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Publications

 

 

Velasco, L. F., Berezovska, I., Boutillara, Y., & Lodewyckx, P. (2017).

The use of organic vapour preadsorption to understand water adsorption on activated carbons. Microporous and Mesoporous Materials, 241, 21-27.

Abstract:
In this work, n-octane preadsorption coupled with water vapour sorption has been assessed as a useful technique for the advanced characterization of porous carbon materials. First, two microporous activated carbons with different oxygen contents were gradually preloaded with the n-alkane and then characterized by different adsorbates. As the micropore system is being filled, a narrowing of the hysteresis loop and a decrease in the slope of the water isotherms at low and medium relative pressures was observed. The latter result indicates that the available surface oxygen content gradually decreased with the blockage of the micropores, thus suggesting that the primary water adsorption centers of activated carbons are located in the narrow pores. Moreover, correlations between the available surface oxygen content and the micropore volumes measured by N2and CO2adsorption were found. Then, the microporous system of two activated carbons with a mainly mesoporous structure was nearly completely blocked. The surface chemistry of these two carbons was modified in order to have a deeper analysis of the role played by the surface oxygen groups on the water adsorption mechanism. The obtained results showed that the water sorption in the mesopores is highly dependent on the available surface oxygen content.


Zhu, M., Zhou, K., Sun, X., Zhao, Z., Tong, Z., & Zhao, Z. (2017).

Hydrophobic N-doped porous biocarbon from dopamine for high selective adsorption of p-Xylene under humid conditions. Chemical Engineering Journal, 317, 660-672.

Abstract:
N-doped hydrophobic microporous carbons (N-PCs) derived from dopamine were synthesized by using different methods. The effects of their graphitic C/N, basic N groups as well as oxygen content on the competitive and selective adsorption towards p-xylene were systematically studied in this work. The synthesized N-PCs possessed higher amount of sp2 C/N than some known activated carbons, enhancing their adsorption interaction towards weakly-polar p-xylene. Meanwhile, the pyrrolic/graphitic N groups and oxygen deficiency could also improve the water resistance of the N-PCs. Temperature programmed desorption (TPD) and inverse gas chromatography (IGC) results showed that the hydrogen-treated HN-PC surface had much higher special interaction towards weakly polar VOCs but lower interaction with H2O than other selected carbon materials with lower sp2 C, free-N and richer O content. Breakthrough experiment of p-xylene/water mixture depicted that the HN-PC samples maintained a very high working capacity of p-xylene (>5.1 mmol/g) at 80% relative humidity. This value was approximately 1–3 times greater than that of some activated carbon and MOF materials. Besides, its diffusion rate constant (kb) of p-xylene was also undisturbed by water molecules. Thus, it can be seen the novel porous N-PCs with high water-resistance can become a good candidate for VOCs pollution control under humid air.

Srinivasan, A., Joshi, S., Tang, Y., Wang, D., Currier, N., & Yezerets, A. (2017).

Development of a Kinetic Model to Evaluate Water Storage on Commercial Cu-Zeolite SCR Catalysts during Cold Start (No. 2017-01-0968). SAE Technical Paper.

Abstract:
Commercial Cu-Zeolite SCR catalyst can store and subsequently release significant amount of H2O. The process is accompanied by large heat effects. It is critical to model this phenomenon to design aftertreatment systems and to provide robust tuning strategies to meet cold start emissions and low temperature operation.

The complex reaction mechanism of water adsorption and desorption over a Cu-exchanged SAPO-34 catalyst at low temperature was studied through steady state and transient experiments. Steady state isotherms were generated using a gravimetric method and then utilized to predict water storage interactions with respect to feed concentration and catalyst temperature. Transient temperature programmed desorption (TPD) experiments provided the kinetic information required to develop a global kinetic model from the experimental data. The model captures fundamental characteristics of water adsorption and desorption accompanied by the heat effects. Steady state test cell and transient truck data were used as a part of the water storage model verification and validation. The kinetic model predicts water storage well, aiding in system evaluation of level control to understand its impact on cold start emissions.




M.P. Gómez-Tena, E. Sánchez, J. Gilabert, E. Zumaquero, C. Machí

Methodology for the Study of the Humidity Adsorption of Raw Materials and Ceramic Products.

Abstract:
There is an entire group of natural and synthetic materials that are used in different industrial settings for their water adsorbing properties. The fields of use are wide ranging and include waste disposal, additives in the food industry, irrigation control, the chemical industry, and medical applications.

Adsorbent or swellable minerals are also used in the ceramic industry as additives to provide the unfired product with greater mechanical strength during transport, before firing, without needing to increase the pressing pressure. In this case, it is important to study not only the humidity-adsorbing properties of the additives used, but also their desorption capacity, since this can influence the industrial drying process.

The present study was undertaken to fine-tune a new test method that would allow the water vapour adsorption isotherms of raw materials used in the ceramic industry, as well as in other industrial sectors, to be determined. The humidity determination was automatically performed, using gravimetry, in an environment with a controlled humidity of up to 90% relative humidity.



Connelly, A., Guy, S., Wainwright, D., Weileder, W., & Wilde, M. (2016).

Catalyst: reimagining sustainability with and through fine art, Ecology and Society, 21(4).

Abstract:
N-doped hydrophobic microporous carbons (N-PCs) derived from dopamine were synthesized by using different methods. The effects of their graphitic C/N, basic N groups as well as oxygen content on the competitive and selective adsorption towards p-xylene were systematically studied in this work. The synthesized N-PCs possessed higher amount of sp2 C/N than some known activated carbons, enhancing their adsorption interaction towards weakly-polar p-xylene. Meanwhile, the pyrrolic/graphitic N groups and oxygen deficiency could also improve the water resistance of the N-PCs. Temperature programmed desorption (TPD) and inverse gas chromatography (IGC) results showed that the hydrogen-treated HN-PC surface had much higher special interaction towards weakly polar VOCs but lower interaction with H2O than other selected carbon materials with lower sp2 C, free-N and richer O content. Breakthrough experiment of p-xylene/water mixture depicted that the HN-PC samples maintained a very high working capacity of p-xylene (>5.1 mmol/g) at 80% relative humidity. This value was approximately 1–3 times greater than that of some activated carbon and MOF materials. Besides, its diffusion rate constant (kb) of p-xylene was also undisturbed by water molecules. Thus, it can be seen the novel porous N-PCs with high water-resistance can become a good candidate for VOCs pollution control under humid air.



Shang, X., Si, C., Wu, J., Miao, Z., Zhang, Y., Wang, Y., ... & Hou, K. (2016).

Comparison of drying methods on physical and chemical properties of Shengli lignite
Drying Technology, 34(4), 454-461.

