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Montazeri SM, Kalogerakis N, Kolliopoulos G. Kinetic Modeling and Assessment of a CO 2 Nanobubble-Enhanced Hydrate-Based Sustainable Water Recovery from Industrial Effluents. JOURNAL OF SUSTAINABLE METALLURGY 2025; 11:1789-1801. [PMID: 40443462 PMCID: PMC12116862 DOI: 10.1007/s40831-025-01081-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2024] [Accepted: 03/27/2025] [Indexed: 06/02/2025]
Abstract
This study evaluates the effectiveness of CO2 nanobubble-enhanced hydrate-based desalination (HBD) to treat industrial effluents from the mining and metals industry. Testing was conducted in a high-pressure reactor apparatus that employed CO2 as the gas hydrate former at 274.15 K and 3.58 MPa. CO2 nanobubbles (NBs) were used to promote hydrate formation, aiming to streamline an HBD process without separation steps for the additives/chemicals used. Due to the limited studies on hydrate formation in sulfate-containing aqueous solutions, this research focused on the kinetics of hydrate formation in varying concentrations of Na2SO4 and MgSO4 (0.1 and 0.5 M). The results showed that CO2 NBs significantly enhanced hydrate formation in both Na2SO4 and MgSO4 solutions, with CO2 consumption increasing by up to approximately 51% and 35%, respectively. Additionally, a kinetics study on a real effluent from the mining and metals industry showed that the presence of CO2 NBs increased CO2 consumption by around 20% after 180 min. This research also evaluated water recovery and desalination efficiency in a 3-stage HBD process applied to the effluent, the concentration of which exceeded the operating range of reverse osmosis. The results indicated an improvement in water recovery from 25.13 ± 2.04% to 40.16 ± 1.43% with CO2 NBs, underscoring their effectiveness in treating highly saline water. Moreover, desalination efficiencies of 49.54 ± 2.39% and 42.03 ± 3.43% were achieved without and with CO2 NBs, respectively. This study represents the successful demonstration of the efficient application of the CO2 NBs-boosted HBD method to treat high-salinity effluents and recover clean water for reuse. Graphical Abstract
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Affiliation(s)
- Seyed Mohammad Montazeri
- Department of Mining, Metallurgical, and Materials Engineering, Université Laval, Québec, QC G1V 0A6 Canada
| | - Nicolas Kalogerakis
- School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Greece
| | - Georgios Kolliopoulos
- Department of Mining, Metallurgical, and Materials Engineering, Université Laval, Québec, QC G1V 0A6 Canada
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2
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Koundle P, Nirmalkar N, Boczkaj G. High performance ozone nanobubbles based advanced oxidation processes (AOPs) for degradation of organic pollutants under high pollutant loading. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2025; 374:124107. [PMID: 39813805 DOI: 10.1016/j.jenvman.2025.124107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2024] [Revised: 11/29/2024] [Accepted: 01/08/2025] [Indexed: 01/18/2025]
Abstract
Advanced Oxidation Processes (AOPs) have proven to be an effective solution for chemical wastewater treatment, particularly for degradation of organic pollutants, especially dyes. Ozonation is recognized as one of the most prevalent AOPs. Nevertheless, some cases show a lowered efficiency of O3 utilization which is attributed to its inadequate distribution in the treated water causing low residence time, low mass transfer coefficient as well as shorter half-life. This study demonstrates the application of ozone nanobubbles to enhance the degradation of organics under high pollution load conditions. We propose an integrated method that utilizes bulk nanobubbles to enhance the reactivity of ozone for the degradation of organics. We examined the degradation of organic pollutants under parameters such as varying pH levels, ozone concentrations and presence of salts and surfactants. The degradation of the organic pollutant by ozone nanobubbles (0.177 L mg-1min-1) demonstrated a threefold increase in reaction rate constants compared to microbubbles (0.025 L mg-1min-1). The plausible reason for these findings is (i) higher mass transfer coefficient (ii) higher ozone solubility (iii) NBs may act as a surface for chemical reaction (iv) NBs may increase the half-life of ozone. The presence of reactive oxygen species was verified using scavenging tests. This part of the studies revealed contribution of reactive oxygen species (ROSs) such as hydroxyl radical (•OH), superoxide radical anion (O2•-) and singlet oxygen (1O2) in the degradation process. The conditions that provide total degradation of 100% in 300 s for both organic pollutants (Green rit and methylene blue dye) are: 5 LPM (Litre per minute) ozone flow rate, acidic pH, monovalent salts (NaCl, 2 mM) and lower concentration of surfactants (CTAB and SDS, 0.3 CMC). A degradation mechanism has been outlined based on intermediates identified by LC-MS. This work presents a new method that combines AOPs with nanobubbles, which should lead to increased environmental sustainability and efficiency.
