VMSs. They require accurate, rapid, and sensitive pretreatment and analysis methods for diverse samples. Herein, the pretreatment and determination methods of VMSs as reported in recent years are reviewed and summarized. Pretreatments include commonly methods such as membrane-assisted solvent extraction, liquid-liquid extraction, and others, while novel methods are solid phase extraction, solid phase microextraction, diverse liquid phase microextraction and others. Analyses are made through gas chromatography-based methods. In addition, the advantages, and disadvantages of techniques are compared, and the prospects of pretreatment and analysis methods are discussed.
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Affiliation(s)
- Wei-Lai Wang
- School of Pharmacy, China Medical University, Shenyang, China
| | - Yuan Zhang
- School of Pharmacy, China Medical University, Shenyang, China
| | - De-Mei Sun
- School of Pharmacy, China Medical University, Shenyang, China
| | - Zu-Yi Chen
- School of Pharmacy, China Medical University, Shenyang, China
| | - Min Qian
- School of Pharmacy, China Medical University, Shenyang, China
| | - Yu Zhou
- Department of Pharmacy, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue-Song Feng
- School of Pharmacy, China Medical University, Shenyang, China
| | - Xin-Yuan Zhang
- School of Forensic Medicine, China Medical University, Shenyang, China
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3
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Liu N, Zhang J, He X, Xu L, Cai Y. Occurrence and fate of chlorinated methylsiloxanes in surrounding aqueous systems of Shengli oilfield, China. J Environ Sci (China) 2023; 125:332-339. [PMID: 36375918 DOI: 10.1016/j.jes.2021.11.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/22/2021] [Accepted: 11/22/2021] [Indexed: 06/16/2023]
Abstract
Mono-chlorinated products of cyclic volatile methylsiloxanes (cVMS), i.e., Monochlormet-hylheptamethylcyclotetrasiloxane [D3D(CH2Cl)], monochlormethylnonamethylcyclopenta-siloxane [D4D(CH2Cl)], and monochlormethylundemethylcyclohexasiloxane [D5D(CH2Cl)], were detected in water [<LOQ (Limit of quantitation) -86.3 ng/L, df (detection frequency) = 23%-38%, n=112] and sediment samples [<LOQ-504 ng/g dw (dry weight), df = 33%-38%, n=112] from 16 lakes located in Shengli oilfield of China, and had apparent increasing trends (31%-34% per annum) in sediments during Year 2014-2020. Simulated experiments showed that chloro-cVMS in sediment-water system had approximately 1.7-2.0 times slower elimination rates than parent cVMS. More specifically, compared with those of parent cVMS, volatilization (86-2558 days) and hydrolysis (135-549 days) half-lives of chloro-cVMS were respectively 1.3-2.0 and 1.8-2.1 times longer. In two species of freshwater mussels (n=1050) collected from six lakes, concentrations of chloro-cVMS ranged from 9.8-998 ng/g dw in Anodonta woodiana and 8.4-970 ng/g dw in Corbicula fluminea. Compared with parent cVMS, chloro-cVMS had 1.1-1.5 times larger biota-sediment accumulation factors (2.1-3.0) and 1.1-1.7 times longer half-lives (13-42 days). Their stronger persistence in sediment and bioaccumulation in freshwater mussels suggested that environmental emission, distribution and risks of chloro-cVMS deserve further attention.
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Affiliation(s)
- Nannan Liu
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China.
| | - Jie Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China
| | - Xudan He
- Institute of Resources and Environment, Beijing Academy of Science and Technology, Beijing 100089, China
| | - Lin Xu
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China.
| | - Yaqi Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China; University of Chinese Academy of Sciences, Beijing 100049, China
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4
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Chen N, Chang B, Shi N, Yan W, Lu F, Liu F. Cross-linked enzyme aggregates immobilization: preparation, characterization, and applications. Crit Rev Biotechnol 2022; 43:369-383. [PMID: 35430938 DOI: 10.1080/07388551.2022.2038073] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Enzymes are commonly used as biocatalysts for various biological and chemical processes. However, some major drawbacks of free enzymes (e.g. poor reusability and instability) significantly restrict their industrial practices. How to overcome these weaknesses remain considerable challenges. Enzyme immobilization is one of the most effective ways to improve the reusability and stability of enzymes. Cross-linked enzyme aggregates (CLEAs) has been known as a novel and versatile carrier-free immobilization method. CLEAs is attractive due to its simplicity and robustness, without purification. It generally shows: high catalytic specificity and selectivity, good operational and storage stabilities, and good reusability. Moreover, co-immobilization of different kinds of enzymes can be acquired. These CLEAs advantages provide opportunities for further industrial applications. Herein, the preparation parameters of CLEAs were first summarized. Next, characterization of structural and catalytic properties, stability and reusability are also proposed. Finally, some important applications of this technique in: environmental protection, industrial chemistry, food industry, and pharmaceutical synthesis and delivery are introduced. Potential challenges and future research directions, such as improving cross-linking efficiency and internal mass transfer efficiency, are also presented. This implies that CLEAs provide an efficient and feasible technique to improve the properties of enzymes for use in the industry.
