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Ji Y, Zheng J, Geng Z, Wang X, Hou Y, Tian J, Hu J, Zhang Y, Zhang L. Fluorocarbon Nanodroplets: Their Formation and Stability in Complex Solution Systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:9108-9119. [PMID: 38632937 DOI: 10.1021/acs.langmuir.4c00475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
Perfluorocarbon (PFC) nanodroplets (NDs) are expanding in a wide range of applications in biotechnology and nanotechnology. Their efficacy in biological systems is significantly influenced by their size uniformity and stability within bioelectrolyte contexts. Presently, methods for creating monodisperse, highly concentrated, and well-stabilized PFC NDs under harsh conditions using low energy consumption methods have not been thoroughly developed, and their stability has not been sufficiently explored. This gap restricts their applicability for advanced medical interventions in tissues with high pH levels and various electrolytic conditions. To tackle these challenges and to circumvent potential toxicity from surface stabilizers, we have conducted an in-depth investigation into the formation and stability of uncoated perfluorohexane (PFH) NDs, which were synthesized by using a low-energy consumption solvent exchange technique, across complex electrolyte compositions or a broad spectrum of pH levels. The results indicated that low concentrations of low-valent electrolyte ions facilitate the nucleation of NDs and consistently accelerate Ostwald ripening over an extended period. Conversely, high concentrations of highly valent electrolyte ions inhibit nucleation and decelerate the ripening process over time. Given the similarities between the properties of NDs and nanobubbles, we propose a potential stabilization mechanism. Electrolytes influence the Ostwald ripening of NDs by adjusting the adsorption and distribution of ions on the NDs' surface, modifying the thickness of the electric double layer, and fine-tuning the energy barrier between droplets. These insights enable precise control over the stability of PFC NDs through the meticulous adjustment of the surrounding electrolyte composition. This offers an effective preparation method and a theoretical foundation for employing bare PFC NDs in physiological settings.
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Affiliation(s)
- Yuwen Ji
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Zheng
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhanli Geng
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, Qinghai 810008, China
- Qinghai Provincial Key Laboratory of Resources and Chemistry of Salt Lakes, Xining, Qinghai 810008, China
| | - Xingya Wang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yangqian Hou
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiakun Tian
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Hu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Institute of Materiobiology, College of Science, Shanghai University, Shanghai 200444, China
- Xiangfu Laboratory, Jiashan 314102, China
| | - Yi Zhang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lijuan Zhang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Yasui K, Tuziuti T, Kanematsu W. Mechanism of the Decrease in Surface Tension by Bulk Nanobubbles (Ultrafine Bubbles). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:16574-16583. [PMID: 37934653 DOI: 10.1021/acs.langmuir.3c02545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
The mechanism of the decrease in the surface tension of water containing bulk nanobubbles (ultrafine bubbles) is studied theoretically by numerical simulations of the adsorption of bulk nanobubbles at the liquid's surface based on the dynamic equilibrium model for the stability of a bulk nanobubble under the conditions of the Tuziuti experiment (Tuziuti, T., et al., Langmuir, 2023, 39, 5771-5778). It is predicted that the concentration of bulk nanobubbles in the bulk liquid decreases considerably with time, as many bulk nanobubbles are gradually adsorbed at the liquid's surface. A part of the decrease in surface tension is due to the Janus-like structure of a bulk nanobubble that could partly break the hydrogen bond network of water molecules at the liquid's surface because more than 50% of the bubble's surface is covered with hydrophobic impurities, according to the dynamic equilibrium model. The theoretically estimated decrease in surface tension due to the Janus-like structure of a bulk nanobubble agrees with the experimental data of the decrease in surface tension solely by bulk nanobubbles obtained by the comparison of before and after the elimination of bulk nanobubbles by the freeze-thaw process. This effect cannot be explained by the electric charge stabilization model widely discussed for the stability of a bulk nanobubble, although the present model is only applicable to the solution containing hydrophobic impurities. Another part of the decrease in surface tension should be due to impurities produced from a nanobubble generator, such as a mechanical seal, which was partly confirmed by the TOC measurements.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
