Mammalian collagens exhibit weak intrinsic UV fluorescence that depends on the age and previous history of the sample. Post-translational modifications result in additional fluorescent products (e.g. DOPA, dityrosine, and advanced glycation end products (AGE)). UV radiation can cause longer wavelength fluorescent oxidative bands. These alterations can assess the extent of photolysis. We describe the ground- and excited-state oxidative transformations of newly-purchased type I calf skin collagens (samples #092014 and #072012) and a 7-year-old sample (#072005). We compare the effects of UV radiation (mainly 254 nm) and age on the photochemical reaction kinetics and fluorescence spectral distribution of type I calf skin collagen at pH 7.4. The fluorescence spectra of samples #072012 and #092014 were similar but not identical to pure tyrosine, whereas #072005 indicated significant “dark” oxidation at the expense of tyrosine. Fading of oxidized product(s) at 270/360 nm is second-order. Build-up of 325/400 nm (dityrosine) fluorescence is linear with time. Rate parameters r2 and r1 were respectively proportional to second order disappearance of ground state oxidation products and the quasi–first-order photochemical formation of dityrosine. There is a reciprocal relationship between the rates of decrease in the 270/360 nm fluorescence and concomitant increase in 325/400 nm fluorescence. Their relative rates depend on the age of the collagen sample. There is a reciprocal relationship between r1 and r2. This relationship results because both ground state autoxidation and excited state photo-dimerization proceed via a common tyrosyl radical intermediate. Water of hydration appears to play a role in generating tyrosyl radical.
{"title":"Thermal and Photochemical Effects on the Fluorescence Properties of Type I Calf Skin Collagen Solutions at Physiological pH","authors":"J. Menter, Latoya Freeman, Otega Edukuye","doi":"10.4236/OJPC.2015.52003","DOIUrl":"https://doi.org/10.4236/OJPC.2015.52003","url":null,"abstract":"Mammalian collagens exhibit weak intrinsic UV fluorescence that depends on the age and previous history of the sample. Post-translational modifications result in additional fluorescent products (e.g. DOPA, dityrosine, and advanced glycation end products (AGE)). UV radiation can cause longer wavelength fluorescent oxidative bands. These alterations can assess the extent of photolysis. We describe the ground- and excited-state oxidative transformations of newly-purchased type I calf skin collagens (samples #092014 and #072012) and a 7-year-old sample (#072005). We compare the effects of UV radiation (mainly 254 nm) and age on the photochemical reaction kinetics and fluorescence spectral distribution of type I calf skin collagen at pH 7.4. The fluorescence spectra of samples #072012 and #092014 were similar but not identical to pure tyrosine, whereas #072005 indicated significant “dark” oxidation at the expense of tyrosine. Fading of oxidized product(s) at 270/360 nm is second-order. Build-up of 325/400 nm (dityrosine) fluorescence is linear with time. Rate parameters r2 and r1 were respectively proportional to second order disappearance of ground state oxidation products and the quasi–first-order photochemical formation of dityrosine. There is a reciprocal relationship between the rates of decrease in the 270/360 nm fluorescence and concomitant increase in 325/400 nm fluorescence. Their relative rates depend on the age of the collagen sample. There is a reciprocal relationship between r1 and r2. This relationship results because both ground state autoxidation and excited state photo-dimerization proceed via a common tyrosyl radical intermediate. Water of hydration appears to play a role in generating tyrosyl radical.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"05 1","pages":"21-27"},"PeriodicalIF":0.0,"publicationDate":"2015-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70501966","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}
Recently a mechanistic understanding of the pressure-and/or temperature-induced coordination change of boron in a borosilicate glass has been demonstrated by Edwards et al. In situ high-pressure 11B solid-state NMR spectroscopy has been used in combination with ab initio calculations in order to obtain insight in the molecular geometry for the pressure-induced conversion. The results indicate a deformation of the B(OH)3 planar triangle, under isotropic stress, into a trigonal pyramid that serves as a precursor for the formation of a tetrahedral boron configuration. From our point of view, the deformation controlling the out-of-plane transition of boron accompanied with a D3h into C3v geometric change is an interesting transformation because it matches with our molecular description based on Van’t Hoff modelling for the tetrahedral change of carbon in CH3X by substitution of X with nucleophiles via a trigonal bipyramid state in which the transferred carbon is present as a methyl planar triangle “cation”. Van’t Hoff modelling and ab initio calculations have been also applied on the dynamics of the out-of-plane geometry of a transient positively charged carbon in a trigonal pyramidal configuration into a planar trivalent carbon cation. Finally the same model is also used for the C3v trigonal pyramidal configurations as NH3 of the group 15 elements in their nucleophilic abilities.