Abstract:
The physicochemical properties of Shengli lignite dewatered by three methods in hot air, microwave, and vacuum conditions were investigated. The effects of drying method on the coal pore structure, surface morphology, surface carbon-containing groups, and moisture readsorption performance of dewatered lignite were studied by the Brunauer-Emmett-Teller (BET) method, mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and dynamic water vapor sorption analysis (DVS). The results indicate that a large quantity of semi-open micropores and open-ended mesopores with a slit-like or cylinder shape exist in lignite. The specific surface area and total pore volume value of dewatered lignite decrease as follows: microwave-dried lignite (MD) > vacuum-dried lignite (VD) > hot air–dried lignite (HAD), which is consistent with MIP results. SEM images show that lignite dried by different methods is characterized by varied surface morphology. The XPS results reveal that VD has the highest content of C–C/C–H and the lowest content of C–O, and HAD has a higher content of C–O and a higher surface oxidation degree (α) than MD. In addition, the moisture readsorption capability of the dewatered lignite follows the sequence MD > VD > HAD.



Shang, X., Hou, K., Wu, J., Zhang, Y., Liu, J., & Qi, J. (2016).

The influence of mineral matter on moisture adsorption property of Shengli lignite.
Fuel, 182, 749-753.

Abstract:
A typical Chinese lignite was subjected to H2O, CH3COONH4/HCl and HCl/HF/HCl leaching procedures, to study the influence of water-soluble salts, alkali and alkaline earth metals (AAEMs) organically bound to the coal substance or occur as acid-decomposable minerals and discrete mineral matters on moisture adsorption property of lignite.

Variations of pore structure and chemical functional groups of coal samples during leaching procedures were determined by the nitrogen adsorption measurements and Fourier transform infrared spectroscopy (FTIR), respectively. Possible interactions between different types of minerals and moisture in lignite were also discussed. The results showed that the specific surface area and porosity of the coal treated by HCl/HF/HCl method increased significantly, while other leaching procedures had slight effect on coal pore structure. The FTIR spectrum of treated samples displayed similar bands of the organic part as those of raw coal. Water-soluble minerals in coal have adversely influence on the sorption behaviour of water molecules. The ionic cross-links forces and the hydration of ions, gradually disappeared with the removal of AAEMs result in the evident decrease of the capacity of moisture adsorption of lignite.

The increase of specific surface area and the concentrations of oxygen-containing functional groups by removing discrete mineral particles could cause the increased equilibrium adsorption moisture content (EMC). On the other hand, a poorer cohesive structure of adsorbing moisture resulted from the presence of discrete mineral matters, raw lignite revealed lower EMC.



Maarten G. Goesten, Jana Juan-Alcañiz, Enrique V. Ramos-Fernandez, K.B. Sai Sankar Gupta, Eli Stavitski, Herman van Bekkum, Jorge Gascon, Freek Kapteijn

Sulfation of metal–organic frameworks: Opportunities for acid catalysis and proton conductivity, Journal of Catalysis, Volume 281, Issue 1, 1 July 2011, Pages 177–187.

doi.org/10.1016/j.jcat.2011.04.015

Abstract:
A new post-functionalization method for metal–organic frameworks (MOFs) has been developed to introduce acidity for catalysis. Upon treatment with a mixture of triflic anhydride and sulfuric acid, chemically stable MOF structures MIL-101(Cr) and MIL-53(Al) can be sulfated, resulting in a Brønsted sulfoxy acid group attached to up to 50% of the aromatic terephthalate linkers of the structure. The sulfated samples have been extensively characterized by solid-state NMR, XANES, and FTIR spectroscopy. The functionalized acidic frameworks show catalytic activity similar to that of acidic polymers like Nafion® display in the esterification of n-butanol with acetic acid (TOF ∼ 1 min−1 @ 343 K). Water adsorbs strongly up to 4 molecules per sulfoxy acid group, and an additional 2 molecules are taken up at lower temperatures in the 1-D pore channels of S-MIL-53(Al). The high water content and Brønsted acidity provide the structure S-MIL-53(Al) a high proton conductivity up to moderate temperatures.



Bernd Wicklein, Margarita Darder, Pilar Aranda, and Eduardo Ruiz-Hitzky

Phospholipid–Sepiolite Biomimetic Interfaces for the Immobilization of Enzymes, ACS Applied Materials & Interfaces, 2011 3 (11), 4339-4348.

DOI: 10.1021/am201000k

Abstract:
Biomimetic interfaces based on phosphatidylcholine (PC) assembled to the natural silicate sepiolite were prepared for the stable immobilization of the urease and cholesterol oxidase enzymes. This is an important issue in practical advanced applications such as biocatalysis or biosensing. The supported lipid bilayer (BL-PC), prepared from PC adsorption, was used for immobilization of enzymes and the resulting biomimetic systems were compared to several other supported layers including a lipid monolayer (ML-PC), a mixed phosphatidylcholine/octyl-galactoside layer (PC-OGal), a cetyltrimethylammonium monolayer (CTA), and also to the bare sepiolite surface. Interfacial characteristics of these layers were investigated with a focus on layer packing density, hydrophilicity/hydrophobicity, and surface charge, which are being considered as key points for enzyme immobilization and stabilization of their biological activity. Cytoplasmic urease and membrane-bound cholesterol oxidase, which served as model enzymes, were immobilized on the different PC-based hybrid materials to probe their biomimetic character. Enzymatic activity was assessed by cyclic voltammetry and UV–vis spectrophotometry. The resulting enzyme/bio-organoclay hybrids were applied as active phase of a voltammetric urea biosensor and cholesterol bioreactor, respectively. Urease supported on sepiolite/BL-PC proved to maintain its enzymatic activity over several months while immobilized cholesterol oxidase demonstrated high reusability as biocatalyst. The results emphasize the good preservation of bioactivity due to the accommodation of the enzymatic system within the biomimetic lipid interface on sepiolite.


Goesten, M. G., Juan-Alcañiz, J., Ramos-Fernandez, E. V., Gupta, K. S. S., Stavitski, E., van Bekkum, H., ... & Kapteijn, F. (2011).

Sulfation of metal–organic frameworks: opportunities for acid catalysis and proton conductivity. Journal of Catalysis, 281(1), 177-187.

doi:10.1016/j.jcat.2011.04.015

Abstract:
new post-functionalization method for metal–organic frameworks (MOFs) has been developed to introduce acidity for catalysis. Upon treatment with a mixture of triflic anhydride and sulfuric acid, chemically stable MOF structures MIL-101(Cr) and MIL-53(Al) can be sulfated, resulting in a Brønsted sulfoxy acid group attached to up to 50% of the aromatic terephthalate linkers of the structure. The sulfated samples have been extensively characterized by solid-state NMR, XANES, and FTIR spectroscopy. The functionalized acidic frameworks show catalytic activity similar to that of acidic polymers like Nafion® display in the esterification of n-butanol with acetic acid (TOF ∼ 1 min−1 @ 343 K). Water adsorbs strongly up to 4 molecules per sulfoxy acid group, and an additional 2 molecules are taken up at lower temperatures in the 1-D pore channels of S-MIL-53(Al). The high water content and Brønsted acidity provide the structure S-MIL-53(Al) a high proton conductivity up to moderate temperatures.


