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.

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.

scholarly journals Maximum Bleaching of Vegetable Oils by Acid-Activated Bentonite: Influence of Nanopore Radius

2012 ◽  
Vol 30 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Müsęerref Önal ◽  
Yüksel Sarıkaya
Keyword(s):  
Vegetable Oils ◽  
Bleaching Earth ◽  
Nitrogen Adsorption ◽  
Mass Range ◽  
Acid Mixture ◽  
Acid Activation ◽  
Physicochemical Interaction ◽  
Activated Bentonite ◽  
The Mean ◽  
Bleaching Power

The optimum conditions necessary for preparing a bleaching earth (BE) with maximum bleaching power (BP) towards soybean oil (SO) and cottonseed oil (CSO) were investigated. BEs were obtained by H2SO4 activation of a white calcium bentonite (CaB) sample from the Kütahya region of Turkey. After drying for 4 h at 105 °C, the CaB samples were activated by heating their acidic aqueous suspensions for 6 h at 97 °C, the acid content of the dry bentonite/acid mixture being varied in the 0–70% mass range. The respective specific surface area (S) and specific nanopore volume (V) of the BEs were determined from nitrogen adsorption/desorption data obtained at −196 °C. For natural CaB, the values of S and V were 44 m2/g and 0.11 cm3/g, respectively. These values attained a maximum of 135 m2/g and 0.30 cm3/g for the BE sample prepared employing 40% H2SO4 for acid activation. Interestingly, the maximum BP was not associated with the maximum S and V values. The optimum values for the percentage H2SO4, S and V for attaining the maximum BP were 20%, 100 m2/g and 0.17 cm3/g, respectively. The mean nanopore radius (r) of each BE was calculated using the corresponding S and V values. Nanopores with a mean radius in the range 3.5–5.5 nm, which was close to the diameter of the coloured pigment, were found to be mostly responsible for the BP towards SO and CSO. The results obtained in the present study indicate that the value of r was more effective than the S and V values of BEs in the bleaching of vegetable oils. Adsorption of a pigment onto a BE was found to depend not only on the physicochemical interaction between the pigment molecule and the BE surface, but also on the mean nanopore size.

scholarly journals Bachmann bundle impairment following linear ablation of left anterior wall: impact on left atrial function

2020 ◽  
Author(s):  
Yanjuan Zhang ◽  
Fengming Wu ◽  
Yu Gao ◽  
Nan Wu ◽  
Gang Yang ◽  
...  
Keyword(s):  
Contractile Function ◽  
Anterior Wall ◽  
Activation Time ◽  
Linear Ablation ◽  
Measured Activation ◽  
Mechanical Remodeling ◽  
Activation Times ◽  
And Function ◽  
Bachmann Bundle

Background: We aimed to evaluate the effect of Bachmann bundle (BB) impairment on electrical and mechanical function of the left atrium (LA), as well as the long-term clinical impact of such impairment. Design: We measured activation time in the five LA walls in 56 patients with atrial fibrillation. LA reservoir, conduit, and contractile function were also evaluated. Patients were divided into two groups based on ablation strategy: the circumferential pulmonary vein isolation (CPVI) group and CPVI with anterior wall linear ablation (LAWA) group. Patients in the CPVI+LAWA group were divided into two sub-groups based on ECG differences following ablation: the BB impairment group and intact BB group. LA activation time and function were then compared between the ablation strategy groups and the CPVI+LAWA subgroups. Results: Patients in the CPVI+LAWA group exhibited longer activation times in the anterior and lateral walls of the LA, poorer LA synchrony, and reduced LA contractile and reservoir function when compared with those in the CPVI group. In the BB impairment subgroup, we observed a discrepancy between electrical/mechanical remodeling. Among five walls, activation time was longest in this region. BB impairment was also associated with reduced LA function. Conclusion: Significant changes in LA function and conductibility were observed in patients with anterior wall ablation, especially those with iatrogenic BB impairment.

