Measurement of Latent Heat of Tetra-n-Butyl Ammonium Bromide Hydrate and Specific Enthalpy of Its Slurry

2015 ◽  
Vol 23 (03) ◽  
pp. 1550025 ◽  
Author(s):  
Hiroyuki Kumano ◽  
Tatsunori Asaoka ◽  
Tatsuya Hayashi ◽  
Peng Zhang
Keyword(s):  
Aqueous Solution ◽  
Phase Equilibrium ◽  
Specific Heat ◽  
Latent Heat ◽  
Specific Enthalpy ◽  
Ammonium Bromide ◽  
Equilibrium Conditions ◽  
Hydrate Form ◽  
Latent Heats ◽  
Storage Characteristics

The specific heat of a tetra-n-butyl ammonium bromide (TBAB) aqueous solution, the latent heat of a TBAB hydrate, and the specific enthalpy of a TBAB hydrate slurry were measured to understand the thermal storage characteristics of TBAB hydrate slurry. A solution sample and the hydrate slurry were heated, the change in temperature was measured, and the specific heat of the TBAB aqueous solution and the specific enthalpy of the hydrate slurry were obtained from the change in temperature. Two types of TBAB hydrate form. Therefore, the hydrates were separated from the hydrate slurry formed from TBAB aqueous solution having several initial concentrations. The hydrate crystals were placed into solution, and the latent heats were obtained from the temperature change of the solution. The specific enthalpy of the hydrate slurry was estimated from the latent heats of the hydrate crystals and the specific heat of the solution under phase equilibrium conditions, and the measured and estimated values were compared.

Using of modified-bentonite as low-cost sorbent for removal of methylene blue dye from aqueous solution

2020 ◽  
Vol 27 (2) ◽  
pp. 45-54
Author(s):  
Saraa Muwafaq Ibrahim ◽  
Ziad T. Abd Ali
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Silanol Group ◽  
Infrared Spectrometry ◽  
Blue Dye ◽  
Ammonium Bromide ◽  
Vibration Band ◽  
Order Kinetic ◽  
Methylene Blue Dye ◽  
Modified Bentonite

Batch experiments have been studied to remove methylene blue dye (MB) from aqueous solution using modified bentonite. The modified bentonite was synthesized by replacing exchangeable calcium cations in natural bentonite with cationic surfactant cetyl trimethyl ammonium bromide (CTAB). The characteristics of modified bentonite were studied using different analysis such as Scanning electronic microscopy (SEM), Fourier transform infrared spectrometry (FTIR) and surface area. Where SEM shows the natural bentonite has a porous structure, a rough and uneven appearance with scattered and different block structure sizes, while the modified bentonite surface morphology was smooth and supplemented by a limited number of holes. On other hand, (FTIR) analysis that proved NH group aliphatic and aromatic group of MB and silanol group are responsible for the sorption of contaminate. The organic matter peaks at 2848 and 2930 cm-1 in the spectra of modified bentonite which are sharper than those of the natural bentonite were assigned to the CH2 scissor vibration band and the symmetrical CH3 stretching absorption band, respectively, also the 2930 cm-1 peak is assigned to CH stretching band. The batch study was provided the maximum removal efficiency (99.99 % MB) with a sorption capacity of 129.87 mg/g at specified conditions (100 mg/L, 25℃, pH 11 and 250rpm). The sorption isotherm data fitted well with the Freundlich isotherm model. The kinetic studies were revealed that the sorption follows a pseudo-second-order kinetic model which indicates chemisorption between sorbent and sorbate molecules.

scholarly journals The Thermal Properties of Sea Ice

1963 ◽  
Vol 4 (36) ◽  
pp. 789-807 ◽  
Author(s):  
Peter Schwerdtfecer
Keyword(s):  
Thermal Conductivity ◽  
Sea Ice ◽  
Physical Properties ◽  
Specific Heat ◽  
Energy Content ◽  
Air Bubbles ◽  
Solid Mixture ◽  
Latent Heats ◽  
Complex Substance ◽  
Ice Model

Abstract Compared with freshwater ice, whose physical properties are well known, sea ice is a relatively complex substance whose transition to a completely solid mixture of pure ice and solid salts is completed only at extremely low temperatures rarely encountered in nature. The physical properties of sea ice are thus strongly dependent on salinity, temperature and time. Many of these properties are still not fully understood or accurately known, particularly those important for the understanding of a natural ice cover. The specific heat for example is an important term in the calculation of the heat energy content of a cover. However, Malmgren (1927), whose calculated values of the specific heat of sea ice are in general use, neglected the direct contribution of the brine present in inclusions. Re-examination of the question of specific and latent heats of sea ice has led to distinguishing between the freezing and melting points and enabled significant observations in this range. Similarly, because the thermal conductivity is a necessary parameter in the description of the thermal behaviour of ice. the sea-ice model suggested by Anderson (1958) has been modified and extended in the present work to the case of saline ice containing air bubbles. This enabled the completion of calculations of density and conductivity. In order to illustrate the theoretically calculated values. measurements were made on sea-ice samples to determine the specific heat, density and thermal conductivity.

scholarly journals Consideration of Latent Heat of Fusion of Ice in Aqueous Solution

Netsu Bussei ◽  
2008 ◽  
Vol 22 (1) ◽  
pp. 18-24
Author(s):  
Tatsunori ASAOKA ◽  
Hiroyuki KUMANO ◽  
Akio SAITO ◽  
Seiji OKAWA
Keyword(s):  
Aqueous Solution ◽  
Latent Heat ◽  
Heat Of Fusion ◽  
Latent Heat Of Fusion
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