scholarly journals PURIFICATION OF FE3+ CONTAINING WASTEWATER USING NATURAL SORBENTS

2020 ◽  
Vol 20 ◽  
pp. 101-105
Author(s):  
K. Stepova ◽  
L. Sysa ◽  
I. Vintonyk
Keyword(s):  
High Frequency ◽  
Bentonite Clay ◽  
Sorption Equilibrium ◽  
Natural Sorbents ◽  
Ultra High Frequency ◽  
Maximum Sorption Capacity ◽  
Treated Sample ◽  
Maximum Sorption ◽  
Pre Treatment ◽  
Static Conditions

Abstract. Bentonites in natural or activated forms, i.e. after chemical treatment with acids, have high adsorption properties and are widely used as a natural adsorbent. The increase in the adsorption capacity of bentonite sorbents during heat treatment at 100–200 ° C is caused by the removal of adsorbed and chemical water that leads to an increase in the overall porosity. By thermal and hydrothermal treatments, the properties of natural sorbents can be varied within wide limits, giving them selectivity with respect to certain dissolved substances. It is known that the irradiation of water systems by microwaves leads to their heating, that is, this method of pre-treatment of sorbents combines their hydro-thermal treatment with high-frequency irradiation. The aim of the work is to investigate the process of absorption of iron (III) by bentonite clay under the influence of microwave radiation. The sorption properties of bentonites were studied under static conditions. For comparison purposes, adsorption was performed on natural bentonite under normal conditions without any pre-treatment and under the action of ultra-high-frequency electromagnetic radiation. The Langmuir equation was used to describe the experimental adsorption isotherms. The maximum sorption capacity of the treated sample was found to be 1.66 times higher than that of the untreated one and was 63.7 and 38.3 mg / g, respectively. The sorption equilibrium constant of the irradiated sample is 42% lower than that of the native one. This indicates that the sorption equilibrium under the action of ultra-high frequency radiation comes in 1.7 times faster than under normal conditions. Therefore, compared to the untreated sample, microwave irradiated bentonite has better sorption characteristics for iron (III), so it can be a promising sorbent for the purification of natural and wastewater.

scholarly journals Quaternization of Composite Algal/PEI Beads for Enhanced Uranium Sorption—Application to Ore Acidic Leachate

Gels ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 12 ◽  
Author(s):  
Mohammed F. Hamza ◽  
Amal E. Mubark ◽  
Yuezou Wei ◽  
Thierry Vincent ◽  
Eric Guibal
Keyword(s):  
Ph Effect ◽  
Sorption Isotherms ◽  
Environmental Safety ◽  
Sorption Properties ◽  
Yellow Cake ◽  
Maximum Sorption Capacity ◽  
Copper Precipitation ◽  
Protonated Amine ◽  
Maximum Sorption ◽  
Pre Treatment

The necessity to recover uranium from dilute solutions (for environmental/safety and resource management) is driving research towards developing new sorbents. This study focuses on the enhancement of U(VI) sorption properties of composite algal/Polyethylenimine beads through the quaternization of the support (by reaction with glycidyltrimethylammonium chloride). The sorbent is fully characterized by FTIR, XPS for confirming the contribution of protonated amine and quaternary ammonium groups on U(VI) binding (with possible contribution of hydroxyl and carboxyl groups, depending on the pH). The sorption properties are investigated in batch with reference to pH effect (optimum value: pH 4), uptake kinetics (equilibrium: 40 min) and sorption isotherms (maximum sorption capacity: 0.86 mmol U g−1). Metal desorption (with 0.5 M NaCl/0.5 M HCl) is highly efficient and the sorbent can be reused for five cycles with limited decrease in performance. The sorbent is successfully applied to the selective recovery of U(VI) from acidic leachate of uranium ore, after pre-treatment (cementation of copper, precipitation of rare earth elements with oxalate, and precipitation of iron). A pure yellow cake is obtained after precipitation of the eluate.

