scholarly journals The Effects of Acid Activation on the Thermal Properties of Polyvinylpyrrolidone and Organoclay Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
F. Kooli
Keyword(s):  
Clay Mineral ◽  
Chemical Exchange ◽  
Basal Spacing ◽  
Activation Process ◽  
Acid Activation ◽  
X Ray Diffraction ◽  
Exchange Reactions ◽  
Thermal Stabilities ◽  
Stable Product ◽  
Acid Activated Clay

The thermal stabilities of polyvinylpyrrolidone-organoclays or organo-acid-activated clay composites prepared by chemical exchange reactions were assessed. The raw clay mineral was acid-activated prior to expansion by cetyltrimethylammonium surfactants. The acid activation process affected the intercalated amount of cetyltrimethylammonium cations in the resulting organoclays and, thus, the amount of polyvinylpyrrolidone in the composite. The content of cetyltrimethylammonium cations decreased with the extent of acid activation. The organophilic modification of the clay mineral was an important step in the intercalation of the polyvinylpyrrolidone molecules and, thus, in the expansion of the silicate sheets from 3.80 nm to 4.20 nm. The composites exhibited better crystalline order with intense reflections at lower angles. The thermal stability of organoclays, acid-activated clays, and composites was studied using thermogravimetric analysis andin situX-ray diffraction. The decomposition of intercalated surfactants occurred at lower temperatures relative to the neat surfactant salt, and the basal spacing of the organoclays (or acid-activated clays) shrunk to 2.0 nm at 215°C. However, the basal spacing of composites exhibited better stability and collapsed to 2.0 nm at 300°C. This type of material could offer an alternative stable product for engineering purposes in the design of new composites.

scholarly journals Preparation of Fe-intercalated Graphite Based on Coal Tailings, Dimensional Structure

2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Irfan Gustian ◽  
Eka Angasa ◽  
Dwi Agustini ◽  
Evi Maryanti ◽  
Dyiah Fitriani
Keyword(s):  
Crystal Lattice ◽  
Lattice Structure ◽  
Dimensional Structure ◽  
Thermal Method ◽  
Activation Process ◽  
Acid Activation ◽  
X Ray Diffraction ◽  
Intercalated Graphite ◽  
Coal Tailings ◽  
Mining Coal

<p>Intercalated graphite from coal tailings have been modified through the intercalation of iron. Coal tailings which is a byproduct of the destruction process and flakes washing results from mining coal. Intercalation of iron goal is to improve the physical properties of graphite and modifying sizes of crystal lattice structure with thermal method. Modification process begins with the carbonization of coal tailings at 500ºC and activated with phosphoric acid. Activation process has done by pyrolysis at 700ºC. The results of pyrolysis was soaked in mineral oil for 24 hours, then pyrolysis again with variations in temperature 800°C and 900ºC for 1 hour and subsequent intercalation iron at 1% and 2%. Material before activated, after activated, and the results of pyrolysis still indicates order nano: 29, 25 and 36 nm respectively. X-ray diffraction characterization results indicate that change in the structure, the sizes crystal lattice structure of the material The greater the concentration of iron was added, the resulting peak at 2θ = 33 and 35 also will be more sharply. The results of SEM showed different morphologies from each treatment.</p>

Influence of Exchanged Surfactant on the Structure and Adsorption Properties of Brazilian Green Mud Clay

2012 ◽  
Vol 727-728 ◽  
pp. 1473-1478
Author(s):  
Mariaugusta Ferreira Mota ◽  
Fabricio Machado ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Ammonium Chloride ◽  
Basal Spacing ◽  
Natural Clay ◽  
X Ray Diffraction ◽  
Exchange Reactions ◽  
X Ray ◽  
Dimethyl Benzyl ◽  
Dimethyl Benzyl Ammonium ◽  
Green Clay

This work presents an experimental study focusing on the preparation and characterization of modified natural green clay-mud with quaternary ammonium salts of chloride and alkyl dimethyl benzyl ammonium chloride (Dodigen) and dimethyl stearyl ammonium chloride (Praepagen). X ray Diffraction (XRD), infrared spectroscopy (IR) and expansion tests (adsorption capacity and Foster swelling) measurements were performed in order to evaluate the performance of the ion exchange reactions and the degree of affinity with oil products. It is observed an increasing in the XRD basal spacing of the modified clays (1.96 nm and 2.25 nm for Praepagen and Dodigen salts, respectively) in comparison to the observed value (1.56 nm) for the natural clay. The IR results showed that salts were successfully incorporated to natural clay structure. Based on the expansion tests the organoclays presented the best efficiency independent on the kind of solvent used in comparison with the natural clay performance.

scholarly journals Characterisation of Natural and HDTMA-Br Modified Dijah-Monkin Bentonite Clay: FTIR, XRF, XRD and SEM