{"title":"Interconversion between Planar-Triangle, Trigonal-Pyramid and Tetrahedral Configurations of Boron (B(OH)3 -B(OH)4- ), Carbon (CH3+ -CH3X) and for the Group 15 Elements as Nitrogen (NH3-NH4+ ). A Modelling Description with Ab Initio Results and Pressure-Induced Experimental Evidence","authors":"H. Buck","doi":"10.4236/OJPC.2015.51001","DOIUrl":"https://doi.org/10.4236/OJPC.2015.51001","url":null,"abstract":"Recently a mechanistic understanding of the pressure-and/or temperature-induced coordination change of boron in a borosilicate glass has been demonstrated by Edwards et al. In situ high-pressure 11B solid-state NMR spectroscopy has been used in combination with ab initio calculations in order to obtain insight in the molecular geometry for the pressure-induced conversion. The results indicate a deformation of the B(OH)3 planar triangle, under isotropic stress, into a trigonal pyramid that serves as a precursor for the formation of a tetrahedral boron configuration. From our point of view, the deformation controlling the out-of-plane transition of boron accompanied with a D3h into C3v geometric change is an interesting transformation because it matches with our molecular description based on Van’t Hoff modelling for the tetrahedral change of carbon in CH3X by substitution of X with nucleophiles via a trigonal bipyramid state in which the transferred carbon is present as a methyl planar triangle “cation”. Van’t Hoff modelling and ab initio calculations have been also applied on the dynamics of the out-of-plane geometry of a transient positively charged carbon in a trigonal pyramidal configuration into a planar trivalent carbon cation. Finally the same model is also used for the C3v trigonal pyramidal configurations as NH3 of the group 15 elements in their nucleophilic abilities.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"05 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2015-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70501665","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}
Complexes of the general formula [MBr2(TMTU)n] (where M is Mn, Fe, Co, Ni, Cu, Zn or Cd; TMTU is Tetramethylthiourea; n is 0.75, 2 or 3) were obtained by the reaction of salts and ligand in solution. The bromides were selected among several other salts because they had thermochemical data in the literature. Properties as capillary melting points; C, H, N, Br and metal contents; TG/DTG and DSC curves; and IR and electronic spectra were determined. The values of several thermodynamic parameters for the complexes were found by solution calorimetry. From them, the standard enthalpies of the metal-sulphur coordinated bonds were calculated. The standard enthalpies of the formation of the gaseous phase adducts also were estimated.
{"title":"Thermochemical Parameters of Tetramethylthiourea Adducts of Certain Metal(II) Bromides","authors":"P. Dunstan","doi":"10.4236/OJPC.2015.51002","DOIUrl":"https://doi.org/10.4236/OJPC.2015.51002","url":null,"abstract":"Complexes of the general formula [MBr2(TMTU)n] (where M is Mn, Fe, Co, Ni, Cu, Zn or Cd; TMTU is Tetramethylthiourea; n is 0.75, 2 or 3) were obtained by the reaction of salts and ligand in solution. The bromides were selected among several other salts because they had thermochemical data in the literature. Properties as capillary melting points; C, H, N, Br and metal contents; TG/DTG and DSC curves; and IR and electronic spectra were determined. The values of several thermodynamic parameters for the complexes were found by solution calorimetry. From them, the standard enthalpies of the metal-sulphur coordinated bonds were calculated. The standard enthalpies of the formation of the gaseous phase adducts also were estimated.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"05 1","pages":"9-19"},"PeriodicalIF":0.0,"publicationDate":"2015-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70501809","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}
On the example of typical metals, it’s found that the activation energy of self-diffusion is above of the melting heat and below of vaporization heat. This corresponds to the existence of liquid-mobile particle classification based on the concept of randomized particles. A formula for estimating the activation energy of self-diffusion by which it is approximately half of the heat of evaporation of the substance is recommended. We derive the temperature dependence for a fraction self-diffusion’s particles.
