scholarly journals Acid Black 194 Dye Clarifications Onto Natural And Acid/Base Activated Smectitic Clays

2021 ◽  
Author(s):  
Salima Chakroun ◽  
Haitham Elleuch ◽  
Dalel Sghaier ◽  
Mohamed Gaied
Keyword(s):  
Surface Area ◽  
Dye Adsorption ◽  
Effluent Treatment ◽  
Acid Activation ◽  
X Ray Diffraction ◽  
Optimum Result ◽  
Batch System ◽  
Before And After ◽  
Activation Conditions ◽  
Better Than

Abstract The present work is concerned the Acid Black 194 dye adsorption by Two smectitic clays (BJ and AJ) aged upper Eocene were sampled from Atlas Central of Tunisia in Kairouan region. Technical characterization was carried out using calcimetry and X-ray diffraction. The activation studies of clays by HCl/ Na2CO3 have been conducted to improve their physicochemical properties. The optimum result of the surface area after acid activation (aa) was 398 m2/g for BJ aa and AJ aa, after basic activation (ab) the surface area was 460 m2 /g for BJ ab and 440 m2/g for AJ ab. The characterization by XRD, chemical analysis and SEM observations, were performed before and after optimum activation.Moreover, the raw and activated samples (aa/ab) under the optimum activation conditions were used in the effluent treatment. Adsorption tests were made by batch system at 25 °C in different pH (2-12) and by varying the adsorbent amount (0.025-0.1 g). The best adsorption results were recorded with pH = 11 and amount adsorbent 0.025 g. The raw clay adsorption capacity was slightly better than activated samples. The best yield was given by BJ (94%). Therefore, clay can be used in various applications without any characteristic modification.

Synthesis and Characterization of Porous Mo-W Oxide Nanostructures

2008 ◽  
Vol 8 (12) ◽  
pp. 6445-6450
Author(s):  
F. Paraguay-Delgado ◽  
Y. Verde ◽  
E. Cizniega ◽  
J. A. Lumbreras ◽  
G. Alonso-Nuñez
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Synthesis Method ◽  
Atomic Ratio ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Before And After

The present study reports the synthesis method, microstructure characterization, and thermal stability of nanostructured porous mixed oxide (MoO3-WO3) at 550 and 900 °C of annealing. The material was synthesized using a hydrothermal method. The precursor was prepared by aqueous solution using ammonium heptamolibdate and ammonium metatungstate, with an atomic ratio of Mo/W = 1. The pH was adjusted to 5, and then the solution was transferred to a teflon-lined stainless steel autoclave and heated at 200 °C for 48 h. The resultant material was washed using deionized water. The specific surface area, morphology, composition, and microstructure before and after annealing were studied by N2 physisorption, scanning electron microscopy (SEM), analytical transmission electron microscopy (TEM), and X-Ray diffraction (XRD). The initial synthesized materials showed low crystallinity and high specific surface area around (141 m2/g). After thermal annealing the material showed higher crystallinity and diminished its specific surface area drastically.

The effect of oxalic acid activation on the bleaching properties of a bentonite from Milos Island, Greece

Clay Minerals ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 541-549 ◽  
Author(s):  
M. Taxiarchou ◽  
I. Douni
Keyword(s):  
Oxalic Acid ◽  
Bleaching Earth ◽  
Activation Parameters ◽  
Pulp Density ◽  
Acid Activation ◽  
Activation Time ◽  
Industrial Use ◽  
Activation Conditions ◽  
Activation Times ◽  
Better Than

AbstractA bentonite from Milos, Greece, was activated with oxalic acid and the effect of acid activation conditions on bleaching of sunflower oil was investigated. The activation parameters studied were temperature, retention time and oxalic acid to bentonite mass ratio. The activated materials produced had good bleaching properties and were suitable for industrial use as bleaching earths. Optimum bleaching properties could be achieved using a variety of combinations of acid to bentonite ratios and activation times. Bleaching efficiency tests indicated that 24 h activation at 100°C with 1m oxalic acid and 25% pulp density (w/v) gave results equivalent to that of a commercial bleaching earth (Tonsil Optimum 210 FF). The combination that is likely to be more preferable on an industrial scale was 100°C, 25% pulp density (w/v), 1m initial oxalic acid concentration, 60% recycling of the oxalate solution (making up an acid to bentonite ratio 0.2 w/w) and 6 h activation time. The materials produced under these conditions have acceptable bleaching properties, corresponding to bleaching capacity greater than 78% compared to commercial Tonsil, and colour index (in red and yellow units) equal or even better than Tonsil.

