scholarly journals Feasibility of a Chemical Washing Method for Treating Soil Enriched with Fluorine Derived from Mica

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 134
Author(s):  
Dong-Jun Baek ◽  
Ye-Eun Kim ◽  
Moon-Young Jung ◽  
Hye-On Yoon ◽  
Jinsung An
Keyword(s):  
Solution Concentration ◽  
Residual Fraction ◽  
Stable Form ◽  
Multi Stage ◽  
Chemical Washing ◽  
Washing Efficiency ◽  
Washing Method ◽  
Management Approaches ◽  
Stable Forms ◽  
Solid Liquid

High levels of fluorine in soil may pose health risks and require remediation. In this study, the feasibility of using a practical chemical washing method for the removal of fluorine from an enriched soil was evaluated. The chemical washing procedures were optimized through experimental analyses of various washing solutions and washing conditions (i.e., washing solution concentration, solid–liquid ratio, agitation speed, and reaction time). Additionally, the effects of techniques for improving the washing efficiency, such as ultrasonic washing, aeration, and multi-stage washing, were evaluated. Herein, among all applied methodologies, the maximum washing efficiency achieved for the total fluorine present in soil was only 6.2%, which indicated that chemical washing was inefficient in remediating this particular soil. Further sequential extraction analysis showed that the fluorine in this soil was present in a chemically stable form (residual fraction), possibly because of the presence of mica minerals. It was demonstrated that chemical washing may not be effective for remediating soils containing such chemically stable forms of fluorine. In these cases, other physical-based remediation technologies or risk management approaches may be more suitable.

scholarly journals Effect of chelating agents on removal of 137Cs from contaminated soil

2018 ◽  
Vol 15 (35) ◽  
pp. 158-168
Author(s):  
Firas M. Radhi
Keyword(s):  
Removal Efficiency ◽  
Contaminated Soil ◽  
Chelating Agents ◽  
Soil Samples ◽  
Coarse Grained ◽  
Tetraacetic Acid ◽  
Mixing Ratio ◽  
Soil Mixing ◽  
Chemical Washing ◽  
Washing Method

In the present research, the chemical washing method has been selected using three chelating agents: citric acid, acetic acid and Ethylene Diamine Tetraacetic Acid (EDTA) to remove 137Cs from two different contaminated soil samples were classified as fine and coarse grained. The factors that affecting removal efficiency such as type of soil, mixing ratio and molarity have been investigated. The results revealed that no correlation relation was found between removal efficiency and the studied factors. The results also showed that conventional chemical washing method was not effective in removing 137Cs and that there are further studies still need to achieve this objective.

Eulerian Simulation of Dense Solid-Liquid Suspension in Multi-Stage Stirred Vessel.

2001 ◽  
Vol 34 (5) ◽  
pp. 585-594 ◽  
Author(s):  
HELENE BARRUE ◽  
JOËL BERTRAND ◽  
BENOÎT CRISTOL ◽  
CATHERINE XUEREB
Keyword(s):  
Stirred Vessel ◽  
Liquid Suspension ◽  
Multi Stage ◽  
Solid Liquid

Investigating the Potential Use of Papaya Leaf Extract as Natural Dyes in the Textile Industry

2020 ◽  
Vol 991 ◽  
pp. 129-134
Author(s):  
Suharno Rusdi ◽  
Huda F. Maulana ◽  
Nuriaji L. Samudro ◽  
Achmad Chafidz
Keyword(s):  
Textile Industry ◽  
Leaf Extract ◽  
Extraction Process ◽  
Natural Dyes ◽  
Raw Material ◽  
Cotton Cloth ◽  
Synthetic Dyes ◽  
Test Results ◽  
Washing Method ◽  
Solid Liquid

