Anh V. Nguyen

Anh V. Nguyen
The University of Queensland | UQ · School of Chemical Engineering

BE, PhD, GradCertHighEduStudies

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428
Publications
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Publications

Publications (428)
Article
Full-text available
The flotation separation of water-soluble salt minerals has to be conducted under the condition of saturation in brines which represents a challenging but exciting topic of colloid and surface chemistry. Despite several proposals on explaining the success of this industrial application for many decades, our understanding of the flotation separation...
Article
Hydrogen and methane can be molecularly incorporated in ice-like water structures up to mass fractions of 4.3% and 13.3%, respectively. The resulting solid structures, called gas hydrates, offer great potential for the efficient storage of hydrogen and natural gas. However, slow gas encapsulation by bulk water hinders this application. Porous struc...
Article
Particle-laden interfaces are critical to the flotation separation of hydrophobic particles using air bubbles. After contacting the particle suspension, the bubble surface is loaded with many hydrophobic particles that can get detached during the bubble rise to the top. While many studies of the capillary stability and detachment of single particle...
Article
Background The rise of gaseous bubbles in shear-thinning liquid is a fundamental issue in fluid physics, particularly the bubbles rise dynamics in water-soluble xanthan gum concentration have a strong link for enhancing the stability of foams that have been encountered extensively in oil recovery, methane hydrate formation processing, froth flotati...
Article
The adsorption of heavy metal ions onto negatively charged oxide (quartz) surface in environmental settings produces three surface charge reversals (CRs) described as CR1 at low pH, CR2 at middle pH, and CR3 at high pH. The available physical quantitative approaches cannot predict all these CRs and are not applicable for low salt concentrations (<...
Article
Fundamental research on liquid marble shells has been hindered due to their opaque and fuzzy appearance. X‐ray computerized microtomography (CMT) can overcome this problem by generating an image with a visible interface between core liquid and the shell. The analysis with X‐ray CMT reveals that the liquid marble shell thickness depends on the liqui...
Article
Liquid marble is a non-wetting droplet encapsulated by micro or nano-sized hydrophobic particles. Recently, liquid marble has been emerging as a tool for digital microfluidics. Thus, a detailed understanding of the fundamentals of liquid marble is essential. The shell of a liquid marble has an opaque and fuzzy appearance which hinders in-depth inve...
Article
Understanding of hydrogen sulfide (H2S) hydrates phase equilibrium is important for sour gas production and transportation. In this study, hydrate dissociation conditions of H2S were measured in aqueous NaCl, KCl, MgCl2, NH4Cl, Na2SO4, and K2SO4 solutions at temperatures ranging from 273.4 to 298.8 K, pressures ranging from 1.13 to 21.90 bar, and w...
Article
Carbon capture and storage (CCS) is vital for reducing CO2 emissions and achieving climate change targets. Despite proven technical viability, the high cost of current CO2 capture methods hinders widespread applications of CCS. Hydrate-based carbon capture (HBCC) is a promising route for energy-efficient CO2 capture. With an estimated cost of 20 –...
Article
The bubble-particle detachment interaction is critical to the flotation of coarse (composite) particles which has attracted significant research interest in recent years. It is principally controlled by the capillary forces arising from the deformation of the air–water interface that has been quantified employing the single-particle models. However...
Article
Thickening as the most widely applied dewatering technique in the coal and mineral processing industry involves the rapid settling of flocculated suspensions of fine tailings particles to produce a compact phase of solid at the bottom and a clear phase of liquid on the top. The mudline separating the two phases can be monitored and used to optimise...
Article
A liquid marble (LM) is a droplet coated with microparticles that isolate the liquid interior from its surroundings, making it perfectly non-wetting. This attractive feature allows the LM to perform useful tasks such as coalescence, targeted delivery, and controlled release. The non-wetting characteristic also allows the LM to float on a carrier li...
Article
Surfactants are centrally important in many scientific and engineering fields and are used for many purposes such as foaming agents and detergents. However, many challenges remain in providing a comprehensive understanding of their behavior. Here, we provide a brief historical overview of the study of surfactant adsorption at the air-water interfac...
Article
Normally fluorite was collected by fatty acid collectors at pH 5–11, rendering the surface to be hydrophobic. In this study, we found that fluorite surfaces are naturally hydrophobic at high pH without any surfactant, which is beneficial for the selective flotation separation of fluorite from calcite. In a flotation test, fluorite recovery showed a...
