scholarly journals Changes in suspension properties of structural modified montmorillonites

Cerâmica ◽  
2001 ◽  
Vol 47 (301) ◽  
pp. 4-8 ◽  
Author(s):  
C. Volzone ◽  
L. B. Garrido

Rheological changes were found in smectite (Wyoming- and Cheto-type montmorillonites) suspensions after structural modifications. The effect of the particle size and Na+ exchange on the flow curves of 6% wt/wt suspensions of smectites with and without Na2CO3 were examined. Mineralogical, structural and physicochemical characteristics were studied by X-ray diffraction (XRD), infrared spectroscopy (IR), cationic exchange capacity (CEC), Mg2+, Al3+ determinations, particle size distribution and swelling index (SI). Grinding in an oscillating mill modified the particle sizes. The montmorillonite grain size and the structural disorder increased after larger grinding times. The grinding treatment modified the apparent viscosity and the yield stress of the montmorillonite suspensions. The homoionic Na Cheto-type montmorillonite with fine particle size (obtained by grinding) increased the flow properties. Nevertheless, rheological properties were lower than those of suspensions of the Wyoming-type montmorillonite. Montmorillonite-types reacted differently with Na2CO3 additions and this behavior may be related to their structural composition. The Na2CO3 activation improved the flow properties of the original Wyoming-type montmorillonite and after 30 s grinding.

2012 ◽  
Vol 510 ◽  
pp. 757-761 ◽  
Author(s):  
Shu’e Duan ◽  
Yun Hui Zhai ◽  
Ying Juan Qu

In this paper a novel colorless and salt-tolerant silver-histidine complex doped montmorillonite (Na-MMT) antibacterial agent (SHMMT) power was synthesized by ion exchange reaction using silver-histidine complex ion [Ag (his)] + as precursor, and characterized by atomic absorption spectrophotometer (AAS) and power X-ray diffraction (XRD). The antibacterial activities against Pseudoalteromonas carrageenovora were examined by a modified broth dilution test and the plate counting method. The salt-tolerant property was determined by the antibacterial activities of the sea water soaked SHMMT. The results showed that the Ag loading amount of SHMMT powder reached 1.7mmol/g, far more than the cationic exchange capacity (CEC) of Na-MMT. SHMMT powder had high bacterial activity eventhough it was soaked in the sea water for 30 days. 1


1966 ◽  
Vol 12 (6) ◽  
pp. 1235-1246 ◽  
Author(s):  
G. Stotzky

The stimulation of bacterial respiration by clay minerals was related to certain physicochemical characteristics of clays. Respiration increased with an increase in the cation exchange capacity and surface area of the particles. The importance of surface area, however, could not be unequivocally established, as some of the methods used to determine this characteristic on certain clay species were questionable. Particle size did not appear to be a critical characteristic. The implications of the cation exchange capacity of clay minerals in the activity, ecology, and population dynamics of microorganisms in nature are discussed.


2021 ◽  
Author(s):  
MAZOURI BELHADRI ◽  
Adel Mokhtar ◽  
Abdelkader Bengueddach Bengueddach ◽  
mohamed sassi

Abstract The current study focused on the modification of Algerian bentonite clay (Bent) with the product of hydrolysis of 3-aminopropyltriethoxysilane (APTES) using the intercalation process. The modified clay (Bent-APTES) was investigated as an adsorbent solid for methylene blue dye (MB) removal from wastewater.The Bent-APTES was characterized by X-ray diffraction (XRD), chemical analyses, Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The cationic exchange capacity was also determined. Several adsorption parameters were evaluated on the adsorption performance. The results showed that the equilibrium adsorption data was found to fit better to the Langmuir adsorption model, and the adsorption capacity for the removal of MB on Bent-APTES was 217.39 mg g-1. The kinetic process of adsorption could be described by the pseudo-second order model. Consequently, the modified clay could be served as an efficient adsorbent for cationic dyes in wastewater treatment.


2012 ◽  
Vol 499 ◽  
pp. 72-75 ◽  
Author(s):  
Yan Lu

Using three natural graphites with different particle size, 35, 50 and 80 mesh, as raw materials, expandable graphites were prepared by intercalating, water-washing and drying the natural graphites. The products were characterized by X-ray diffraction, Infrared spectroscopy, scanning electron microscope and Raman spectroscopy. Results show that the structure of expandable graphite is affected strongly by the particle size of natural graphite. With increasing the particle size of natural graphite, for expandable graphite, the expansion degree of graphite flakes along the c-axis and the relative ratio of intercalating agents increase, while the structural disorder increases.


2014 ◽  
Vol 1015 ◽  
pp. 713-720
Author(s):  
Si Tao Yang ◽  
Hui Tang ◽  
Yan Fang Liu ◽  
Xue Ying

Gossypol (GP) is a kind of poorly water-soluble polyphenolic compounds. In this study, freeze dried gossypol nanosuspensions (GP-NS) were prepared by high-pressure homogenization and Freeze-drying technique. Bovine serum albumin (BSA) and D-alpha-tocopheryl polyethylene glycol succinate (TPGS) were used as stabilizing agents for the nanosuspensions while mannitol were used as lyophilized protecting medium. The physicochemical characteristics of the GP-NS were investigated when it was found that the mean particle size and zeta potential of the GP-NS were 217±23 nm and-21.4±2.7 mV, respectively, and the saturation solubility was 586.48±23.03 μg.mL-1. Differential scanning calorimetry and X-Ray Diffraction indicated that GP was in a crystalline state in nanosuspensions. GP-NS with a small particle size, and high saturation solubility, can be produced by the method described in this study.


