ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymerization and dechlorination of chloroethenes on copper(II)-smectite via radical-cation intermediatesMax M. Mortland and Stephen A. BoydCite this: Environ. Sci. Technol. 1989, 23, 2, 223–227Publication Date (Print):February 1, 1989Publication History Published online1 May 2002Published inissue 1 February 1989https://pubs.acs.org/doi/10.1021/es00179a015https://doi.org/10.1021/es00179a015research-articleACS PublicationsRequest reuse permissionsArticle Views102Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The adsorption of aromatic compounds by smectite exchanged with tetramethylammonium (TMA) has been studied. Aromatic compounds adsorbed by TMA–smectite are assumed to adopt a tilted orientation in a face-to-face arrangment with the TMA tetrahedra. The sorptive characteristics of TMA–smectite were influenced strongly by the presence of water. The dry TMA–smectite showed little selectivity in the uptake of benzen, toluene and xylene. In the presence of water, TMA–smectite showed a high degree of selectivity based on molecular size/shape, resulting in high uptake of benzene and progressively lower uptake of larger aromatic molecules. This selectivity appeared to result from the shrinkage of interlamellar cavities by water.

Low organic matter clays, soils and aquifer materials have very little sorptive capability for common groundwater contaminants. Here we use organic cations of the form [(CH3)3NR]+ to displace naturally occurring exchange ions resulting in significantly higher organic matter contents, and greatly enhanced sorptive properties for nonionic organic solutes. The organic phase derived from exchanged hexadecyltrimethylammonium, where R is a C-16 hydrocarbon, behaved as a powerful partitioning medium that was 10 to 30 times more effective on a unit weight basis than natural soil organic matter for removing benzene, dichlorobenzene and perchloroethene from water. This simple soil modification might be used to improve the retardation capabilities of low organic matter soils and aquifer materials, and to enhance the containment capabilities of clay landfill liners and bentonite slurry walls.

AbstractWhen hexadedyltrimethylammonium (HDTMA) ion is exchanged for metal cations like calcium in smectite, the sorptive properties of the clay are greatly modified. The resultant HDTMA‐smectite complex behaves as a dual sorbent, in the sorption of organic compounds, in which the mineral fraction functions as a solid adsorbent and the organic (HDTMA) phase as a partition medium. Capacities of mineral adsorption and partition uptake by HDTMA in the HDTMA‐smectites are illustrated by sorption of benzene, trichloroethene (TCE), and water as vapors on the dry sample and by sorption of benzene and TCE from water. The exchanged HDTMA in clay is found to be a much more powerful partition medium than ordinary soil organic matter in the uptake of benzene and TCE. Based on this finding, HDTMA‐smectite appears to be an effective sorbent for removing organic contaminants from water. It is suggested that such sorptive organo‐clay complexes could be used to enhance the containment capabilities of clay landfill liners and bentonite slurry walls.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSingle electron transfer mechanism of oxidative dechlorination of 4-chloroanisole on copper(II)-smectiteNarayanan. Govindaraj, Max M. Mortland, and Stephen A. BoydCite this: Environ. Sci. Technol. 1987, 21, 11, 1119–1123Publication Date (Print):November 1, 1987Publication History Published online1 May 2002Published inissue 1 November 1987https://doi.org/10.1021/es00164a014RIGHTS & PERMISSIONSArticle Views322Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (662 KB) Get e-Alerts Get e-Alerts

Smectite-organic complexes may adsorb enzymes by hydrophobic bonding mechanisms. The complexes are prepared by saturating the exchange capacity of smectite clay with organic cations; in this study hexa-decyltrimethylammonium+ trimethylphenylammonium+, hexadecylpyridinium+ and [Fe(bipyridyl)3]2+ cations were used. The immobilized enzyme may or may not be active depending upon the nature of the organic species comprising the smectite-organic complex and the nature of the enzyme. Loading capacities of the smectite-organic complexes for urease varied greatly (from 1 to 40 mg urease per 100 mg adsorbent). Enzymes immobilized on these surfaces were less thermally stable than when in homogeneous solution. Differences in thermal stability were also found between the matrices. The immobilized enzymes were much more easily acted upon by the hydrolytic enzyme, pronase, unless the pronase itself is inactive on the matrix. It is suggested that similar organo-clay-enzyme complexes may be useful as models for enzymes in natural systems, and for industrial and medical applications.