2021 ◽  
Vol 7 (5) ◽  
pp. 2010-2018
Author(s):  
Olukayode Gideon Oloyede ◽  
◽  
Umar Omeiza Aroke ◽  
Saidat Olanipekun Giwa ◽  
Alexander Asanja Jock ◽  
...  
Keyword(s):  
Cation Exchange Capacity ◽  
Bentonite Clay ◽  
Exchange Capacity ◽  
Basal Spacing ◽  
Hexadecyltrimethylammonium Bromide ◽  
Acid Activation ◽  
X Ray Diffraction ◽  
X Ray ◽  
North East ◽  
Scanning Electron

In this study, Dijah-Monkin bentonite clay was modified with a cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) at the level of twice the cation exchange capacity (CEC). This process results in the development of hydrophobic organoclay with an improved adsorption capacity. The clay obtained from Zing LGA Taraba State, North-East Nigeria, was beneficiated and pulverised to a particle size of 125 µm. The modification was performed without acid activation to prevent damages to the clay’s crystal structure. The organoclay was characterised for chemical composition, functional groups, mineralogical and surface morphology using X-ray fluorescence (XRF), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The XRD showed an increase in the basal spacing from 15.681Å to 17.758 Å, while the XRF revealed a 5.35% concentration of Br on the modified clay, indicating successful intercalation. The FTIR spectra also revealed the appearance of symmetric and asymmetric stretching bands at 2847.7cm-1 and 2914.8cm-1, respectively, as a consequence of the modification, resulting in more sites for adsorption.

Adsorption of cetyltrimethylammonium ions on an acid-activated smectite and their thermal stability

Clay Minerals ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 233-243 ◽  
Author(s):  
F. Kooli ◽  
P. C. M. M. Magusin
Keyword(s):  
Surfactant Solution ◽  
Significant Degree ◽  
Magic Angle Spinning ◽  
Basal Spacing ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
Intercalated Compounds ◽  
Angle Spinning ◽  
Acid Activated Clay

AbstractThe intercalation of the cationic surfactant cetyltrimethylammonium (C16TMA) into the interlayer of an acid-activated clay in the presence of different anions has been studied in detail. When Br or OH anions were used, the basal spacing increased significantly, the increase being related to the loading concentration of the surfactant solution. For intercalated compounds prepared from the hydroxide form, the basal spacing at room temperature varied from 1.6 to 3.8 nm. However, for organoclays prepared from the surfactant bromide, the basal spacing is almost loading- independent (1.9 nm). The use of hydroxide and bromide at higher pH is crucial to intercalating larger amounts of C16TMA cations and, hence, to improving the exfoliation of the silicate sheets. Magic-angle spinning 13C nuclear magnetic resonance spectroscopy indicates that the intercalated surfactants exhibit a significant degree of gauche conformation. According to in situ powder X-ray diffraction, an increase of the basal spacing to 4.08 nm is observed at intermediate temperatures of 50 to 150°C for organoclay with an initial basal spacing of 3.7 nm. At higher temperatures, decomposition of the surfactant occurs and the basal spacing decreases to ~1.4 nm.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Characterization and catalytic properties of a saponite clay modified by acid activation

Clay Minerals ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 633-643 ◽  
Author(s):  
F. Kooli ◽  
W. Jones
Keyword(s):  
Infrared Spectroscopy ◽  
Room Temperature ◽  
Textural Properties ◽  
Acid Sites ◽  
Single Type ◽  
Activation Process ◽  
Acid Activation ◽  
Strongly Correlated ◽  
Lewis Site ◽  
Adsorbed Pyridine

AbstractA natural saponite was acid activated at room temperature or 90°C with different acid/clay ratios and the products were characterized by powder X-ray diffraction, infrared spectroscopy and thermogravimetry. The leaching of Mg from the octahedral sheets is enhanced by an increase in the acid/clay ratio and by an increase in temperature of activation. Textural properties are reported, and it appears that they are strongly correlated to the presence of a noncrystalline silica phase which is formed during the acid activation process. The desorption of cyclohexylamine indicates that for samples activated at 90°C the number of acid sites in the acidactivated saponites decreases following severe acid treatment. Infrared spectroscopy of adsorbed pyridine on samples after calcination at 500°C suggests that acid activation at 90°C produces a single type of Bronsted site but two types of Lewis sites whereas activation at room temperature results in only one type of Lewis site in addition to a Brønsted site. The two Lewis sites are suggested to originate from residual Al in the clay structure and to AI exsolved from the layers during activation. The dehydration of pentan-1-ol has been used as a further probe to measure acidity by monitoring the degree of conversion and selectivity for the different samples.