Technology of Obtaining Sorbents Based on Metal Dust and Carbonized Biopolymers for Purification of Surface and Waste Water From Oil and Oil Products

2020 ◽  
Vol 24 (3) ◽  
pp. 24-28
Author(s):  
L.N. Olshanskaya ◽  
M.A. Chernova ◽  
O.A. Aref'eva ◽  
E.M. Bakanova ◽  
E.V. Yakovleva ◽  
...  
Keyword(s):  
Waste Water ◽  
Sorption Process ◽  
Product Layer ◽  
Contaminated Water ◽  
Sorption Equilibrium ◽  
Gas Treatment ◽  
Maximum Sorption Capacity ◽  
Maximum Sorption ◽  
Metal Dust ◽  
Oil And Oil Products

The results on the production of composite magnetosorbents (CMS) based on agricultural wastes (uncontaminated steel gas treatment dust – PGSN, sunflower husk, paraffin) for the treatment of contaminated water from oil and its products and minimizing the environmental impact of petrochemical enterprises are presented. Biotesting at two test sites (crustaceans Daphnia magna and algae Scenedesmus quadricauda) allowed us to establish that PSGN is non-toxic and can be used as a component of magnetosorbents. The resulting materials showed good physicochemical properties. It was shown that CMC have high hydrophobicity – the contact angle of contact was 125–137 degrees; buoyancy of the material for 96 hours did not decrease below 97–99 %; CMC had a low water absorption of 0.132–0.114 g/g. The oil intensity of the sorbents was 6.0 ± 0.15 g/g. Sorption equilibrium was achieved during the first 10–20 minutes contact of the material with oil and oil productsand remained constant. It has been established that the sorption process is influenced by the nature and thickness of the oil product layer. The maximum sorption capacity is achieved with a film thickness of 3.5 ± 0.15 mm.

Природные материалы для сорбционной очистки хром- и кадмийсодержащих инфильтратов полигонов ТБО

2019 ◽  
pp. 13-19
Author(s):  
A. Safonov ◽  
N. Andriushchenko ◽  
N. Popova ◽  
K. Boldyrev
Keyword(s):  
Sorption Capacity ◽  
Electron Acceptors ◽  
Bacterial Cells ◽  
Maximum Sorption Capacity ◽  
Sorption Material ◽  
Maximum Sorption ◽  
Properties Of Materials ◽  
Solid Waste Landfills ◽  
Sorption Characteristics

Проведен анализ сорбционных характеристик природных материалов (вермикулит, керамзит, перлит, цеолит Трейд ) при очистке кадмий- и хромсодержащих сточных вод с высокой нагрузкой по ХПК. Установлено, что цеолит обладает максимальными сорбционными характеристиками для Cd и Cr и наименьшим биологическим обрастанием. При использовании вермикулита и керамзита или смесей на их основе можно ожидать увеличения сорбционной емкости для Cd и Сr при микробном обрастании, неизбежно происходящем в условиях контакта с водами, загрязненными органическими соединениями и биогенами. При этом биообрастание может повысить иммобилизационную способность материалов для редоксзависимых металлов за счет ферментативных ресурсов бактериальных клеток, использующих их в качестве акцепторов электронов. Эффект микробного обрастания разнонаправленно изменял параметры материалов: для Cr в большинстве случаев уменьшение и для Cd значительное увеличение. При этом дополнительным эффектом иммобилизации Cr является его биологическое восстановление биопленками. Варьируя состав сорбционного материала, можно подбирать смеси, оптимально подходящие для очистки вод инфильтратов с полигонов твердых бытовых отходов с высокой нагрузкой по ХПК и биогенным элементам как при использовании in situ, так и в системах на поверхности.The analysis of the sorption characteristics of natural materials (vermiculite, expanded clay, perlite, Trade zeolite) during the purification of cadmium and chromium-containing leachate with a high COD load was carried out. It was determined that zeolite had the maximum sorption capacity for Cd and Cr and the lowest biological fouling. When using vermiculite and expanded clay or mixtures on their basis, one can expect an increase in the sorption capacity for Cd and Cr during microbial fouling that inevitably occurs during contacting with water polluted with organic compounds and nutrients. In this case biofouling can increase the immobilization properties of materials for redox-dependent metals due to the enzymatic resources of bacterial cells that use them as electron acceptors. The effect of microbial fouling changed the parameters of materials in different directions: for Cr, in most cases, downward, and for Cd, significantly upward. Moreover, chromium biological recovery by biofilms is an additional effect of immobilization. Varying the composition of the sorption material provides for selecting mixtures that are optimally suitable for the purification of leachates from solid waste landfills with high COD and nutrients load, both when used in situ and in surface systems.