Decontamination of hazardous wastes containing dioxins (dibenzo-p-dioxin and its chlorinated analogues) remains a serious problem and new approaches for the degradation or alteration of dioxins are needed. We describe here dibenzo-p-dioxin radical cation formation and polymerization on a simple clay mineral (Cu(II)-smectite) in mild reaction conditions. Existence of the radical species was conclusively demonstrated using electron spin resonance (ESR), ultraviolet-visible, and infrared spectroscopy. The radical cation polymerized to form dimers and trimers as revealed by mass spectroscopy. Radical cations of 1- and 2-chlorodibenzo-p-dioxin were also formed on Cu(II)-smectite. The radical cations are formed by electron transfer from the dioxins to Cu(II). The formation of dioxin radicals may provide the basis for new detoxification methods in which the reactive radical species is coupled to other molecules or degraded by subsequent reactions.

Adsorption isotherms and UV-visible and Mössbauer spectroscopic data point to specific interactions between flavomononucleotide (FMN) and Fe3+-smectite. The maximum amount of FMN adsorption was 0.3 mmole/g of Fe3+-smectite giving a 1:1 molar proportion of Fe3+ and FMN. The results suggest a Fe3+-FMN complex residing at the smectite surface. Other homoionic smectites (Cu2+, Zn2+, and Ca2+) exhibited lower levels of adsorption and less apparent specific interaction.

Glutamic acid is selectively deaminated by a combination of pyridoxal phosphate (PLP) and Cu2+-smectite, a swelling phyllosilicate. In addition to ammonia as a product, α-ketoglutaric acid was formed. The reaction was much more active with Cu2+-smectite than when the Cu2+ was present as a dissolved salt. Cu2+-kaolinite, vermiculite, and faujasites X and Y were also active but at a considerably lower rate, suggesting their activity may be restricted to external surfaces, while that of the smectites involves intracrystal catalysis. An activation energy of ca. 14 kcal mol−1 was found for the reaction. As the catalyst concentration is doubled, the reaction velocity is doubled up to the point where the rate becomes dependent upon the substrate concentration. When a strong ligand (o-phenanthroline) was added to the reaction the reaction velocity decreased, strongly suggesting that coordination of the reacting species with Cu2+ on the silicate surface is required. The reaction pathway is suggested to be the formation of a Schiff base between the amino acid and pyridoxal phosphate, followed by complexation with Cu2+ at the mineral surface. At this point the complex is hydrolyzed to NH3 and the α-keto acid, or transamination occurs to form pyridoxamine phosphate which is then deaminated by the Cu2+-smectite. The pyridoxal phosphate-Cu2+-smectite acts like a pseudo-enzyme wherein the silicate structure substitutes for the apoenzyme.

The reactions of the tris(acetylacetonato)silicone(IV) cation (Si(acac)3+) with Na+-, Mg2+-, and Co2+-exchange forms of hectorite and montmorillonite have been investigated to understand better the formation process of clays pillared by silicic acid. In acetone as the solvating medium, Si(acac)3+ binds to the Na+- and Mg2+-clays with the desorption of only a small fraction (~5%) of the initial exchange cation, suggesting that the complex binds as the ion pair [Si(acac)3+][Cl−]. With the Co2+-clays, however, the exchange cation is desorbed quantitatively, and Si(acac)3+ binding is accompanied by the formation of an acetone-solvated CoCl2 solution complex which helps to drive the ion-exchange reaction. Thus, Co2+-smectites react with Si(acac)3+ in acetone to produce homoionic Si(acac)3+ intercalates, whereas Na+-and Mg2+-smectites produce mixed-ion intercalates. The interlayer hydrolysis of Si(acac)3+ to silicic acid in the homoionic Si(acac)3+- and mixed-ion Na+/Si(acac)3+- and Mg2+/Si(acac)3+-exchange forms of montmorillonite films is diffusion controlled. In water as the solvating medium, the reaction of Si(acac)3+ with Mg2+- or Co2+-montmorillonite results in the desorption of the exchange cations on a time scale which is comparable to that observed for the solution hydrolysis of Si(acac)3+. Thus, the precipitation of silicic acid from aqueous solution competes strongly with the formation of interlayer silicic acid. With aqueous Na+-montmorillonite dispersions, however, a significant fraction of the exchange cations desorbed rapidly upon Si(acac)3+ binding, and the formation of interlayer silicic acid is favored over the precipitation of Si(OH)4.