Alcântara, A., Darder, M., Aranda, P., & Ruiz‐Hitzky, E. (2012).

Zein–fibrous clays biohybrid materials. European Journal of Inorganic Chemistry, 2012(32), 5216-5224.

doi.org/10.1002/ejic.201200582

Abstract:
The present work introduces a new type of biohybrid materials that is based on the combination of fibrous clays (sepiolite or palygorskite) with zein, a highly hydrophobic protein extracted from corn. C, H, N, and S chemical analyses, FTIR spectroscopy, 13C solid-state NMR spectroscopy, field-emission scanning electron microscopy (FESEM), thermal analysis, as well as dynamic vapor sorption were employed in the characterization of the resulting biohybrids to discern the type of interaction between the protein and the clay fibers and to evaluate the reduced hydrophilic character of the novel biohybrids in comparison to the pristine clays. With the aim of profiting from such a property, zein–fibrous clay biohybrids were tested as additives in the preparation of nanocomposites. For this purpose, alginate was chosen as a model polymer matrix, as it forms suitable self-supporting films and is a biocompatible and biodegradable material; but one of its main drawbacks for applications is its high hydrophilic character. In a similar way to conventional organoclays that are based on alkylammonium compounds, the zein–clay biohybrids reported here were effective in improving several features of the biopolymer matrix, mainly those related to mechanical and barrier properties. In addition, the nontoxic character of zein-based bioorganoclays is an advantageous feature that would allow the application of these new eco-friendly materials in the food-packaging sector.


Thommes, M., Mitchell, S., & Pérez-Ramírez, J. (2012).

Surface and pore structure assessment of hierarchical MFI zeolites by advanced water and argon sorption studies. The Journal of Physical Chemistry C, 116(35), 18816-18823.

doi.org/10.1021/jp3051214

Abstract:
Advanced physicochemical characterization of the pore structure of hierarchical zeolites, including the precise knowledge of pore size, interconnectivity, and surface properties, is crucial in order to interpret their superior performance in catalytic and adsorption applications. Postsynthetic mesopore formation by alkaline treatment of zeolites leads to simultaneous compositional changes due to the selective dissolution of silicon. By careful tuning of these effects through subsequent acid treatment, the Si/Al ratio can be restored to that of the parent zeolite. We evaluate the application of argon (87.3 K) and water (298.5 K) adsorption to assess the porous properties of mesoporous ZSM-5 zeolites with equivalent porosity, but differing composition. An accurate and combined micro/mesopore size analysis is obtained by applying NLDFT (nonlocal density functional theory) analysis on the argon isotherms. The argon adsorption data clearly reveal the two different relative pressure regions of micro- and mesopore filling of hierarchical zeolites. In contrast, the two filling regions overlap upon adsorption of water due to the hydrophobic nature of the ZSM-5 micropores and the much more hydrophilic nature of the mesopores. This indicates that water adsorption is sensitive to the Si/Al ratio, the distribution of aluminum species in the zeolite, and to the presence of polar groups on the mesopore surface. Thus, further insights into the surface and structural properties of the pores in hierarchical zeolites prepared by desilication can be gained. Based on our results, we put forward a hydrophilicity index capable of identifying differences in surface chemistry between distinct porous materials, and also between the micro- and mesopores present within hierarchically structured nanoporous materials.


Jing-hua, W. X. L. Z., Jiang, D. J. J. G. L., & Jian-ping, Y. (2012).

Synthesis and Water Vapor Adsorption Property of Meso-Porous Adsorbent SiO2-TiO2, Journal of South China University of Technology (Natural Science Edition), 9, 005.

Abstract:
First,the meso-porous adsorbent SiO2-TiO2 was synthesized via the sol-gel method.Next,its structure and morphology are characterized by using N2 adsorption and desorption isotherms and by means of TEM so as to reveal the influence of the titanium content in the titanium-doped silica gel on the silica gel structure.Then,the water vapor adsorption and regeneration properties of the adsorbent SiO2-TiO2 are investigated by using a dynamic water vapor sorption analyzer(DVSA),and the desorption activation energy of water molecules on absorbent was also estimated by a temperature programmed desorption(TPD) test.Finally,the Frenkel-Halsey-Hill(FHH) model is used to analyze the surface roughness and pore size distribution of the adsorbent.The experimental results show that,with the decrease of the titanium-to-silicon molar ratio,the specific surface area of the adsorbent increases with a narrower pore size distribution and a smaller average pore size,and the desorption activation energy of water molecules on absorbent decreases,and that,the adsorbent SiO2-TiO2 is of a lower regeneration temperature,and its water vapor adsorption capacity is greater than that of MCM-41 silica under a low relative humidity of less than 30%.


Moira A. Wilson, Andrea Hamilton, Ceren Ince, Margaret A. Carter, Christopher Hall

Rehydroxylation (RHX) dating of archaeological pottery, Proceedings of the Royal Society (A), Mathematical, Physical and Engineering Sciences, 27 September 2012.

doi.org/10.1098/rspa.2012.0109

Abstract:
We show that the rehydroxylation (RHX) method can be used to date archaeological pottery, and give the first RHX dates for three disparate items of excavated material. These are in agreement with independently assigned dates. We define precisely the mass components of the ceramic material before, during and after dehydroxylation. These include the masses of three types of water present in the sample: capillary water, weakly chemisorbed molecular water and chemically combined RHX water. We describe the main steps of the RHX dating process: sample preparation, drying, conditioning, reheating and measurement of RHX mass gain. We propose a statistical criterion for isolating the RHX component of the measured mass gain data after reheating and demonstrate how to calculate the RHX age. An effective lifetime temperature (ELT) is defined, and we show how this is related to the temperature history of a sample. The ELT is used to adjust the RHX rate constant obtained at the measurement temperature to the effective lifetime value used in the RHX age calculation. Our results suggest that RHX has the potential to be a reliable and technically straightforward method of dating archaeological pottery, thus filling a long-standing gap in dating methods.


Arana, I. (Ed.). (2012).

Physical properties of foods: novel measurement techniques and applications. CRC Press.

Chapter 13: Physical Properties of Cereal Products: Measurement Techniques and Applications.
In this chapter new methods to characterize cereals and their products are described in order to determine the effects of manufacturing processes and storage conditions on the thermal, mechanical, and structural properties of grains, cereal flours, and their products. The methods to determine physical properties in cereals have been classified in three different cases depending on raw matter state: before, during, and after production; and the current techniques in image analysis, light and electron microscopy, and NMR spectroscopy used to analyze the microstructure of cereal products. This chapter also discusses the methods used to optimize processing parameters and formulations to produce end products with desirable sensory and textural properties, the shelf life of cereal products, and the relationships between the sensory and physical characteristics of cereal foods.


Klank, D., & Lohmeier, S. J. (2012).