{"title":"The Relation between the Heat of Melting Point, Boiling Point, and the Activation Energy of Self-Diffusion in Accordance with the Concept of Randomized Particles","authors":"V. P. Malyshev, A. Makasheva","doi":"10.4236/OJPC.2014.44019","DOIUrl":"https://doi.org/10.4236/OJPC.2014.44019","url":null,"abstract":"On the example of typical metals, it’s found that the activation energy of self-diffusion is above of the melting heat and below of vaporization heat. This corresponds to the existence of liquid-mobile particle classification based on the concept of randomized particles. A formula for estimating the activation energy of self-diffusion by which it is approximately half of the heat of evaporation of the substance is recommended. We derive the temperature dependence for a fraction self-diffusion’s particles.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"04 1","pages":"166-172"},"PeriodicalIF":0.0,"publicationDate":"2014-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70501886","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 corrosion behavior of Maraging steel has been studied by using different techniques, including open circuit potential and polarization measurements in addition to microstructure examination such as optical microscopy and XRD (X-Ray Diffraction) investigation. The corrosion behavior of Maraging steel has been examined in sodium chloride solutions with different concentrations from 0.1 M to 2 M. It was found that the corrosion resistance of Maraging steel is inversely proportional with the concentration of sodium chloride solution. The corrosion resistance is directly proportional to the Mo and Ti content in the Maraging steel. Heat treatment of the Maraging steel improved its mechanical properties with no effect on the corrosion behavior as the precipitation of inter-metallic compounds leading to some galvanic action. However, sample IV having lower Mo content than sample V showed after heat treatment an improvement in the corrosion resistance.
{"title":"Effect of Chloride Concentration on the Corrosion Rate of Maraging Steel","authors":"H. E. Desouky, H. Abo-Eldahab","doi":"10.4236/OJPC.2014.44018","DOIUrl":"https://doi.org/10.4236/OJPC.2014.44018","url":null,"abstract":"The corrosion behavior of \u0000Maraging steel has been studied by using different techniques, including open \u0000circuit potential and polarization measurements in addition to microstructure \u0000examination such as optical microscopy and XRD (X-Ray Diffraction) \u0000investigation. The corrosion behavior of Maraging steel has been examined in \u0000sodium chloride solutions with different concentrations from 0.1 M to 2 M. It \u0000was found that the corrosion resistance of Maraging steel is inversely proportional \u0000with the concentration of sodium chloride solution. The corrosion resistance is \u0000directly proportional to the Mo and Ti content in the Maraging steel. Heat \u0000treatment of the Maraging steel improved its mechanical properties with no \u0000effect on the corrosion behavior as the precipitation of inter-metallic \u0000compounds leading to some galvanic action. However, sample IV having lower Mo \u0000content than sample V showed after heat treatment an improvement in the \u0000corrosion resistance.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"04 1","pages":"147-165"},"PeriodicalIF":0.0,"publicationDate":"2014-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70501696","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}
Equilibrium adsorption studies for detoxification of Congo Red (CR) dye from single component model wastewater by powdered watermelon rinds and neem leaves adsorbents were carried out with the view to test the applicability of the adsorption process to Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Harkins-Jura isotherm models. The values of correlation coefficient, R2 (0.9359 - 0.9998), showed that all the experimental data fitted the linear plots of the tested isotherm models. Dubinin-Radushkevich’s monolayer maximum adsorption capacity qD (20.72 - 26.06 mg/g) is better than Langmuir’s qm (18.62 - 24.75 mg/g) for both adsorbents with the capacities higher for adsorption on watermelon rind than on neem leaves. Values of Langmuir separation factor (RL) suggest unfavourable adsorption processes (i.e. chemisorption) of the dye on both the adsorbents, while Freundlich constant (nF) indicates unfavourable process only for CR adsorption onto neem leaves. The Dubinin-Radushkevich’s mean free energy of adsorption, E (0.29 - 0.32 kJ/mol), suggests physical adsorption processes. Values for Temkin’s heat of adsorption, bT (-0.95 to 0.74 kJ/mol), also show physical adsorption process.
