The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform

M Ruiz D Cruz - One of the best experts on this subject based on the ideXlab platform.

  • a comparative study of the dehydroxylation process in untreated and hydrazine deintercalated Dickite
    Journal of Thermal Analysis and Calorimetry, 2006
    Co-Authors: F Franco, M Ruiz D Cruz
    Abstract:

    A Dickite from Tarifa (Spain) was used to study the influence of the intercalation and the later deintercalation of hydrazine on the dehydroxylation process.

  • thermal behaviour of Dickite dimethylsulfoxide intercalation complex
    Journal of Thermal Analysis and Calorimetry, 2003
    Co-Authors: F Franco, M Ruiz D Cruz
    Abstract:

    The thermal behaviour of the intercalation complex of a Dickite from Tarifa, Spain, with dimethylsulfoxide was studied by high-temperature X-ray diffraction, differential thermal analysis and thermogravimetry, and attenuated total reflectance infrared spectroscopy. The ATR-FTIR study indicated that the heating between room temperature and 75°C produced the elimination of adsorbed molecules. Above this temperature the elimination of intercalated molecules occurs through several stages. Loss of 6.5% of the intercalated DMSO first causes a slight contraction of the basal spacing at 90sC due to a rearrangement of the DMSO molecules in the interlayers positions. This contraction is followed by the formation of a single layer complex and the restoring of the Dickite structure, at 300°C, when the loss of intercalated species have been completed.

  • kaolinite and Dickite formation during shale diagenesis isotopic data
    Applied Geochemistry, 1998
    Co-Authors: M Ruiz D Cruz, E Reyes
    Abstract:

    Abstract X-ray diffraction, scanning electron microscopy and O-isotope geochemistry have been used to investigate the origin and possible controls on polymorphic transformation of kaolin minerals filling veins in Cretaceous shales from the Gibraltar Strait area (southern Spain). The mineralogy of the enclosing shales indicates that kaolin minerals formed from smectite dissolution, a process that silmultaneously originated I/S mixed-layers and quartz. Kaolinite and Dickite δ18O values suggest that an increase in the water isotopic composition, from Cretaceous sea water values (−1%) to values of about 3%, occurred parallel to smectite dissolution, the intensity of this process being the main factor controlling the isotopic composition of kaolin minerals. The minimum formation temperature ranges from 62°C for kaolinite to 86–96°C for Dickite, indicating that the depth of burial was the main control on polymorph formation. This temperature range agrees with that deduced for illite/smectite ordering. The passage from kaolinite- to Dickite-rich veins was accompanied, as deduced from SEM examination, by a morphologic evolution characterized by the division of large vermiculae, dominant in kaolinite samples, and the formation of short stacks and platy crystals, which are predominant in Dickite. The mechanism of Dickite formation, however, remains uncertain.

  • Dickite nacrite and possible Dickite nacrite mixed layers from the betic cordilleras spain
    Clays and Clay Minerals, 1996
    Co-Authors: M Ruiz D Cruz
    Abstract:

    Nacrite, Dickite and intermediate Dickite-nacrite phases have been identified from the upper Paleozoic sequences of the Malaguide Complex (Betic Cordilleras, Spain). Nacrite developed as euhedral, pseudohexagonal or elongated crystals within sandstones and thin, irregular veins. Dickite developed preferently within extensive zones of fractures as very irregular, compact packets. Intermediate phases occurred in the sandstones and veins similar to the nacrite, or accompanying Dickite. The mineral assemblage of the sandstones includes quartz-muscovite-kaolinite-type minerals, with or without albite, carbonates, chlorite and mixed-layers containing chlorite. The metamorphic conditions in which these minerals formed belong to anchizone, as can be deduced from the IC values. Dickite, nacrite and intermediate phases were studied by X-ray diffraction, infrared spectroscopy, differential thermal analysis and micros-copy. The results for Dickite indicate a well-ordered mineral and agree with most of the published data. Conversely, IR spectra and DTA curves of nacrite show some differences in relation to the available data for this mineral. Based on the comparison with Dickite and nacrite data, intermediate phases can be interpreted either as disordered varieties or as mixed-layered Dickite/nacrite.

