Adsorptive Properties of Biobased Adsorbents

Czepirski, L.; Komorowska-Czepirska, E.; Szymońska, Joanna

doi:10.1007/s10450-005-6019-z

Cited by 14 publications

(9 citation statements)

References 12 publications

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“…With the exception of PVP, all of the powders showed s-shaped adsorption isotherms indicating type II isotherms. This type of isotherm has also been reported in the literature for these powders (8,9,14,(25)(26)(27). PVP showed a type III isotherm with the moisture content increasing very rapidly at high air humidities; Oksanen and Zografi (6) also reported a type III isotherm for PVP.…”

Section: Discussionsupporting

confidence: 76%

The Effect of Moisture on the Flowability of Pharmaceutical Excipients

2013

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Abstract. The effect of moisture content on flowability of six pharmaceutical powders (microcrystalline cellulose (MCC), hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP), corn starch, and potato starch) was investigated. Powder flowability was measured using established static techniques and emerging dynamic avalanche behavior measurements. Static techniques did not provide enough resolution to clearly identify changes in flowability due to increasing powder moisture content. Avalanche time and its standard deviation showed that flowability of MCC, CMC, PVP, and potato starch decreased after a critical moisture content, flowability of corn starch increased and flowability did not significantly change for HPMC. The moisture decreased flowability by forming stronger interparticle liquid bridges and increased flowability by acting as a lubricant. The dynamic density of the celluloses and PVP decreased linearly with increasing moisture content as the particles swelled with water. The starches also swelled and decreased in dynamic density, but only after a moisture content corresponding to monolayer coverage of water around the particles was reached. As flowability and dynamic density change with moisture content, to ensure consistent production of high-quality tablets, the moisture content of the powders must be measured and controlled.

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Section: Discussionsupporting

confidence: 76%

The Effect of Moisture on the Flowability of Pharmaceutical Excipients

2013

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“…The plots of isosteric water vapor sorption enthalpy on studied products plotted according to Eqs. (13) and (14) and using the values of parameters collected in Table 3 (all data generated for T ¼ 298 K). WATER VAPOR SORPTION ISOTHERMS 989 Eqs.…”

Section: Water Vapor Sorptionmentioning

confidence: 99%

“…Different models and equations have been proposed for this purpose. [9][10][11][12][13][14][15][16] The major aim of this study is to perform the detailed analysis of this proposed recently by Blahovec and Yanniotis (called the BY equation). [16] Finally we also propose a simpler method of isotherms classification.…”

Section: Introductionmentioning

confidence: 99%

Some Remarks on the Classification of Water Vapor Sorption Isotherms and Blahovec and Yanniotis Isotherm Equation

2011

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Mathematical analysis was performed on equations describing water vapor sorption isotherms. It was shown that an identity exists between the Blahovec and Yanniotis (BY), D'Arcy and Watt (DW), and generalized D'Arcy and Watt (GDW) models. The original BY model has been modified to account for temperature dependence of the model parameters. This modification enables the application of this model to describe sorption data obtained at different temperatures. A new method for classification of sorption isotherms has been proposed that is much simpler than the classification established by Blahovec and Yanniotis.

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“…Adsorption isotherms are essential in optimising the engineering design of dyeing processes . Advantages and disadvantages of various adsorption models are presented in the literature, where many thermodynamic parameters such as affinity and enthalpy can be evaluated from such adsorption isotherms . Various models such as Nernst, Langmuir, Freundlich, Scatchard, BET(modified by Brunauer, Emmett and Teller) and Tempkin have been suggested in order to best correlate the experimental results to one such adsorption isotherm for a particular dyeing system.…”

Section: Introductionmentioning

confidence: 99%

A novel utilisation of principal component analysis to optimise sorption isotherms and determine diffusion coefficients of five naphthalimide disperse dyes on polyester fibres

et al. 2013

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Experimental data was gathered from more than 700 dyeings of polyester fibres with five naphthalimide disperse dyes. The dyeing process which was the same for all the dyes was carried out separately at five different temperatures, namely: 40°, 60°, 80°, 100° and 120° centigrade. Dye sorption was measured at 10 min time intervals at each temperature until the completion of the dyeing process. Additionally, the raw data was modified by the principal components analysis (PCA) in order to extract the highly informative part of the raw data (i.e. principal components). Such modified data was correlated with the six main sorption models. The results illustrate that unmodified raw data fit a dual combination of sorption models of the Nernst–Freundlich or Nernst–Scatchard type. However, the novel utilisation of PCA‐modified data illustrate that a linear Nernst type sorption model is appropriate, making it less dependent on dye structure and aggregation. The validity of this approach was confirmed by sensitivity analysis, affinity calculations and diffusivity determination. Furthermore, a novel ‘To To’ numerical method worked extremely well in determining diffusion coefficients based on the Hill's approximate solution.

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Adsorptive Properties of Biobased Adsorbents

Cited by 14 publications

References 12 publications

The Effect of Moisture on the Flowability of Pharmaceutical Excipients

The Effect of Moisture on the Flowability of Pharmaceutical Excipients

Some Remarks on the Classification of Water Vapor Sorption Isotherms and Blahovec and Yanniotis Isotherm Equation

A novel utilisation of principal component analysis to optimise sorption isotherms and determine diffusion coefficients of five naphthalimide disperse dyes on polyester fibres

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