{"title":"Comparative Isotherms Studies on Adsorptive Removal of Congo Red from Wastewater by Watermelon Rinds and Neem-Tree Leaves","authors":"M. Ibrahim, Sadiq Sani","doi":"10.4236/OJPC.2014.44017","DOIUrl":"https://doi.org/10.4236/OJPC.2014.44017","url":null,"abstract":"Equilibrium adsorption studies for detoxification of Congo Red (CR) dye from single component model wastewater by powdered watermelon rinds and neem leaves adsorbents were carried out with the view to test the applicability of the adsorption process to Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Harkins-Jura isotherm models. The values of correlation coefficient, R2 (0.9359 - 0.9998), showed that all the experimental data fitted the linear plots of the tested isotherm models. Dubinin-Radushkevich’s monolayer maximum adsorption capacity qD (20.72 - 26.06 mg/g) is better than Langmuir’s qm (18.62 - 24.75 mg/g) for both adsorbents with the capacities higher for adsorption on watermelon rind than on neem leaves. Values of Langmuir separation factor (RL) suggest unfavourable adsorption processes (i.e. chemisorption) of the dye on both the adsorbents, while Freundlich constant (nF) indicates unfavourable process only for CR adsorption onto neem leaves. The Dubinin-Radushkevich’s mean free energy of adsorption, E (0.29 - 0.32 kJ/mol), suggests physical adsorption processes. Values for Temkin’s heat of adsorption, bT (-0.95 to 0.74 kJ/mol), also show physical adsorption process.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"04 1","pages":"139-146"},"PeriodicalIF":0.0,"publicationDate":"2014-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70501648","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}
In organic chemistry, as defined by Abegg, Kossel, Lewis and Langmuir, compounds are normally represented using structural formulas called Lewis structures. In these structures, the octet rule is used to define the number of covalent bonds that each atom forms with its neighbors and multiple bonds are frequent. Lewis’ octet rule has unfortunately shown limitations very early when applied to non-organic compounds: most of them remain incompatible with the “rule of eight” and location of charges is uncertain. In an attempt to unify structural formulas of octet and non-octet molecules or single-charge ions, an even-odd rule was recently proposed, together with a procedure to locate charge precisely. This even-odd rule has introduced a charge-dependent effective-valence number calculated for each atom. With this number and the number of covalent bonds of each element, two even numbers are calculated. These numbers are both used to understand and draw structuralformulas of single-covalent-bonded compounds. In the present paper, a procedure is proposed to adjust structural formulas of compounds that are commonly represented with multiple bonds. In order to keep them compatible with the even-odd rule, they will be represented using only single covalent bonds. The procedure will then describe the consequences of bond simplification on charges locations. The newly obtained representations are compared to their conventional structural formulas, i.e. single-bond representation vs. multiple-bond structures. Throughout the comparison process, charges are precisely located and assigned to specific atoms. After discussion of particular cases of compounds, the paper finally concludes that a rule limiting representations of multiplecovalent bonds to single covalent bonds, seems to be suitable for numerous known compounds.
{"title":"The Even-Odd Rule on Single Covalent-Bonded Structural Formulas as a Modification of Classical Structural Formulas of Multiple-Bonded Ions and Molecules","authors":"G. Auvert","doi":"10.4236/OJPC.2014.44020","DOIUrl":"https://doi.org/10.4236/OJPC.2014.44020","url":null,"abstract":"In organic chemistry, as defined by Abegg, Kossel, Lewis and Langmuir, compounds are normally represented using structural formulas called Lewis structures. In these structures, the octet rule is used to define the number of covalent bonds that each atom forms with its neighbors and multiple bonds are frequent. Lewis’ octet rule has unfortunately shown limitations very early when applied to non-organic compounds: most of them remain incompatible with the “rule of eight” and location of charges is uncertain. In an attempt to unify structural formulas of octet and non-octet molecules or single-charge ions, an even-odd rule was recently proposed, together with a procedure to locate charge precisely. This even-odd rule has introduced a charge-dependent effective-valence number calculated for each atom. With this number and the number of covalent bonds of each element, two even numbers are calculated. These numbers are both used to understand and draw structuralformulas of single-covalent-bonded compounds. In the present paper, a procedure is proposed to adjust structural formulas of compounds that are commonly represented with multiple bonds. In order to keep them compatible with the even-odd rule, they will be represented using only single covalent bonds. The procedure will then describe the consequences of bond simplification on charges locations. The newly obtained representations are compared to their conventional structural formulas, i.e. single-bond representation vs. multiple-bond structures. Throughout the comparison process, charges are precisely located and assigned to specific atoms. After discussion of particular cases of compounds, the paper finally concludes that a rule limiting representations of multiplecovalent bonds to single covalent bonds, seems to be suitable for numerous known compounds.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"04 1","pages":"173-184"},"PeriodicalIF":0.0,"publicationDate":"2014-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70502025","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}
