The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Barbara Mazzarotta - One of the best experts on this subject based on the ideXlab platform.

  • primary nucleation of Citric Acid Monohydrate influence of selected impurities
    Chemical Engineering Journal, 1998
    Co-Authors: Marco Bravi, Barbara Mazzarotta
    Abstract:

    An experimental study is presented concerning solubility and primary nucleation kinetics of Monohydrate Citric Acid from pure and selectively impure (KH2PO4, MgSO4·7H2O and FeSO4·7H2O) aqueous solutions. The metastable range of pure solutions is wide, ranging from 6 to 14°C, and the order of primary nucleation, equal to 2.51, is quite low. The addition of the tested impurities, which are usual fermentation aids, at concentrations lower than wt. 1%, produces negligible effects on the solubility and slightly enhances the primary nucleation rate. However, the presence of these compounds modifies the crystal habit at birth: in particular, the addition of MgSO4·7H2O and FeSO4·7H2O makes these crystals more elongated, but this effect diminishes as the crystals grow.

  • Size dependency of Citric Acid Monohydrate growth kinetics
    Chemical Engineering Journal, 1998
    Co-Authors: Marco Bravi, Barbara Mazzarotta
    Abstract:

    Abstract An experimental study concerned with the growth kinetics of Citric Acid Monohydrate crystals is presented. Due to the properties of the system, which is very soluble, with low solid-liquid density difference and high liquid viscosity, two different techniques were used: large crystals (710–850 μm) were grown in a fluidized bed crystallizer; small crystals, belonging to three size ranges from 90 to 355 μm, were grown in the cell of a laser light diffraction granulometer. A first order growth kinetics resulted in both cases; a comparative analysis of both the present data and those reported in the literature relevant to larger or smaller crystals, indicates that the system exhibits size-dependent growth, which increases linearly with the crystal size.

  • Size dependency of Citric Acid Monohydrate growth kinetics
    'Elsevier BV', 1998
    Co-Authors: Marco Bravi, Barbara Mazzarotta
    Abstract:

    An experimental study concerned with the growth kinetics of Citric Acid Monohydrate crystals is presented. Due to the properties of the system, which is very soluble, with low solid-liquid density difference and high liquid viscosity, two different techniques were used: large crystals (710-850 mu m) were grown in a fluidized bed crystallizer; small crystals, belonging to three size ranges from 90 to 355 mu m, were grown in the cell of a laser light diffraction granulometer. A first order growth kinetics resulted in both cases; a comparative analysis of both the present data and those reported in the literature relevant to larger or smaller crystals, indicates that the system exhibits size-dependent growth, which increases linearly with the crystal size. (C) 1998 Elsevier Science S.A. All rights reserved

  • Primary nucleation of Citric Acid Monohydrate: influence of selected impurities
    'Elsevier BV', 1998
    Co-Authors: Marco Bravi, Barbara Mazzarotta
    Abstract:

    An experimental study is presented concerning solubility and primary nucleation kinetics of Monohydrate Citric Acid from pure and selectively impure (KH2PO4, MgSO4. 7H(2)O and FeSO4. 7H(2)O) aqueous solutions. The metastable range of pure solutions is wide, ranging from 6 to 14 degrees C, and the order of primary nucleation, equal to 2.51, is quite low. The addition of the tested impurities, which are usual fermentation aids, at concentrations lower than wt. 1%, produces negligible effects on the solubility and slightly enhances the primary nucleation rate. However, the presence of these compounds modifies the crystal habit at birth: in particular, the addition of MgSO4. 7H(2)O and FeSO4. 7H(2)O makes these crystals more elongated, but this effect diminishes as the crystals grow. (C) 1998 Elsevier Science S.A. All rights reserved

Zhong H Zhu - One of the best experts on this subject based on the ideXlab platform.