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Affiliation(s)
- Priya Koundle
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar, 140001, India
| | - Neelkanth Nirmalkar
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar, 140001, India.
| | - Grzegorz Boczkaj
- Department of Sanitary Engineering, Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Narutowicza 11/12 Str., 80-233, Gdansk, Poland; School of Civil, Environmental, and Architectural Engineering, College of Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
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Xu L, Zhao Q, Liu H, Liao D, Tang A, Liu Y. Efficient epoxidation of (R)-(+)-limonene to limonene dioxide through peracids generated using whole-cell Rhizopus oryzae lipase. BIORESOURCE TECHNOLOGY 2025; 415:131645. [PMID: 39419407 DOI: 10.1016/j.biortech.2024.131645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 10/12/2024] [Accepted: 10/13/2024] [Indexed: 10/19/2024]
Abstract
Limonene dioxide (LDO) is essential for manufacturing bio-based polycarbonate and non-isocyanate polyurethanes. Herein, we report a strategy for the chemoenzymatic epoxidation of (R)-(+)-limonene to LDO with high selectivity using Rhizopus oryzae whole cells. The presence of sufficient excess acid in the system is essential, in addition to overcoming the hydrolysis of the intermediate product, 1,2-limonene oxide, to accomplish the double epoxidation of limonene. When using a high concentration of H2O2 and trisodium citrate, the conditions were effectively established, even when Novozym 435 was substituted, which had previously been reported to be ineffective in achieving high-yield double epoxidation of limonene. The transfer of H2O2 and peracids between the cell and solvent slowed production. The total amount of peracids generated remained constant, but their concentrations remained moderate, favoring the double epoxidation of limonene. An LDO yield of 93 % and no intermediate product, limonene oxide, were obtained under optimized conditions within 20 h.
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Affiliation(s)
- Lili Xu
- Medical College, Guangxi University, Nanning 530004, China; College of Marine Sciences, Beibu Gulf University, Qinzhou 535011, China; School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Qingqing Zhao
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Haibo Liu
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China; Key Laboratory of Guangxi Biorefinery, Guangxi University, Nanning 530004, China
| | - Dankui Liao
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Aixing Tang
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China; Key Laboratory of Guangxi Biorefinery, Guangxi University, Nanning 530004, China.
| | - Youyan Liu
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China; Key Laboratory of Guangxi Biorefinery, Guangxi University, Nanning 530004, China.
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Li X, He Y, Wang Y, Lin K, Lin X. CHARMM36 All-Atom Gas Model for Lipid Nanobubble Simulation. J Chem Inf Model 2024; 64:7503-7512. [PMID: 39262130 DOI: 10.1021/acs.jcim.4c01027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2024]
Abstract
Lipid nanobubbles with different gas cores may integrate the biocompatibility of lipids, powerful physicochemical properties of nanobubbles, and therapeutic effects of gas molecules, which thus promote enormous biomedical applications such as ultrasound molecular imaging, gene/drug delivery, and gas therapy. In order for further more precise applications, the exact molecular mechanisms for the interactions between lipid nanobubbles and biological systems should be studied. Molecular dynamics (MD) simulation provides a powerful computational tool for this purpose. However, previous state-of-the-art MD simulations of free gas nanobubble/lipid nanobubble employed the vacuum as their gas cores, which is not suitable for studying the interactions between functional lipid nanobubbles and biological systems and revealing the biological roles of gas molecules. Hence, in this work, we developed and optimized the CHARMM36 all-atom gas parameters for six gases including N2, O2, H2, CO, CO2, and SO2, which accurately reproduced the gas density at different pressures as well as the spontaneous formation of gas nanobubbles. Subsequent applications of these gas parameters for lipid nanobubble simulations also reproduced the self-assembly process of the lipid nanobubble. We further developed a Python script to generate all-atom lipid nanobubble simulation systems, which was proven to be efficient for all-atom MD simulations of lipid nanobubbles and to be able to capture the exact dynamics of gas molecules at the gas-lipid and lipid-water interfaces of the lipid nanobubble. In summary, the all-atom gas models proposed in this work are suitable for simulating free gas nanobubbles and lipid nanobubbles, which are supposed to overcome the shortcomings of previous state-of-the-art MD simulations with the vacuum replacing the gas core and play key roles in revealing the molecular-level interactions between lipid nanobubbles and biological systems.