| | - Toru Tuziuti
- National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
| | - Wataru Kanematsu
- National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
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3
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Yasui K. Critical Roles of Impurities and Imperfections in Various Phases of Materials. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16041612. [PMID: 36837241 PMCID: PMC9960772 DOI: 10.3390/ma16041612] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/08/2023] [Accepted: 02/13/2023] [Indexed: 06/01/2023]
Abstract
In many materials, impurities and imperfections play a critical role on the physical and chemical properties. In the present review, some examples of such materials are discussed. A bulk nanobubble (an ultrafine bubble) is stabilized against dissolution by hydrophobic impurities attached to the bubble surface. An acoustic cavitation threshold in various liquids decreases significantly by the presence of impurities such as solid particles, etc. The strength of brittle ceramics is determined by the size and number of pre-existing microcracks (imperfections) in the specimen. The size effect of a BaTiO3 nanocrystal is influenced by the amount and species of adsorbates (impurities) on its surface as adsorbate-induced charge-screening changes the free energy. The dielectric constant of an assembly of BaTiO3 nanocubes is influenced by a small tilt angle (imperfection) between two attached nanocubes, which induces strain inside a nanocube, and is also influenced by the spatial strain-relaxation due to defects and dislocations (imperfections), resulting in flexoelectric polarization.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
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4
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On Some Aspects of Nanobubble-Containing Systems. NANOMATERIALS 2022; 12:nano12132175. [PMID: 35808010 PMCID: PMC9268271 DOI: 10.3390/nano12132175] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 11/17/2022]
Abstract
Theoretical studies are reviewed for bulk nanobubbles (ultrafine bubbles (UFBs)), which are gas bubbles smaller than 1 μm in diameter. The dynamic equilibrium model is discussed as a promising model for the stability of a UFB against dissolution; more than half of the surface of a UFB should be covered with hydrophobic material (impurity). OH radicals are produced during hydrodynamic or acoustic cavitation to produce UFBs. After stopping cavitation, OH radicals are generated through chemical reactions of H2O2 and O3 in the liquid water. The possibility of radical generation during the bubble dissolution is also discussed based on numerical simulations. UFBs are concentrated on the liquid surface according to the dynamic equilibrium model. As a result, rupture of liquid film is accelerated by the presence of UFBs, which results in a reduction in “surface tension”, measured by the du Noüy ring method. Finally, the interaction of UFBs with a solid surface is discussed.
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Interaction Mechanisms and Application of Ozone Micro/Nanobubbles and Nanoparticles: A Review and Perspective. NANOMATERIALS 2022; 12:nano12121958. [PMID: 35745296 PMCID: PMC9228162 DOI: 10.3390/nano12121958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/26/2022] [Accepted: 06/02/2022] [Indexed: 11/16/2022]
Abstract
Ozone micro/nanobubbles with catalytic processes are widely used in the treatment of refractory organic wastewater. Micro/nanobubble technology overcomes the limitations of ozone mass transfer and ozone utilization in the application of ozone oxidation, and effectively improves the oxidation efficiency of ozone. The presence of micro/nanobubbles keeps the catalyst particles in a dynamic discrete state, which effectively increases the contact frequency between the catalyst and refractory organic matter and greatly improves the mineralization efficiency of refractory organic matter. This paper expounds on the characteristics and advantages of micro/nanobubble technology and summarizes the synergistic mechanism of microbubble nanoparticles and the mechanism of catalyst ozone micro/nanobubble systems in the treatment of refractory organics. An interaction mechanism of nanoparticles and ozone microbubbles is suggested, and the proposed theories on ozone microbubble systems are discussed with suggestions for future studies on systems of nanoparticles and ozone microbubbles.
