An enhanced thermal decomposition of chemical compounds in aqueous solution has been achieved at reduced solution temperatures. The technique exploits hitherto unrecognized properties of a bubble column evaporator (BCE). It offers better heat transfer efficiency than conventional heat transfer equipment. This is obtained via a continuous flow of hot, dry air bubbles of optimal (1-3 mm) size. Optimal bubble size is maintained by using the bubble coalescence inhibition property of some salts. This novel method is illustrated by a study of thermal decomposition of ammonium bicarbonate (NH4HCO3) and potassium persulfate (K2S2O8) in aqueous solutions. The decomposition occurs at significantly lower temperatures than those needed in bulk solution. The process appears to work via the continuous production of hot (e.g., 150 °C) dry air bubbles, which do not heat the solution significantly but produce a transient hot surface layer around each rising bubble. This causes the thermal decomposition of the solute. The decomposition occurs due to the effective collision of the solute with the surface of the hot bubbles. The new process could, for example, be applied to the regeneration of the ammonium bicarbonate draw solution used in forward osmosis.
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http://dx.doi.org/10.1021/acs.jpcb.5b02808 | DOI Listing |
Phys Rev Lett
December 2024
Université Paris-Saclay, CNRS, LPTMS, 91405, Orsay, France.
Energy-filtered quantum states are promising candidates for efficiently simulating thermal states. We explore a protocol designed to transition a product state into an eigenstate located in the middle of the spectrum; this is achieved by gradually reducing its energy variance, which allows us to comprehensively understand the crossover phenomenon and the subsequent convergence toward thermal behavior. We introduce and discuss three energy-filtering regimes (short, medium, and long), and we interpret them as stages of thermalization.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
McKetta Department of Chemical Engineering and Texas Material Institute, The University of Texas at Austin, Austin, Texas 78712, United States.
Germanium (Ge) colloidal quantum dots (CQDs) were synthesized by thermal decomposition of GeI using capping ligand mixtures of oleylamine (OAm), octadecene (ODE), and trioctylphosphine (TOP). Average diameters could be tuned across a wide range, from 3 to 18 nm, by adjusting reactant concentrations, heating rates, and reaction temperatures. OAm promotes decomposition of GeI to Ge and serves as a weakly bound capping ligand.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Korea.
The field of perovskite optoelectronics and electronics has rapidly advanced, driven by excellent material properties and a diverse range of fabrication methods available. Among them, triple-cation perovskites such as CsFAMAPbI offer enhanced stability and superior performance, making them ideal candidates for advanced applications. However, the multicomponent nature of these perovskites introduces complexity, particularly in how their structural, optical, and electrical properties are influenced by thermal annealing─a critical step for achieving high-quality thin films.
View Article and Find Full Text PDFInorg Chem
January 2025
Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007 Huelva, Spain.
Phosphinoazide complexes of the composition TpM-L (M = Cu, Ag, and L = 2-azido-1,3-bis(2,6-diisopropylphenyl)-2,3-dihydro-1-1,3,2-diazaphosphole) have been synthesized and structurally characterized. Their thermal decomposition led to cyclodiphosphazenes as a result of the metal-mediated coupling of two nitrene units in a process that takes place in both a stoichiometric and catalytic manner. Experimental data have allowed proposing a mechanistic pathway for this new transformation.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China. Electronic address:
Developing an efficient and economical indoor air purification system for catalytic decomposition of formaldehyde is of great significance. In this work, an indoor air conditioner capable of purifying formaldehyde was designed by directly integrating defective WO/TiO nanotube catalytic fin, with both thermal conductivity and gas-phase photoelectrocatalytic (GPEC) properties, onto the condenser component. The electrochemical treatment of the catalytic fin introduced a substantial number of oxygen vacancies, resulting in a significant increase in carrier concentration and mobility to the semi-metallic level.
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