Article
The HydroFloat cells made by Eriez are designed for floating coarse particles using fluidization involving bubble–liquid–particle suspensions. The operational optimization and control of these cells can be a challenging task and require various correlations that are difficult to establish by theory. Here, experiments were performed to study the eff...
Article
Gas hydrates offer potential methods for the storage and transportation of gases. However, factors such as slow kinetics can hinder storage applications. Here we demonstrate the use of cyclodextrins (CDs) as green chemicals for accelerating methane hydration formation. A second generation high pressure, stirred, automated lag time apparatus (HPS-AL...
Article
Although available flotation experiments show that sulphide flotation recovery increases with increasing xanthate chain length, quantitative analysis to reveal the underlying mechanisms is missing. Herein, we investigate the chain length effect by using a recently developed attachment apparatus and an advanced theory to determine and validate the a...
Article
The flotation of coarse in particular partially liberated particles has attracted both industry and research interests in recent years as it can bring several benefits to existing operations, including the decrease in grinding energy and media consumption, the increase in plant throughput, and environmental benefits. The bubble-particle detachment...
Article
Solid-liquid separation to dewater mine tailings is critical to transforming tailings dams that are hazardous to the environment and surrounding communities into safer and sustainable disposal storages by dry stacking and co-disposals. Current tailings dewatering by thickening and filtration has experienced big challenges due to the presence of fin...
Article
Ionic surfactants behave differently in the presence of various counterions, which plays an important role in many scientific and engineering processes. Previous work has shown that the counterion-specific surface tension can be reproduced with classical adsorption models, but the underlying origin of this effect has not been explained. In this pap...
Article
The separation of coarse particles by flotation can be maximized by the support of fluidized bed hydrodynamics. Here, we investigated the effect of particle size and shape on the liquid-solid fluidization in a HydroFloat cell that was developed for the special separation process using CFD results and experimental data. Specifically, a 3D CFD model...
Article
The short-range attractive forces between hydrophobic surfaces are key factors in a wide range of areas such as protein folding, lipid self-assembly, and particle-bubble interaction such as in industrial flotation. Little is certain about the effect of dissolved (well-controlled) gases on the interaction forces, in particular in those systems where...
Article
Holistically, air bubbles in flotation must rise to the top surface while free solid particles must settle to the cell bottom. Inside the stator-rotor space of the mechanical flotation cells, the turbulence of mixing can surpass the gravity-driven motion of the bubble-particle suspension. Outside the space, the bubbles rise to the surface, but it i...
Article
Full-text available
Surfactants and/or salts at low concentrations are inherently relevant to gas hydrate formation in nature and industry. However, the combined effects of surfactants and salts at low concentrations on gas hydrate formation are poorly understood. Here, we aim to fill this gap of knowledge by examining the effects of sodium dodecyl sulfate (SDS) and s...
Article
Over 150 million tons of high-alkaline bauxite residue was produced during the Bayer process of Bauxite smelting in the world annually, causing massive encroachment and irreversible pollution of soil. In this work, we proposed a new way out of bauxite residue, synthesizing a micro-electrolysis composite material (MECM) by carbothermal reduction of...
Article
Foam films formed at the air-water interface do not have fixed adsorption sites where adsorbed surfactants can arrange themselves, resulting in the formation of thick adsorption layers. Current theories of equilibrium foam films fail to account for this feature and significantly underestimate the adsorption layer thickness. Here we show that this t...
Article
Full-text available
Gas hydrates are crystalline solids composed of water and gases. They occur abundantly in nature and are potentially significant to the industry. Solid surfaces and confined spaces strongly affect the formation of gas hydrates. Research into this particular topic is active, particularly aiming to understand the effects of solid surfaces and confine...
Article
In flotation, the fluidization can enhance the coarse particle recovery which is dependent on the quiescent flow condition and is also affected by the liquid-solid interphase drag force. In this study, the liquid and particle flow behaviors are investigated by using the Eulerian-Eulerian two-fluid model combining the kinetic theory of granular flow...