Neutral, cationic and anionic forms of glucose oxidase (pH 3.0–8.0) bind to the external surfaces of hexadecyltrimethylammonium montmoril-lonite by a hydrophobic mechanism. At pH 4.0 the adsorption limit is 4.7 g/ 100 g clay. The pH for optimum activity is similar for the immobilized and free forms of the enzyme, but the immobilized conjugate is more sensitive to changes in pH. In contrast, Na+-montmorillonite binds active forms of glucose oxidase by an ionic intercalation mechanism at pH values below the isoelectric point. Denaturation of the intercalated enzyme occurs by two pathways. The faster pathway is inhibited by high enzyme loadings and by co-adsorption of tetrabutylammonium ions, suggesting that the enzyme uncoils on the interlayer surfaces of the mineral. Lower than expected values for the adsorption limit ($̃97 g/100 g clay) and for the 00l lattice expansion ($̃35 Å) also indicate uncoiling or flattening of the enzyme in the intercalated state. The slower denaturation pathway, which is less sensitive to surface coverage, may involve hydrolysis and loss of FAD cofactor.

Silica-intercalated hectorite with an 001 spacing of 12.6 Å and a N 2 BET surface area of 220 m 2 / g was prepared by hydrolysis and oxidation at 500°C of hectorite containing a silicon acetylacetonate complex. The intercalate swelled to higher spacings upon adsorption of water, glycerol, and pyridine, but the silica was not expelled when the interlayers swelled and contracted in successive adsorption/desorption cycles. The surface area measured by isobutane adsorption agrees with the N 2 BET surface area, suggesting that the interlayers are available for adsorption of aliphatic hydrocarbons. The intercalated silica did not inhibit the ability of the interlayers to enter into cation-exchange reactions, as judged from Cu 2+ -binding experiments. Infrared studies of NH 3 -, pyridine-, and NO 2 -adsorption indicate the presence of Bronsted acidity and the absence of Lewis acidity in the interlayer regions.

The newly developed herbicide buthidazole {3-[5-(1,1-dimethylethyl)-1,3,4-thiadizol-2-yl]-4-hydroxy-1-methyl-2-imidazolidinone} was studied with respect to its interaction with soils and homoionic clay minerals and its response to irradiation with ultraviolet light. Results showed that it could enter the interlamellar spaces of swelling clays such as smectite. Isothermic adsorption studies indicated that Cu+2-smectite adsorbed more buthidazole than Cu+2-kaolinite. The Cu+2-clay adsorption isotherm fitted the Langmuir model. The effect of exchangeable cations on adsorption was not significant in soils of high organic matter content. Bioassay studies indicated that buthidazole's phytotoxicity was not decreased in either clays or in organic soils. Infrared spectroscopic studies showed the coordination of buthidazole with Cu+2through C=O Cu interaction with buthidazole resulted in a ligand-to-metal ratio to 1:1. Protonation of buthidazole occurred in Al+3-and H+-smectite. The herbicide was labile to UV-light irradiation at 254 nm but not at 366 nm. The photoconversion indicated a first-order reaction. The photolytic product(s) included the –N=C=O structure. Copper(II) ions, which form complexes, retarded photolysis of buthidazole in UV-light, but the Ca+2ion, which is unable to form complexes, did not.