Untersuchungen zur Porenbildung von Feststoffen. Chemie Ingenieur Technik, 84(3), 373-381.

doi.org/10.1002/cite.201100181

Abstract:
This article presents a comprehensive overview on the formation and investigation of porous systems and surface area characteristics of micro-, mesoporous zeolitic materials based on aluminum phosphate materials, microporous carbons, building materials in terms of cement stone and natural soil samples. The results of the gas sorption experiments performed on the different materials will be discussed in detail, especially when sorption phenomena like kinetic restricted diffusion, sorption hysteresis and materials where the pore system is undergoing a structural deformation with time can be observed.


Ruiz-García, C., Pérez-Carvajal, J., Berenguer-Murcia, A., Darder, M., Aranda, P., Cazorla-Amorós, D., & Ruiz-Hitzky, E. (2013).

Clay-supported graphene materials: application to hydrogen storage. Physical Chemistry Chemical Physics, 15(42), 18635-18641.

doi.org/10.1039/C3CP53258E

Abstract:
The present work refers to clay-graphene nanomaterials prepared by a green way using sucrose (caramel) and two types of natural clays (montmorillonite and sepiolite) as precursors, with the aim to evaluate their potential use in hydrogen storage . The impregnation of the clay substrates by caramel in aqueous media followed by a thermal treatment in absence of oxygen of these clay-caramel intermediates gives rise to graphene-like materials, which remain strongly bound to the silicate support. The nature of the resulting materials was characterized by different techniques such as XRD, Raman spectroscopy and TEM, as well as by adsorption isotherms of N2, CO2 and H2O. These carbon-clay nanocomposites can act as adsorbents for hydrogen storage, achieving, at 298 K and 20 MPa, over 0.1 wt % of hydrogen adsorption excess related to the total mass of the system and a maximum value close to 0.4 wt % of hydrogen specifically related to the carbon mass. The very high isosteric heat for hydrogen sorption determined from adsorption isotherms at different temperatures (14.5 kJ/mol) fits well with the theoretical values available for hydrogen storage on materials which show a strong stabilization of the H2 molecule upon adsorption.


Thommes, M., Morell, J., Cychosz, K. A., & Fröba, M. (2013).

Combining nitrogen, argon, and water adsorption for advanced characterization of ordered mesoporous carbons (CMKs) and periodic mesoporous organosilicas (PMOs). Langmuir, 29(48), 14893-14902.

doi.org/10.1021/la402832b

Abstract:
Ordered mesoporous CMK carbons and periodic mesoporous organosilica (PMO) materials have been characterized by combining nitrogen (77.4 K) and argon (87.3 K) adsorption with recently developed quenched solid density functional theory (QSDFT). Systematic, high-resolution water adsorption experiments have been performed in the temperature range from 298 to 318 K in order to ascertain the effect of surface chemistry (using periodic mesoporous organosilicas (PMOs) of given pore size) and pore size/pore geometry (using CMK-3, CMK-8 carbons) on the adsorption, pore filling, condensation and hysteresis behavior. These data reveal how the interplay between confined geometry effects and the strength of the adsorption forces influence the adsorption, wetting, and phase behavior of pore fluids. Further, our results indicate that water adsorption is quite sensitive to both small changes in pore structure and surface chemistry, showing the potential of water adsorption as a powerful complementary tool for the characterization of nanoporous solids.


Propst, C. W., & Meadows, M. W. (2013).

U.S. Patent Application No. 14/397,011.

Abstract:
The present invention relates to microspheres and compositions comprising a plurality of microspheres, wherein the microspheres are perfectly spherical and have a moisture content less than 1%, and the method of manufacturing the same. The present invention is useful in the manufacture of sustained and modified release active pharmaceutical ingredient (API) microspheres, as a free flowing excipient for mini-tablets and in the manufacture of API dispersions.


David, P. O. L. Y. A. (2014).

Des (bio) nano-composites utilisés dans le traitement d'eaux contaminées par de l'arsenic/gentamicine ou pour des applications médicales (Doctoral dissertation, UNIVERSITÉ DE GRENOBLE).

Abstract:
Bionanocomposites represent an emerging group of nano-structured hybrid materials. They are formed by the combination of natural polymers and inorganic solids and show at least one dimension on the nanometer scale. These hybrid materials retain the structural and functional properties of nano-structured materials. Meanwhile, the presence of biopolymer can reduce the public health and environmental risks of nano-sized materials. Properties inherent to the biopolymers, notably, biocompatibility and biodegradability, open new prospects for these hybrid materials particularly in regenerative medicine and in environmental engineering (Darder et al., 2007). Fabrication of large-sized bionanocomposites, rather than nano-sized particles, can prevent possible harmful nanoparticle (NP) intake by humans and other living things. Synergistic assembling of biopolymers with inorganic nano-sized solids leads to multifunctional bionanocomposites which can be synthesized and applied in several areas for designed purposes.


Tazibet, S., Lodewyckx, P., & Boucheffa, Y. (2014).

The influence of the cooling down step in the heat treatment on the stability of activated carbons hydrophobicity. Adsorption, 20(4), 545-553.

doi.org/10.1007/s10450-013-9599-z

Abstract:
Two samples of an activated carbon are heat treated at 500 °C for 2 h under a flow of inert gas. The only difference between the treatments of the two carbons is the cooling down step. After these treatments, the two carbons were hydrophobic and presented similar adsorption properties and an identical behavior toward water and cyclohexane uptakes. After being stored in ambient conditions for 20 months, the stability of oxygen functional groups is studied. The quantification of various oxygen groups is done by Boehm’s titration and by thermogravimetry–mass spectroscopy analysis. It is found that the creation of oxygen groups, especially carboxylic acids, which are very attractive to water molecules, depends on the cooling down step. This is confirmed by both water isotherms and cyclohexane breakthrough measurements. Cyclohexane breakthrough times show that one of the heat treated carbons does not preserve its hydrophobic character compared to the other carbon, which presents a breakthrough time value close to that obtained before the storage.



Alcântara, A. C., Darder, M., Aranda, P., Tateyama, S., Okajima, M. K., Kaneko, T., ... & Ruiz-Hitzky, E. (2014)

The Clay-bionanocomposites with sacran megamolecules for the selective uptake of neodymium. Journal of Materials Chemistry A, 2(5), 1391-1399.

http://dx.doi.org/10.1039/C3TA14145D

Abstract:
Sacran, an anionic megamolecular polysaccharide extracted from the cyanobacterium Aphanothece sacrum, is an interesting biopolymer for developing functional clay-based bionanocomposites due to its colloidal and metal complexing properties. This work introduces novel bionanocomposites based on the assembly of sacran to sepiolite, a fibrous hydrated magnesium silicate, reporting some of their special features. Sacran–sepiolite films show tensile moduli about twice that of neat sacran films, and improved resistance and integrity in aqueous solutions. These materials can act as adsorbents of lanthanide ions, profiting from the well-known adsorption properties of sepiolite and the ability of sacran to complex rare earth and heavy metal ions. Sacran–sepiolite materials show a clear preference for Nd3+ ions over Ce3+, Eu3+ and Gd3+, and the results confirm the influence of the conformation of sacran chains in crystalline domains on the adsorption properties. In fact, only those materials prepared from concentrated sacran solutions, with the polysaccharide chains arranged as liquid crystals, and involving around 27% (w/w) of sepiolite showed a remarkable synergistic effect on the retention of Nd3+ ions, being promising as biosorbents for the effective and selective recovery of neodymium from aqueous media.