Optimization of the acid activation process of bentonite

2021 ◽  
Vol 11 (9) ◽  
pp. 589-597
Author(s):  
Jobir X. Xamroyev ◽  
Normurot I. Fayzullayev ◽  
Jasur H. Shukurov ◽  
Rustam D. Berdiyev
Keyword(s):  
Activation Process ◽  
Acid Activation

scholarly journals Chemical Interaction-Induced Evolution of Phase Compatibilization in Blends of Poly(hydroxy ether of bisphenol-A)/Poly(1,4-butylene terephthalate)

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1667
Author(s):  
Jing Liu ◽  
Hsiang-Ching Wang ◽  
Chean-Cheng Su ◽  
Cheng-Fu Yang
Keyword(s):  
Bisphenol A ◽  
Chemical Interaction ◽  
Chemical Exchange ◽  
Hydroxyl Group ◽  
Random Copolymers ◽  
Exchange Reactions ◽  
Butylene Terephthalate ◽  
Alcoholysis Reaction ◽  
Immiscible Blend ◽  
Hydroxy Ether

An immiscible blend of poly(hydroxy ether of bisphenol-A) (phenoxy) and poly(1,4-butylene terephthalate) (PBT) with phase separation was observed in as-blended samples. The compatibilization of phenoxy/PBT blends can be promoted through chemical exchange reactions of phenoxy with PBT upon annealing. The annealed phenoxy/PBT blends had a homogeneous phase with a single Tg that could be enhanced by annealing at 260 °C. Infrared (IR) spectroscopy demonstrated that phase homogenization could be promoted by annealing the phenoxy/PBT blend, where alcoholytic exchange occurred between the dangling hydroxyl group (–OH) in phenoxy and the carbonyl group (C=O) in PBT in the heated blends. The alcoholysis reaction changed the aromatic linkages to aliphatic linkages in the carbonyl groups, which initially led to the formation of a graft copolymer of phenoxy and PBT with an aliphatic/aliphatic carbonyl link. The progressive alcoholysis reaction resulted in the transformation of the initial homopolymers into block copolymers and finally into random copolymers, which promoted phase compatibilization in blends of phenoxy with PBT. As the amount of copolymers increased upon annealing, the crystallization of PBT was inhibited by alcoholytic exchange in the blends.

Syntheses, Crystal Structures and Thermal Stability of Co(II) and Zn(II) Complexes with Ethyl Carbazate

2005 ◽  
Vol 60 (5) ◽  
pp. 505-510 ◽  
Author(s):  
Tong-Lai Zhang ◽  
Jiang-Chuang Song ◽  
Jian-Guo Zhang ◽  
Gui-Xia Ma ◽  
Kai-Bei Yu
Keyword(s):  
Thermal Stability ◽  
Aqueous Solutions ◽  
Diffraction Analysis ◽  
Single Crystals ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
Element Analysis ◽  
Thermal Stabilities ◽  
X Ray ◽  
Thermal Stability Of

Cobalt(II) and zinc(II) complexes of ethyl carbazate (ECZ), [Co(ECZ)3](NO3)2 and [Zn(ECZ)3] (NO3)2, were synthesized. Single crystals of these two compounds were grown from aqueous solutions using a slow evaporation method. Their structures have been determined by X-ray diffraction analysis. Both of them are monoclinic with space group P21/n. The complexes are further characterized by element analysis and IR measurements. Their thermal stabilities are studied by using TG-DTG, DSC techniques. When heated to 350 °C, only metal oxide was left for both complexes.

scholarly journals Preparation and Characterization of Polyhydroxybutyrate/Polycaprolactone Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Cha Ping Liau ◽  
Mansor Bin Ahmad ◽  
Kamyar Shameli ◽  
Wan Md Zin Wan Yunus ◽  
Nor Azowa Ibrahim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Basal Spacing ◽  
Cooh Group ◽  
Physical Interaction ◽  
X Ray Diffraction ◽  
Ion Exchange Reaction ◽  
Transmission Electron ◽  
Matrix Enhancement ◽  
Double Hydroxide

Polyhydroxybutyrate (PHB)/polycaprolactone (PCL)/stearate Mg-Al layered double hydroxide (LDH) nanocomposites were prepared via solution casting intercalation method. Coprecipitation method was used to prepare the anionic clay Mg-Al LDH from nitrate salt solution. Modification of nitrate anions by stearate anions between the LDH layers via ion exchange reaction. FTIR spectra showed the presence of carboxylic acid (COOH) group which indicates that stearate anions were successfully intercalated into the Mg-Al LDH. The formation of nanocomposites only involves physical interaction as there are no new functional groups or new bonding formed. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the mixtures of nanocomposites are intercalated and exfoliated types. XRD results showed increasing of basal spacing from 8.66 to 32.97 Å in modified stearate Mg-Al LDH, and TEM results revealed that the stearate Mg-Al LDH layers are homogeneously distributed in the PHB/PCL polymer blends matrix. Enhancement in 300% elongation at break and 66% tensile strength in the presence of 1.0 wt % of the stearate Mg-Al LDH as compare with PHB/PCL blends. Scanning electron microscopy (SEM) proved that clay improves compatibility between polymer matrix and the best ratio 80PHB/20PCL/1stearate Mg-Al LDH surface is well dispersed and stretched before it breaks.

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