Phosphate and Stannate Chemical Conversion Coatings Formed on AZ91D Alloys

2009 ◽  
Vol 610-613 ◽  
pp. 1407-1413 ◽  
Author(s):  
Xiang Jie Yang ◽  
Hua Lan Jin
Keyword(s):  
Phase Composition ◽  
Chemical Conversion ◽  
Conversion Coating ◽  
Conversion Coatings ◽  
X Ray Diffraction ◽  
Alloy Matrix ◽  
Β Phase ◽  
Before And After ◽  
Loss Method ◽  
Better Than

The morphology and the mass change of the AZ91D alloys matrix after pretreatment, the morphology and the phase composition of chemical conversion coatings formed by phosphate and stannate were studied using scanning electron microscope, X-ray diffraction and the mass loss method. The corrosion resistance of the coatings were studied by salt spay test and damp heat test. The results show that the phase composition of matrix before and after pretreatment is almost changeless and the mass diminishes a litter, the deep micro flaw appears near between α-Mg and β phase during acidic pickling. The phosphate chemical conversion coating is mainly composed of Mg, MgO and some amorphous phase, and the stannate conversion coating is crystal structure and mainly composed of Mg, Al12Mg17 and MgSnO3•3H2O. Results from salt spay test and damp heat test indicate that the two coatings also can provide good protection for the magnesium alloy matrix, and stannate is better than phosphate.

Functionalization of Multi-Walled Carbon Nanotubes Using Microwave Method

2021 ◽  
Vol 1039 ◽  
pp. 237-244
Author(s):  
Firas K. Mohamad Alosfur ◽  
Noor J. Ridha ◽  
Mohammad Hafizuddin Haji Jumali ◽  
S. Radiman ◽  
Khawla J. Tahir ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Area ◽  
Structural Integrity ◽  
Area Measurement ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Before And After ◽  
Multi Walled Carbon Nanotubes ◽  
Dispersion Test ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs) probably hold with each other and agglomerated due to van der Waals force. Functionalized process was used to reduce its ability to agglomerate and to increase dispersion in solution. The present work is focused on the microwave irradiation in order to achieve rapid functionalization of MWCNTs compared with other known techniques. The power of microwave radiation was selected by investigating the structural integrity of the samples by X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FE-SEM), while BET surface area measurement was used to measure the MWCNT surface area before and after treatment. The dispersion test in the solution was performed to determine the separation capability of untreated MWCNTs and f-MWCNTs.

scholarly journals Preparation of Stellerite Loading Titanium Dioxide Photocatalyst and Its Catalytic Performance on Methyl Orange

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Hua Chen ◽  
Jianhua Wang ◽  
Huajun Wang ◽  
Fei Yang ◽  
Jia-nan Zhou ◽  
...  
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Photocatalytic Ability ◽  
X Ray ◽  
Composite Photocatalysts ◽  
Ft Ir ◽  
Better Than

TiO2/stellerite composite photocatalysts were prepared by dispersing TiO2 onto the surface of HCl, NaOH, or NaCl treated stellerite using a sol-gel method. The materials were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR), BET surface area analysis, and X-ray diffraction (XRD). HCl and NaCl modification result in the promotion of the pore formation at the stellerite surfaces and induced the microscopic changes, while the surface morphology and structure of the stellerite were almost ruined by NaOH modification. Supported TiO2 calcinated at 200°C presented anatase structure. The photocatalytic degradation activities of TiO2 loaded HCl and NaCl modified stellerite were better than that of natural stellerite, accompanied with increasing specific surface area. On the contrary, NaOH modification induced the loss of photocatalytic ability of composite due to the generation of silicates.

scholarly journals Adsorption Characteristics of Bixin on Acid- and Alkali-Treated Kaolinite in Aprotic Solvents

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Winda Rahmalia ◽  
Jean-François Fabre ◽  
Thamrin Usman ◽  
Zéphirin Mouloungui
Keyword(s):  
Adsorption Capacity ◽  
Dimethyl Carbonate ◽  
Dye Adsorption ◽  
Aprotic Solvents ◽  
Band Position ◽  
Before And After ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Kinetics Of ◽  
Better Than

The adsorption of bixin in aprotic solvents onto acid- and alkali-treated kaolinite was investigated. Kaolinite was treated three times, for 6 h each, with 8 M HCl or 5 M KOH. The adsorbents were characterized by XRD, FT-IR, EDS, and BET-N2. The effects of contact time and dye concentration on adsorption capacity and kinetics, electronic transition of bixin before and after adsorption, and also mechanism of bixin-kaolinite adsorption were investigated. Dye adsorption followed pseudo-second order kinetics and was faster in acetone than in dimethyl carbonate. The best adsorption results were obtained for KOH-treated kaolinite. In both of the solvents, the adsorption isotherm followed the Langmuir model and adsorption capacity was higher in dimethyl carbonate (qm = 0.43 mg/g) than in acetone (0.29 mg/g). The adsorption capacity and kinetics of KOH-treated kaolinite (qm = 0.43 mg/g,k2 = 3.27 g/mg·min) were better than those of HCl-treated kaolinite (qm = 0.21 mg/g,k2 = 0.25 g/mg·min) and natural kaolinite (qm = 0.18 mg/g,k2 = 0.32 g/mg·min). There are shift in the band position of maximum intensity of bixin after adsorption on this adsorbent. Adsorption in this system seemed to be based essentially on chemisorption due to the electrostatic interaction of bixin with the strong basic and reducing sites of kaolinite.