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Affiliation(s)
- Ning Chen
- Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, P. R. China
| | - Baogen Chang
- Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, P. R. China
| | - Nian Shi
- Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, P. R. China
| | - Wenxing Yan
- Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, P. R. China
| | - Fuping Lu
- Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, P. R. China
| | - Fufeng Liu
- Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, P. R. China
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Liu N, Zhao X, Xu L, Cai Y. Temporal and spatial variation, input fluxes and risk assessment of cyclic methylsiloxanes in Rivers-Bohai Sea System. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 231:113169. [PMID: 35032727 DOI: 10.1016/j.ecoenv.2022.113169] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 12/23/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
In the present study, the total concentrations of three cyclic methylsiloxanes (ΣCMSs), including octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6), in surface water and sediment samples of five main rivers draining into the Bohai Sea were in the range of 1.62-1.39 × 103 ng/L and 1.92-1.69 × 103 ng/g dw, respectively. Riverine input had great influence on the coastal distribution of siloxanes in the Bohai Sea. The concentrations of ΣCMSs in coastal sediments farthest away (40-50 Km) from the estuaries were only 4-33% of those close to the estuaries. But surprisingly, compared with those in coastal sediments (1.03-1.44 × 103 ng/g dw), the concentrations of CMSs (1.56-2.67 × 103 ng/g dw) in some deep-sea sediments were higher, and certain positive correlation existed between sediment ΣCMSs in this area with the total petroleum hydrocarbons concentration (R2 = 0.92, p < 0.05) suggested offshore oil exploitation as one important emission source of siloxanes. Overall, calculated based on their sediment concentrations, D4-D6 had negligible ecological risks to the benthic organisms in river-Bohai Sea system, i.e. HQs < 1. However, sediment-accumulation of siloxanes should be paid attention, especially for some deep-sea sediments nearby drilling platforms, where it will take only less than 1 year for D4 to reach its threshold.
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Affiliation(s)
- Nannan Liu
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China
| | - Xuesheng Zhao
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; Joint Research Centre for Protective Infrastructure Technology and Environmental Green Bioprocess, Tianjin 300384, China
| | - Lin Xu
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China.
| | - Yaqi Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Xiang X, Liu N, Xu L, Cai Y. Review of recent findings on occurrence and fates of siloxanes in environmental compartments. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 224:112631. [PMID: 34416634 DOI: 10.1016/j.ecoenv.2021.112631] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/08/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
In view of their vast global usage in both consumer products and industrial processes, environmental emission and fates of siloxanes have become concerned issue. This review summarized the research progress, especially in the last decade, on production/consumption data, toxicities, analysis methods, environmental distribution, migration and degradation/transformation of both dimethylsiloxanes and modified siloxanes in atmospheric, aquatic and terrestrial compartments from various areas (especially in China). In spite of their fast degradation (hydrolysis and hydroxylation, etc) in various matrices (except sediment), dimethylsiloxane oligomers have been found in various environmental matrices from many countries due to their constant usage and emission. Moreover, recent literatures have paid attention to behaviors of dimethylsiloxanes in industrial areas, e.g., their higher residual levels compared with residential areas and unique transformed products (such as halogenated products) arose from special industrial production scenarios. Meanwhile, although most prior studies focused on dimethylsiloxanes, identification of modified-siloxanes with other functional groups in environment have been beginning to attract the attention of scientists. Furthermore, related literatures indicated that compared with dimethylsiloxanes, both halogenated-dimethylsiloxanes and modified methylsiloxanes (phenylsiloxanes and trifluoropropylsiloxanes) could have stronger persistence due to their weaker volatilization and degradation, especially in terrestrial matrices.
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Affiliation(s)
- Xiaoling Xiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Nannan Liu
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China
| | - Lin Xu
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China.