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Zhang M, Li P, Yao W, Xu Z, Fan R. Enhanced kaolinite flotation using amine coated nanobubbles. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ma X, Li M, Pfeiffer P, Eisener J, Ohl CD, Sun C. Ion adsorption stabilizes bulk nanobubbles. J Colloid Interface Sci 2022; 606:1380-1394. [PMID: 34492474 DOI: 10.1016/j.jcis.2021.08.101] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 08/11/2021] [Accepted: 08/16/2021] [Indexed: 12/11/2022]
Abstract
The mechanism leading to the extraordinary stability of bulk nanobubbles in aqueous solutions remains an outstanding problem in soft matter, modern surface science, and physical chemistry science. In this work, the stability of bulk nanobubbles in electrolyte solutions under different pH levels and ionic strengths is studied. Nanobubbles are generated via the technique of ultrasonic cavitation, and characterized for size, number concentration and zeta potential under ambient conditions. Experimental results show that nanobubbles can survive in both acidic and basic solutions with pH values far away from the isoelectric point. We attribute the enhanced stability with increasing acidity or alkalinity of the aqueous solutions to the effective accumulation of net charges, regardless of their sign. The kinetic stability of the nanobubbles in various aqueous solutions is evaluated within the classic DLVO framework. Further, by combining a modified Poisson-Boltzmann equation with a modified Langmuir adsorption model, we describe a simple model that captures the influence of ion species and bulk concentration and reproduce the dependence of the nanobubble's surface potential on pH. We also discuss the apparent contradiction between quantitative calculation by ion stabilization model and experimental results. This essentially requires insight into the structure and dynamics of interfacial water on the atomic-scale.
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Affiliation(s)
- Xiaotong Ma
- Center for Combustion Energy, Key laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Mingbo Li
- Center for Combustion Energy, Key laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China.
| | - Patricia Pfeiffer
- Otto von Guericke University Magdeburg, Institute of Experimental Physics, Universitätsplatz 2, 39016 Magdeburg, Germany
| | - Julian Eisener
- Otto von Guericke University Magdeburg, Institute of Experimental Physics, Universitätsplatz 2, 39016 Magdeburg, Germany
| | - Claus-Dieter Ohl
- Otto von Guericke University Magdeburg, Institute of Experimental Physics, Universitätsplatz 2, 39016 Magdeburg, Germany
| | - Chao Sun
- Center for Combustion Energy, Key laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China.
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8
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9
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Zhou L, Wang S, Zhang L, Hu J. Generation and stability of bulk nanobubbles: A review and perspective. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2021.101439] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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10
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Pourkarimi Z, Rezai B, Noaparast M, Nguyen A, Chehreh Chelgani S. Proving the existence of nanobubbles produced by hydrodynamic cavitation and their significant effects in powder flotation. ADV POWDER TECHNOL 2021. [DOI: 10.1016/j.apt.2021.03.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Zhang F, Sun L, Yang H, Gui X, Schönherr H, Kappl M, Cao Y, Xing Y. Recent advances for understanding the role of nanobubbles in particles flotation. Adv Colloid Interface Sci 2021; 291:102403. [PMID: 33780858 DOI: 10.1016/j.cis.2021.102403] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 12/01/2022]
Abstract
Traditional froth flotation is the primary method for the separation and upgrading of fine mineral particles. However, it is still difficult for micro-fine and low-quality minerals to effectively separate. It is generally believed that bubble miniaturization is of great significance to improve flotation efficiency. Due to their unique physical and chemical properties, the application of nanobubbles (NBs) in ore flotation and other fields has been widely investigated as an important means to solve the problems of fine particle separation. Therefore, a fundamental understanding of the effect of NBs on flotation is a prerequisite to adapt it for the treatment of fine and low-quality minerals for separation. In this paper, recent advances in the field of nanobubble (NB) formation, preparation and stability are reviewed. In particular, we highlight the latest progress in the role of NBs on particles flotation and focus in particular on the particle-particle and particle-bubble interaction. A discussion of the current knowledge gap and future directions is provided.