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Affiliation(s)
- Xiu Li
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Engineering Medicine & School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Yuan He
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Engineering Medicine & School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Yuxuan Wang
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Engineering Medicine & School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Kaidong Lin
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Engineering Medicine & School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Xubo Lin
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Engineering Medicine & School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
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Koundle P, Nirmalkar N, Momotko M, Boczkaj G. Ozone nanobubble technology as a novel AOPs for pollutants degradation under high salinity conditions. WATER RESEARCH 2024; 263:122148. [PMID: 39098154 DOI: 10.1016/j.watres.2024.122148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 04/26/2024] [Accepted: 07/24/2024] [Indexed: 08/06/2024]
Abstract
Conventional water treatment systems frequently exhibit diminished efficiency at high salinity - a significant issue especially for real industrial effluents - mostly due to the creation of intricate structures between pollutants and salts. One of the primary obstacles associated with high salinity conditions is the generation of by-products that pose additional hurdles for treatment. In this work, we have investigated the novel advanced oxidation process a so-called ozone nanobubble technology for degradation of the pollutants at high salinity conditions. The mass transfer is often the rate-limiting step in gas-liquid process and the poor rate of mass transfer diminishes the overall efficacy. One of the primary disadvantages associated with ozone is its restricted solubility and instability when dissolved in an aqueous solution. These characteristics impose limitations on its potential applications and need the use of specialized systems to facilitate gas-liquid interaction. In this work, we have also suggested enhancing the ozonation process through the utilization of ozone nanobubbles. The findings of our experiment and subsequent analysis indicate that the presence of nanobubbles enhances the process of ozonation through three key mechanisms: (i) an increased mass transfer coefficient, (ii) a higher rate of reactive oxygen species (ROS) generation attributed to the charged interface, and (iii) the nanobubble interface serving as an active surface for chemical reactions. The predicted mass transfer coefficients were found to range from 3 to 3.5 min-1, a value that is notably greater than that seen for microbubbles. The study showcased the degradation of methylene blue dye through the utilization of ozone nanobubbles, which exhibited a much higher rate of dye degradation compared to ozone microbubbles. The confirmation of the radical degradation mechanism was achieved by the utilization of electron spin resonance (ESR) measurements. The developed process has high potential for application in industrial scale textile wastewater treatment.
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Affiliation(s)
- Priya Koundle
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, India
| | - Neelkanth Nirmalkar
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, India.
| | - Malwina Momotko
- Department of Sanitary Engineering, Civil and Environment Engineering, Faculty of Civil and Environmental Engineering, Gdansk University of Technology, G. Narutowicza St. 11/12, Gdansk 80-233, Poland
| | - Grzegorz Boczkaj
- Department of Sanitary Engineering, Civil and Environment Engineering, Faculty of Civil and Environmental Engineering, Gdansk University of Technology, G. Narutowicza St. 11/12, Gdansk 80-233, Poland; School of Civil, Environmental, and Architectural Engineering, College of Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
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Karimi M, Parsafar G, Samouei H. Polarizing Perspectives: Ion- and Dipole-Induced Dipole Interactions Dictate Bulk Nanobubble Stability. J Phys Chem B 2024; 128:7263-7270. [PMID: 38990291 DOI: 10.1021/acs.jpcb.4c03973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
The origin of the stability of bulk Nanobubbles (NBs) has been the object of scrutiny in recent years. The interplay between the surface charge on the NBs and the Laplace pressure resulting from the surface tension at the solvent-NB interface has often been evoked to explain the stability of the dispersed NBs. While the Laplace pressure is well understood in the community, the nature of the surface charge on the NBs has remained obscure. In this work, we aim to show that the solvent and the present ions can effectively polarize the NB surface by inducing a dipole moment, which in turn controls the NB stability. We show that the polarizability of the dispersed gas and the polarity of the dispersing solvent control the dipole-induced dipole interactions between the solvent and the NBs, and that, in turn, determines their stability in solution.
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Affiliation(s)
- Mohammadjavad Karimi
- Department of Petroleum Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Gholamabbas Parsafar
- Department of Petroleum Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Hamidreza Samouei
- Department of Petroleum Engineering, Texas A&M University, College Station, Texas 77843, United States
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Sharma H, Nirmalkar N, Zhang W. Nanobubbles produced by nanopores to probe gas-liquid mass transfer characteristics. J Colloid Interface Sci 2024; 665:274-285. [PMID: 38531273 DOI: 10.1016/j.jcis.2024.03.080] [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: 12/12/2023] [Revised: 02/27/2024] [Accepted: 03/11/2024] [Indexed: 03/28/2024]
Abstract
HYPOTHESIS This study tested the hypothesis of how the nanopore size of membranes and how the surface charge of nanobubbles responds to its pinch-off from the nanopore. This study also tested the hypothesis that nanobubbles that remain in solution after production may increase the dissolved oxygen content in water. EXPERIMENTS The effect of membrane pore size, hydrodynamic conditions (gas and liquid flow rates), and physicochemical parameters (pH and temperature) on volumetric mass transfer coefficient (kLa) for oxygen nanobubbles formed by the nanopore diffusion technique was investigated. This study experimentally determined the kLa by carefully removing the dissolved oxygen by nitrogen purging from nanobubble suspension to examine the sole contribution of nanobubble dissolution in water to the reaeration. RESULTS Scaling estimates indicate that the nanobubble pinch-off radius and nanopore radius have a power-law correlation and that nanobubble size declines with the nanopore size. This is in line with our experimental results. The surface charge of nanobubbles delays its pinch-off at the gas-liquid interface. Nanobubbles offered 3-4 times higher kLa than microbubbles. Standard oxygen transfer efficiency in water was found to be 78%, significantly higher than that in microbubbles. However, dissolving stable nanobubbles in water does not considerably increase dissolved oxygen levels.