  • synthesis and structure characterization of chromium oxide prepared by solid thermal decomposition reaction
    Journal of Physical Chemistry B, 2006
    Co-Authors: Zi F Yan, Zhong H Zhu
    Abstract:

    Mesoporous chromium oxide (Cr2O3) nanocrystals were first synthesized by the thermal decomposition reaction of Cr(NO3)3.9H2O using Citric Acid Monohydrate (CA) as the mesoporous template agent. The texture and chemistry of chromium oxide nanocrystals were characterized by N2 adsorption-desorption isotherms, FTIR, X-ray diffraction (XRD), UV-vis, and thermoanalytical methods. It was shown that the hydrate water and CA are the crucial factors in influencing the formation of mesoporous Cr2O3 nanocrystals in the mixture system. The decomposition of CA results in the formation of a mesoporous structure with wormlike pores. The hydrate water of the mixture provides surface hydroxyls that act as binders, making the nanocrystals aggregate. The pore structures and phases of chromium oxide are affected by the ratio of precursor-to-CA, thermal temperature, and time.

  • Synthesis and Structure Characterization of Chromium Oxide Prepared by Solid Thermal Decomposition Reaction
    The Journal of Physical Chemistry B, 2006
    Co-Authors: Zi F Yan, Zhong H Zhu
    Abstract:

    Mesoporous chromium oxide (Cr2O3) nanocrystals were first synthesized by the thermal decomposition reaction of Cr(NO3)(3)(circle)9H(2)O using Citric Acid Monohydrate (CA) as the mesoporous template agent. The texture and chemistry of chromium oxide nanocrystals were characterized by N-2 adsorption-desorption isotherms, FTIR, X-ray diffraction (XRD), UV-vis, and thermoanalytical methods. It was shown that the hydrate water and CA are the crucial factors in influencing the formation of mesoporous Cr2O3 nanocrystals in the mixture system. The decomposition of CA results in the formation of a mesoporous structure with wormlike pores. The hydrate water of the mixture provides surface hydroxyls that act as binders, making the nanocrystals aggregate. The pore structures and phases of chromium oxide are affected by the ratio of precursor-to-CA, thermal temperature, and time.

Cheeyuen Gan - One of the best experts on this subject based on the ideXlab platform.

  • could choline chloride Citric Acid Monohydrate molar ratio in deep eutectic solvent affect structural functional and antioxidant properties of pectin
    International Journal of Biological Macromolecules, 2020
    Co-Authors: Muhammad Hakimin Shafie, Cheeyuen Gan
    Abstract:

    The deep eutectic solvents (DESs), which were made from different molar ratios (3:1, 2:1, 1:1, 1:2, 1:3) of choline chloride and Citric Acid Monohydrate, were used as media for the pectic polysaccharide extraction from Averrhoa bilmbi (ABP). The physico-chemical, structural, functional and antioxidant properties of ABP were subsequently determined. The ABP was found to be xylogalacturonan. Moreover, results showed that different structures (i.e. linearity of pectin and branch size) of ABP were obtained, hence, affecting the solubility and functional properties due to the surface availability and steric effect. In addition, when increasing the molar ratio of Citric Acid Monohydrate in DES, lower pH and higher TPC values were observed. These values were correlated with antioxidant activities (i.e. free radical scavenging activity and ferric reducing antioxidant power) of ABP. In conclusion, the molar ratio of the DES components plays an important role in extracting ABP with the aforementioned properties.

  • synthesis of Citric Acid Monohydrate choline chloride based deep eutectic solvents des and characterization of their physicochemical properties
    Journal of Molecular Liquids, 2019
    Co-Authors: Muhammad Hakimin Shafie, Rizana Yusof, Cheeyuen Gan
    Abstract:

    Abstract The objective of the study was to synthesize deep eutectic solvents (DES) using choline chloride and Citric Acid Monohydrate at different molar ratios (i.e. DES 3:1, 2:1, 1:1, 1:2 and 1:3) followed by physicochemical characterization. The DES produced were clear and homogenized liquids under a microscopic observation, and DES 1:1 was found to meet the eutectic point with the lowest melting temperature. Fourier-transform infrared spectroscopy (FTIR) analysis showed the hydrogen bond interaction between the components in DES where the wavenumbers of functional groups were shifted. Results also showed that when the molar ratio of Citric Acid Monohydrate increased in DES, higher values of viscosity, surface tension and density were observed. It was also found that the DES produced were classified as hydrophilic DES because of their solubility in water, highly polar and most semi polar solvents. In summary, the DES synthesized was suggested to be used as a medium for the extraction of hydrophilic components from plant or animal materials.

