Binary Sorbents Research Articles

Thermodynamics of Sorption of Organic Compounds by Sorbents Based on Supramolecular Liquid Crystal HPFAB and β-Cyclodextrin Derivatives under Gas Chromatography Conditions

Using gas chromatography, we studied the influence of the nature of substituents in the β-cyclodextrin (CD) molecule on the sorption properties and the possibility of complex formation with the macrocycle of 26 organic compounds (hydrocarbons and alcohols) in binary sorbents based on the smectic–nematic supramolecular liquid crystal 4-(3-hydroxypropyloxy)-4'-formylazobenzene (HPOFAB) and four derivatives β-CD. It has been established that the nature of the substituents in the β-CD molecule significantly affects the manifestation of solvation interactions between LC and macrocyclic additive and, as a consequence, the mesomorphic, sorption, and selective properties of the studied composite sorbents.

ОСОБЕННОСТИ АДСОРБЦИИ ХЛОРИДА КАЛЬЦИЯ БИНАРНЫМИ СОРБЕНТАМИ НА ОСНОВЕ ОКСИДОВ ЖЕЛЕЗА, ХРОМА, НИКЕЛЯ И ЦИРКОНИЯ

Comparative studies of the sorption of CaCl2 by Fe2O3, NiO, Cr2O3 and ZrO2, as well as binary sorbents obtained from mixed oxides at a molar ratio of 1 : 1 were carried out. The formation of new active centers on the surface of binary sorbents was shown by using the method of mathematical modeling. Those active centers are not the mechanical sum of the active centers of individual oxides that are part of binary ones. The greatest increase in the sorption properties of binary sorbents compared with the additive sum of individual oxides is observed at relatively low concentrations of CaCl2 less than 3 g/dm3.

Binary mineral sulfides sorbent with wide temperature range for rapid elemental mercury uptake from coal combustion flue gas

ABSTRACT Developing efficient sorbents with rapid kinetics is the main challenge encountered for Hg0 capture from coal combustion flue gas in a sorbent injection scenario. Binary mineral sulfide-based materials combining copper sulfide (CuS) and zinc sulfide (ZnS) to exert their capabilities for Hg0 capture at the low- and high-temperature was for the first time reported for Hg0 removal to realize a wide temperature range sorbents. When the molar ratio between CuS and ZnS was 10%, the as-synthesized 10Cu-Zn nanocomposite exhibited excellent Hg0 uptake rate at 150°C that could degrade 40 μg/m3 of Hg0 to undetectable level at the end of a 60-s experiment with the dosage of only 1 mg. This Hg0 uptake rate is folds higher compared to that when bare CuS or ZnS was adopted alone at this specific temperature. The typical flue gas atmospheres had negligible effect on Hg0 removal over 10Cu-Zn in a short contact time, which further suggests that the binary sorbents were proper to be injected before the electrostatic precipitator system. Moreover, it is found that, by adjusting the ratio between CuS and ZnS, it is potential to develop binary sorbent suiting any temperature conditions that may achieve an exceedingly high Hg0 capture performance. Thus, this work not only justified the candidature of 10Cu-Zn as a promising alternative to traditional activated carbon for Hg0 capture from coal combustion flue gas but also guided the future development of multi-component mineral sulfide-based sorbents for Hg0 pollution remediation from various industrial flue gases.

Characterizing Preferential Adsorption of Phosphate on Binary Sorbents of Goethite and Maghaemite using in situ ATR-FTIR and 2D Correlation Spectroscopy

Recent developments in analytics using infrared spectroscopy have enabled us to identify the adsorption mechanism at interfaces, but such methods are applicable only for simple systems. In this study, the preferential adsorption of phosphate on binary goethite and maghaemite was investigated. As a result, monodentate and bidentate complexes were the major complexes on goethite and maghaemite, respectively. A shrinking effect in goethite and a swelling effect in maghaemite were identified, and environmental perturbations caused a significant decrease in the integrated absorbance of phosphate complexes on maghaemite, while no effect was observed on goethite, which implies that different adsorption mechanisms were involved. Based on the results, a bridging complex was proposed, and the swelling effect is explained by the negatively charged maghaemite surface resulting from the bidentate complex. The isolation of phosphate by the shrinking effect explains the low phosphate bioavailability in the soil environment, while the colloidal properties of the bidentate complex on maghaemite are the reason for colloidal mobilization. To the best of our knowledge, this study not only addresses the shrinking and swelling properties of iron (hydr)oxide nanoparticles but also demonstrates preferential adsorption on binary sorbents using in situ ATR-FTIR for the first time.

New Sorbents for Metal Salts based on Cation Exchange Extractants and Anion Exchange Resins: Their Preparation and Properties

Preparation and properties of binary sorbents containing a salt of cation exchange organic extractant in the matrix of a strongly basic anion exchanger were studied. Analysis of isotherms of exchange of chloride ions for dialkyldithiophosphate ions in the systems of various anion exchangers led to the conclusion that the stability of the binary sorbents depends on the amount of free water in the sorbent matrix. To improve the stability, it was proposed to use low cross-linked anion exchange resins or to use cation exchange extractants of moderate molecular volume. On the example of anion exchanger ММ-22x6.5 in the dibutyldithiophosphate form, it was shown that the binary sorbents efficiently recover chlorides of non-ferrous metals. The recovery increases in the series Ca2+<<Ni2+<Zn2+<<Cu2+. Because, in the systems studied, the anions are recovered together with cations, this leads to an increase in metal recovery in the presence of salting-out agents, and allows the desorbtion of the salts with water or with solutions of complexing agents. The binary sorbents offer good prospects for the recovery and separation of metal salts.