Absorption Performance of Activated Carbon with Orange Peel through Phosphoric Acid Activation Method

2012 ◽  
Vol 518-523 ◽  
pp. 2298-2302
Author(s):  
Yue Zhou ◽  
Wei Guo Pan ◽  
Rui Tang Guo ◽  
Xiao Bo Zhang ◽  
Xue Ping Wen ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Phosphoric Acid ◽  
Raw Materials ◽  
Orange Peel ◽  
Carbonization Temperature ◽  
Operating Conditions ◽  
Acid Activation ◽  
Activation Time ◽  
Methylene Blue Adsorption

In order to reduce power plant nitric oxide emission with gaining economical adsorbent, activated carbon was prepared from the raw materials of orange peel under different operating conditions in this paper. The methylene blue adsorption value of different activated carbon has also been tested, and the effects on the methylene blue adsorption performance of different dipping concentration, activation time and carbonization temperature were studied. The finding is that the dipping concentration has the most important impact on methylene blue adsorption value. The highest methylene blue adsorption value of orange peel activated carbon has shown as 277.746mg/g under the following conditions: phosphoric acid concentration was 40%, activation time was 12 hours and carbonization temperature was 500°C. It is a economically feasible absorbent material through a great deal of experiments and analysis.

Ultra-high Rhodamine B adsorption capacities from an aqueous solution by activated carbon derived from Phragmites australis doped with organic acid by phosphoric acid activation

RSC Advances ◽  
2016 ◽  
Vol 6 (47) ◽  
pp. 40818-40827 ◽  
Author(s):  
Zizhang Guo ◽  
Jian Zhang ◽  
Hai Liu
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Oxalic Acid ◽  
Phosphoric Acid ◽  
Phragmites Australis ◽  
Rhodamine B ◽  
Activated Carbons ◽  
Acid Activation ◽  
Adsorption Capacities ◽  
Phosphoric Acid Activation

This study shows that oxalic acid (OA) and succinic acid (SA) were employed to modify Phragmites australis (PA)-based activated carbons (ACs) during phosphoric acid activation to improve Rhodamine B (RhB) removal from aqueous solutions.

Recherche de nouvelles activités saccharifiantes thermostables chez les champignons filamenteux

1990 ◽  
Vol 36 (9) ◽  
pp. 625-630 ◽  
Author(s):  
P. Vanacker ◽  
B. Bacle ◽  
G. Vidal ◽  
L. Lacoste
Keyword(s):  
Aspergillus Niger ◽  
Aspergillus Fumigatus ◽  
Key Words ◽  
Filamentous Fungi ◽  
Half Life ◽  
The Other ◽  
Thermostable Enzymes ◽  
Life Measure ◽  
Industrial Use ◽  
Better Than

We have searched for producers of a saccharifying activity with improved thermostability compared with industrial amyloglucosidases. These producers were chosen among thermophilic, thermotolerant, or even mesophilic fungi. Among the 846 isolated strains, five species (two Thermoascus spp., a member of the Aspergillus fumigatus group, and two members of the Aspergillus niger group) showed an amyloglucosidasic complex with the required property. Whereas the first three of these were thermophilic or thermotolerant strains, the latter two strengthen the idea that mesophilic strains can produce thermostable enzymes. The thermostability of the saccharifying complex of the Thermoascus spp., established with a half-life measure, was found to be far better than the other ones. The industrial use of these strains was discussed, and Thermoascus crustaceus seems to be the most advantageous one. Key words: filamentous fungi, amyloglucosidases, thermostability, Thermoascus.

Preparation and Preliminary Characterization of Chitosan from Catharsius molossus Discards

2012 ◽  
Vol 548 ◽  
pp. 77-81
Author(s):  
Jia Hua Ma ◽  
Cheng Jia Tan ◽  
Xia Deng ◽  
Chao Xin
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Oxalic Acid ◽  
Room Temperature ◽  
Orthogonal Design ◽  
X Ray Diffraction ◽  
X Ray ◽  
Preparation Techniques ◽  
Better Than

Preparation techniques of chitosan from Catharsius molossus L. processing discards were studied by orthogonal design. Preparation techniques were as follows:demineralizing: soaked for 30 min at 80 °C with 1.3 mol•L-1 HCl, then kept for 12 h under room temperature. Deproteinization and delipidation: treated for 6 h at 90 °C with 4 mol•L-1 NaOH. Decolorizing: soaked at room temperature with 3% KMnO4, then treated with 2% oxalic acid at 70 °C. Deacetylation: treated for 6 h at 110 °Cwith 14 mol•L-1 NaOH. Properties of chitosan were characterized by Fourier transform infrared spectroscopy(FTIR), X-ray diffraction (XRD), etc. It proved the technique was stable and feasible. The result also preliminarily showed that chitosan from Catharsius molossus L. was better than shrimp’s. It will be widely applicated in biomedical and other industrial areas with such exiciting properties.