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Affiliation(s)
- Harsh Sharma
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar-140001, India
| | - Neelkanth Nirmalkar
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar-140001, India.
| | - Wen Zhang
- John A. Reif, Jr. Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA
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Sharma A, Nirmalkar N. Bulk Nanobubbles through Gas Supersaturation Originated by Hot and Cold Solvent Mixing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:12729-12743. [PMID: 38845184 DOI: 10.1021/acs.langmuir.4c01358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2024]
Abstract
The nucleation mechanism of bulk nanobubbles remains unclear despite the considerable attention they have received in recent years. We propose two hypotheses: (i) The gas supersaturation in the bulk liquid is the primary factor for nanobubble nucleation, and (ii) the mixing of the same solvent at varying gas solubilities should produce nanobubbles, provided that the first hypothesis is correct. To test this hypothesis, we performed extensive experiments on nanobubble nucleation in both water and organic solvents. The temperature difference between hot and cold samples ranged from 10 to 80 °C in pure solvents such as water, methanol, ethanol, propanol, and butanol prepared and mixed in equal proportions. To the best of our knowledge, we report bulk nanobubble nucleation by mixing hot and cold solvents for the first time. The refractive index value calculations using Mie scattering theory confirmed the existence of nanobubbles. When surface tension dominates over surface charge, the critical work for nanobubble formation is ΔFc ∝ 1/ξ2, and when surface charge dominates over surface tension, the critical work is ΔFc ∝ ξ1/4. Our experimental results verify such dependency by measuring nanobubbles nucleated with varying degrees of gas supersaturation.
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Affiliation(s)
- Aakriti Sharma
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
| | - Neelkanth Nirmalkar
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
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Yadav G, Nirmalkar N, Ohl CD. Electrochemically reactive colloidal nanobubbles by water splitting. J Colloid Interface Sci 2024; 663:518-531. [PMID: 38422977 DOI: 10.1016/j.jcis.2024.02.148] [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: 11/16/2023] [Revised: 02/07/2024] [Accepted: 02/19/2024] [Indexed: 03/02/2024]
Abstract
HYPOTHESIS The existing literature reports have conflicting views on reactive oxygen species (ROS) generation by bulk nanobubbles. Consequently, we propose the hypothesis that (i) ROS may be generated during the process of nanobubble generation through water splitting, and (ii) bulk nanobubbles possess electrochemical reactivity, which could potentially lead to continuous ROS generation even after the cessation of nanobubble production. EXPERIMENTS A comprehensive set of experiments was conducted to generate nanobubbles in pure water using the water-splitting method. The primary aims of this study are as follows: (i) nanobubble generation by electrolysis and its characterization; (ii) to provide conclusive evidence that the nano-entities are indeed nanobubbles; (iii) to quantify the production of reactive oxygen species during the process of nanobubble generation and (iv) to establish evidence for the presence of electrochemically reactive nanobubbles. The findings of our experiment suggest that bulk nanobubbles possess the ability to generate reactive oxygen species (ROS) during the process of nanobubble nucleation. Additionally, our results indicate that bulk nanobubbles are electrochemically reactive after the cessation of nanobubble production. The electron spin spectroscopy (ESR) response and degradation of the dye compound over time confirm the electrochemical reactivity of bulk nanobubbles.
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Affiliation(s)
- Gaurav Yadav
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar, 140001, Punjab, India
| | - Neelkanth Nirmalkar
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar, 140001, Punjab, India.
| | - Claus-Dieter Ohl
- Otto von Guerricke University, Institute for Physics, Universitätsplatz, Magdeburg, 39106, Germany
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Jia N, Ma M, Wang X, Wang X, Ma J, Li Y, Li D. Indirect catalytic oxidation of multi-pollutants in diesel exhaust by ozone/micro-nano bubbles system. ENVIRONMENTAL TECHNOLOGY 2024; 45:2417-2426. [PMID: 36843385 DOI: 10.1080/09593330.2023.2174047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
Wet oxidation absorption is an efficient and promising method of exhaust gas treatment. When the micro-nano bubbles collapse, they can generate hydroxyl radicals with strong oxidising ability, which can oxidise a variety of pollutants in diesel exhaust. Ozone has strong oxidising properties, and the coupling of ozone and micro-nano bubbles can improve the oxidation and removal effects of polluted gases. In this study, the ozone micro-nano bubbles system was used to oxidise NOx, SO2, and CO to gases that were more readily dissolved in water, such as NO2, SO3, and CO2, and the gases were removed through the absorbent solution. The effects of surfactant, catalyst, urea, pH value, and salinity on the removal efficiency of NOx, SO2, and CO from diesel exhaust were investigated. Through experiments, it was found that the removal efficiency of pollutants was enhanced and then weakened with the increasing concentrations of surfactants, catalysts, and salinity, and continued to decrease with increasing concentrations of urea. When the pH value was < 7, the removal efficiency increased first and then weakened with the increase of the pH value. When the pH value was > 7, it mainly depended on the absorption of acid gas by the alkali solution. Under optimal conditions, the removal efficiencies were 86.3% for NO, 92.1% for SO2, and 65.4% for CO. This study could provide important theoretical support for the industrial application of this technology.
