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Scientific Reports Oct 2022Improving boiling is challenging due to the unpredictable nature of bubbles. One way to enhance boiling is with surfactants, which alter the solid-liquid and...
Improving boiling is challenging due to the unpredictable nature of bubbles. One way to enhance boiling is with surfactants, which alter the solid-liquid and liquid-vapor interfaces. The conventional wisdom established by previous studies suggests that heat transfer enhancement is optimized near the critical micelle concentration (CMC), which is an equilibrium property that depends on surfactant type. However, these studies only tested a limited number of surfactants over small concentration ranges. Here, we test a larger variety of nonionic and anionic surfactants over the widest concentration range and find that a universal, optimal concentration range exists, irrespective of CMC. To explain this, we show that surfactant-enhanced boiling is controlled by two competing phenomena: (1) the dynamic adsorption of surfactants to the interfaces and (2) the increase in liquid dynamic viscosity at very high surfactant concentrations. This dynamic adsorption is time-limited by the millisecond-lifetime of bubbles on the boiling surface-much shorter than the timescales required to see equilibrium behaviors such as CMC. At very high concentrations, increased viscosity inhibits rapid bubble growth, reducing heat transfer. We combine the effects of adsorption and viscosity through a simple proportionality, providing a succinct and useful understanding of this enhancement behavior for boiling applications.
Topics: Surface-Active Agents; Adsorption; Micelles; Pulmonary Surfactants; Excipients
PubMed: 36307430
DOI: 10.1038/s41598-022-21313-1 -
Toxins Jan 2024With the rapid advancement of nanotechnology and its widespread applications, increasing amounts of manufactured and natural nanoparticles (NPs) have been tested for... (Review)
Review
With the rapid advancement of nanotechnology and its widespread applications, increasing amounts of manufactured and natural nanoparticles (NPs) have been tested for their potential utilization in treating harmful cyanobacterial blooms (HCBs). NPs can be used as a photocatalyst, algaecide, adsorbent, flocculant, or coagulant. The primary mechanisms explored for NPs to mitigate HCBs include photocatalysis, metal ion-induced cytotoxicity, physical disruption of the cell membrane, light-shielding, flocculation/coagulation/sedimentation of cyanobacterial cells, and the removal of phosphorus (P) and cyanotoxins from bloom water by adsorption. As an emerging and promising chemical/physical approach for HCB mitigation, versatile NP-based technologies offer great advantages, such as being environmentally benign, cost-effective, highly efficient, recyclable, and adaptable. The challenges we face include cost reduction, scalability, and impacts on non-target species co-inhabiting in the same environment. Further efforts are required to scale up to real-world operations through developing more efficient, recoverable, reusable, and deployable NP-based lattices or materials that are adaptable to bloom events in different water bodies of different sizes, such as reservoirs, lakes, rivers, and marine environments.
Topics: Cyanobacteria; Adsorption; Biological Assay; Nanoparticles; Water
PubMed: 38251256
DOI: 10.3390/toxins16010041 -
Chemical Reviews Dec 2022Zeolites have been widely used as catalysts, ion exchangers, and adsorbents since their industrial breakthrough in the 1950s and continue to be state-of the-art... (Review)
Review
Zeolites have been widely used as catalysts, ion exchangers, and adsorbents since their industrial breakthrough in the 1950s and continue to be state-of the-art adsorbents in many separation processes. Furthermore, their properties make them materials of choice for developing and emerging separation applications. The aim of this review is to put into context the relevance of zeolites and their use and prospects in adsorption technology. It has been divided into three different sections, i.e., zeolites, adsorption on nanoporous materials, and chemical separations by zeolites. In the first section, zeolites are explained in terms of their structure, composition, preparation, and properties, and a brief review of their applications is given. In the second section, the fundamentals of adsorption science are presented, with special attention to its industrial application and our case of interest, which is adsorption on zeolites. Finally, the state-of-the-art relevant separations related to chemical and energy production, in which zeolites have a practical or potential applicability, are presented. The replacement of some of the current separation methods by optimized adsorption processes using zeolites could mean an improvement in terms of sustainability and energy savings. Different separation mechanisms and the underlying adsorption properties that make zeolites interesting for these applications are discussed.