Marco Bravi - One of the best experts on this subject based on the ideXlab platform.

  • primary nucleation of Citric Acid Monohydrate influence of selected impurities
    Chemical Engineering Journal, 1998
    Co-Authors: Marco Bravi, Barbara Mazzarotta
    Abstract:

    An experimental study is presented concerning solubility and primary nucleation kinetics of Monohydrate Citric Acid from pure and selectively impure (KH2PO4, MgSO4·7H2O and FeSO4·7H2O) aqueous solutions. The metastable range of pure solutions is wide, ranging from 6 to 14°C, and the order of primary nucleation, equal to 2.51, is quite low. The addition of the tested impurities, which are usual fermentation aids, at concentrations lower than wt. 1%, produces negligible effects on the solubility and slightly enhances the primary nucleation rate. However, the presence of these compounds modifies the crystal habit at birth: in particular, the addition of MgSO4·7H2O and FeSO4·7H2O makes these crystals more elongated, but this effect diminishes as the crystals grow.

  • Size dependency of Citric Acid Monohydrate growth kinetics
    Chemical Engineering Journal, 1998
    Co-Authors: Marco Bravi, Barbara Mazzarotta
    Abstract:

    Abstract An experimental study concerned with the growth kinetics of Citric Acid Monohydrate crystals is presented. Due to the properties of the system, which is very soluble, with low solid-liquid density difference and high liquid viscosity, two different techniques were used: large crystals (710–850 μm) were grown in a fluidized bed crystallizer; small crystals, belonging to three size ranges from 90 to 355 μm, were grown in the cell of a laser light diffraction granulometer. A first order growth kinetics resulted in both cases; a comparative analysis of both the present data and those reported in the literature relevant to larger or smaller crystals, indicates that the system exhibits size-dependent growth, which increases linearly with the crystal size.

  • Size dependency of Citric Acid Monohydrate growth kinetics
    'Elsevier BV', 1998
    Co-Authors: Marco Bravi, Barbara Mazzarotta
    Abstract:

    An experimental study concerned with the growth kinetics of Citric Acid Monohydrate crystals is presented. Due to the properties of the system, which is very soluble, with low solid-liquid density difference and high liquid viscosity, two different techniques were used: large crystals (710-850 mu m) were grown in a fluidized bed crystallizer; small crystals, belonging to three size ranges from 90 to 355 mu m, were grown in the cell of a laser light diffraction granulometer. A first order growth kinetics resulted in both cases; a comparative analysis of both the present data and those reported in the literature relevant to larger or smaller crystals, indicates that the system exhibits size-dependent growth, which increases linearly with the crystal size. (C) 1998 Elsevier Science S.A. All rights reserved

  • Primary nucleation of Citric Acid Monohydrate: influence of selected impurities
    'Elsevier BV', 1998
    Co-Authors: Marco Bravi, Barbara Mazzarotta
    Abstract:

    An experimental study is presented concerning solubility and primary nucleation kinetics of Monohydrate Citric Acid from pure and selectively impure (KH2PO4, MgSO4. 7H(2)O and FeSO4. 7H(2)O) aqueous solutions. The metastable range of pure solutions is wide, ranging from 6 to 14 degrees C, and the order of primary nucleation, equal to 2.51, is quite low. The addition of the tested impurities, which are usual fermentation aids, at concentrations lower than wt. 1%, produces negligible effects on the solubility and slightly enhances the primary nucleation rate. However, the presence of these compounds modifies the crystal habit at birth: in particular, the addition of MgSO4. 7H(2)O and FeSO4. 7H(2)O makes these crystals more elongated, but this effect diminishes as the crystals grow. (C) 1998 Elsevier Science S.A. All rights reserved

Muhammad Hakimin Shafie - One of the best experts on this subject based on the ideXlab platform.

