CHEMOSPHERE
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2020
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IF 5.778
Xiangnan Zhang,Kai Yu,Hong Zhang,Yuning Liu,Jing He,Xiangyu Liu,Jie Jiang
Microplastics (MPs) pollution in the marine has become a global concern. To obtain accurate measurements of MPs in the marine sediments is important for understanding its effects and potential risks to the environment. In this study, we developed a novel method for extracting MPs from sediments by density flotation of sodium dihydrogen phosphate (NaH 2 PO 4 ) solution, which utilized the heating-assisted to increase the density of separation solution. It features high density, nontoxic, and economic, indicating its promising application in the MPs extraction. A standard procedure based on NaH 2 PO 4 for extracting MPs from sediments was established and validated by the recovery experiments of seven common plastics. Results showed NaH 2 PO 4 solution exhibited higher recovery rates than the commonly-used NaCl solution; three plastics with high density couldn’t be recovered by NaCl, while NaH 2 PO 4 was available for all the studied MPs. A large number of real beach samples was collected and validated by this method, and the abundance and characteristic of the collected MPs were further analyzed. Results exhibited the heating-assisted NaH 2 PO 4 could be a promising way for extracting MPs in environmental samples.
研究领域:
环境科学
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海洋学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL RESEARCH
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2024
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IF 7.7
Yiming Wang,Fangwei Hou,Yining Gai,Xu Pan,Zongshan Zhao,Yaru Li
Microplastics (MPs) recycling, a promising approach to tackle its pollution, faces significant challenges due to the lack of effective separation methods. Herein, the optimized density separation accompanied with nonionic surfactants was employed to purify single MPs species from mixed systems. By adjusting the flotation fluid density, the single MPs can be separated from their mixtures in equal proportions (e.x., 97 ± 2% pure polyethylene terephthalate (PET) was extracted from polystyrene (PS)/PET mixed system). Under the optimized density separation conditions, nonionic surfactants of Tween 20 (TW20) enhanced the purity of the separated MPs for all MPs mixture systems (from 69%-85% to 76%–96%). The enhanced separations can be mainly attributed to adsorption of surfactant onto the surface of MPs which would alter hydrophilic and hydrophobic properties of MPs. But anionic surfactants could reduce or promote the separated efficiencies of MPs (e.x., the purity of separated polyvinylchloride increased by 4.8% in Thermoplastic polyurethanes/polyvinylchloride group by added sodium dodecyl benzene sulfonate, and the purity of PS decreased by 8.3% in PS/PET group in presence of hexadecyl trimethyl ammonium bromide). The efficient separations have also been obtained in simulated environmental aqueous experiments where TW20 promoted the separated purity of PET from 83.4% to 91.8% in the PS/PET group, consistent with the separation effect in the laboratory environment. This paper provided a convenient and cost-effective method to separate mixed MPs to high-purity MPs, which would be improve the quality of plastic recycling.
研究领域:
环境科学
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材料科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
FUEL
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2022
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IF 8.035
Chen Li,Chuncai Zhou,Wenwen Li,Wenrui Zhu,Jiaqian Shi,Guijian Liu
The increasing demand for critical elements and the depletion of conventional ores have stimulated the recovery of critical elements from secondary resources. The concentration of critical elements in coal fly ash (CFA) are significant, which makes it a potential alternative source for the recovery of critical elements. Preconcentration treatment is an important step to recover critical elements, which not only directly affects the subsequent leaching and extraction efficiency, but also determines the reagent and energy consumption. The distribution and enrichment characteristics of critical elements in different physical separation fractions of CFA are worthy of further elucidation. In this paper, the physicochemical characteristics and the modes of occurrence of critical elements (Li, Be, Rb, Sr, Zr, Nb, Cs, Hf, Ta, Ga, Ge, Se, Cd, Tl, In, Te, and Re) of CFA from Pingwei power generation plant in Huainan, Anhui Province, China were investigated, with emphasis on several physical (particle size, density, magnetic) separation methods and the enrichment characteristics of critical elements in each physical fraction. The density and magnetic separation of CFA after particle size classification was proposed, and different sorting combinations were adopted for various types of critical elements, to achieve efficient enrichment of critical elements. The results show that the critical elements in CFA are mainly enriched in the residual state, which consists of aluminosilicate minerals and amorphous glass. The CFA with greater recovery potential exists in smaller particle size. Higher Rb, Sr, Zr, and Cs concentrations were found in the low-density fractions of fine particle size CFA, while Li, Be, and Ga are mainly enriched in the non-magnetic fractions of fine particle size CFA. Some critical elements could be further enriched by density separation or magnetic separation of CFA after particle size classification. The combination of different physically separated fractions is considered as an effective way to maximize the enrichment of critical elements from CFA.
研究领域:
环境科学
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矿物加工工程
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资源回收技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）