Ions or molecules are said to be isoelectronic if they are composed of different elements but have the same number of electrons, the same number of covalent bonds and the same structure. This criterion is unfortunately not sufficient to ensure that a chemical structure is a valid chemical compound. In a previous article, a procedure has been described to draw 2D valid structural formulas: the even-odd rule. This rule has been applied first to single-bonded molecules then to single-charged single-bonded ions. It covers hypovalent, hypervalent or classic Lewis’ octet compounds. The funding principle of the even-odd rule is that each atom of the compound possesses an outer-shell filled only with pairs of electrons. The application of this rule guarantees validity of any single-covalent-bond chemical structure. In the present paper, this even-odd rule and its electron-pair criterion are checked for coherence with an effective-valence isoelectronic rule using numerous known compounds having single-covalent-bond connections. The test addresses Lewis’ octet ions or molecules as well as hypovalent and hypervalent compounds. The article concludes that the even-odd rule and the effective-valence isoelectronicity rule are coherent for known single-covalent-bond chemical compounds.
{"title":"Coherence of the Even-Odd Rule with an Effective-Valence Isoelectronicity Rule for Chemical Structural Formulas: Application to Known and Unknown Single-Covalent-Bonded Compounds","authors":"G. Auvert","doi":"10.4236/OJPC.2014.43015","DOIUrl":"https://doi.org/10.4236/OJPC.2014.43015","url":null,"abstract":"Ions or molecules are said \u0000to be isoelectronic if they are composed of different elements but have the \u0000same number of electrons, the same number of covalent bonds and the same \u0000structure. This criterion is unfortunately not sufficient to ensure that a \u0000chemical structure is a valid chemical compound. In a previous article, a \u0000procedure has been described to draw 2D valid structural formulas: the even-odd \u0000rule. This rule has been applied first to single-bonded molecules then to \u0000single-charged single-bonded ions. It covers hypovalent, hypervalent or classic \u0000Lewis’ octet compounds. The funding principle of the even-odd rule is that each \u0000atom of the compound possesses an outer-shell filled only with pairs of \u0000electrons. The application of this rule guarantees validity of any \u0000single-covalent-bond chemical structure. In the present paper, this even-odd \u0000rule and its electron-pair criterion are checked for coherence with an \u0000effective-valence isoelectronic rule using numerous known compounds having \u0000single-covalent-bond connections. The test addresses Lewis’ octet ions or \u0000molecules as well as hypovalent and hypervalent compounds. The article \u0000concludes that the even-odd rule and the effective-valence isoelectronicity \u0000rule are coherent for known single-covalent-bond chemical compounds.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"4 1","pages":"126-133"},"PeriodicalIF":0.0,"publicationDate":"2014-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70501248","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}
M. E. miz, S. Salhi, Ikrame Chraibi, A. Bachiri, M. Fauconnier, A. Tahani
Pillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of thymol by aluminum pillared clay (PILC). The PILCs displayed a total surface area of 270 m2/g, a total pore volume of 0.246 cm3/g and an average pore diameter of 8.9 A, which corresponds to the size of Al13 forming the pillars between the clay layers. The adsorption capacity shown by the PILCs for thymol from water is close to 319 mg?g-1 for low solid/liquid ratio (0.2%). This result suggests that the PILCs have both hydrophobic and hydrophilic characteristics, as a result of the presence of silanol and siloxane groups formed during the pillaring and calcination of the PILCs. The experimental data were analyzed by the Freundlich and the Langmuir isotherm types for low values of equilibrium concentration. The rise of the isotherm in this range of concentrations was related to the affinity of thymol for clay sites, and the equilibrium data fitted well with the Freundlich model with maximum adsorption capacity of 319.51 mg/g for a ratio RS/L = 0.2%. Pseudo-first and pseudo-second-order kinetic models were tested with the experimental data and pseudo-first order kinetics was the best for the adsorption of thymol with coefficients of correlation R2 ≥0.986, and the adsorption was rapid with 90% of the thymol adsorbed within the first 20 min.