Article
Wash water is widely used in flotation to increase the gravity-driven drainage rate of water within the froth phase and the efficiency of removing entrained (hydrophilic) particles. At a high rate, it can disturb the froth. Here, we investigate the drainage instability caused by wash water using the forced drainage experiments. We quantitatively co...
Article
Soluble surfactants form thick adsorption layers at the air-liquid interface, but classical adsorption models fail to account for it as they treat the adsorption layer as a mathematical plane (of zero thickness). This simplification has produced several inconsistencies between theoretical predictions and experimental results, especially for the sur...
Article
Full-text available
The attachment of air bubbles to solid surfaces in water is encountered in many natural processes and industrial applications. It has been established that the attachment can occur between hydrophobic surfaces and air bubbles. In this paper, we present novel experimental results to quantify the attachment in terms of the attachment time. We show th...
Article
Hypothesis: Bubble attachment to hydrophobic solid surfaces is influenced by the liquid film instability. Inclusion of transiently formed holes within the film rather than the so-called hydrophobic force in the theory is expected to better describe and explain film rupture and triple contact line formation in the bubble-surface attachment process....
Article
The machine acceleration introduced by H. J. Schulze has been a cornerstone of the bubble-particle (BP) detachment theory. It connects the mean dissipation rate of turbulence energy of water in a flotation machine with the BP detachment. In a recent paper, we scrutinized the theory and recommended its extension to cover both the longitudinal (centr...
Article
It is difficult to separate scheelite especially from fluorite with fatty acid collectors because the adsorption mechanism of these collectors occurs through chemisorption of the oleate ion onto the mineral surface. A simplified flotation process using Pb-BHA complexes was developed to replace the energy-inefficient Petrov’s process of using a fatt...
Article
Activation of sphalerite flotation by lead ions (Pb) is an important aspect of selective separation of sphalerite and galena, but its molecular mechanism remains poorly understood. In this paper, the surface chemistry of sphalerite in the Pb activation process at pHs 4 and 9 was investigated using inductively coupled plasma-atomic mission spectrome...
Article
The Navier-Stokes equation governing the water flow around a rising air bubble is highly nonlinear and produces the fore-and-aft asymmetry (FAA) of water streamlines about the horizontal plane of the bubble equator (perpendicular to the direction of bubble rise). In this paper, the effect of FAA on the collision interaction between a particle and a...
Article
We review the experimental and theoretical results for the adsorption and structure of ionic surfactants at the air-liquid interface. The results show that ionic surfactants form thick adsorption layers at the interfacial region. We also review several adsorption models for ionic surfactants, which become increasingly complex as they capture the ma...
Article
Flocculants are widely used in ultrafine coal dewatering to improve the particles settling rate. However, water entraps inside flocs that consequently increase generated filter cake moisture. In this paper, we report the effectiveness of a chemically enhanced approach to effectively increase particles settling rate and reducing filter cake moisture...
Article
Full-text available
Surface sulfidization is the key to achieving good flotation performance of smithsonite, but its reaction mechanism at the atomic level remains poorly understood. In this work, the interaction of two S-species, i.e., S2− and SH− with smithsonite (0 0 1) surface in presence of water molecule was investigated using the density functional theory (DFT)...
Article
Sodium silicate (SS) is often used as a depressant or a dispersant to improve the selectivity of froth flotation. The depressing ability of SS changes with its concentration and the solution pH. However, the depressing mechanism is unclear. In this paper, sum frequency generation spectroscopy was used to investigate the water structure at the miner...
Article
Full-text available
Hydrodynamic behavior of fine particles and bubbles and their influences on the particle–bubble collision efficiency (Ec) in an electro‐flotation system were analyzed in this study. The influence of sodium oleate on the agglomeration of cassiterite particles and the effect of electrolyte (Na2SO4) concentration on the zeta potential of cassiterite w...
Article
Techniques for dry processing low-grade iron ores and tailings are being investigated. Dry desliming tests using a rotating wheel air classifier and factorial design were performed on a difficult-to-treat low-grade high-goethite Australian iron ore tailings. The results were compared with theoretically ideal size separation and a hydrocyclone desli...
Article
Full-text available
Manipulation of a floating liquid marble (LM) plays an important role in LM-based digital microfluidics for three-dimensional cell culture. Dielectrophoretic (DEP) actuation is a simple yet versatile manipulation technique that enables small droplets to be delivered across an open liquid surface. This paper reports the concept of accurately positio...