Topics: Zeolites; Adsorption; Technology; Catalysis
PubMed: 36260918
DOI: 10.1021/acs.chemrev.2c00140 -
Molecules (Basel, Switzerland) Mar 2020Metal-organic frameworks (MOFs) have found uses in adsorption, catalysis, gas storage and other industrial applications. Metal Biomolecule Frameworks (bioMOFs) represent... (Review)
Review
Metal-organic frameworks (MOFs) have found uses in adsorption, catalysis, gas storage and other industrial applications. Metal Biomolecule Frameworks (bioMOFs) represent an overlap between inorganic, material and medicinal sciences, utilising the porous frameworks for biologically relevant purposes. This review details advances in bioMOFs, looking at the synthesis, properties and applications of both bioinspired materials and MOFs used for bioapplications, such as drug delivery, imaging and catalysis, with a focus on examples from the last five years.
Topics: Adsorption; Catalysis; Drug Delivery Systems; Humans; Metal-Organic Frameworks; Molecular Imaging
PubMed: 32178399
DOI: 10.3390/molecules25061291 -
Journal of Colloid and Interface Science Feb 2021Adsorption of proteins to fluid interfaces is critical in many industries, scientific disciplines, and biological processes. However, the structural transitions of...
Adsorption of proteins to fluid interfaces is critical in many industries, scientific disciplines, and biological processes. However, the structural transitions of proteins upon adsorption and the effect of the hydrophobic subphase, such as oil, have received little attention. Herein, we present a comprehensive study on the effect of the hydrophobic subphase on the adsorption behavior of globular and random-coil proteins. The adsorption of proteins is limited by their structural stability, and accordingly, is faster for less stable globular proteins and fastest for random-coil proteins. Protein adsorption is slower at more polar oils, regardless of the protein type, structure, and stability. Moreover, we found a correlation of oil polarity and the induced surface pressure of proteins, which seems universally applicable and describes the experimental data of over 30 previous studies. The model works for all commonly applied subphases, with the exception of oils that chemically react with proteins (e.g. octanal) and air, due to the lack of hydrophobic interactions. These results foster our understanding of protein adsorption and allow the prediction of protein unfolding depending on protein-subphase interactions.
Topics: Adsorption; Hydrophobic and Hydrophilic Interactions; Oils; Proteins; Water
PubMed: 33091866
DOI: 10.1016/j.jcis.2020.09.118 -
Molecules (Basel, Switzerland) Dec 2022Recent studies on the removal of pollutants via adsorption include the use of carbon-based adsorbents, due to their high porosity and large surface area; however, such...
Recent studies on the removal of pollutants via adsorption include the use of carbon-based adsorbents, due to their high porosity and large surface area; however, such materials lack photoactive properties. This study evaluates the synergistic effect of integrated mesoporous carbon xerogel (derived from resorcinol formaldehyde) and titanium dioxide (TiO) for combined adsorption and photodegradation application. The complex formed between carbon xerogel and TiO phase was investigated through FTIR, proving the presence of a Ti-O-C chemical linkage. The physicochemical properties of the synthesised adsorbent-photocatalyst were probed using FESEM, BET analysis and UV-Vis analysis. The kinetics, equilibrium adsorption, effect of pH, and effect of adsorbent dosage were investigated. The expansion of the absorbance range to the visible range was verified, and the corresponding band gap evaluated. These properties enabled a visible light response when the system was exposed to visible light post adsorption. Hence, an assistive adsorption-photodegradation phenomenon was successfully executed. The adsorption performance exhibited 85% dye degradation which improved to 99% following photodegradation. Further experiments showed the reduction of microorganisms under visible light, where no microbial colonies were observed after treatment, indicating the potential application of these composite materials.
Topics: Environmental Pollutants; Photolysis; Titanium; Adsorption; Carbon; Catalysis
PubMed: 36500576
DOI: 10.3390/molecules27238483 -
Biophysical Journal Nov 2020Bacteria often arrange themselves in various spatial configurations, which changes how they interact with their surroundings. In this work, we investigate how the...
Bacteria often arrange themselves in various spatial configurations, which changes how they interact with their surroundings. In this work, we investigate how the structure of the bacterial arrangements influences the adsorption of bacteriophages. We quantify how the adsorption rate scales with the number of bacteria in the arrangement and show that the adsorption rates for microcolonies (increasing with exponent ∼1/3) and bacterial chains (increasing with exponent ∼0.5-0.8) are substantially lower than for well-mixed bacteria (increasing with exponent 1). We further show that, after infection, the spatially clustered arrangements reduce the effective burst size by more than 50% and cause substantial superinfections in a very short time interval after phage lysis.