  • genesis and transformation of Dickite in permo triassic sediments betic cordilleras spain
    Clay Minerals, 1996
    Co-Authors: M Ruiz D Cruz, Bartolome Andreo
    Abstract:

    In the Malaguide Complex (Betic Cordilleras, Spain), Dickite is widely developed in clastic Permo-Triassic sequences. The lateral extent stretches at least 300 km along the Betic range, whilst vertical extent is variable and appears limited to the lowest 20-150 m of these sequences. Textural, chemical and crystallochemical characteristics of the Dickite, illite/mica and chlorite in Dickite-bearing rocks and in the overlying (Permo-Triassic) and underlying (Carboniferous) rocks have been investigated to determine the approximate conditions in which Dickite has developed. Using the chlorite geothermometer (based on Al IV contents), temperatures of 146±28°C and 169 ±12°C have been deduced for two Permo-Triassic members, and 305±12°C for Carboniferous. The Si content in illites has been used as a geobarometer, and pressures of 4.8±2 kbar have been estimated in Carboniferous rocks and tentative pressures of 2.7±3 and 2.1±2 kbar in Permo-Triassic members. Chemical evolution of phyllosilicates is accompanied by increasing illite crystallinity and % 2M 1 polytype.

Yoshio Waseda - One of the best experts on this subject based on the ideXlab platform.

Kazumasa Sugiyama - One of the best experts on this subject based on the ideXlab platform.

F Franco - One of the best experts on this subject based on the ideXlab platform.

  • particle size reduction of Dickite by ultrasound treatments effect on the structure shape and particle size distribution
    Applied Clay Science, 2007
    Co-Authors: F Franco, J A Cecila, Luis A Perezmaqueda, J L Perezrodriguez, Celso Gomes
    Abstract:

    This paper reports on the effects of ultrasound treatment on Dickite from Tragos, Mangualde, in Portugal. Ultrasonic treatment modifies both particle size and morphology. The elongated crystals observed in the sample are broken up, after their treatment, along the cleavage planes 001 and 110, mainly along the largest direction (a axis), into smaller units that retain the typical lamellar morphology of the starting crystals. The decrease in particle size results in a significant increase in the specific surface area (SSA). When compared to the structure of the untreated Dickite, X-ray Diffraction (XRD) patterns of the sonicated sample do not reveal appreciable structural modifications. On the contrary, previous results reported for sonicated kaolinite show a progressive decrease of its structural order. The corresponding Fourier Transform Infrared (FTIR) spectra show a decrease of the intensity of the OH stretching bands, which are related to the loss of some OH groups due to prototropic mechanism.

  • a comparative study of the dehydroxylation process in untreated and hydrazine deintercalated Dickite
    Journal of Thermal Analysis and Calorimetry, 2006
    Co-Authors: F Franco, M Ruiz D Cruz
    Abstract:

    A Dickite from Tarifa (Spain) was used to study the influence of the intercalation and the later deintercalation of hydrazine on the dehydroxylation process.

  • thermal behaviour of Dickite dimethylsulfoxide intercalation complex
    Journal of Thermal Analysis and Calorimetry, 2003
    Co-Authors: F Franco, M Ruiz D Cruz
    Abstract:

    The thermal behaviour of the intercalation complex of a Dickite from Tarifa, Spain, with dimethylsulfoxide was studied by high-temperature X-ray diffraction, differential thermal analysis and thermogravimetry, and attenuated total reflectance infrared spectroscopy. The ATR-FTIR study indicated that the heating between room temperature and 75°C produced the elimination of adsorbed molecules. Above this temperature the elimination of intercalated molecules occurs through several stages. Loss of 6.5% of the intercalated DMSO first causes a slight contraction of the basal spacing at 90sC due to a rearrangement of the DMSO molecules in the interlayers positions. This contraction is followed by the formation of a single layer complex and the restoring of the Dickite structure, at 300°C, when the loss of intercalated species have been completed.