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Affiliation(s)
- Nan Jia
- College of Environmental Science and Engineering, Donghua University, Shanghai, People's Republic of China
| | - Mengdie Ma
- College of Environmental Science and Engineering, Donghua University, Shanghai, People's Republic of China
| | - Xing Wang
- College of Environmental Science and Engineering, Donghua University, Shanghai, People's Republic of China
| | - Xi Wang
- College of Environmental Science and Engineering, Donghua University, Shanghai, People's Republic of China
| | - Jingyi Ma
- College of Environmental Science and Engineering, Donghua University, Shanghai, People's Republic of China
| | - Yongkuan Li
- College of Environmental Science and Engineering, Donghua University, Shanghai, People's Republic of China
| | - Dengxin Li
- College of Environmental Science and Engineering, Donghua University, Shanghai, People's Republic of China
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, People's Republic of China
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Dutta N, Mitra S, Nirmalkar N. Understanding the Role of Surface Charge on Nanobubble Capillary Bridging during Particle-Particle Interaction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:4475-4488. [PMID: 38356240 DOI: 10.1021/acs.langmuir.3c03963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
The interactions between particles due to long-range hydrophobic forces have been extensively investigated. The hydrophobic force is likely a capillary force that arises from the formation of capillary bridges due to the merging of nanobubbles. In this study, we aim to investigate the impact of the nanobubble surface charge on the capillary bridge and, subsequently, the interaction between particles. The surface charge of the nanobubbles was altered in the presence of various surfactants (cationic, anionic, and nonionic) and salts (mono-, di-, and trivalent). The particle-particle interaction was quantified by measuring the aggregate size of the hydrophobized glass particles. Both experimental and theoretical findings confirm that the interaction between particles was enhanced when the surface potential of the nanobubble was around the neutral regime. This is probably because, when the surface potential was close to neutral, the interaction between two surface-deposited nanobubbles dominated over electrostatic repulsion, which was more conducive to the formation of the nanobubble capillary bridge. The estimation of the constrained Gibbs potential also showed the capillary bridge to be more stable when surface charge density along the bridge gas-liquid interface was minimal.
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Affiliation(s)
- Nilanjan Dutta
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
| | - Subhasish Mitra
- ARC Center of Excellence for Enabling Eco-efficient Beneficiation of Minerals, School of Engineering, The University of Newcastle, New South Wales 2308, Australia
| | - Neelkanth Nirmalkar
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
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Sharma H, Trivedi M, Nirmalkar N. Do Nanobubbles Exist in Pure Alcohol? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1534-1543. [PMID: 38176064 DOI: 10.1021/acs.langmuir.3c03592] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
The existence of nanobubbles in pure water has been extensively debated in recent years, and it is speculated that nanobubbles may be ion-stabilized. However, nanobubbles in the alcohol-water mixture and pure alcohols are still controversial due to the lack of ions present in the alcohol system. This work tested the hypothesis that stable nanobubbles exist in pure alcohol. The ultrasound and oscillatory pressure fields are used to generate nanobubbles in pure alcohol. The size distribution, concentration, diameter, and scattering intensity of the nanobubbles were measured by nanoparticle tracking analysis. The light scattering method measures the zeta potential. The Mie scattering theory and electromagnetic wave simulation are utilized to estimate the refractive index (RI) of nanobubbles from the experimentally measured scattering light intensity. The average RI of the nanobubbles in pure alcohols produced by ultrasound and oscillating pressure fields was estimated to be 1.17 ± 0.03. Degassing the nanobubble sample reduces its concentration and increases its size. The average zeta potential of the nanobubbles in pure alcohol was measured to be -5 ± 0.9 mV. The mechanical stability model, which depends on force balance around a single nanobubble, also predicts the presence of nanobubbles in pure alcohol. The nanobubbles in higher-order alcohols were found to be marginally colloidally stable. In summary, both experimental and theoretical results suggest the existence of nanobubbles in pure alcohol.