2007 ◽  
Vol 334-335 ◽  
pp. 825-828 ◽  
Author(s):  
Wei Tan ◽  
Yi He Zhang ◽  
Yau Shan Szeto ◽  
Li Bing Liao

It was shown that chitosan and hydroxy-aluminum pillared montmorillonites were excellent materials for the removal of dyes and metal ions from effluent of dying and finishing. Chitosan/ hydroxy-aluminum pillared montmorillonite nanocomposites are expected to play a multiplex role in the treating process. In this study, the nanocomposite was prepared by incorporating hydroxy-aluminum pillared montmorillonite into chitosan solution that diluted acetic acid was used as solvent for dissolving the chitosan. The ratio of chitosan to the cationic exchange capacity of the montmorillonite was about 1:1, 2:1, 3:1, 4:1 and 6:1, respectively. The nanocomposites were characterized by XRD (X-ray diffraction), SEM (Scanning Electron Microscopy). The experimental results indicated that the presence of hydroxy-aluminum cation was in favor of the chitosan intercalation and the interlayers of MMT was intercalated with the bilayers of chitosan sheets. and they can be used in absorption of organic and metal ions for dying and finishing effluent.


2014 ◽  
Vol 798-799 ◽  
pp. 582-587 ◽  
Author(s):  
Joseane Damasceno Mota ◽  
Rochélia Silva Souza Cunha ◽  
Meiry Glaúcia Freire Rodrigues

The clays are emerging as excellent alternative materials in the process of removing organic and inorganic contaminants, that due to it's physicochemical characteristics, it’s easy to obtain and also for low cost. The initial objective of this ( study was to characterize the clay Chocolate B by the techniques of X-ray diffraction (XRD) and cation exchange capacity (CEC). In addition, the testing of finite bath under certain conditions (pH, concentration) in order to better evaluate the efficiency of clay in the removal of heavy metals zinc and lead. It was used a factorial design 22 with addition at the central point, being evaluated the percentage removal (% Rem) and the removal capacity (qeq) by Chocolate B Clay. It was observed that the Chocolate B clay belongs to the smectites group. The results have shown promise in the removal process of the metals zinc and lead by Chocolate B clay.


2013 ◽  
Vol 829 ◽  
pp. 274-278 ◽  
Author(s):  
Mahdokht Faham ◽  
Hooman Shokrollahi ◽  
Gholamhossein Yousefi ◽  
Sahar Abbasi

Our goal is to develop methoxy poly (ethylene glycol) (m-PEG) decorated, glycine capped magnetic nanoparticles (MNPs) with proper physicochemical characteristics including particle size and magnetic property. MNP were synthesized by a biocompatible chemical co-precipitation of Mn2+and Fe3+in a sodium hydroxide solution. In order to covalently modify nanoparticles surface by previously prepared m-PEG aldehyde, glycine was used as linker. X-ray diffraction analysis showed successful formation of pure nanocrystalline single phase of Mn-Ferrite and FT-IR spectroscopy approved that m-PEG and glycine were covalently bound to nanoparticles surface. Particle size study showed significant change after modification. In addition, the Vibrating sample magnetometry was done for measuring the magnetic properties (Ms: 52 emu/g) and showing the superparamagnetism behavior.


2012 ◽  
Vol 727-728 ◽  
pp. 929-934
Author(s):  
Pedro Garcia Lins ◽  
Ticiane Sanches Valera ◽  
Nicole Raymonde Demarquette

In this work, a commercial Brazilian clay (BUN Bentonit União Nordeste), was purified by three different processes. Impurities and iron oxides limit the use of the Brazilian clays in applications such as filler for nanocomposites. The first purification method refers to the separation of the colloidal fraction of the clay, to remove the remaining larger than clay-size impurities. The second step involves the removal of iron oxide or hydroxide (dithionite-citrate-bicarbonate method). Finally, hydrogen peroxide was used to remove from the clay the organic residues. The clays were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and had their particle size distribution measured (laser scattering). The clays were treated with a quaternary ammonium salt, to investigate the modification in its cationic exchange capacity. XRD results showed that the structure of the clay was not significantly modified with the removal of iron, and that there was incorporation of the organic salt into the interlayer space. Approximately 30wt.% of the iron ion content was removed (XRF).


Cerâmica ◽  
2016 ◽  
Vol 62 (363) ◽  
pp. 272-277 ◽  
Author(s):  
C. I. R. de Oliveira ◽  
M. C. G. Rocha ◽  
A. L. N. da Silva ◽  
L. C. Bertolino

Abstract Clays of different composition have been used in the development of polymer nanocomposites. The utilization of bentonite clays of the State of Paraíba, Brazil, has been emphasized mainly due to their availability. However, these bentonite deposits are becoming exhausted after several years of exploitation. Thus, the aim of this work was to characterize bentonite clays recently discovered in the municipality of Cubati, Paraíba. The samples underwent a particle size classification step and were characterized by granulometric analysis by laser diffraction, X-ray fluorescence, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis and cation exchange capacity. The results of particle size distribution showed that the clay samples have similar physical characteristics to bentonite clays of Boa Vista, Paraíba. Results of X-ray diffraction indicated that the mineralogical composition of the samples consisted of montmorillonite, kaolinite and quartz. The characterization of the samples by FTIR confirmed these results. Results of chemical analysis showed that the samples are polycationic bentonite clays and have predominantly different exchangeable cations similar to those seen in South American bentonites.


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