  • thermal decomposition of a Dickite hydrazine intercalation complex
    Clays and Clay Minerals, 2000
    Co-Authors: María Dolores Ruiz Cruz, F Franco
    Abstract:

    The intercalation complex of a low-defect Dickite from Tarifa, Spain, with hydrazine was studied by high-temperature X-ray diffraction (HTXRD). differential thermal analysis (DTA), and ther-mogravimetry (TG). The X-ray diffraction (XRD) pattern obtained at room temperature indicated that the intercalation of hydrazine and H2O into Dickite caused an increase of the basal spacing from 7.08 to 10.24 A, which is slightly lower than the 10.4-A spacing commonly observed after intercalation into kaolinite. Heating between 25–50°C produced a structural rearrangement of the complex, which decreased the basal spacing from 10.24 to 9.4 A, and the resulting 9.4-A complex was stable between 50–90°C. Heating between 90–300°C caused a gradual reduction in spacing, which occurred through a set of intermediate phases. These phases were interpreted to be interstratifications of intercalated and non-intercalated layers. These changes were also observed by DTA and TG. Two main endothermic reactions and two main stages of mass loss, respectively, were indicated in the DTA and the TG curves in the temperature range 25–200°C. This behavior suggests that intercalated molecules, hydrazine and H2O, occupied well-defined sites in the interlayer of the Dickite. The intercalated molecules were lost in an ordered fashion as confirmed by the infrared analysis of the decomposition products; H2O was lost in the first stage and ammonia was identified in the second stage. Above 300°C, complete removal of the intercalated molecules restored the basal spacing of the Dickite. However, the basal reflections were broadened, the relative intensities were changed, and changes in the dehydroxylation temperature indicated that the intercalation-desorption process induced some stacking disorder in the Dickite structure.

Yinshan Jiang - One of the best experts on this subject based on the ideXlab platform.

  • the role of potassium chlorate on expansion of Dickite layers and the preparation of a novel tio2 impregnated Dickite photocatalyst using expanded Dickite as carrier
    RSC Advances, 2016
    Co-Authors: Kuo Yang, Xingyuan Wang, Yinshan Jiang
    Abstract:

    The layered Dickite particles were expanded by rapidly heating the mixture of Dickite–urea intercalation complex and KClO3. Then a novel TiO2 impregnated Dickite photocatalyst was prepared from expanded Dickite (used as a carrier) and TiOSO4 aqueous suspension. The resulting expanded Dickite particles and the reaction mechanism were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive spectrometry and specific surface area test. Results showed KClO3 reacted rapidly with the urea molecules remaining on the surfaces of the Dickite–urea intercalation complex in the rapid heating process. A large number of gases produced from the reaction expanded the Dickite layers. The expanded layers could reach 20 nm thick and their average specific surface area was nearly ten times larger than that of raw Dickite. The exposed inner surfaces of the expanded Dickite were new places where TiO2 particles deposited. Photocatalytic activity was evaluated by the degradation of methyl orange in aqueous solutions. The TiO2/Dickite photocatalyst had a porous layer structure and nano-size TiO2 particles, and demonstrated an enhanced adsorption and photocatalytic ability for the removal of methyl orange.