Zhao, G., Zhao, Z., Wu, J., & Ye, D. (2014).

Synthesis of hydrophobic mesoporous material MFS and its adsorption properties of water vapor. Journal of Spectroscopy, 2014.

doi.org/10.1155/2014/965037

Abstract:
Fluorine-containing hydrophobic mesoporous material (MFS) with high surface area is successfully synthesized with hydrothermal synthesis method by using a perfluorinated surfactant SURFLON S-386 template. The adsorption properties of water vapor on the synthesized MFS are also investigated by using gravimetric method. Results show that SEM image of the MFS depicted roundish morphology with the average crystal size of 1-2 μm. The BET surface area and total pore volume of the MFS are 865.4 m2g−1and 0.74 cm3g−1with a narrow pore size distribution at 4.9 nm. The amount of water vapor on the MFS is about 0.41 mmol g−1 at 303 K, which is only 52.6% and 55.4% of MCM-41 and SBA-15 under the similar conditions, separately. The isosteric adsorption heat of water on the MFS is gradually about 27.0–19.8 kJ mol−1, which decreases as the absorbed water vapor amount increases. The value is much smaller than that on MCM-41 and SBA-15. Therefore, the MFS shows more hydrophobic surface properties than the MCM-41 and SBA-15. It may be a kind of good candidate for adsorption of large molecule and catalyst carrier with high moisture resistance.


Zhao, Z., Wang, S., Yang, Y., Li, X., Li, J., & Li, Z. (2015).

Competitive adsorption and selectivity of benzene and water vapor on the microporous metal organic frameworks (HKUST-1). Chemical Engineering Journal, 259, 79-89.

doi.org/10.1016/j.cej.2014.08.012

Abstract:
Competitive adsorption and selectivity of benzene and water vapor were studied on the microporous metal organic frameworks (HKUST-1). The adsorption equilibrium and kinetics of pure component as well as binary mixtures of benzene and water vapor were systematically investigated on the HKUST-1. Their binary adsorption selectivity and permeation selectivity are predicted via the IAST method. Results showed that the equilibrium data of benzene and water vapor depicted the Langmuir–Freundlich and Dual Site Langmuir–Freundlich (DSLF) type adsorption isotherms, respectively. Benzene exhibited much higher isosteric heat and desorption activation energy than water vapor, indicating a stronger interaction with the HKUST-1. The adsorption selectivity of benzene/water on the HKUST-1 was of about ∼8.32 at 318 K and 1.0 mbar, and its diffusivity selectivity was about 17.6 at 298 K and 1.5 mbar, respectively. Breakthrough curves of benzene showed a remaining capacity of about 94.7% and 72.9% in the presence of 13 and 34 RH%. Thus, the HKUST-1 is more selective or preferential adsorption for benzene molecules in comparison to water molecules at high temperature and low pressure. Also, it shows the advantage of kinetic separation for VOCs and water vapor.


Moinester, M., Piasetzky, E., & Braverman, M. (2015).

RHX Dating of Archeological Ceramics Via a New Method to Determine Effective Lifetime Temperature. Journal of the American Ceramic Society, 98(3), 913-919.

doi.org/10.1111/jace.13343

Abstract:
Determining the absolute chronology of ceramic artifacts has significant implications for archeological and historical research. Wilson, Hall et al. recently suggested a new technique for direct absolute dating of archeological ceramics based on a moisture-induced chemical reaction, called rehydroxylation (RHX) dating. RHX dating proceeds by measuring the mass of chemically combined water in the ceramics in the form of OH hydroxyls, and the mass gain rate at the Effective Lifetime Temperature (ELT) that the ceramics experienced over its lifetime. To date, ELT determinations have been based on estimates of the ceramic's lifetime temperature history; taking into account weather and climate data and the depth at which the artifact was found. The uncertainty in determining the ELT can be a major component of the overall dating uncertainty. Here, we propose an alternative method which relies minimally on weather and climate data, and provides more precise determinations of the ELT and the ceramic age. The proposed method (SAS: Same Age Samples) involves a minimum of four measurements of the RHX mass gain rate constant for two ceramic samples of the same age at two temperatures. We show via simulations that the proposed SAS method can determine the ELT with a precision of 0.2 K which is comparable to the best ELT determination based on lifetime temperature history, and also comparable to available microbalance temperature resolutions of around 0.1 K. The corresponding percent age error is then 1.4%, or 43 yr for a 3000-yr-old ceramic. The proposed SAS method should be tested with ceramic samples of different ages, whose ELT are well-known.


Fried, D. I., Bednarski, D., Dreifke, M., Brieler, F. J., Thommes, M., & Fröba, M. (2015).

Influence of the hydrophilic–hydrophobic contrast of porous surfaces on the enzymatic performance. Journal of Materials Chemistry B,3(11), 2341-2349.

doi.org/10.1039/C4TB01700E

Abstract:
Herein we report the dependency of the performance (uptake, activity, stability) of hydrophilic glucose-6-phosphate dehydrogenase (G6PDH) onto mesoporous cellular foams (MCF) grafted with aminosilanes of different chain length. The resulting hydrophobic–hydrophilic contrast was carefully evaluated by combined argon and water sorption and quantified with a newly developed hydrophilicity index suitable for the characterization of large-pore materials. The enzymatic behaviour was influenced by electrostatic and hydrophobic interactions between both reaction partners due to the creation of specific microenvironments inside the pore system. The microenvironment created by the materials with high hydrophobicity did not contribute to the beneficial electrostatic interactions of the charged amine groups by increased hydrophobic forces instead a competition of both forces was present. Thus an improved biocatalytic performance was not observed for materials with high hydrophobicity but short-chain functionalized MCFs led to highly stable and active biocatalysts.


Fried, D. I., Bednarski, D., Dreifke, M., Brieler, F. J., Thommes, M., & Fröba, M. (2015).

