B. Derjaguin, I. Dzyaloshinsky, M. M. Koptelova, L. P. Pitayevsky
Abstract A formula is deduced for the potential energy of a molecule of solute in a dilute solution of low concentration as a function of an interface distance. A procedure is suggested for the determination of this energy by using the measurement of the flow rate of the solution across a membrane under the action of a concentration gradient. The flow rate of the solution is measured by means of a radioactive tracer and related to the energy of solute molecules on the basis of the thermodynamics of irreversible steady processes. An example of such measurements is given; the applicability of the calculations is not quite clear due to possible effect of electro-osmosis.
{"title":"Molecular-surface forces in binary solutions","authors":"B. Derjaguin, I. Dzyaloshinsky, M. M. Koptelova, L. P. Pitayevsky","doi":"10.1039/DF9654000246","DOIUrl":"https://doi.org/10.1039/DF9654000246","url":null,"abstract":"Abstract A formula is deduced for the potential energy of a molecule of solute in a dilute solution of low concentration as a function of an interface distance. A procedure is suggested for the determination of this energy by using the measurement of the flow rate of the solution across a membrane under the action of a concentration gradient. The flow rate of the solution is measured by means of a radioactive tracer and related to the energy of solute molecules on the basis of the thermodynamics of irreversible steady processes. An example of such measurements is given; the applicability of the calculations is not quite clear due to possible effect of electro-osmosis.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"77 1","pages":"246-252"},"PeriodicalIF":0.0,"publicationDate":"1993-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78822033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Microwave dielectric and Hall effect measurements on biological materials.","authors":"D D Eley, R Pethig","doi":"10.1039/df9715100164","DOIUrl":"https://doi.org/10.1039/df9715100164","url":null,"abstract":"","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"51 ","pages":"164-75"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/df9715100164","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16224381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrical conductivity, activation energy for conduction, thermoelectric power and Hall mobility have been measured in compactions of a series of simple and complex TCNQ salts. The results indicate nearly intrinsic semi-conduction in extremely narrow bands, with an average drift mobility of about 10–2 cm2/Vs.
{"title":"Measurement of Seebeck and Hall effects in compactions of TCNQ salts","authors":"A. R. Blythe, M. R. Boon, P. Wright","doi":"10.1039/DF9715100110","DOIUrl":"https://doi.org/10.1039/DF9715100110","url":null,"abstract":"Electrical conductivity, activation energy for conduction, thermoelectric power and Hall mobility have been measured in compactions of a series of simple and complex TCNQ salts. The results indicate nearly intrinsic semi-conduction in extremely narrow bands, with an average drift mobility of about 10–2 cm2/Vs.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"13 1","pages":"110-115"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74031256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Borello, A. Cimino, G. Ghiotti, M. Jacono, M. Schiavello, A. Zecchina
An infra-red investigation has been carried out of CO adsorbed onto Ni2+/η-Al2O3 and Ni2+/γ-Al2O3 catalysts. These contain a “surface spinel” phase in which nickel ions are present both in octahedral and tetrahedral sites. Their relative concentrations are primarily determined by the atmosphere (damp or dry) in which the preparation at 600°C has been carried out. Upon CO adsorption four bands appear in the 2250–2150 cm–1 region due to molecules linked to coordinatively unsaturated surface cations. The relative intensities are related to the preliminary treatment of the sample and are therefore discussed in terms of the possible surface configurations and of the relative amounts of tetrahedral and octahedral sites occupied. The infra-red spectrum of CO adsorbed on hydrogen reduced samples has also been investigated and the importance of the preliminary treatment on the reducibility has been confirmed.
{"title":"Surface configurations and infra-red studies on nickel oxide supported on η- and γ-Al2O3","authors":"E. Borello, A. Cimino, G. Ghiotti, M. Jacono, M. Schiavello, A. Zecchina","doi":"10.1039/DF9715200149","DOIUrl":"https://doi.org/10.1039/DF9715200149","url":null,"abstract":"An infra-red investigation has been carried out of CO adsorbed onto Ni2+/η-Al2O3 and Ni2+/γ-Al2O3 catalysts. These contain a “surface spinel” phase in which nickel ions are present both in octahedral and tetrahedral sites. Their relative concentrations are primarily determined by the atmosphere (damp or dry) in which the preparation at 600°C has been carried out. Upon CO adsorption four bands appear in the 2250–2150 cm–1 region due to molecules linked to coordinatively unsaturated surface cations. The relative intensities are related to the preliminary treatment of the sample and are therefore discussed in terms of the possible surface configurations and of the relative amounts of tetrahedral and octahedral sites occupied. The infra-red spectrum of CO adsorbed on hydrogen reduced samples has also been investigated and the importance of the preliminary treatment on the reducibility has been confirmed.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"28 1","pages":"149-160"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75158449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
After storage under ambient conditions zinc oxide, prepared by the combustion of metallic zinc, carries both carbonate and hydroxylic species. The former are removed by heating the oxide in oxygen and water vapour at 673 K. Subsequent cooling to ambient temperatures in a moist oxygen atmosphere yields a surface carrying hydroxyls. The corresponding infra-red absorption spectrum exhibits four major absorption bands. Two narrow bands are present at 3670 and 3620 cm–1 and two broad absorptions are centred about 3555 and 3440 cm–1. Outgassing the sample at 625 K removes the surface species corresponding to the 3555 cm–1 band and reduces the concentration of that associated with the absorption at 3440 cm–1. The intensities of the 3670 and 3620 cm–1 absorptions are little affected by this outgassing procedure. Rehydroxylation of such outgassed samples by exposure to water vapour at ambient temperatures indicates that the thermal dehydroxylation process involves a “mobile” surface state. The absorption bands observed in the spectra are tentatively assigned to isolated and hydrogen-bonded surface hydroxyls sited on different surface crystal planes. Studies of the adsorption of CO2 show that this gas chemisorbs rapidly at ambient temperatures on a partially dehydroxylated sample to form a carbonate species but the chemisorption is much reduced if the surface is in the “fully” hydroxylated state. HCl gas also reacts with the surface layers of zinc oxide but in such a way as to promote the formation of the bulk hydroxide on exposure of the chlorine-containing sample to water vapour at ambient temperatures.