  • preparation of cu Dickite lldpe nanocomposites and synergistic effect of exfoliated Dickite and nano cu in lldpe matrix
    Polymer Composites, 2013
    Co-Authors: Bing Xue, Yinshan Jiang
    Abstract:

    A novel anticorrosion packaging nanocomposite composed of LLDPE (linear low-density polyethylene), nano-sized Cu, and exfoliated Dickite was prepared via melt mixing combined with melt extruding process. X-ray diffraction and transmission electron microscopy (TEM) were employed to characterize the resultant nanocomposite. The results showed that most Dickite layers were exfoliated and the nano-Cu particles were distributed uniformly in the polymer matrix. The characteristic properties of the Cu/Dickite/LLDPE nanocomposite were investigated using salt spray test, thermogravimetry analysis, mechanical test, and antibacterial test. The salt spray test results showed that exfoliated Dickite and nano-Cu improved the anticorrosion properties of the Cu/Dickite/LLDPE nanocomposite in simulated ocean environment, respectively. Furthermore, the coexistence of exfoliated Dickite and nano-Cu in Cu/Dickite/LLDPE nanocomposite produced a synergistic effect on enhancing the anticorrosion properties. Additionally, the co-incorporation of exfoliated Dickite and nano-Cu in LLDPE matrix also improved the thermal-oxidative stability and mechanical properties of the polymer matrix. The bactericidal properties evaluation showed that the Cu/Dickite/LLDPE nanocomposite had better bactericidal ability because of the presence of nano-Cu in LLDPE matrix. POLYM. COMPOS., 34:1061–1070, 2013. © 2013 Society of Plastics Engineers

  • preparation and characterization of linear low density polyethylene Dickite nanocomposites prepared by the direct melt blending of linear low density polyethylene with exfoliated Dickite
    Journal of Applied Polymer Science, 2011
    Co-Authors: Bing Xue, Yinshan Jiang, Mengmeng Sun, Peiping Zhang, Darui Liu
    Abstract:

    Dickite particles were exfoliated by the thermal decomposition of molecular urea in the interlayer of Dickite. The exfoliated Dickite (ED) was composed with linear low-density polyethylene (LLDPE) to prepare a novel LLDPE/Dickite nanocomposite (LDN-5). X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to evaluate the exfoliation effect. FTIR spectra showed that the inner-surface hydroxyls of Dickite decreased because of the sufficient exfoliation of the Dickite layers. The 001 diffraction of Dickite in the XRD pattern almost disappeared after exfoliation; this indicated the random orientation of Dickite platelets. SEM and TEM micrographs confirmed the effective thermal decomposition of the interlamellar molecular urea ED layers, which resulted in smaller particle sizes and better dispersions of Dickite in the resulting LLDPE/Dickite composite. The microstructure of LDN-5 showed that most of the Dickite platelets were exfoliated and homogeneously dispersed in the LLDPE; this led to increases in the anticorrosion properties and thermal stabilities of LDN-5. The results of salt-spray tests illustrated that the corrosion rate of the iron coupon decreased from 23% (LLDPE packing) to 0.4% (LDN-5 packing). Moreover, the thermal degradation temperature corresponding to a mass loss of 10% increased from 330°C (pure LLDPE) to 379°C (LDN-5). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

  • hydrophobic modification of Dickite and salt spray test study on lldpe modified Dickite composite
    Journal of Applied Polymer Science, 2010
    Co-Authors: Bing Xue, Yinshan Jiang, Maosheng Xia, Mengmeng Sun, Darui Liu, Xuguang Zhang
    Abstract:

    Dickite particles were modified by silane coupling agent, hexadecyl phosphate, oleic acid, and stearic acid (SA), respectively. Modified Dickite was composed with linear low-density polyethylene (LLDPE) to prepare a series of LLDPE/modified Dickite composites. Hydrophilicity of modified Dickite was characterized by dispersion experiments and contact angle tests. The results indicated that hydrophilicity of modified Dickite decreases sharply, compared with nonmodified Dickite. Among four modifying agents, SA had obvious effect on hydrophobic modification of Dickite. Fourier-transform infrared spectra results suggested that chemical bonding between modifying agent and Dickite was beneficial to the hydrophobic modification. Results of salt spray tests illustrated that the introduction of modified Dickite into LLDPE improved the anticorrosion properties of the polymer universally. The anticorrosion mechanism of LLDPE/modified Dickite was analyzed by scanning electron microscope micrograph. The mechanical properties of the resultant composites displayed a fact of reinforcement of modified Dickite. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010