Synthetic dyes are widely used in the majority of the large textile industry. The use of synthetic dyes can cause water pollution from sewage disposal of the textile industry. Some types of synthetic dyes contain heavy metals that are harmful to human health and can damage the environment. With increasing awareness of the current environmental problems, people begin to focus on returning back to natural dyes. These natural dyes can be extracted from various parts of plants, such as leaves, flowers, fruit, wood or stems, and roots. Papaya leaves have the potential to be used as a basic ingredient to make natural dyes due to fairly high chlorophyll content. Therefore, we took the initiative to conduct research on the production of natural dyes from papaya leaf extract. Papaya leaf extract was produced by using a solid-liquid extraction process using two different solvents, ethanol (96%) and n-hexane. From the results of the study, it was found that the most optimum extract results in the extraction process was about 2.20% of the raw material of dried papaya leaves by using ethanol solvent. The prepared cotton cloth was then colored with papaya leaf extract through three simple steps, namely: mordanting, dyeing, and fixation. Fabric staining results then tested its fastness by two methods, namely the rub method and the washing method with soap. From the test results it was found that the fabric which was dyed with papaya leaf extract was not too resistant to fade from rubbing and soap washing. Therefore, further research is needed, such as using other agents during the mordanting and fixation processes.

True moving bed chromatography: solid–liquid multi-stage counter-current extraction

1999 ◽  
Vol 849 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Hideyuki Nishizawa ◽  
Kayoko Tahara ◽  
Shinobu Miyamori ◽  
Yoko Motegi ◽  
Tomoko Shoji ◽  
...  
Keyword(s):  
Moving Bed ◽  
Multi Stage ◽  
Solid Liquid ◽  
Counter Current

scholarly journals Role of halogen substituents in a series of polymorphic 2,5-diamino-3,6-dicyanopyrazine derivatives with highly flexible groups

2017 ◽  
Vol 232 (5) ◽  
pp. 395-405 ◽  
Author(s):  
Yoko Akune ◽  
Risa Hirosawa ◽  
Atsushi Koseki ◽  
Shinya Matsumoto
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Electrostatic Interactions ◽  
Crystal Structure Analysis ◽  
Stable Form ◽  
Thermally Stable ◽  
Close Packed Structure ◽  
Packed Structure ◽  
Stable Forms ◽  
Metastable Forms

AbstractThe crystal structures of the ortho-X-benzyl derivatives, where X=F, Cl, Br, I, and Me, of 2,5-bis(N,N-dibenzylamino)-3,6-dicyanopyrazine dyes (C34H24N6X4) were analysed to evaluate the effect of a systematic series of structures on the occurrence of polymorphism. Detailed crystal structure analysis indicated that the thermally stable forms of the polymorphic derivatives (Cl and Br derivatives) were close-packed, whereas those of the non-polymorphic derivatives (F and I derivatives) were stabilised by an intermolecular interaction involving the ortho-substituents. In the thermally metastable forms of the polymorphic derivative, halogen-halogen and halogen-nitrogen interactions contributed to the stabilisation of these crystals in the same way as the thermally stable form of the non-polymorphic derivatives. This indicated that the ease of polymorph occurrence would require an appropriate balance between the crystal energy of the close-packed structure and that of the crystal structure generated mainly by the electrostatic interactions involving the halogens in these halogenated pyrazine derivatives. In addition, the similar tendency of the occurrence of polymorphs in these halogenated pyrazine derivatives was found in 19 sets of halogenated compounds having known crystal structures of F, Cl, Br and I derivatives including at least one polymorphic derivative in the crystal structure database.

scholarly journals Proteinaceous Residue Removal from Oat β-Glucan Extracts Obtained by Alkaline Water Extraction

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1729 ◽  
Author(s):  
Joanna Harasym ◽  
Ewa Żyła ◽  
Katarzyna Dziendzikowska ◽  
Joanna Gromadzka-Ostrowska
Keyword(s):  
Molar Mass ◽  
Raw Material ◽  
Starch Hydrolysis ◽  
Amine Nitrogen ◽  
Residue Removal ◽  
Multi Stage ◽  
Aqueous Solvent ◽  
Oat Bran ◽  
Complex Procedure ◽  
Solid Liquid