{"title":"Characterization and Adsorption Study of Thymol on Pillared Bentonite","authors":"M. E. miz, S. Salhi, Ikrame Chraibi, A. Bachiri, M. Fauconnier, A. Tahani","doi":"10.4236/OJPC.2014.43013","DOIUrl":"https://doi.org/10.4236/OJPC.2014.43013","url":null,"abstract":"Pillared clay (PILC) was prepared from Moroccan clay and \u0000characterized, and its aqueous thymol adsorption capacities were studied using \u0000a batch equilibrium technique. So, we tested the encapsulation of thymol by \u0000aluminum pillared clay (PILC). The PILCs displayed a total surface area of 270 \u0000m2/g, a total pore volume of 0.246 cm3/g and an average \u0000pore diameter of 8.9 A, which corresponds to the size of Al13 forming the pillars between the clay \u0000layers. The adsorption capacity shown by the PILCs for thymol from water is \u0000close to 319 mg?g-1 for \u0000low solid/liquid ratio (0.2%). This result suggests that the PILCs have both \u0000hydrophobic and hydrophilic characteristics, as a result of the presence of \u0000silanol and siloxane groups formed during the pillaring and calcination of the \u0000PILCs. The experimental data were analyzed by the Freundlich and the Langmuir \u0000isotherm types for low values of equilibrium concentration. The rise of the \u0000isotherm in this range of concentrations was related to the affinity of thymol \u0000for clay sites, and the equilibrium data fitted well with the Freundlich model \u0000with maximum adsorption capacity of 319.51 mg/g for a ratio RS/L = 0.2%. Pseudo-first and \u0000pseudo-second-order kinetic models were tested with the experimental data and \u0000pseudo-first order kinetics was the best for the adsorption of thymol with \u0000coefficients of correlation R2 ≥0.986, and the adsorption was rapid with 90% of \u0000the thymol adsorbed within the first 20 min.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"4 1","pages":"98-116"},"PeriodicalIF":0.0,"publicationDate":"2014-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4236/OJPC.2014.43013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70501543","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}
Surfactant-grafted Polyacrylamide (S-PAM), as a new type of oil displacement agent in oilfield, integrates the advantages of both polymer and surfactant. The oil displacement experiments using S-PAM in multi-blocks reveal that in-use S-PAMs differ greatly from ordinary polymers and the physical properties remain unclear. This is unfavorable to production application and occupational health and safety. This research compared the physical properties of S-PAMs selected from two producing area, including specific gravity, particle size and viscosity. The compared results showed that specific gravity of Lianhua S-PAM was smaller than Haibo S-PAM; Lianhua S-PAM and Haibo S-PAM accounted for the 93.8% and 80.1% of the total amount via the particles with 40 mesh and 60 mesh; the viscosity of Lianhua S-PAM was higher than that of Haibo S-PAM in two S-PAM solutions with different concentrations.
{"title":"Comparative Study of Physical Properties of In-Use Surfactant-Grafted Polyacrylamides for Oilfield","authors":"Tingting Jiang, Haiyu Wang, Baohui Wang","doi":"10.4236/OJPC.2014.43016","DOIUrl":"https://doi.org/10.4236/OJPC.2014.43016","url":null,"abstract":"Surfactant-grafted \u0000Polyacrylamide (S-PAM), as a new type of oil displacement agent in oilfield, \u0000integrates the advantages of both polymer and surfactant. The oil displacement \u0000experiments using S-PAM in multi-blocks reveal that in-use S-PAMs differ \u0000greatly from ordinary polymers and the physical properties remain unclear. This \u0000is unfavorable to production application and occupational health and safety. This \u0000research compared the physical properties of S-PAMs selected from two producing \u0000area, including specific gravity, particle size and viscosity. The compared \u0000results showed that specific gravity of Lianhua S-PAM was smaller than Haibo \u0000S-PAM; Lianhua S-PAM and Haibo S-PAM accounted for the 93.8% and 80.1% of the \u0000total amount via the particles with 40 mesh and 60 mesh; the viscosity of \u0000Lianhua S-PAM was higher than that of Haibo S-PAM in two S-PAM solutions with \u0000different concentrations.","PeriodicalId":59839,"journal":{"name":"物理化学期刊(英文)","volume":"2014 1","pages":"134-138"},"PeriodicalIF":0.0,"publicationDate":"2014-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70502062","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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