Influence of the hydrophilic–hydrophobic contrast of porous surfaces on the enzymatic performance. Journal of Materials Chemistry B,3(11), 2341-2349.

doi.org/10.1016/j.applthermaleng.2015.03.040

Abstract:
A novel composite (MIL-101@GO) of MIL-101 (Cr) and graphite oxide (GO) with high water vapor capacity for adsorption heat pumps (AHPs) was developed in this work. A series of composites MIL-101@GO with varied GO loading were synthesized using a hydrothermal method, and characterized by N<sup>2 </sup>adsorption test, SEM, XRD, thermal gravimetric analysis. The adsorption isotherms and kinetics of water vapor over the composites were determined by gravimetric method. Regeneration performance of the composites was evaluated in multiple adsorption–desorption cycles. Results showed that MIL-101@GO possessed a super-high adsorption capacity for water vapor up to 1.58 g/g, which was attributed to its ultrahigh Langmuir specific surface area (5188 m2/g) and pore volume (1.78 cm3/g). The isosteric heat of water vapor adsorption on MIL-101@GO was calculated to be in the range of 44–56 kJ/mol, slightly higher than that on MIL-101 (44–53 kJ/mol). Diffusion coefficients of water vapor over MIL-101@GO composites were ranged from 0.133 × 10−10 to 4.485 × 10−10 cm2/s at 298–313 K. Additionally, six consecutive adsorption–desorption cycles suggesting that the synthesized MIL-101@GO had excellent reversibility and stability for water vapor adsorption. These superior water vapor adsorption/desorption performances make MIL-101@GO a promising candidate as the water vapor adsorbent for AHPs process.


Veverka, M., Dubaj, T., Gallovič, J., Jorík, V., Veverková, E., Danihelová, M., & Šimon, P. (2015).

Cocrystals of quercetin: synthesis, characterization, and screening of biological activity. Monatshefte für Chemie-Chemical Monthly, 146(1), 99-109.

doi.org/10.1007/s00706-014-1314-6

Abstract:
Cocrystallization of quercetin with 22 cocrystal formers, i.e. phenolic acids, proline, urea, N-acetylcytosine, carnitine, dacarbazine, diflunisal, kojic acid, lactamide, baclofen, pyrazole, edaravone, salicylamide, O-acetylsalicylamide, 2-imidazolidinone, allopurinol, dipyridamole, 5-sulfosalicylic acid, and 4-sulfobenzoic acid resulted in cocrystals with various stoichiometric ratios. The cocrystals were characterized by FT-IR, DSC, and XRPD. Some of them were non-hygroscopic and stable to thermal stress. The cocrystals quercetin:pyrazole (1:1), quercetin:imidazolidinone (1:1), and quercetin:baclofen (1:2) were found to be stable at various relative humidity conditions at 20–40 °C for up to 3 months. The in vitro antioxidant activity, cytotoxicity, and serine protease inhibitory activity were tested. The best inhibitory activity to pathophysiological proteases was observed for cocrystals with N-acetylcytosine, carnitine, and kojic acid; these cocrystals were the most potent inhibitors of thrombin. About two times better cytotoxic activity to human cervical cancer cells (HeLa) and human colon cancer cells (Caco-2) in comparison with quercetin itself was observed for quercetin:kojic acid (2:1).


Martinelli, F., Frascio, D., Di Cuia, M., Balducci, A. G., Colombo, P., Buttini, F., & Bettini, R. (2015, August).

Solid-state characterization of tobramycin powders for inhalation. In JOURNAL OF AEROSOL MEDICINE AND PULMONARY DRUG DELIVERY (Vol. 28, No. 4, pp. A10-A10). 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA: MARY ANN LIEBERT, INC.

http://ddl-conference.com/files/DDL24Abstracts/34.Martinelli.pdf

Abstract:
Parenteral delivery is commonly used to treat acute lung infection as in the case of cystic fibrosis, pneumonia and chronic obstructive pulmonary disease (COPD). To overcome poor antibiotic distribution to the lung, high doses (10 mg/kg) are required, especially for aminoglycosides. The administration of antibiotics to the respiratory tract of patients with lung infections is a well-established therapeutic approach for the stabilization and restoration of lung function. Thus, the administration of aminoglycosides by inhalation is an attractive route since allows reducing side effects like ototoxicity and nephrotoxicity. Dry powder inhaler formulations incorporate a powder containing the drug as micronsized particles (aerodynamic diameter less then ‹5 μm) that, upon inhalation are aerosolised from the device to deposit in the respiratory tract. Dry powder inhalers have many advantages over liquid formulation, including relatively high dose delivery, better physico-chemical stability, no need of patient coordination and absence of propellant. When dry powders are considered, the solid state characteristic of the active ingredient, i.e. polymorphism, represents an issue that should be addressed because it may affect the quality and the performance of a drug product. Indeed, drug stability and respirability are critical quality attributes which need to be evaluated during pharmaceutical development and kept constant during clinical studies and marketing. Powders may have different polymorphic phases and this topic is crucial during pharmaceutical development. The aim of this work was to investigate the solid state properties of a spray-dried powder intended for pulmonary delivery in comparison with different tobramycin raw materials.



Terra, M. T. (2016).

Cinética de secagem dos frutos de macaúba (acrocomia aculeata).

http://hdl.handle.net/123456789/400

Abstract:
Na busca de novas alternativas para a substituição de combustíveis fósseis não renováveis e poluentes por combustíveis renováveis menos poluentes, entra o cultivo de oleaginosas na produção de óleo vegetal para a obtenção do biodiesel, como é o caso do fruto da macaúba que possui alta produtividade em óleo. Para melhor aproveitamento dos processos industriais, a secagem é uma eficiente maneira de estabilizar a atividade aquosa do fruto, mantendo suas características químicas e físicas adequadas. Nesse contexto, objetivou-se com o presente trabalho realizar a secagem em camada delgada dos frutos de macaúba, acompanhar os processos obtidos durante a secagem, definir o melhor modelo matemático que se ajusta aos dados e estimar os valores de coeficiente de difusão efetiva e calcular a energia de ativação. Foram realizadas duas repetições, sob temperaturas do ar de secagem de 40, 50, 60, 70 e 80°C, e velocidade do ar de secagem de 0,4 e 2,0 m s-1. Os frutos de macaúba foram coletados próximo a região de Dourados-MS, local de execução do trabalho. Inicialmente, os frutos continham, em média, 42,85% de b.s., os tratamentos foram realizados até os frutos alcançarem valor menor ou igual a 11,1% b.s. Concluiu-se que a elevação da temperatura e da velocidade do ar de secagem gerou redução do tempo necessário, para a retirada de água dos frutos de macaúba. Os modelos matemáticos que apresentaram melhores ajustes aos dados experimentais foram Page, Dois termos, Midilli, Exponencial de dois termos, Logarítmica e Thompson.O coeficiente de difusão efetiva aumentou com a elevação das temperaturas para o mesmo fluxo de ar de secagem.


Velasco, L. F., Guillet-Nicolas, R., Dobos, G., Thommes, M., & Lodewyckx, P. (2016).

Towards a better understanding of water adsorption hysteresis in activated carbons by scanning isotherms. Carbon, 96, 753-758.

doi.org/10.1016/j.carbon.2015.10.017

Abstract:
The occurrence of water sorption hysteresis associated with the filling of micro and narrow mesopores (particularly for pores of widths smaller than ca. 3 nm, where nitrogen and argon isotherms at their boiling temperatures, i.e. 77 K and 87 K, respectively, are known to be reversible) provides additional opportunities for textural characterization. In this work systematic water scanning desorption isotherms within the hysteresis loop were carried out on well-characterized activated carbons with varied textural features and surface chemistry. Accurate micro-mesopore analysis was obtained by means of nitrogen, argon and carbon dioxide adsorption experiments coupled with advanced density functional theory methods (i.e., NLDFT, QSDFT). The obtained results indicated that water adsorption/desorption phenomena for pores of different sizes take place independently from each other. This investigation constitutes a starting point for the interpretation of water adsorption hysteresis by means of scanning desorption measurements.