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Affiliation(s)
- Harsh Sharma
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, India
| | - Mohit Trivedi
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, India
| | - Neelkanth Nirmalkar
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, India
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Jia M, Farid MU, Kharraz JA, Kumar NM, Chopra SS, Jang A, Chew J, Khanal SK, Chen G, An AK. Nanobubbles in water and wastewater treatment systems: Small bubbles making big difference. WATER RESEARCH 2023; 245:120613. [PMID: 37738940 DOI: 10.1016/j.watres.2023.120613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/22/2023] [Accepted: 09/09/2023] [Indexed: 09/24/2023]
Abstract
Since the discovery of nanobubbles (NBs) in 1994, NBs have been attracting growing attention for their fascinating properties and have been studied for application in various environmental fields, including water and wastewater treatment. However, despite the intensive research efforts on NBs' fundamental properties, especially in the past five years, controversies and disagreements in the published literature have hindered their practical implementation. So far, reviews of NB research have mainly focused on NBs' role in specific treatment processes or general applications, highlighting proof-of-concept and success stories primarily at the laboratory scale. As such, there lacks a rigorous review that authenticates NBs' potential beyond the bench scale. This review aims to provide a comprehensive and up-to-date analysis of the recent progress in NB research in the field of water and wastewater treatment at different scales, along with identifying and discussing the challenges and prospects of the technology. Herein, we systematically analyze (1) the fundamental properties of NBs and their relevancy to water treatment processes, (2) recent advances in NB applications for various treatment processes beyond the lab scale, including over 20 pilot and full-scale case studies, (3) a preliminary economic consideration of NB-integrated treatment processes (the case of NB-flotation), and (4) existing controversies in NBs research and the outlook for future research. This review is organized with the aim to provide readers with a step-by-step understanding of the subject matter while highlighting key insights as well as knowledge gaps requiring research to advance the use of NBs in the wastewater treatment industry.
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Affiliation(s)
- Mingyi Jia
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region
| | - Muhammad Usman Farid
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region.
| | - Jehad A Kharraz
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region; Department of Chemical and Petroleum Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, UAE
| | - Nallapaneni Manoj Kumar
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region; Center for Circular Supplies, HICCER - Hariterde International Council of Circular Economy Research, Palakkad, Kerala 678631, India
| | - Shauhrat S Chopra
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region
| | - Am Jang
- Department of Global Smart City, Sungkyunkwan University (SKKU), 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Republic of Korea
| | - John Chew
- Department of Chemical Engineering, University of Bath, Bath BA2 7AY, UK
| | - Samir Kumar Khanal
- Department of Molecular Biosciences and Bioengineering, University of Hawai'i at Manoa, 1955 East-West Road, Honolulu, HI 96822, United States
| | - Guanghao Chen
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution and Water Technology Center, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Alicia Kyoungjin An
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region.
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14
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Chae S, Kim MS, Kim JH, Fortner JD. Nanobubble Reactivity: Evaluating Hydroxyl Radical Generation (or Lack Thereof) under Ambient Conditions. ACS ES&T ENGINEERING 2023; 3:1504-1510. [PMID: 37854075 PMCID: PMC10581208 DOI: 10.1021/acsestengg.3c00124] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 10/20/2023]
Abstract
Nanobubble (NB) generation of reactive oxygen species (ROS), especially hydroxyl radical (·OH), has been controversial. In this work, we extensively characterize NBs in solution, with a focus on ROS generation (as ·OH), through a number of methods including degradation of ·OH-specific target compounds, electron paramagnetic resonance (EPR), and a fluorescence-based indicator. Generated NBs exhibit consistent physical characteristics (size, surface potential, and concentration) when compared with previous studies. For conditions described, which are considered as high O2 NB concentrations, no degradation of benzoic acid (BA), a well-studied ·OH scavenger, was observed in the presence of NBs (over 24 h) and no EPR signal for ·OH was detected. While a positive fluorescence response was measured when using a fluorescence probe for ·OH, aminophenyl fluorescein (APF), we provide an alternate explanation for the result. Gas/liquid interfacial characterization indicates that the surface of a NB is proton-rich and capable of inducing acid-catalyzed hydrolysis of APF, which results in a false (positive) fluorescence response. Given these negative results, we conclude that NB-induced ·OH generation is minimal, if at all, for conditions evaluated.