| | - Yaqi Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China
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7
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Cheng Z, Qiu X, Shi X, Zhu T. Identification of organosiloxanes in ambient fine particulate matters using an untargeted strategy via gas chromatography and time-of-flight mass spectrometry. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 271:116128. [PMID: 33421844 DOI: 10.1016/j.envpol.2020.116128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
Organosilicons are widely used in consumer products and are ubiquitous in living environments. However, there is little systemic information on this group of pollutants in ambient particles. This study proposes a novel untargeted strategy based mainly on the mass difference of three silicon isotopes to screen organosilicon compounds from 2-year PM2.5 samples of Beijing using gas chromatography and high-resolution time-of-flight mass spectrometry. 61 organosilicons were filtered from 1019 peaks, and 35 ones were identified as organosiloxanes including 17 methylsiloxanes and 18 phenylmethylsiloxanes, of which 6 and 3 species were confirmed using reference standards, respectively. These organosiloxanes could be clustered into three groups: low-silicon-number methylsiloxanes, high-silicon-number methylsiloxanes, and phenylmethylsiloxanes. Low-silicon-number methylsiloxanes showed high abundance in the heating season but low abundance in the non-heating season, whereas high-silicon-number methylsiloxanes showed the opposite seasonal variation. This study provides a promising strategy for screening organosilicon compounds through an untargeted approach and gives insights for further investigation of the sources and health risks of organosiloxanes.
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Affiliation(s)
- Zhen Cheng
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China
| | - Xinghua Qiu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China.
| | - Xiaodi Shi
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China
| | - Tong Zhu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China
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Zhi L, Sun H, Xu L, Cai Y. Distribution and Elimination of Trifluoropropylmethylsiloxane Oligomers in Both Biosolid-Amended Soils and Earthworms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:985-993. [PMID: 33356203 DOI: 10.1021/acs.est.0c05443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
During a primary screening in 2015 and 2016, tris(trifluoropropyl)trimethylcyclotrisiloxane (D3F) and cis-/trans-tetrakis(trifluoropropyl)tetramethylcyclotetrasiloxane isomers (cis-D4F, trans-D4Fa,b,c) were detected in 12 biosolid-amended soils from Laixi and Shijiazhuang Cities of China, with mean concentrations being 10.3 ng/g dry weight (dw) and 2.7 ng/g dw for D3F and D4F, respectively. Subsequently, one further systematical survey found that although repeatedly amended by biosolids containing trifluoropropylmethylsiloxanes (4.2-724 ng/g dw), these compounds had no increasing trend in biosolid-amended soils (n = 100) collected from Laixi City at five sampling events from February 2017 to June 2019. Simulated experiments indicated that hydrolysis half-lives (1.8-28.0 days) of trifluoropropylmethylsiloxanes in soils were 3.0-18.3 times shorter than volatilization half-lives (7.4-362 days). Compared with those of octamethylcyclotetrasiloxane (D4), the hydrolysis rates of D4F isomers were faster in soils with total organic carbon (TOC) ≤80 mg/g but lower in soils with TOC ≥ 150 mg/g. In earthworm bodies, trifluoropropylmethylsiloxanes had 1.03-1.5 times lower biota-soil accumulation factors (1.3-3.2) but 1.4-3.0 times longer half-lives (2.6-5.7 days) than D4. The stronger persistence of fluorinated-siloxane than the corresponding dimethylsiloxane in both soils (at high TOC levels) and earthworms indicated that environmental risks of these compounds deserve further investigation.
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Affiliation(s)
- Liqin Zhi
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China
- Environmental Protection Research Institute of Light Industry, Beijing 100089, China
| | - Hongyu Sun
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China
| | - Lin Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China
| | - Yaqi Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China
- Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China
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Yang Y, Wang Y, Hou X, Lin Y, Yang L, Hou X, Zheng C. Can low-temperature point discharge Be used as atomic emission source for sensitive determination of cyclic volatile methylsiloxanes? Anal Chim Acta 2020; 1124:121-128. [PMID: 32534664 DOI: 10.1016/j.aca.2020.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/17/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
Abstract
Despite of increased interest in the application of miniature microplasma atomic spectrometry for environmental analytical chemistry, the amenable element detection range is limited to some metal elements and carbon due to it low power consumption. In this work, the generation of silicon atomic emission (251.6 nm and 288.2 nm) from the organosiloxanes was found possible in a low-temperature, low-power, and compact point discharge. Consequence, a tiny point discharge silicon optical emission spectrometer (μPD-OES) was exploited, and used as a novel GC detector for the determination of various cyclic volatile methyl siloxanes (cVMSs). Under the optimized conditions, the developed system provided limits of detection (LODs) of 0.2 mg L-1, 0.04 mg L-1, 0.03 mg L-1 and 0.02 mg L-1 of Si for hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane, respectively. Meanwhile, relative standard deviations (RSDs) of better than 2.3% were obtained. In contrast to gas chromatography mass spectrometer, GC-μPD-OES significantly simplifies the experimental setup with low power consumption and a miniature configuration. As far as we know, this work reports for the first time that silicon atomic emission can be generated in such low temperature microplasma. The accuracy of this system was validated by determining cVMSs in five daily-used shampoo samples collected from retail store, providing satisfactory recoveries (84%-114%) and excellent agreement with values determined by GC-MS at the 95% confidence level.