Article
Kaolinite is one of the main associated minerals (gangue) in the processing of diasporic bauxites. Sulfuric acid pretreatment has been shown to have an improving effect on kaolinite-diaspore flotation separation, but the mechanism underpinning this effect is not well known. This study reports the surface chemistry of acid-treated kaolinite and dias...
Article
Evaluating and predicting evaporation kinetics of a sessile droplet present challenging exercises because of its strong dependence on the substrate hydrophobicity (contact angle) and the evaporation mode at the three-phase contact line. For sessile water droplets containing surfactants, the existence of surfactant would not only change droplet’s ge...
Article
Full-text available
The relationship between electrochemical oxidation (Chronoamperometry) of galena surfaces and collocterless galena flotation was investigated in detail. The chronoamperometry (CA) micro flotation experiments and zeta potential experiments were performed with ground galena particles (106x53 mu m). In addition, contact angle measurements were carried...
Article
The bubble-particle (BP) detachment is a significant factor in controlling the recovery of coarse particles in mechanical flotation cells. It has been quantified by balancing the restoring force of surface tension and the centrifugal force exerted on the particle-bubble aggregate by the turbulent flow field using a “machine acceleration”. The conce...
Article
The stability of water films has been the focus of many researchers in the recent decades. Unfortunately, there is no consensus on the stability of these foam films or on the mechanisms responsible for stabilizing water films. This paper examines the reported results on this matter and scrutinizes them based on speciation analysis of the dissolved...
Article
Full-text available
Solid liquid fluidised beds (SLFB) are frequently encountered in the mineral processing applications including ore leaching/washing and particle size classification based on difference in settling velocity. Due to complex phase interactions, SLFB shows interesting characteristics such as phase segregation and mixing depending on variation in partic...
Article
Inorganic salts can thermodynamically inhibit gas hydrate formation. However, some inorganic salts at low concentration can act as a kinetic hydrate promoter. The mechanism of kinetic hydrate promotion in the presence of low concentration of inorganic salts is still unknown. This paper presents an experimental study into methane hydrate formation i...
Article
Details about molecular structures of surfactant mixtures adsorbed at the air-water have been controversial. Using sum frequency generation vibrational spectroscopy (SFG) and isotope labelling we show here for the first time that mixtures of dodecanol (DOH) and sodium dodecyl sulphate (SDS) adsorb at the air-water interface with the formation of th...
Article
Full-text available
The attachment of copper matte by bubbles in slags, during the copper smelting process, plays a key role in the copper loss. This paper aims to provide an in-depth insight into the copper matte entrainment by bubbles in the copper production. The bubble size distribution and matte film thickness as well as the bubble detachment height were consider...
Article
The stability of water films has been the focus of many researchers in the recent decades. Unfortunately, there is no consensus on the stability of these foam films or on the mechanisms responsible for stabilizing water films. This paper examines the reported results on this matter and scrutinizes them based on speciation analysis of the dissolved...
Article
Interfacial gas enrichment (IGE) of dissolved gases in water is shown to govern the strong attraction between solid hydrophobic surfaces of an atomic force microscopy (AFM) colloidal probe and a solid substrate. However, the role of IGE in controlling the attraction between fluid-fluid interfaces of foam films and emulsion films is difficult to est...
Article
Capillary force is critical to the floatability of particles at the air-water interface. Quantification of the capillary force requires solving the Young-Laplace equation using suitable boundary conditions (BCs) at the triple contact line. For axisymmetric (2D) systems, such as single spheres floating at an initially flat air-water surface, both th...
Article
The surface tension of dilute salt water is a fundamental property that is crucial to understanding the complexity of many aqueous phase processes. Small ions are known to be repelled from the air-water surface leading to an increase in the surface tension in accordance with the Gibbs adsorption isotherm. The Jones-Ray effect refers to the observat...
Article
Full-text available
A liquid marble is a droplet coated with hydrophobic powder. The porous and hydrophobic coating prevents physical contact between the liquid and its surroundings without compromising gas exchange. As such, the liquid marble is an excellent platform for culturing cells. With the promising biomedical applications of the liquid marble, numerous studie...
Article
A liquid marble is a microliter-sized droplet coated with hydrophobic powder. The porous coating prevents the liquid content from direct physical contact with its surrounding, making the liquid marble perfectly non-wetting. On the one hand, the non-wetting ability allows the liquid marble to float and move across a liquid surface with little resist...
