Sorption desorption hysteresis

Talbert and Fletchall (1965) found that increasing temperature resulted in decreased sorption of simazine and atrazine. Similarly, Santana-Casiano and Gonzalez-Davila (1992) found that the sorption of lindane to chitin decreased as temperature increased from 5 to 45°C. In addition, sorption-desorption hysteresis, observed at lower temperatures, was reduced dramatically at the highest temperature. However, Chiou et al. (1979) observed decreased aqueous solubility and increased sorption at higher temperature for 1,1,1-trichloroethane. 

FIG. 1.—Water-vapor sorption-desorption hysteresis for maize starch at 40°C (from Ref. 19). 

This chapter details the findings of the sorption/desorption hysteresis and desorption kinetic studies and how the results of these environmental chemodynamic studies impacted remediation of the PPI sites. The literature on the topic is presented below.. In the next section, we present some of the results of our research on sorption/desorption hysteresis and desorption kinetics for freshly contaminated soils as well as aged soils. The experimental protocols are published elsewhere [6-10]. 

Miller, C. T., and J. A. Pedit. 1992. Use of reactive surface-diffusion model to describe apparent sorption-desorption hysteresis and abiotic degradation of lindane in subsurface material. Environ. Sci. Technol. 26 1417-1427. 

Water-vapor sorption/desorption hysteresis in concentrated food polymer systems. 

Indeed, as Tnmg et al. [297] reported. X-ray diffraction analysis imam-biguously confirms the expansion of MNLL-53(A1, Cr) that accompanies absorption of normal alkanes into its interior. The breathing also manifests itself on the sorption isotherm as an unusual stepwise increase in the MOF capacity at rather low relative pressures. The same type of stepwise sorption isotherm for carbon dioxide at 196 K and clear-cut sorption—desorption hysteresis was also observed [298] for a flexible MOF formed by zinc carboxylate units joined by l,4-diazobicyclo[2,2,2]octyl groups in one direction and by 2-amino-1,4-benzenedicarboxylates in the other direction. The amino functions of the MOF were then converted into amide by modification with alkyl anhydrides of various lengths. Short alkyl chains thus introduced narrow the pores and the longer chains hold the pores... 

Several other aspects of organophosphorus insecticide sorption require further study. Although sorption-desorption hysteresis (20), aging and bound residue formation (30) have been noted, the molecular mechanisms responsible for these phenomena have not been elucidated. The kinetics of organophosphorus insecticide release from soil particles including the effects of biosurfactants (31) have not been extensively investigated, nor have the effects of formulation ingredients on sorption processes (32). 

The swelling in liquid water could be a nonrelevant value to describe the membrane behavior in fuel cells. As an example, the sulfonated polyether ketones suffer from an excessive water uptake when immersed in hquid water at elevated temperatures [110], while a high-temperature fuel eeU test over 1400 h has been performed with fully hydrated gases [2]. Therefore, the swelling in hquid water at elevated temperature is of limited value. Most of the authors prefer nowadays to determine the water uptake under defined temperature and RH conditions. Water sorption isotherms have been measured and analyzed [40,104,119]. These results confirmed the previous data since the sorption isotherms are superimposable when expressed in 2 values for different ion contents and chemical structures [40,48,49,56]. The sorption isotherms were classically analyzed as the superposition of different phenomena (Henry, clustering, dual-mode, Flory-Huggins, and BET II processes) [119]. The water sorption isotherms exhibit a distinct sorption-desorption hysteresis, which was attributed to the very low desorption process [40]. 

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