Velasco, L. F., Snoeck, D., Mignon, A., Misseeuw, L., Ania, C. O., Van Vlierberghe, S., ... & Lodewyckx, P. (2016).

Role of the surface chemistry of the adsorbent on the initialization step of the water sorption process. Carbon,106, 284-288.

doi.org/10.1016/j.carbon.2016.05.042

Abstract:
In this work, an equation for the prediction of the low pressure region of the water adsorption isotherms of activated carbons, based on their amount of surface groups, has been further developed in order to account for porous carbonaceous materials with an oxygen-rich surface chemistry. To attain this goal, highly hydrophilic carbon materials were selected and their surface chemistry was modified by several techniques (mainly thermal and plasma treatments) in order to obtain a series of samples with a surface oxygen content up to 45 wt%. Then, their water sorption isotherms were measured and the amount of surface groups obtained by fitting them by the proposed equation was compared with the one resulting from direct X-ray photoelectron spectroscopy (XPS) measurements. Based on the obtained results, it seems that beyond a certain concentration of surface oxygen, there is a change in the sorption mechanism (from clustering to layering) and consequently, on the size of the water cluster formed before the micropore filling. These findings have allowed us to go a step further in the modelling of this part of the water sorption isotherms and to find a correlation between the surface oxygen content and the water cluster size.


Wan, K., He, Q., Miao, Z., Liu, X., & Huang, S. (2016).

Water desorption isotherms and net isosteric heat of desorption on lignite. Fuel, 171, 101-107.

doi.org/10.1016/j.fuel.2015.12.054

Abstract:
Water vapor desorption isotherm studies were performed on lignite at the temperature 30, 40 and 50 °C to investigate the behavior of water on coal. For a description of desorption process, a Guggenheim–Anderson–de-Boer (GAB) model provided a good fit. At the monolayer region, the overlapping isotherms at different temperatures could not provide valid data to calculate the isosteric heat by applying the Clausius–Clapeyron equation, and hence the isosteric heat was only determined at the moisture content from 0.125 to 0.280 mg/mg dry coal. Then, the Brunner–Emmet–Teller (BET) theory was applied to calculate the isosteric heat at the moisture content below 0.125 mg/mg dry coal. Net isosteric heat of desorption determined from the isotherms increases from 1.88 kJ/mol in the capillary water to 8.17 kJ/mol at the monolayer region. This increase is most likely that the forces from coal surface act on all types of water in raw lignite, and as the moisture content decreases, the forces are becoming stronger. Besides, with the effect of the interaction among adsorbed water molecules and the bonding force between water molecules and active sites, at the monolayer region, a maximum energy peak appears on the curve of isosteric heat.


Hoyos-Leyva, J. D., Agama-Acevedo, E., Bello-Perez, L. A., Vernon-Carter, E. J., & Alvarez-Ramirez, J. (2016).

Assessing the structural stability of gluten-free snacks with different dietary fiber contents from adsorption isotherms. LWT-Food Science and Technology, 73, 576-583.

doi.org/10.1016/j.lwt.2016.06.042

Abstract:
Gluten-free snacks (GFS) with high dietary fiber and relatively low-fat contents were made by combining unripe plantain:chickpea:maize flours in the following proportions 50:30:0; 10:60:30; and 33:33:34, respectively. The adsorption isotherms built from equilibrium moisture content data of the snacks exposed to water activity (aw = 0.10–0.90) at different temperatures (20, 25, 30, 35, 40, or 45 °C) environments, using a dynamic vapor sorption analyzer, were compared to those of a commercial snack control with high-fat content (33.85 g/100 g). All the snacks reached equilibrium moisture content within 5 h for most values of aw, and the experimental data were fitted with the Guggenheim-Anderson-de Boer model. The monolayer moisture content and the critical water activity (linked to glassy-to-rubbery phase transitions) of the GFS were significantly lower than that of the commercial snack, indicative that GFS underwent structural weakening under humidity stress. Also, the GFS showed a crossover in the isosteric heat of adsorption (estimated with Clausius-Clayperon equation) at approx. 11% relative moisture content that could be related to the formation of complex multilayered structures. The differences in the adsorption characteristics between GFS and commercial snack can be attributed to the chemical composition, mainly to the fat content.


Fikry, M., & Al-Awaadh, A. M.

Characteristics of Dynamics Sorption Isotherms of Date Flesh Powder Rich in Fiber. International Journal of Food Engineering.

doi.org/10.1515/ijfe-2015-0223

Abstract:
Dynamic vapor sorption equipment (AQUADVS) was used to determine adsorption and desorption isotherms for powder rich in fiber (PRF) produced from Palm Date flesh of Sifri cultivar (Phoenix dactylifera L.) at temperatures 25, 35 and 45 °C in a wide range of water activity (0.09–0.87). Equilibrium was achieved within 29 and 25 h for the adsorption and desorption process respectively. The obtained data were fitted to ten models (Peleg, GAB, BET, Halsey, Oswin, Smith, Modified Henderson, Adam and Shove, Modified Oswin and Modified Halsey). The results indicated that the PRF followed type III behavior. The empirical Peleg model was found to be the best to represent the experimental data in the water activity range 0.09–0.87. The isosteric heat of sorption and the differential entropy decreased by increasing the moisture content and can be predicted by polynomial functions. Glass transition temperatures (Tg) of PRF were determined. The Tg decreased as the moisture content increased and can be correlated using the Gordon and Taylor model (R2 = 0.976). The PRF should be stored at moisture less than 9 d.b.% and temperature less than 35 °C.


Bui, D. T., Nida, A., Ng, K. C., & Chua, K. J. (2016).

Water vapor permeation and dehumidification performance of poly (vinyl alcohol)/lithium chloride composite membranes. Journal of Membrane Science, 498, 254-262.

http://dx.doi.org/10.1016/j.memsci.2015.10.021

Abstract:
Thin and robust composite membranes comprising stainless steel scaffold, fine and porous TiO2 and polyvinyl alcohol/lithium chloride were fabricated and studied for air dehumidification application. Higher hydrophilicity, sorption and permeation were observed for membranes with increased lithium chloride content up to 50%. The permeation and sorption properties of the membranes were investigated under different temperatures. The results provided a deeper insight into the membrane water vapor permeation process. It was specifically noted that lithium chloride significantly reduces water diffusion energy barrier, resulting in the change of permeation energy from positive to negative values. Higher water vapor permeance was observed for the membrane with higher LiCl content at lower temperature. The isothermal air dehumidification tests show that the membrane is suitable for dehumidifying air in high humid condition. Additionally, results also indicate a trade-off between the humidity ratio drop with the water vapor removal rate when varying air flowrate.