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Affiliation(s)
- Fanfan Zhang
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
| | - Lijuan Sun
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
| | - Haichang Yang
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
| | - Xiahui Gui
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
| | - Holger Schönherr
- Physical Chemistry I & Research Center of Micro and Nanochemistry and Engineering (Cμ), Department of Chemistry and Biology, University of Siegen, Adolf-Reichwein-Straße 2, Siegen 57076, Germany
| | - Michael Kappl
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Yijun Cao
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; School of Chemical Engineering and Technology, Zhengzhou University, Zhengzhou 450066, Henan, China).
| | - Yaowen Xing
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China.
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12
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Yasui K, Tuziuti T, Kanematsu W. Interaction of Bulk Nanobubbles (Ultrafine Bubbles) with a Solid Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1674-1681. [PMID: 33496599 DOI: 10.1021/acs.langmuir.0c02844] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The experimental results [Kanematsu, W. Chem. Eng. Sci. 2020, 219, 115594] on the temporal variations of number concentrations of bulk nanobubbles (ultrafine bubbles) in contact with polymer materials are theoretically analyzed based on the dynamic equilibrium model of bulk nanobubbles partly covered with hydrophobic materials (impurities). It is suggested that bulk nanobubbles are adsorbed on a polymer surface by attractive hydrophobic interaction between a polymer surface and a hydrophobic material partly covering the bubble surface, overcoming the repulsive double-layer interaction. There are two mysteries. One is that the maximum surface number concentration of bulk nanobubbles of about 70 nm in diameter adsorbed on a hydrophobic polymer surface is more than an order of magnitude lower than the typical value for colloid particles of a similar or larger size. The other is that the experimental adsorption rate of bulk nanobubbles on hydrophobic polymer surface is several orders of magnitude lower than the theoretically estimated one. The mysteries are resolved if many of the bulk nanobubbles adsorbed on a hydrophobic polymer surface change to surface nanobubbles with a footprint diameter of about 1 μm.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Toru Tuziuti
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
| | - Wataru Kanematsu
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan
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13
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Ji Y, Guo Z, Tan T, Wang Y, Zhang L, Hu J, Zhang Y. Generating Bulk Nanobubbles in Alcohol Systems. ACS OMEGA 2021; 6:2873-2881. [PMID: 33553905 PMCID: PMC7860054 DOI: 10.1021/acsomega.0c05222] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
Bulk nanobubbles (NBs) have attracted wide attention due to their peculiar physicochemical properties and great potential in applications in various fields. However, so far there are no reports on bulk NBs generated in pure organic systems, which we think is very important as NBs would largely improve the efficiency of gas-liquid mass transfer and facilitate chemical reactions to take place. In this paper, we verified that air and N2 NBs could be generated in a series of alcohol solutions by using various methods including acoustical cavitation, pressurization-depressurization, and vibration. The experiments proved that NBs existed in alcohol solutions, with a highest density of 5.8 × 107 bubble/mL in propanol. Our results also indicated that bulk NBs could stably exist for at least hours in alcohol systems. The parameters in generating NBs in alcohols were optimized. Our findings open up an opportunity for improving gas-liquid mass transfer efficiency in the field of the chemical industry.