Optimizing the production of activated carbon from fast pyrolysis char

TECHNOLOGY ◽  
2015 ◽  
Vol 03 (02n03) ◽  
pp. 104-113 ◽  
Author(s):  
B.G. del-Campo ◽  
M.D. Morris ◽  
D.A. Laird ◽  
M.M. Kieffer ◽  
R.C. Brown
Keyword(s):  
Response Surface Methodology ◽  
Activated Carbon ◽  
Economic Benefit ◽  
Fast Pyrolysis ◽  
Activation Parameters ◽  
Steam Activation ◽  
Oak Wood ◽  
Net Revenue ◽  
Activation Conditions ◽  
The Relationship

Fast pyrolysis of red oak wood yields approximately 10–30 wt% biochar, which is considered a low value co-product. Production of high value activated carbon using steam was investigated at different activation conditions. The relationship between activation parameters, surface area and revenue was evaluated using response surface methodology. A second degree model showed a maximum economic benefit at 800°C with 5 minutes of steam activation, resulting in $907 of net revenue per metric ton of biochar.

scholarly journals THE IMPACT OF ACID ACTIVATION PARAMETERS OF DARK BROWN LOAM ON ITS SORPTION PROPERTIES TO CHROMIUM (III) IONS

2012 ◽  
Vol 53 (4) ◽  
Author(s):  
Є.О. Бовсуновський ◽  
О.В. Рябчевський ◽  
Ю.Я. Годовська ◽  
О.Г. Личманенко
Keyword(s):  
Activation Parameters ◽  
Sorption Properties ◽  
Acid Activation ◽  
The Impact

scholarly journals The Thermal Activation of Nsu Clay for Enhanced Alumina Leaching Response

2019 ◽  
Vol 16 ◽  
pp. 34-46
Author(s):  
Udochukwu Mark ◽  
Charles Nwachukwu Anyakwo ◽  
Okechukwu Onyemaobi ◽  
Chijioke Samson Nwobodo
Keyword(s):  
Activation Energy ◽  
Thermal Activation ◽  
Leach Solution ◽  
Kaolinite Clay ◽  
Alumina Production ◽  
Calcination Temperatures ◽  
Activation Conditions ◽  
Solid Liquid ◽  
Heating Up ◽  
Better Than

The thermal activation conditions for enhancing the leaching of alumina from Nsu clay from south-eastern Nigeria was investigated. The clay assayed 28.9% and 50.59% , comprising mainly kaolinite mineral (82.6%) and quartz (12.5%). Thermal activation rendered the alumina in the clay acid-soluble by transforming the clay from its crystalline nature to an amorphous phase or metakaolinite. The clay samples were heated at calcination temperatures of 500, 600, 700, 800, and 900 °C at holding times of 30, 60, and 90 minutes. Uncalcined clay samples and samples calcined at 1000 °C (holding for 60 minutes) were used in the control experiments. Leaching of alumina from the resulting clay calcines passing 300 μm sieve (-50 mesh) was done in 1M hydrochloric acid solution at room temperature using a solid/liquid ratio of 0.02g/ml and shaking speed of 100 rpm. The solubility data given by the fraction of Al ion taken into leach solution showed that the clay calcined at 700 °C (holding for 60 minutes) responded most to leaching. In general, it was observed that samples calcined for 60 minutes responded better than those held for 30 or 90 minutes. The activation energies for leaching the clay calcines were 29.50, 32.92, 26.71, 30.18, 29.18, and 33.24 kJ/mol for samples calcined for 60 minutes at 500, 600, 700, 800, 900, and 1000 °C, respectively. The activation energy of leaching for the uncalcined sample was 35.07 kJ/mol. Thus, calcines produced at 700 °C (holding for 60 minutes) had the highest leaching response for alumina and the lowest leaching activation energy of 26.71 kJ/mol. It is concluded therefore that Nsu kaolinite clay should be best calcined for alumina yield by heating up to 700 °C and holding for 60 minutes at that temperature. The clay deposit can be used as alternative resource for alumina production.

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