Della Bella, A., Müller, M., Soldati, L., Elviri, L., & Bettini, R. (2016).

Quantitative determination of micronization-induced changes in the solid state of lactose. International journal of pharmaceutics, 505(1), 383-393.

doi.org/10.1016/j.ijpharm.2016.04.015

Abstract:
Lactose, in particular α-lactose monohydrate, is the most used carrier for inhalation. Its surface and solid-state properties play a key role in determining Dry Powder Inhalers (DPIs) performance. Techniques such as X-Ray Powder Diffraction (XRPD) and Differential Scanning Calorimetry (DSC), which are commonly used for the characterization of lactose, are not always capable of explaining the solid-state changes induced by processing, such as micronization. In the present work, the evaluation of the effect of the micronization process on the solid-state properties of lactose was carried out by XRPD and DSC and a satisfactory, although not unequivocal, interpretation of the thermal behaviour of lactose was obtained. Thus, a new gravimetric method correlating in a quantitative manner the weight change in specific sections of the Dynamic Vapour Sorption (DVS) profile and the amount of different forms of α-lactose (hygroscopic anhydrous, stable anhydrous and amorphous) simultaneously present in a given sample was developed and validated. The method is very simple and provides acceptable accuracy in phase quantitation (LOD = 1.6, 2.4 and 2.7%, LOQ = 5.4, 8.0 and 8.9% for hygroscopic anhydrous, stable anhydrous and amorphous α-lactose, respectively). The application of this method to a sample of micronized lactose led to results in agreement with those obtained by DSC and evidenced that hygroscopic anhydrous α-lactose, rather than amorphous lactose, can be generated in the micronization process. The proposed method may find a more general application for the quantification of polymorphs of compounds different than lactose, provided that the various solid phases afford different weight variations in specific regions of the DVS profile.


He, Q., Huang, S., Wan, K., Xu, H., & Miao, Z. (2016).

A comparison of desorption process of Chinese and Australian lignites by dynamic vapour sorption. Separation Science and Technology, 51(8), 1307-1316.

doi.org/10.1080/01496395.2016.1158192

Abstract:
Modified BET model and Do and Do (D.D.) model were chosen to interpret the desorption process of water on hard and soft lignites. The organic and inorganic hydrophilic sites were determined by X-ray photoelectron spectroscopy and X-Ray fluorescence spectroscopy. From the modified BET model, only a small part of hydrophilic sites (HSs) acted as effective primary sites due to space restraint, intramolecular hydrogen bond and maybe more than one hydrophilic site connecting with one water molecule. From the D.D. model, the total adsorption sites (St) of Loy Yang lignite (LY) is 18.7 mmol/g, which is higher than that of Shengli (SL) 17.0 mmol/g in spite of lower primary sites, and the saturation concentration of water (qus) in the micropore of LY is 33.7 mmol/g, which is much higher than that of SL (12.5 mmol/g). So the high moisture-holding capacity of LY is mainly determined by the high St and qus, and not the primary sites. The size of water clusters entering the micropores is 7 for SL and 6 for LY, which is related to relative location of HS. When dewatered, the higher total sites density and smaller water cluster size of LY both implied higher dewatering energy.


Veverka, M., Murányi, A., Bakoš, D., Kochan, J., Jorík, V., & Omastová, M. (2016).

Arabinogalactan: β-glucan as novel biodegradable carriers for recombinant human thrombin. Journal of Biomaterials Science, Polymer Edition, 27(3), 202-217.

doi.org/10.1080/09205063.2015.1116886

Abstract:
The aim of this work was to evaluate the effects of incorporating thrombin in arabinogalactan (AG)/β-glucan (BG)-based carriers. The products were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy techniques. Results, especially deconvoluted XRPD patterns indicated creation of new phases and potential complex formation. Results also highlighted that the AG carrier leads to higher residual thrombin-specific activity, while the in vivo haemostatic effect was enhanced when insoluble BG was present in the matrix. Our results confirm that thrombin can be successfully added to the carriers and that these materials are promising alternatives to standard vehicles.


Vaishali, L. (2016).

Formulation Studies of Extended Release Matrix Tablet of Some Antiviral Drugs.

http://hdl.handle.net/10603/72672

Abstract:
Antiviral drug are commonly prescribed for the treatment of Acquired Immunodeficiency Syndrome (AIDS), one of .the most serious disease states worldwide. The antiviral drugs selected for this study are Zidovudine and Nevirapine. They have a short elimination half-life, necessitating multiple doses per day and therefore the development of extended release dosage forms incorporating these drugs was considered beneficial in terms of extending the dosing interval, with the aim of improving patient compliance and subsequent therapeutic outcomes. Formulation approach was to have a composition qualitatively similar to that of the innovator by using different grades of release controlling polymer i.e. Hydroxyl propyl methyl cellulose (HPMC) for extended release matrix tablets. For the solid state characterization of both APIs, different tests were performed like FTIR optical microscopy, powder X-ray diffractometry (XRD), differentials scanning calorimetric (DSC), dynamic vapor absorption (DVS). Stress stability data was also generated. API and excipient compatibility was conducted at different ratios using moist and dry conditions. Samples were kept at 50oC and 40oC/75 % RH and evaluated for impurities For the Nevirapine ER tablets, QbD based approach was implemented. Initial composition was arrived with different design trials by changing the concentration of HPMC polymer ratio and also grades of HPMC. Wet granulation technique was used for both drugs. Formulation showing desired dissolution profile was finalized and complete characterization like description, identification, assay, content uniformity, and dissolution was done. For the Zidovudine ER tablets, in vivo studies were carried out which show drug release for 20 hrs.


Gustavsson, C., & Piculell, L. (2016).

Isotherms and Kinetics of Water Vapor Sorption/Desorption for Surface Films of Polyion-Surfactant Ion Complex Salts. The Journal of Physical Chemistry B.

doi.org/10.1021/acs.jpcb.6b02983

Abstract:
Thin films of “complex salts” (CS = ionic surfactants with polymeric counterions) have recently been shown to respond to humidity changes in ambient air by changing their liquid crystalline structure. We here report isotherms and kinetics of water sorption/desorption for ∼10–100 μm films of alkyltrimethylammonium polyacrylate CS, measured in a dynamic gravimetric vapor sorption instrument over a 0–95% relative humidity (RH) range. The sorption per ion pair was similar to that observed for common ionomers. A kinetic model for the water exchange is presented, assuming that the “external” transport between the vapor reservoir and the film surface is rate-determining. The model predicts that the water content, after a small stepwise change of the reservoir RH, should vary exponentially with time, with a time constant proportional to both the slope of the sorption isotherm and the film thickness. These predictions were confirmed for our films over large RH ranges, and the external mass transfer coefficient in our setup was calculated from the experimental data. Expressions derived for the Biot number (ratio of characteristic times for internal and external water transport) for the considered limiting case strongly indicate that external water transport should quite generally affect, or even dominate, the measured kinetics for similarly thin hydrated films.