Topics: Adsorption; Bacteria; Bacteriophages
PubMed: 33069271
DOI: 10.1016/j.bpj.2020.09.027 -
Scientific Reports Apr 2023Contamination of water resources by industrial effluents containing heavy metal ions and management of solid waste from agricultural and food industries is a serious...
Contamination of water resources by industrial effluents containing heavy metal ions and management of solid waste from agricultural and food industries is a serious issue. This study presents the valorization of waste walnut shells as an effective and environment-friendly biosorbent for sequestrating Cr(VI) from aqueous media. The native walnut shell powder (NWP) was chemically modified with alkali (AWP) and citric acid (CWP) to obtain modified biosorbents with abundant availability of pores as active centers, as confirmed by BET analysis. During batch adsorption studies, the process parameters for Cr(VI) adsorption were optimized at pH 2.0. The adsorption data were fitted to isotherm and kinetic models to compute various adsorption parameters. The adsorption pattern of Cr(VI) was well explained by the Langmuir model suggesting the adsorbate monolayer formation on the surface of the biosorbents. The maximum adsorption capacity, q for Cr(VI) was achieved for CWP (75.26 mg/g), followed by AWP (69.56 mg/g) and NWP (64.82 mg/g). Treatment with sodium hydroxide and citric acid improved the adsorption efficiency of the biosorbent by 4.5 and 8.2%, respectively. The endothermic and spontaneous adsorption was observed to trail the pseudo-second-order kinetics under optimized process parameters. Thus, the chemically modified walnut shell powder can be an eco-friendly adsorbent for Cr(VI) from aqueous solutions.
Topics: Wastewater; Juglans; Adsorption; Powders; Chromium; Water; Kinetics; Hydrogen-Ion Concentration; Water Pollutants, Chemical; Thermodynamics
PubMed: 37100812
DOI: 10.1038/s41598-023-33843-3 -
Molecules (Basel, Switzerland) Jun 2023The adsorption of hexylamine at the solution-gold interface in 1 M HClO in the presence of 0.1 M Fe and 0.1 Fe was studied by potentiodynamic, chronoamperometric and EIS...
The adsorption of hexylamine at the solution-gold interface in 1 M HClO in the presence of 0.1 M Fe and 0.1 Fe was studied by potentiodynamic, chronoamperometric and EIS methods. The main kinetic characteristics of the oxidation-reduction reaction iron ions (exchange current density, transfer coefficient, diffusion coefficients of iron ions) were determined. It was shown that the physical adsorption of hexylamine on gold can be described by the Dhar-Flory-Huggins isotherm. The values of the adsorption constant and the Gibbs free adsorption energy were obtained. A comparison of the free adsorption energy at these interfaces with the interaction energies of hexylamine and water molecules, and hexylamine molecules with each other was carried out. It was shown that hexylamine adsorption at all of these interfaces is due mainly to the hydrophobic effect of the interaction of hexylamine and water molecules.
Topics: Gold; Adsorption; Iron; Ions; Water
PubMed: 37446732
DOI: 10.3390/molecules28135070 -
International Journal of Environmental... Aug 2021Arsenic (As) and lead (Pb) contamination in groundwater is a serious problem in countries that use groundwater as drinking water. In this study, composite beads, called...
Arsenic (As) and lead (Pb) contamination in groundwater is a serious problem in countries that use groundwater as drinking water. In this study, composite beads, called SCM beads, synthesized using stone powder (SP), chitosan (Ch), and maghemite (Mag) with different weight ratios (1/1/0.1, 1/1/0.3, and 1/1/0.5 for SP/Ch/Mag) were prepared, characterized and used as adsorbents for the removal of As and Pb from artificially contaminated water samples. Adsorption isotherm experiments of As and Pb onto the beads were conducted and single-solute adsorption isotherm models such as the Langmuir, Freundlich, Dubinin-Radushkevich (DR), and dual mode (DM) models were fitted to the experimental data to analyze the adsorption characteristics. The maximum adsorption capacities of the SCM beads were 75.7 and 232.8 mmol/kg for As and Pb, respectively, which were 40 and 5.6 times higher than that of SP according to the Langmuir model analyses. However, the DM model had the highest determinant coefficient (R) values for both As and Pb adsorption, indicating that the beads had heterogenous adsorption sites with different adsorption affinities. These magnetic beads could be utilized to treat contaminated groundwater.
Topics: Adsorption; Arsenic; Chitosan; Ferric Compounds; Hydrogen-Ion Concentration; Kinetics; Lead; Powders; Water Pollutants, Chemical; Water Purification
PubMed: 34444552
DOI: 10.3390/ijerph18168808