Water sorption desorption

In the first stage, unfixed dyes, salt and alkali present in the liquor phase must be removed and this is best done by replacing this liquor with fresh water. Sorption, desorption and diffusion processes play only subordinate roles in this stage, the key factors being liquor flow, mechanical action and liquor exchange. The dilution laws are generally applicable. 

The most fundamental manner of demonstrating the relationship between sorbed water vapor and a solid is the water sorption-desorption isotherm. The water sorption-desorption isotherm describes the relationship between the equilibrium amount of water vapor sorbed to a solid (usually expressed as amount per unit mass or per unit surface area of solid) and the thermodynamic quantity, water activity (aw), at constant temperature and pressure. At equilibrium the chemical potential of water sorbed to the solid must equal the chemical potential of water in the vapor phase. Water activity in the vapor phase is related to chemical potential by... 

Generation of water sorption/desorption isotherms in a controlled relative humidity environment can be carried out either gravimetrically or volumetrically. Gravimetric methods require... 

Tagami, H., Kanamaru, Y., Inoue, K. et al. Water sorption-desorption test of the skin in vivo for functional assessment of the stratum corneum. J. Invest. Dermatol. 78, 425-428 (1982). 

It is known that the origin of starch controls the amylose-to-amylopectin ratio, the granule size, and other properties. The role of the origin of starch on water sorption-desorption (Tables XIV and XV) and related... 

Water sorption-desorption isotherms can be carried out by using thermobalances. Now specific instruments allow to measure water sorption-desorption isotherms at different constant temperatures (e.g., dynamic vapor sorption instrument (DVS), Surface Measurement Systems Ltd., Monarch Beach, US). 

Hogan SE, Buckton G. Water sorption/desorption—near IR and calorimetric study of crystalline and amorphous raffinose. Int J Pharm 2001 227 57-69. 

The dynamic moisture adsorption isotherm is another useful tool, exemplified by the water sorption/desorption of DMP 728 zwitterion as shown in Figure 16. DSC may not be helpful unless the technique is modified by punching a tiny hole in the pneumatic sample cap, from which the moisture or solvent may escape with a narrow thermal peak. Another method is to place the sample in silicon oil on the sample pan. The thermal effect of solvent boiling out is observed in the thermograph. 

Pineri, M., G. Gebel, R. J. Davies, and O. Diat. 2007. Water sorption-desorption in Nafion membranes at low temperature, probed by micro X-ray diffraction. /. Power Sources 172 587-596. 

SantoveaA, Piero MJ, Uabres M (2010) Comparison between DSC tmd TMDSC in the investigation into frozen aqueous cryoprotectants solutions. Drag Dev Ind Pharm 36 1413-1421 Saxena A, Jean YC, Suryanarayanan R (2013) Annealing effect reversal by water sorption-desorption and heating above the glass transition temperature—comparison of properties. Mol Pharm 10 3005-3012... 

Further evidence of interfacial transport limitations were provided by Satterfield and Benziger who measmed water sorption/desorption rates from H -Nafion films 52-630 pm thick [34]. Dimensional analysis of water sorption/desorption rates as functions of a scaled time variable demonstrated that the rates of both sorption and... 

Majsztrik PW et al (2007) Water sorption, desorption and transport in Nafion membranes. J Memb Sci 301 93-106... 

Rueda RD, Varkalis A (1995) Water sorption/desorption kinetics in poly(ethylene naphthalene-2,6-dicarboxylate) and poly(ethylene terephthalate). J Polym Sci Part B Polym Phys 33 2263-2268... 

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