Thermodynamics of Sorption in the Binary Liquid Crystalline System Composed of the Poly(propyleneimine) Dendrimer and p-n-Pentyloxy-p′-cyanobyphenyl by Inverse Gas Chromatography

A binary system composed of the liquid crystalline poly(propyleneimine) dendrimer and nematic p-n-pentyloxy-p'-cyanobyphenyl has been studied by thermomicroscopy, scanning calorimetry, and inverse gas chromatography. In this system, there is the columnar phase being stable within broad ranges of temperature and component ratio. Dependences of the retention volumes of various solutes, namely, hydrocarbons, alcohols, and amines, on composition of the sorbents are revealed to exhibit the maximum. Thermodynamic functions of sorption of n-alkanes and n-alcohols on the binary sorbents composed of the said liquid crystals have been calculated specifically. Thermodynamic solute-sorbent compatibility characterized by the activity coefficients of the solutes is dependent on the sorbent composition; namely, it is controlled by counterbalancing of the enthalpy or entropy factors. The nonadditive mode of the solute-sorbent interaction is explained by arising of the microdomain nematic structure enclosed in the columnar structure of the dendrimer.

Sorption of 2,4-Dichlorophenoxyacetic Acid by Model Particles Simulating Naturally Occurring Soil Colloids

Binary and ternary model particles containing montmorillonite, ferrihydrite, and humic acid (HA) were used to determine the changes in the sorption behavior of the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid) upon the interassociation of these three major soil constituents. On single sorbents, 2,4-D sorption was high with S-type isotherms on ferrihydrite, moderate with L-type isotherms on HA, and zero on montmorillonite. In binary sorbents, ferrihydrite and humic acid coatings on montmorillonite provided sorption sites for 2,4-D, although the exclusion of the anionic form from highly charged clay surfaces partially obscured the role of Fe and HA as sorbents of 2,4-D. Sorption of 2,4-D on ferrihydrite-HA binary particles was not very different from that on pure ferrihydrite because most of the ferrihydrite surface area was from micropores being not accessible to large humic macromolecules and hence remained available for herbicide sorption. In ternary sorbents HA coatings reduced the sorption of 2,4-D ...

ChemInform Abstract: Enhancement of Sulfation of CaO by Fe2O3 in the Oxidative‐Sorption Process for SO2 Removal Using Fe2O3/CaO Binary Sorbents.

ChemInformVolume 19, Issue 30 Other Subjects ChemInform Abstract: Enhancement of Sulfation of CaO by Fe2O3 in the Oxidative-Sorption Process for SO2 Removal Using Fe2O3/CaO Binary Sorbents. Y. DAIRAKU, Y. DAIRAKU Dep. Ind. Chem., Fac. Eng., Chiba Univ., Chiba 260Search for more papers by this authorS. SATO, S. SATO Dep. Ind. Chem., Fac. Eng., Chiba Univ., Chiba 260Search for more papers by this authorT. SODESAWA, T. SODESAWA Dep. Ind. Chem., Fac. Eng., Chiba Univ., Chiba 260Search for more papers by this authorF. NOZAKI, F. NOZAKI Dep. Ind. Chem., Fac. Eng., Chiba Univ., Chiba 260Search for more papers by this author Y. DAIRAKU, Y. DAIRAKU Dep. Ind. Chem., Fac. Eng., Chiba Univ., Chiba 260Search for more papers by this authorS. SATO, S. SATO Dep. Ind. Chem., Fac. Eng., Chiba Univ., Chiba 260Search for more papers by this authorT. SODESAWA, T. SODESAWA Dep. Ind. Chem., Fac. Eng., Chiba Univ., Chiba 260Search for more papers by this authorF. NOZAKI, F. NOZAKI Dep. Ind. Chem., Fac. Eng., Chiba Univ., Chiba 260Search for more papers by this author First published: July 26, 1988 https://doi.org/10.1002/chin.198830339Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume19, Issue30July 26, 1988 RelatedInformation

Enhancement of Sulfation of CaO by Fe2O3 in the Oxidative-Sorption Process for SO2 Removal Using Fe2O3/CaO Binary Sorbents

Abstract For the oxidative sorption of SO2 using Fe2O3/CaO binary sorbents prepared by the usual impregnation method, reactivities and capacities for SO2 removal have been investigated with TG measurements at temperatures near 500 °C in a stream of air containing SO2 in concentration from 2 to 11%. Both the reactivities and the capacities of the sorbents were exceedingly enhanced by addition of Fe2O3 into CaO such small amounts as 0.1–0.8wt%, and further Fe2O3-loading over 1.0wt% resulted in a lowering in promoting effects. The changes in surface area and pore-size distribution with a variation of Fe2O3 content were also measured in order to discuss the correlation between chemical reactivity for SO2 removal and physical property of the Fe2O3/CaO sorbents. In addition, Fe2O3–CaO mechanically mixed sorbents and the other binary sorbents such as Fe2O3/MgO or V2O5/CaO were tested to compare with the Fe2O3/CaO sorbents.