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Affiliation(s)
- Yuwen Ji
- Key
Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Guo
- Key
Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Tingyuan Tan
- Key
Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Yujiao Wang
- Key
Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Lijuan Zhang
- Key
Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Zhangjiang
Lab, Shanghai Advanced Research Institute,
Chinese Academy of Sciences, Shanghai 201210, China
| | - Jun Hu
- Key
Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Zhangjiang
Lab, Shanghai Advanced Research Institute,
Chinese Academy of Sciences, Shanghai 201210, China
| | - Yi Zhang
- Key
Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Zhangjiang
Lab, Shanghai Advanced Research Institute,
Chinese Academy of Sciences, Shanghai 201210, China
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14
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Zhou W, Liu L, Zhou B, Weng L, Li J, Liu C, Yang S, Wu C, Liu K. Electrokinetic potential reduction of fine particles induced by gas nucleation. ULTRASONICS SONOCHEMISTRY 2020; 67:105167. [PMID: 32442929 DOI: 10.1016/j.ultsonch.2020.105167] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/10/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
Electrokinetic potential of particles has been extensively studied in colloidal systems over the past century, while up to date, the influence of gas on electrokinetic behaviors of particles has not been fully understood yet. In this study, the electrokinetic response of particles to gas nucleation was systematically investigated with coal as the object. The results showed that the nucleation of gas (both on particle surfaces and in water) significantly changed the particle' electrokinetic behaviors. Higher gas content and particle's surface hydrophobicity normally trigger more intensive gas nucleation, thus inducing more significant reduction of particle zeta potential. After gas nucleation, numerous nanobubbles (NBs) appear in the suspensions mainly in two forms: NBs adhering onto solid surfaces (ANBs) and NBs stagnating in bulk solutions (BNBs). ANBs not only enhance the surface heterogeneity, but also cause the "steric hindrance" effect, and electric double layer (EDL) overlapping and associated ions shielding towards charged particles, which significantly decrease their electrokinetic potentials. Although BNBs can also reduce the zeta potential of particles by EDL compressing, their functions are rather limited.
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Affiliation(s)
- Weiguang Zhou
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Liming Liu
- School of Innovation and Entrepreneurship, Southern University of Science and Technology, Shenzhen 518055, China
| | - Baonan Zhou
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Li Weng
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China; Clean Energy Institute, Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China
| | - Junguo Li
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China; Clean Energy Institute, Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China
| | - Cheng Liu
- School of Resources and Environment Engineering, Wuhan University of Technology, Wuhan 430070, China
| | - Siyuan Yang
- School of Resources and Environment Engineering, Wuhan University of Technology, Wuhan 430070, China
| | - Changning Wu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China; Clean Energy Institute, Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Ke Liu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China; School of Innovation and Entrepreneurship, Southern University of Science and Technology, Shenzhen 518055, China; Clean Energy Institute, Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China.
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15
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The Effect of Surface Charge on the Separation of Pyrite from Serpentine by Flotation. MINERALS 2019. [DOI: 10.3390/min9100629] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Serpentine, a magnesium silicate mineral with positive surface charge in many sulfide ores around the world, usually deteriorates the flotation behavior by covering the target mineral surface. In this paper, the effect of surface potential regulation on serpentine flotation was revealed by flocculation experiments, zeta potential measurements, infrared spectrum analysis, and DLVO theoretical calculations. The experimental results of flocculation and sedimentation show that heterogeneous coagulation easily occurs between serpentine and pyrite particles, which reduces the floatability of pyrite. Reducing the surface potential of serpentine is an effective way to eliminate heterogeneous coagulation between minerals. The key to regulating the surface potential of serpentine is Mg2+ ion dissolution from the serpentine surface to the liquid phase. Phosphates, especially sodium hexametaphosphate, can enhance Mg2+ ion dissolution from the serpentine surface to the liquid phase and react with Mg2+ ions in the liquid phase to form stable soluble complexes.