scholarly journals Synthesis of Magnesium Silicate Hydrate as an Adsorbent for Different Dyes

2019 ◽  
Vol 35 (4) ◽  
pp. 1407-1413
Author(s):  
Pasinee Panith ◽  
Worawat Wattanathana ◽  
Wanchai Deeloed ◽  
Ratthapit Wuttisarn ◽  
Suttipong Wannapaiboon ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Surface Area ◽  
Organic Dyes ◽  
High Surface ◽  
High Surface Area ◽  
Dye Adsorption ◽  
Magnesium Silicate ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
The Fourier Transform

Magnesium silicate hydrate was synthesized for using as an adsorbent for different commercial organic dyes. X-ray diffraction (XRD) confirmed the crystalline phase of magnesium silicate hydrate. Some characteristic absorption bands of the magnesium silicate hydrate structure were observed in the Fourier transform infrared spectroscopy (FTIR) spectrum which supported the result identified from XRD data. Analysis of surface area and porosity by surface area analyzer showed that the synthesized magnesium silicate had high surface area of 634.63 m2/g and also showed the average BJH pore size of 3.72 nm. Insight into the sorption isotherm curve, the hysteresis characteristic was clearly observed suggesting a presence of mesopores within the obtained material. Dye adsorption study revealed that the synthesized adsorbent had the strongest affinity to the cationic dye (methylene blue) on account of the negative charge on the surface of the adsorbent. Hence, the adsorption of methylene blue was reached the equilibrium at the fastest time. In all, the results showed a possibility to apply this prepared magnesium silicate materials as a selective adsorbent for cationic dyes.

scholarly journals Leachability and Stability of Hexavalent-Chromium-Contaminated Soil Stabilized by Ferrous Sulfate and Calcium Polysulfide

2018 ◽  
Vol 8 (9) ◽  
pp. 1431 ◽  
Author(s):  
Ting-Ting Zhang ◽  
Qiang Xue ◽  
Ming-Li Wei
Keyword(s):  
Hexavalent Chromium ◽  
Contaminated Soil ◽  
Ferrous Sulfate ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
X Ray ◽  
Acid Buffering ◽  
Before And After ◽  
Calcium Polysulfide ◽  
Better Than

Ferrous sulfate (FeSO4) and calcium polysulfide (CaS5) stabilization are practical approaches to stabilizing hexavalent chromium (Cr(VI))-contaminated soil. The leachability and stability of Cr(VI) and Cr are important factors affecting the effectiveness of stabilized Cr(VI)-contaminated soil. This study compared the leachability and stability of Cr(VI) and Cr in Cr(VI)-contaminated soil stabilized by using FeSO4 and CaS5. The contaminated soil was characterized before and after stabilization, and the effectiveness of FeSO4 and CaS5 stabilization was assessed using leaching, bioaccessibility, alkaline digestion, sequential extraction, and X-ray diffraction tests. Results showed that FeSO4 and CaS5 significantly reduced the leachability and Cr(VI) content in the contaminated soil. The acid-buffering capacity and stability (leachability, bioaccessibility, speciation distribution, and mineral composition) of the Cr(VI)/Cr and Cr(VI) content of CaS5 were better than those of FeSO4. This study demonstrated that CaS5 had a better effect than FeSO4 on the stabilization of Cr(VI) in Cr(VI)-contaminated soil. The CaS5 significantly enhanced the stabilization and immobilization of Cr(VI) and reduced its leachability and toxicity.

Study of Characteristic of Vetiver Fiber Before and after Alkaline Treatment

2010 ◽  
Vol 123-125 ◽  
pp. 1191-1194 ◽  
Author(s):  
Wimonlak Sutapun ◽  
Nitinat Suppakarn ◽  
Yupaporn Ruksakulpiwat
Keyword(s):  
Thermogravimetric Analysis ◽  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Surface Analysis ◽  
Alkaline Treatment ◽  
X Ray Diffraction ◽  
Surface Functional Groups ◽  
X Ray ◽  
Before And After

In this study, untreated and alkali-treated vetiver fibers were characterized by thermogravimetric analysis, BET surface analysis, X-ray diffraction and FTIR (ATR) microspectroscopy,. It was revealed that the alkaline treatment influenced properties of vetiver fiber. By the treatment, some hemicellulose and lignin were removed, resulting in higher decomposition temperatures. In addition, the specific surface area were decreased, and crystalline structure was altered. However, no evidence of changes in surface functional groups was observed.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

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