  • A comparison of properties between the Citric Acid Monohydrate and deep eutectic solvent extracted Averrhoa bilimbi pectins
    Journal of Food Measurement and Characterization, 2020
    Co-Authors: Muhammad Hakimin Shafie
    Abstract:

    Previous study showed that deep eutectic solvent (DES)-extracted pectin exhibited undesirable structural and functional properties. It has to be noted that most of the researchers were seeking the parameters that could increase the extraction yield and neglected the importance of the pectin structures that could ultimately affect the functional properties. Hence, a comparison between the use of DES and less Acidic medium (Citric Acid Monohydrate, CAM) in extracting the pectin was conducted. This study demonstrated that the mediums used significantly influenced these aforementioned properties and the optimum extraction parameters. The maximum Averrhoa bilimbi pectin (ABP) yield (9.34%) was obtained at the optimal condition: CAM percentage = 3.71% (w/v), extraction temperature = 80 °C and extraction time = 3.0 h. The result showed that extraction using CAM required longer time (30 min more) than DES and the yield was lower (4.96% less). Apart from that, ABP-CAM was found lower in linearity with higher contribution of RG and branch size of the pectin compared to the ABP-DES which was found to be more linear pectin with a lower contribution of RG and less branch size. Besides that, it was also observed that using CAM as the extraction medium had improved the water holding capacity (6.22%), emulsifying activity (145.59%) and ferric reducing antioxidant power (38.26%) compared to ABP-DES. Overall, it suggested that the extraction medium plays an important role in the extraction of the pectin, structure of the pectin and, hence affects the properties of the extracted pectin.

  • could choline chloride Citric Acid Monohydrate molar ratio in deep eutectic solvent affect structural functional and antioxidant properties of pectin
    International Journal of Biological Macromolecules, 2020
    Co-Authors: Muhammad Hakimin Shafie, Cheeyuen Gan
    Abstract:

    The deep eutectic solvents (DESs), which were made from different molar ratios (3:1, 2:1, 1:1, 1:2, 1:3) of choline chloride and Citric Acid Monohydrate, were used as media for the pectic polysaccharide extraction from Averrhoa bilmbi (ABP). The physico-chemical, structural, functional and antioxidant properties of ABP were subsequently determined. The ABP was found to be xylogalacturonan. Moreover, results showed that different structures (i.e. linearity of pectin and branch size) of ABP were obtained, hence, affecting the solubility and functional properties due to the surface availability and steric effect. In addition, when increasing the molar ratio of Citric Acid Monohydrate in DES, lower pH and higher TPC values were observed. These values were correlated with antioxidant activities (i.e. free radical scavenging activity and ferric reducing antioxidant power) of ABP. In conclusion, the molar ratio of the DES components plays an important role in extracting ABP with the aforementioned properties.

  • synthesis of Citric Acid Monohydrate choline chloride based deep eutectic solvents des and characterization of their physicochemical properties
    Journal of Molecular Liquids, 2019
    Co-Authors: Muhammad Hakimin Shafie, Rizana Yusof, Cheeyuen Gan
    Abstract:

    Abstract The objective of the study was to synthesize deep eutectic solvents (DES) using choline chloride and Citric Acid Monohydrate at different molar ratios (i.e. DES 3:1, 2:1, 1:1, 1:2 and 1:3) followed by physicochemical characterization. The DES produced were clear and homogenized liquids under a microscopic observation, and DES 1:1 was found to meet the eutectic point with the lowest melting temperature. Fourier-transform infrared spectroscopy (FTIR) analysis showed the hydrogen bond interaction between the components in DES where the wavenumbers of functional groups were shifted. Results also showed that when the molar ratio of Citric Acid Monohydrate increased in DES, higher values of viscosity, surface tension and density were observed. It was also found that the DES produced were classified as hydrophilic DES because of their solubility in water, highly polar and most semi polar solvents. In summary, the DES synthesized was suggested to be used as a medium for the extraction of hydrophilic components from plant or animal materials.