Background: Wet methods of 1-3, 1-4 -β-D-glucan isolation from cereals differ mainly in the type of grain fraction used as raw material, the solid-liquid ratio of β-glucan in raw material vs. solvent used, and the type of aqueous solvent modification (alkali, neutral or acidic). All these factors impact the characterization of the residues finally found in extracts. Oat bran is a rich source of globulin fraction which can be transferred into the extracts, especially when a high pH is employed. Methods: A multi-stage (enzymatic and acidic) purification procedure was performed to remove the residues, especially starch and protein, from β-glucan isolates from oat of different molar mass. Pancreatin, thermostable α-amylase, amyloglucosidase, and papain were used for consecutive residue removal. Three levels of low pH = 4.5, 3.5 and 3.0 were also tested for effective protein precipitation. Results: The starch hydrolysis and liquefaction significantly facilitate the proteinaceous matter removal although papain usage showed an intensive unfavorable impact on β-glucan molar mass. Soluble protein content was significantly decreased after pancreatin and α-amylase treatment, while the significant reduction of amine nitrogen was noted after complete starch hydrolysis and a second acidification step. Conclusions: A complex procedure employing different enzymes is needed to successfully reduce the possibly bioactive residues in isolated oat β-glucan fractions.

Performance and membrane foulant in the pilot operation of a novel biofilm-membrane reactor

2002 ◽  
Vol 2 (2) ◽  
pp. 177-183
Author(s):  
K. Kimura ◽  
Y. Watanabe
Keyword(s):  
Membrane Fouling ◽  
Membrane Reactor ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Manganese Concentration ◽  
Membrane Cleaning ◽  
Chemical Washing ◽  
Pre Treatment ◽  
Solid Liquid ◽  
Solid Liquid Separation

We have developed a novel biofilm-membrane reactor (BMR) in which a nitrifying biofilm is fixed on the surface of a rotating membrane disk. With this reactor, both strict solid-liquid separation and oxidation of ammonia nitrogen can be simultaneously performed. Based on the results obtained in previous bench-scale experiments, a pilot-scale study was conducted using river water at a water purification plant. The results obtained in the pilot study can be summarized as follows. (1) By implementation of pre-treatment (coagulation and sedimentation) and simple membrane cleaning (sponge cleaning), the filter run could be continued for 17 months without any chemical washing. (2) Sufficient nitrification was observed when water temperature was high. Deterioration in nitrification efficiency during winter was reduced by the addition of phosphorus. (3) In addition to nitrification, biological oxidation of AOC and manganese can be expected with the BMR. In this study, both AOC and manganese concentration in the permeate decreased to a level less than 10 μg/L. (4) Irreversible membrane fouling, which was thought to be mainly caused by manganese, became significant as the operation period became longer.

Study on Influence Factors of Fly Ash and Metakaolin Based Geopolymer

2012 ◽  
Vol 538-541 ◽  
pp. 2322-2328 ◽  
Author(s):  
Jing Zhong Kuang ◽  
Xiang Chuan Zhao ◽  
Fang Shi ◽  
Hai Ying Cao
Keyword(s):  
Fly Ash ◽  
Liquid Phase ◽  
Sodium Silicate ◽  
Influence Factors ◽  
Solution Concentration ◽  
Organic Polymer ◽  
Liquid Ratio ◽  
Naoh Solution ◽  
Solid Liquid ◽  
Orthogonal Tests

Gepolymeric material is a new building material, which not only has the characteristics of organic polymer, ceramic and cement but also unique properties. The effects of four factors on the strength of fly ash and metakaolin based geopolymer were discussed with the orthogonal tests in this study, including fly ash content, NaOH solution concentration, solid-liquid ratio and the content of sodium silicate in the liquid phase. The results show that: content of fly ash 30%, NaOH solution concentration 12mol/L, solid-to-liquid ratio 4.5 and the content of sodium silicate in the liquid phase 65% is the best condition preparation of fly ash and metakaolin based geopolymer.

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