Silica has been intercalated in swelling clays by hydrolysis and/or oxidation of tris(acetylacetonato)siIicon(IV) cations, Si(acac)3+, and polychlorosiloxanes, (-SiOCl2-)n, in the interla-mellar regions of the minerals. The Si(acac)3+ ions have been placed on the interlamellar surfaces by ion exchange and by in situ reaction of the acetylacetone-solvated clays with SiCl4. The (-SiOCl2-)n polymers were formed in the interlayers by reaction of adsorbed benzaldehyde with SiCl4. The optimum (001) spacing observed after firing the clays in air at 500°C (12.6 Å) corresponds to the presence of a monolayer of siloxane chains. Nitrogen BET surface areas range from 40 to 240 m2/g, depending on the amount of internal surface covered by the intercalated silica. In some cases, highly ordered products were formed which exhibit four orders of (00ℓ) reflection. Interstratifled products with d(001) values between 9.6 and 12.6 Å exhibit surface areas consistent with the presence of a random mixture of totally collapsed interlayers and interlayers containing siloxane monolayers. Attempts to achieve silica intercalation by hydrolysis of SiCl4 in the clay interlayers were not productive.

When aqueous dispersions of Na+-smectite or n-butylammonium-vermiculite react with sulfate salts of Fe(II), Co(II), or Ni(II) bipyridyl or 1, 10-phenanthroline complexes in excess of the cation-exchange capacities, intersalated phases with spacings of about 29.5 Å are obtained. Thermal decomposition of the intersalated complex cations affords expanded phases with a d(001) spacing near 18 Å for the smectites and near 28 Å for the vermiculites. These phases are stable to temperatures of at least 550°C. Nitrogen surface areas of the fired products are as high as 400 m2/g.

The rates of dehydroxylation of smectites intercalated with the decomposition products of Ni(phen) 3 SO 4 are from 2 to 4 times greater than those of clays without the heat-stable intercalate. These results suggest that the intercalated material, in keeping the clay sheets separated, provides a more ready avenue for water loss during the dehydroxylation process.

Research Article| February 01, 1979 Differentiation of surficial glacial drift in southeastern Michigan from 7-Å/10-Å X-ray diffraction ratios of clays RICHARD L. RIECK; RICHARD L. RIECK 1Department of Geography and Department of Geology, Western Illinois University, Macomh, Illinois 61455 Search for other works by this author on: GSW Google Scholar HAROLD A. WINTERS; HAROLD A. WINTERS 2Department of Geography, Michigan State University, East Lansing, Michigan 48824 Search for other works by this author on: GSW Google Scholar DELBERT L. MOKMA; DELBERT L. MOKMA 3 Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan 48824 Search for other works by this author on: GSW Google Scholar MAX M. MORTLAND MAX M. MORTLAND 3 Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan 48824 Search for other works by this author on: GSW Google Scholar Author and Article Information RICHARD L. RIECK 1Department of Geography and Department of Geology, Western Illinois University, Macomh, Illinois 61455 HAROLD A. WINTERS 2Department of Geography, Michigan State University, East Lansing, Michigan 48824 DELBERT L. MOKMA 3 Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan 48824 MAX M. MORTLAND 3 Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan 48824 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1979) 90 (2): 216–220. https://doi.org/10.1130/0016-7606(1979)90<216:DOSGDI>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation RICHARD L. RIECK, HAROLD A. WINTERS, DELBERT L. MOKMA, MAX M. MORTLAND; Differentiation of surficial glacial drift in southeastern Michigan from 7-Å/10-Å X-ray diffraction ratios of clays. GSA Bulletin 1979;; 90 (2): 216–220. doi: https://doi.org/10.1130/0016-7606(1979)90<216:DOSGDI>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Woodfordian till deposited by the juxtaposed Saginaw and Huron-Erie glacial lobes in southeastern Michigan appears similar in many respects but may be differentiated on the basis of certain mineralogical characteristics of clay-sized particles. This is apparent from X-ray diffractograms of basally oriented, magnesium-saturated, and glycerol-solvated specimens. Thirty-five till samples from the converging Kalamazoo (Saginaw lobe) and Mississinewa (Huron-Erie lobe) moraines and their interlobate tract have 7-Å/10-Å peak height ratios that differ significantly according to provenance. Every sample from locations within and proximal to the Kalamazoo moraine has a ratio of 0.91 or more. All but one of the samples from the Mississinewa moraine and areas to the east have ratios less than 0.91. Data from several other sources indicate that the same relationships also exist on a larger scale in southeastern Michigan. The findings are consistent with previous interpretations of the area's geology and may provide a reliable basis for the placement of the surficial boundary between drifts deposited in a complex interlobate area. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.