{"title":"Infra-red spectroscopic studies of zinc oxide surfaces","authors":"K. Atherton, G. Newbold, J. A. Hockey","doi":"10.1039/DF9715200033","DOIUrl":"https://doi.org/10.1039/DF9715200033","url":null,"abstract":"After storage under ambient conditions zinc oxide, prepared by the combustion of metallic zinc, carries both carbonate and hydroxylic species. The former are removed by heating the oxide in oxygen and water vapour at 673 K. Subsequent cooling to ambient temperatures in a moist oxygen atmosphere yields a surface carrying hydroxyls. The corresponding infra-red absorption spectrum exhibits four major absorption bands. Two narrow bands are present at 3670 and 3620 cm–1 and two broad absorptions are centred about 3555 and 3440 cm–1. Outgassing the sample at 625 K removes the surface species corresponding to the 3555 cm–1 band and reduces the concentration of that associated with the absorption at 3440 cm–1. The intensities of the 3670 and 3620 cm–1 absorptions are little affected by this outgassing procedure. Rehydroxylation of such outgassed samples by exposure to water vapour at ambient temperatures indicates that the thermal dehydroxylation process involves a “mobile” surface state. The absorption bands observed in the spectra are tentatively assigned to isolated and hydrogen-bonded surface hydroxyls sited on different surface crystal planes. Studies of the adsorption of CO2 show that this gas chemisorbs rapidly at ambient temperatures on a partially dehydroxylated sample to form a carbonate species but the chemisorption is much reduced if the surface is in the “fully” hydroxylated state. HCl gas also reacts with the surface layers of zinc oxide but in such a way as to promote the formation of the bulk hydroxide on exposure of the chlorine-containing sample to water vapour at ambient temperatures.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"23 1","pages":"33-43"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85556442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sorption data of nitrogen at 77 K, water and ethanol at 298 K and n-pentane at 273 K have been obtained for pure rutile outgassed at 673 K and modified by presorption of water, ethanol, hexan-1-ol and hexan-1 : 6-diol. All adsorbates interact strongly with the unmodified surface. With presorbed water and organics the extent and energy of nitrogen sorption is reduced. Organic-pretreated surfaces are largely hydrophobic, but also show reduced n-pentane adsorption. Hexan-1 : 6-diol is oriented parallel to the rutile surface by strong interactions through the hydrocarbon chain and both hydroxyl groups. Although not initially adsorbed in perpendicular orientation, hexanol has this configuration at high relative pressures of n-pentane which then penetrates the presorbed layer. Ethanol exchanges with both presorbed water and hexan-1-ol but not with hexan-1 : 6-diol.
{"title":"Vapour adsorption on rutile pretreated with water, ethanol, hexan-1-ol and hexan-1 : 6-diol","authors":"R. E. Day, G. D. Parfitt, J. Peacock","doi":"10.1039/DF9715200215","DOIUrl":"https://doi.org/10.1039/DF9715200215","url":null,"abstract":"Sorption data of nitrogen at 77 K, water and ethanol at 298 K and n-pentane at 273 K have been obtained for pure rutile outgassed at 673 K and modified by presorption of water, ethanol, hexan-1-ol and hexan-1 : 6-diol. All adsorbates interact strongly with the unmodified surface. With presorbed water and organics the extent and energy of nitrogen sorption is reduced. Organic-pretreated surfaces are largely hydrophobic, but also show reduced n-pentane adsorption. Hexan-1 : 6-diol is oriented parallel to the rutile surface by strong interactions through the hydrocarbon chain and both hydroxyl groups. Although not initially adsorbed in perpendicular orientation, hexanol has this configuration at high relative pressures of n-pentane which then penetrates the presorbed layer. Ethanol exchanges with both presorbed water and hexan-1-ol but not with hexan-1 : 6-diol.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"61 1","pages":"215-225"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89361539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Semiconductive and photoconductive properties of bimolecular lipid membranes.","authors":"B Rosenberg","doi":"10.1039/df9715100190","DOIUrl":"https://doi.org/10.1039/df9715100190","url":null,"abstract":"","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"51 ","pages":"190-201"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/df9715100190","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16224384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Experimental results are given for the temperature dependency of the zeta potential and adsorption density in the system of quartz + dodecylammonium acetate solutions. Utilizing the experimental adsorption densities and the Stern-Grahame equation, calculations indicate large entropic effects which are attributed to the phenomenon of hydrophobic bonding. A change in the adsorption mechanism in the temperature range greater than 25°C may be due to a major breakdown of the ordered water structure at the solid surface. The electrokinetic results appear contrary to the prediction of both the simple Gouy-Chapman and the modified Stern theory allowing for a distance of closest approach. It is concluded that the measured effects must be due to changes occurring at, or associated with, both the plane of closest approach and the shear plane.