Article
We reviewed eight commonly used equilibrium adsorption models and examined their underlying assumptions, fitting qualities, and parameter stabilities. We compared several objective functions that have been applied to curve fitting analysis and a few statistics tests that have been performed to evaluate regression quality. The iteratively reweighted...
Article
Float and sink testing is the standard laboratory method for determining the coal washability characteristics using heavy liquids. In this paper, we describe an alternative technique for determining coal washability using High-Resolution X-ray Microcomputed Tomography (HRXMT). Specifically, the application of HRXMT and specialized software have ena...
Article
Full-text available
Turbulence and mechanical flotation cells have been the workhorse of the mining industry to process the high tonnage but low-grade ores for more than a century. However, our quantitative understanding of the effect of turbulence on flotation is still limited. Here we theoretically investigate the bubble-particle collision in flotation in homogeneou...
Article
The active sites of mineral surfaces play an important role in many industrial processes, such as mineral flotation and dewatering. This paper was aimed to investigate the effect of Al- and Si-active sites on the mineral crystal faces exposed to water on the electrokinetic properties, surfactant adsorption, and floatability of diaspore and kaolinit...
Article
Some salts have been recently shown to decrease the SFG (sum frequency generation spectroscopy) intensity of the hydrogen-bonded water molecules, but a quantitative explanation is still awaited. Here we report a similar trend for the chloride salts of monovalent cations, i.e., LiCl, NaCl, and CsCl, at low concentrations. Specifically, we revealed n...
Article
Current analytical models for sessile droplet evaporation do not consider the non-uniform temperature field within the droplet and can over-predict the evaporation by 20%. This deviation can be attributed to a significant temperature drop due to the release of the latent heat of evaporation along the air-liquid interface. We report, for the first t...
Article
In recent years, significant progress has been achieved in the study of aqueous foams. Having said this, a better understanding of foam physics requires a deeper and profound study of foam elements. This paper reviews the studies in the microscale of aqueous foams. The elements of aqueous foams are interior Plateau borders, exterior Plateau borders...
Article
We investigated structure properties of structure-making salts (LiCl, NaCl, and NaBr) and structure-breaking salts (KCl and KBr) solutions of 0.5 M to 4 M using TIP4P/2005 water model and OPLS ionic force fields. The viscosity results show a good trend with experimental values for all salts. For the water structure, the O–O number decreased with in...
Article
To improve the floatability of tungsten minerals, lead ions (lead nitrate) were used to modify the surface properties of the minerals and benzohydroxamic acid (BHA) was used as a collector in the flotation system. Pb²⁺-BHA complexes are inevitably present in this process and the role of it is unclear. This investigation is going to describe a new a...
Article
During the thermal drying process of coal, the sufficient attention has been paid to the changes in the properties of coal before and after the drying process. However, the volatility characteristics of harmful trace elements in coal during the drying process are always neglected to date, whereas the volatilization of harmful trace elements not onl...
Article
Diasporic bauxite represents one of the major aluminum resources. Its upgrading for further processing involves a separation of diaspore (the valuable mineral) from aluminosilicates (the gangue minerals) such as kaolinite, illite, and pyrophyllite. Flotation is one of the most effective ways to realize the upgrading. Since flotation is a physicoche...
Article
Carbonation using CO2 appears as an attractive solution for disposing of red mud suspensions, an aluminum industry hazardous waste since it also offers an option for CO2 sequestration. Here we report the novel findings that CO32- together with Ca2+ can significantly affect the surface properties and settling of goethite, a major component of red mu...
Article
The diffusion-driven evaporation of sessile droplets from planar surfaces is influenced by cooling at the air-liquid interface. Here, corrections to the available models for predicting the evaporation process are presented. The mass conservation for diffusion-driven evaporation is resolved by considering the effect of interface cooling on the chang...
Article
Tolerance and accumulation of multiple trace elements simultaneously in hyperaccumulator species enable these plants to grow on sites contaminated with these elements. In this study, accumulation and tolerance to zinc (Zn) and lead (Pb) by the hyperaccumulator Noccaea caerulescens (Brassicaceae) was investigated using different Zn 2+ and Pb 2+ trea...