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Affiliation(s)
- Yuan Yang
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Yao Wang
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Xiaoling Hou
- Chengdu Environmental Monitoring Center, Chengdu, Sichuan, 610072, China
| | - Yao Lin
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Lu Yang
- National Research Council Canada, Ottawa, Ontario, Canada, K1A 0R6
| | - Xiandeng Hou
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Chengbin Zheng
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China.
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10
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Wang N, Tan L, Xie L, Wang Y, Ellis T. Investigation of volatile methyl siloxanes in biogas and the ambient environment in a landfill. J Environ Sci (China) 2020; 91:54-61. [PMID: 32172982 DOI: 10.1016/j.jes.2020.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/06/2020] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
Landfill biogas is a potential alternative for fossil fuel, but the containing impurities, volatile methyl siloxanes (simplified as siloxanes), often cause serious problems in gas turbines when applied to generate electricity. In this research, a collecting and analyzing method based on solvent adsorption and purge and trap-gas chromatography-mass spectrometry was established to determine the siloxanes in biogas from a landfill in Jinan, China, and adjacent ambient samples, such as soil, air, and leachate of the landfill. The results showed that, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) accounted for 63% of total siloxanes; and without considering D4 and D5, the order of detected siloxanes in concentration was found relating to Gibbs free energies of molecules, namely that higher abundant siloxane (except for D4 and D5) usually had lower Gibbs free energy. Additionally, the mass ratio between D4 and octamethyltrisiloxane (L3) in the biogas varied with different garbage age in landfills, possibly revealing the breaking-down of larger siloxane molecules with time. The samples, which were collected from environmental samples adjacent to the landfill, such as soil, water, and air, presented much higher siloxane level than urban or rural area away from landfills. The current H2S scrubber of the landfill biogas could decrease the total siloxanes from 10.7 to 5.75 mg/m3 due to Fe2O3 and a refrigerant drier in a purification system and cyclic siloxanes were more easily removed than linear ones.
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Affiliation(s)
- Ning Wang
- School of Environmental Science and Engineering, Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong University, Jinan, 266237, China; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP(3)), Shanghai, 200433, China; School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, 250100, China.
| | - Li Tan
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, 250100, China
| | - Lianke Xie
- State Grid Shandong Electric Power Company, Electric Power Science Research Institute, Jinan, 250100, China
| | - Yu Wang
- Beijing Key Laboratory of Water Resources & Environment Engineering, China University of Geosciences (Beijing), Beijing, 100083, China.
| | - Timothy Ellis
- Department of Civil, Construction, and Environmental Engineering, Iowa State University, Iowa, USA
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11
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Xu L, Huang Z, Zhang Q, Xiang X, Zhang S, Cai Y. Methylsiloxanes and Their Brominated Products in One e-Waste Recycling Area in China: Emission, Environmental Distribution, and Elimination. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:4267-4274. [PMID: 32162911 DOI: 10.1021/acs.est.0c00056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The present study investigated the sources and fates of methylsiloxanes and their brominated products in one e-waste recycling area of China. During thermal (30-1000 °C) recycling experiments for printed wiring boards (PWBs), besides volatile methylsiloxanes (D4, D5, and D6), their monobrominated products, that is, D3D(CH2Br), D4D(CH2Br), and D5D(CH2Br), were also found by quadrupole time-of-flight gas chromatography-mass spectrometry to have 2-3 orders of magnitude lower emissions (0.31-1.3 μg/g) than those (18.1-866 μg/g) of parent methylsiloxanes. Overall, the fastest emissions of methylsiloxanes and bromo-methylsiloxanes occurred at 300-400 and 400-500 °C, respectively, accounting for 35.3-51.0 and 39.4-82.1% of their total emission. In the e-waste recycling area, concentrations of D4-D6 were 1.1-75.0 μg/g dw [detection frequency (df) = 100%] in 31 dusts from PWB treatment workshops, while limits of detection (LOD) < 683 ng/g dw (df = 69-100%) in 48 surrounding soils were up to 3 orders of magnitudes higher than those in reference areas. Meanwhile, D3D(CH2Br)-D5D(CH2Br) were detected in both dusts (<LOD-1.2 μg/g dw, df = 48-52%) and soils (<LOD-70.3 ng/g dw, df = 23-77%) from the e-waste recycling area, but they were not present in reference samples. Simulating experiments showed that hydrolysis (9.07-378 d) and volatilization (8.55-1007 d) half-lives of monobrominated D4-D6 in soils were 1.6-5.0 times longer than those of their parent methylsiloxanes.
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Affiliation(s)
- Lin Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zichun Huang
- Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Qiaoli Zhang
- School of Chemistry & Material Science, Ludong University, Yantai 264025, China
| | - Xiaoling Xiang
- Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Shengxiao Zhang
- School of Chemistry & Material Science, Ludong University, Yantai 264025, China
| | - Yaqi Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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