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Affiliation(s)
- Seung
Hee Chae
- Department
of Chemical and Environmental Engineering, Yale University, 17 Hillhouse Ave., New Haven, Connecticut 06520, United States
| | - Min Sik Kim
- Department
of Environmental Engineering and Soil Environment Research Center, Jeonbuk National University, Jeonju, Jeollabukdo 54896, Republic of Korea
| | - Jae-Hong Kim
- Department
of Chemical and Environmental Engineering, Yale University, 17 Hillhouse Ave., New Haven, Connecticut 06520, United States
| | - John D. Fortner
- Department
of Chemical and Environmental Engineering, Yale University, 17 Hillhouse Ave., New Haven, Connecticut 06520, United States
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15
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Montazeri SM, Kalogerakis N, Kolliopoulos G. Effect of chemical species and temperature on the stability of air nanobubbles. Sci Rep 2023; 13:16716. [PMID: 37794127 PMCID: PMC10550960 DOI: 10.1038/s41598-023-43803-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 09/28/2023] [Indexed: 10/06/2023] Open
Abstract
The colloidal stability of air nanobubbles (NBs) was studied at different temperatures (0-30 °C) and in the presence of sulfates, typically found in mining effluents, in a wide range of Na2SO4 concentrations (0.001 to 1 M), along with the effect of surfactants (sodium dodecyl sulfate), chloride salts (NaCl), and acid/base reagents at a pH range from 4 to 9. Using a nanobubble generator based on hydrodynamic cavitation, 1.2 × 108 bubbles/mL with a typical radius of 84.66 ± 7.88 nm were generated in deionized water. Multiple evidence is provided to prove their presence in suspension, including the Tyndall effect, dynamic light scattering, and nanoparticle size analysis. Zeta potential measurements revealed that NBs are negatively charged even after two months (from - 19.48 ± 1.89 to - 10.13 ± 1.71 mV), suggesting that their stability is due to the negative charge on their surface. NBs were found to be more stable in alkaline solutions compared to acidic ones. Further, low amounts of both chloride and sulfate dissolved salts led to a reduction of the size of NBs. However, when high amounts of dissolved salts are present, NBs are more likely to coalesce, and their size to be increased. Finally, the investigation of the stability of air NBs at low temperatures revealed a non-monotonic relationship between temperature and NBs upon considering water self-ionization and ion mobility. This research aims to open a new frontier towards the application of the highly innovative NBs technology on the treatment of mining, mineral, and metal processing effluents, which are challenging aqueous solutions containing chloride and sulfate species.
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Affiliation(s)
- Seyed Mohammad Montazeri
- Department of Mining, Metallurgical, and Materials Engineering, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Nicolas Kalogerakis
- School of Chemical and Environmental Engineering, Technical University of Crete, 73100, Chania, Greece
| | - Georgios Kolliopoulos
- Department of Mining, Metallurgical, and Materials Engineering, Université Laval, Québec, QC, G1V 0A6, Canada.
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16
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Agarwal K, Trivedi M, Ohl CD, Nirmalkar N. On Nanobubble Dynamics under an Oscillating Pressure Field during Salting-out Effects and Its DLVO Potential. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5250-5262. [PMID: 37014662 DOI: 10.1021/acs.langmuir.2c03085] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
We have investigated the origin, stability, and nanobubble dynamics under an oscillating pressure field followed by the salting-out effects. The higher solubility ratio (salting-out parameter) of the dissolved gases and pure solvent nucleates nanobubbles during the salting-out effect, and the oscillating pressure field enhances the nanobubble density further as solubility varies linearly with gas pressure by Henry's law. A novel method for refractive index estimation is developed to differentiate nanobubbles and nanoparticles based on the scattering intensity of light. The electromagnetic wave equations have been numerically solved and compared with the Mie scattering theory. The scattering cross-section of the nanobubbles was estimated to be smaller than the nanoparticles. The DLVO potentials of the nanobubbles predict the stable colloidal system. The zeta potential of nanobubbles varied by generating nanobubbles in different salt solutions, and it is characterized by particle tracking, dynamic light scattering, and cryo-TEM. The size of nanobubbles in salt solutions was reported to be higher than that in pure water. The novel mechanical stability model is proposed by considering both ionic cloud and electrostatic pressure at the charged interface. The ionic cloud pressure is derived by electric flux balance, and it is found to be twice the electrostatic pressure. The mechanical stability model for a single nanobubble predicts the existence of stable nanobubbles in the stability map.