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16
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Xiao W, Zhao Y, Yang J, Ren Y, Yang W, Huang X, Zhang L. Effect of Sodium Oleate on the Adsorption Morphology and Mechanism of Nanobubbles on the Mica Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:9239-9245. [PMID: 31268336 DOI: 10.1021/acs.langmuir.9b01384] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nanobubbles promote the flotation of fine-grained minerals. In the associated mechanism, the aggregation of fine particles is first promoted, which increases the probability of collision between particles and bubbles. However, the interaction between nanobubbles and mineral particles is often neglected, especially when the surface properties of the nanobubbles are modified by flotation collectors. In this study, the interaction mechanism between nanobubbles and the mica surface is investigated by nanoparticle tracking analysis, zeta potential measurement, and atomic force microscopy. The results reveal that the hydrophobic group of sodium oleate points toward the inside of the nanobubble and the hydrophilic group faces outward after the interaction of sodium oleate molecules and nanobubbles. A surfactant micelle with nanobubbles as the core is formed, thus considerably reducing the concentration of sodium oleate to form micelles. The adsorption of the modified nanobubbles on the mineral surface is carried out by the specific adsorption of the exposed hydrophilic group and the mineral surface. This adsorption method is superior to the hydrophobic interaction between the nanobubbles and the hydrophobic mineral surface. Further, the nanobubbles are highly selective for the activation sites on the mineral surface in the adsorption mode. This study will help understand the interaction between nanobubbles and collectors to further apply nanobubbles to treat fine-grained mineral particles.
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Affiliation(s)
- Wei Xiao
- School of Resources Engineering , Xi'an University of Architecture and Technology , Xi'an 710055 , China
| | - Yulong Zhao
- School of Resources Engineering , Xi'an University of Architecture and Technology , Xi'an 710055 , China
| | - Juan Yang
- School of Resources Engineering , Xi'an University of Architecture and Technology , Xi'an 710055 , China
| | - Yaxin Ren
- School of Resources Engineering , Xi'an University of Architecture and Technology , Xi'an 710055 , China
| | - Wei Yang
- School of Resources Engineering , Xi'an University of Architecture and Technology , Xi'an 710055 , China
| | - Xiaotao Huang
- The Institute for Advanced Studies , Wuhan University , Wuhan 430072 , China
| | - Lijuan Zhang
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute , Chinese Academy of Sciences , Shanghai 201204 , China
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Ke S, Xiao W, Quan N, Dong Y, Zhang L, Hu J. Formation and Stability of Bulk Nanobubbles in Different Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5250-5256. [PMID: 30909695 DOI: 10.1021/acs.langmuir.9b00144] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The existence of bulk nanobubbles is still controversial in spite of their significance in a large range of applications. Here, we developed a new method of compression-decompression to produce controllably bulk nanobubbles. Then, we further investigated the generation of bulk nanobubbles in pure water, acid, alkaline, and salt solutions using nanoparticle tracking analysis. The results indicated that the concentration of bulk nanobubbles depends on the decompression time and would reach a maximum value when the decompression time is about 30 min for the pure water system. More importantly, we gave a relatively direct evidence of the existence of bulk nanobubbles by measuring the X-ray fluorescence intensity of Kr in acid, alkaline, and salt solutions. It is shown that the decrease tendency in intensity of Kr in alkaline solution is similar to that in the concentration of bulk nanobubbles with the deposited time, indicating that the bulk nanobubbles produced indeed have gas inside. Furthermore, the concentration and stability of bulk nanobubbles in an alkaline solution are greatest compared with other two solutions regardless of gas types. The concentration of bulk nanobubbles will decrease in the order alkaline > acid/pure water > salt solutions. We believe that our results should be very helpful in understanding the formation and stability of bulk nanobubbles in different solutions.
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Affiliation(s)
- Shuo Ke
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Life and Environment Science College , Shanghai Normal University , Shanghai 200234 , China
| | - Wei Xiao
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- School of Resources Engineering , Xi'an University of Architecture and Technology , Xi'an 710055 , China
| | - Nannan Quan
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Life and Environment Science College , Shanghai Normal University , Shanghai 200234 , China
| | - Yaming Dong
- Life and Environment Science College , Shanghai Normal University , Shanghai 200234 , China
| | - Lijuan Zhang
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
| | - Jun Hu
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
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