{"title":"Thermodynamics and adsorption behaviour in the quartz/aqueous surfactant system","authors":"B. Ball, D. Fuerstenau","doi":"10.1039/DF9715200361","DOIUrl":"https://doi.org/10.1039/DF9715200361","url":null,"abstract":"Experimental results are given for the temperature dependency of the zeta potential and adsorption density in the system of quartz + dodecylammonium acetate solutions. Utilizing the experimental adsorption densities and the Stern-Grahame equation, calculations indicate large entropic effects which are attributed to the phenomenon of hydrophobic bonding. A change in the adsorption mechanism in the temperature range greater than 25°C may be due to a major breakdown of the ordered water structure at the solid surface. The electrokinetic results appear contrary to the prediction of both the simple Gouy-Chapman and the modified Stern theory allowing for a distance of closest approach. It is concluded that the measured effects must be due to changes occurring at, or associated with, both the plane of closest approach and the shear plane.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"110 1","pages":"361-371"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76304822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The wavelength dependence of the fluorescence yield and of the photocurrent for anthracene crystals in contact with an electrolyte solution has been measured. A correlation between the fluorescence yield and the quantum efficiency of charge carrier generation at the contact has been derived which provides a means for determination of the contribution of the charge and energy transfer to the fluorescence quenching process. Experiments with a solution of Na2IrCl6 in 0.5 N HCl showed that for this system quenching of the fluorescence occurs predominantly by energy transfer with a small contribution of charge transfer.
测量了与电解质溶液接触的蒽晶体的荧光产率和光电流的波长依赖性。导出了荧光产率与接触处电荷载流子产生的量子效率之间的相关性，这为确定电荷和能量转移对荧光猝灭过程的贡献提供了一种方法。Na2IrCl6在0.5 N HCl溶液中的实验表明，该体系的荧光猝灭主要是通过能量转移实现的，电荷转移的贡献很小。
{"title":"Quenching of excited states at the interface, molecular crystal/electrolyte","authors":"J. Hale, W. Mehl","doi":"10.1039/DF9715100054","DOIUrl":"https://doi.org/10.1039/DF9715100054","url":null,"abstract":"The wavelength dependence of the fluorescence yield and of the photocurrent for anthracene crystals in contact with an electrolyte solution has been measured. A correlation between the fluorescence yield and the quantum efficiency of charge carrier generation at the contact has been derived which provides a means for determination of the contribution of the charge and energy transfer to the fluorescence quenching process. Experiments with a solution of Na2IrCl6 in 0.5 N HCl showed that for this system quenching of the fluorescence occurs predominantly by energy transfer with a small contribution of charge transfer.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"65 3","pages":"54-60"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91507284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The competitive adsorption of phosphate + arsenate and phosphate + selenite on goethite and gibbsite has been measured. The oxide surface contains sites common to both anions on which competitive adsorption takes place and sites on which only one or the other anion is able to adsorb. The maximum amount of anions adsorbed from a mixture is approximately equal to the sum of the maximum adsorption for each anion in the absence of competition. The number of sites at which competition takes place is almost equal to the number of sites available to the anion with the lower adsorption in the absence of a competitor. Competition is described by a Langmuir-type exchange equation.
{"title":"Competitive adsorption of negatively charged ligands on oxide surfaces","authors":"F. Hingston, A. M. Posner, J. Quirk","doi":"10.1039/DF9715200334","DOIUrl":"https://doi.org/10.1039/DF9715200334","url":null,"abstract":"The competitive adsorption of phosphate + arsenate and phosphate + selenite on goethite and gibbsite has been measured. The oxide surface contains sites common to both anions on which competitive adsorption takes place and sites on which only one or the other anion is able to adsorb. The maximum amount of anions adsorbed from a mixture is approximately equal to the sum of the maximum adsorption for each anion in the absence of competition. The number of sites at which competition takes place is almost equal to the number of sites available to the anion with the lower adsorption in the absence of a competitor. Competition is described by a Langmuir-type exchange equation.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"1 1","pages":"334-342"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78547865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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