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Affiliation(s)
- Kalyani Agarwal
- Department of Chemical Engineering, Indian Institute of Technology, Ropar 140001, India
| | - Mohit Trivedi
- Department of Chemical Engineering, Indian Institute of Technology, Ropar 140001, India
| | - Claus-Dieter Ohl
- Otto-von-Guericke University Magdeburg, Faculty of Natural Sciences, Institute for Physics, Department Soft Matter, Universitaetsplatz 2, Magdeburg 39106, Germany
| | - Neelkanth Nirmalkar
- Department of Chemical Engineering, Indian Institute of Technology, Ropar 140001, India
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17
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Prakash R, Lee J, Moon Y, Pradhan D, Kim SH, Lee HY, Lee J. Experimental Investigation of Cavitation Bulk Nanobubbles Characteristics: Effects of pH and Surface-Active Agents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:1968-1986. [PMID: 36692411 DOI: 10.1021/acs.langmuir.2c03027] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Nanobubbles (NBs) have a widespread application in antimicrobial activity, wastewater treatment, and ecological restoration due to numerous peculiar characteristics, such as small diameter, long-term stability, and ability to produce hydroxyl radicals. Despite significant applications, only limited comprehensive investigations are available on the role of surfactants and pH in NBs characteristics. Therefore, this study examines the effects of different surfactants (i.e., anionic, cationic, and nonionic) and pH medium on bulk NB formation, diameter, concentration, bubble size distribution (BSD), ζ-potential, and stability. The effect of surfactant at concentrations above and below the critical micelle concentration was investigated. NBs were generated in deionized (DI) water using a piezoelectric transducer. The stability of NBs was assessed by tracking the variation in diameter and concentration over time. In a neutral medium, the diameter of NBs is smaller than in other surfactant or pH mediums. The diameter, concentration, BSD, and stability of NBs are strongly influenced by the ζ-potential rather than the solution medium. BSD curve shifts to a smaller bubble diameter when the magnitude of ζ-potential is high in any solution. In pure water, surfactant, and pH mediums, NBs have existed for a long time. NBs have a shorter life span in environments with a pH ≤ 3. Surfactant adsorption on the surface of NBs increases with increasing surfactant concentration up to a certain limit, beyond which it declines substantially. The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was used to interpret the NBs stability, resulting in a total potential energy barrier that is positive and greater than 45.55 kBT for 6 ≤ pH ≤ 11, whereas for pH < 6, the potential energy barrier essentially vanishes. Moreover, an effort has also been made to explicate the plausible prospect of ion distribution and its alignment surrounding NBs in cationic and anionic surfactants. This study will extend the in-depth investigation of NBs for industrial applications involving NBs.
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Affiliation(s)
- Ritesh Prakash
- Microfluidic Convergence Laboratory, Institute of Quantum Biophysics, Sungkyunkwan University, Suwon16419, Republic of Korea
| | - Jinseok Lee
- Microfluidic Convergence Laboratory, School of Mechanical Engineering, Sungkyunkwan University, Suwon16419, Republic of Korea
| | - Youngkwang Moon
- Microfluidic Convergence Laboratory, School of Mechanical Engineering, Sungkyunkwan University, Suwon16419, Republic of Korea
| | - Diva Pradhan
- Microfluidic Convergence Laboratory, School of Mechanical Engineering, Sungkyunkwan University, Suwon16419, Republic of Korea
| | - Seung-Hyun Kim
- School of Engineering, Brown University, Providence, Rhode Island02912, United States
| | - Ho-Yong Lee
- Department of Material Science and Engineering, Sunmoon University, Asan31460, Republic of Korea
| | - Jinkee Lee
- Microfluidic Convergence Laboratory, Institute of Quantum Biophysics, Sungkyunkwan University, Suwon16419, Republic of Korea
- Microfluidic Convergence Laboratory, School of Mechanical Engineering, Sungkyunkwan University, Suwon16419, Republic of Korea
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18
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Vara Prasad GVVS, Sharma H, Nirmalkar N, Dhar P, Samanta D. Augmenting the Leidenfrost Temperature of Droplets via Nanobubble Dispersion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15925-15936. [PMID: 36508708 DOI: 10.1021/acs.langmuir.2c01891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Droplets may rebound/levitate when deposited over a hot substrate (beyond a critical temperature) due to the formation of a stable vapor microcushion between the droplet and the substrate. This is known as the Leidenfrost phenomenon. In this article, we experimentally allow droplets to impact the hot surface with a certain velocity, and the temperature at which droplets show the onset of rebound with minimal spraying is known as the dynamic Leidenfrost temperature (TDL). Here we propose and validate a novel paradigm of augmenting the TDL by employing droplets with stable nanobubbles dispersed in the fluid. In this first-of-its-kind report, we show that the TDL can be delayed significantly by the aid of nanobubble-dispersed droplets. We explore the influence of the impact Weber number (We), the Ohnesorge number (Oh), and the role of nanobubble concentration on the TDL. At a fixed impact velocity, the TDL was noted to increase with the increase in nanobubble concentration and decrease with an increase in impact velocity for a particular nanobubble concentration. Finally, we elucidated the overall boiling behaviors of nanobubble-dispersed fluid droplets with the substrate temperature in the range of 150-400 °C against varied impact We through a detailed phase map. These findings may be useful for further exploration of the use of nanobubble-dispersed fluids in high heat flux and high-temperature-related problems and devices.
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Affiliation(s)
| | - Harsh Sharma
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Punjab140001, India
| | - Neelkanth Nirmalkar
- Department of Chemical Engineering, Indian Institute of Technology Ropar, Punjab140001, India
| | - Purbarun Dhar
- Hydrodynamics and Thermal Multiphysics Lab (HTML), Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, West Bengal721302, India
| | - Devranjan Samanta
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Punjab140001, India
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