A Broadband High-Gain Bi-Layer Log-Periodic Dipole Array (LPDA) for Ultra High Frequency (UHF) Conformal Load Bearing Antenna Structures (CLAS) Applications

2014 ◽  
Author(s):  
Nicholas A. Bishop ◽  
Mohammod Ali ◽  
Jason Miller ◽  
David L. Zeppettella ◽  
William Baron ◽  
...  
Keyword(s):  
High Frequency ◽  
High Gain ◽  
Load Bearing ◽  
Ultra High Frequency

Ultra-High-Frequency Pairs Trading in Gold ETFs

2017 ◽  
Author(s):  
Thong Dao ◽  
Frank McGroarty ◽  
Andrew Urquhart
Keyword(s):  
High Frequency ◽  
Pairs Trading ◽  
Ultra High Frequency

MODELING AND EXPERIMENTAL VERIFICATION OF AIR-THERMAL AND MICROWAVE-CONVECTIVE PRESOWING SEED TREATMENT

2020 ◽  
Vol 4 (41) ◽  
pp. 35-43
Author(s):  
ALEKSEY A. VASIL’EV ◽  
◽  
ALEKSEY N. VASIL’EV ◽  
DMITRIY BUDNIKOV ◽  
ANTON SHARKO
Keyword(s):  
High Frequency ◽  
Seed Treatment ◽  
Field Experiments ◽  
Research Purpose ◽  
Dense Layer ◽  
Technological Equipment ◽  
External Influence ◽  
Ultra High Frequency ◽  
Grain Processing ◽  
Seed Processing

The use of electrophysical influences for pre-sowing treatment of seeds is an effective way to increase their sowing quality. The use of these methods is limited by the fact that their implementation requires new technological equipment in grain processing lines. This problem is solved more easily when pre-sowing processing is performed using installations for active ventilation and grain drying. (Research purpose) The research purpose is in determining the possibility of using active ventilation units and ultra-high-frequency convective grain dryers for pre-sowing grain processing and to evaluating the effectiveness of such processing using computer modeling. (Materials and methods) It is necessary to ensure the uniformity of processing with external influence the seeds placed in a dense layer. Authors carried out pre-sowing treatment of seeds on real installations. Treated seeds were sown in experimental plots and the results of treatment were evaluated. (Results and discussion) The article presents graphs of changes in grain temperature and humidity during processing. To check the feasibility of pre-sowing treatment, authors performed modeling of air-heat and ultra-high-frequency convective seed treatment processes. Based on the results of field experiments, air-heat treatment stimulates the development of secondary plant roots, contributes to an intensive increase in the green mass of plants; ultra-high-frequency convective seed treatment allows increasing the number of productive stems in plants, the number of ears in one plant. (Conclusions) Technological equipment designed for drying and active ventilation of grain can be effectively used for pre-sowing seed processing. In the course of field experiments, it was revealed the possibility of controlling the structure of the crop using different types of external influence on seeds during their pre-sowing processing.

scholarly journals Phosphate Removal Using Polyethylenimine Functionalized Silica-Based Materials

2021 ◽  
Vol 13 (3) ◽  
pp. 1502
Author(s):  
Maria Xanthopoulou ◽  
Dimitrios Giliopoulos ◽  
Nikolaos Tzollas ◽  
Konstantinos S. Triantafyllidis ◽  
Margaritis Kostoglou ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Removal Rate ◽  
Phosphate Concentration ◽  
Phosphate Removal ◽  
Equilibrium Studies ◽  
Maximum Sorption Capacity ◽  
Algae Blooms ◽  
Maximum Sorption ◽  
Phosphate Anions ◽  
Adsorbent Dose

In water and wastewater, phosphate anions are considered critical contaminants because they cause algae blooms and eutrophication. The present work aims at studying the removal of phosphate anions from aqueous solutions using silica particles functionalized with polyethylenimine. The parameters affecting the adsorption process such as pH, initial concentration, adsorbent dose, and the presence of competitive anions, such as carbonate, nitrate, sulfate and chromate ions, were studied. Equilibrium studies were carried out to determine their sorption capacity and the rate of phosphate ions uptake. The adsorption isotherm data fitted well with the Langmuir and Sips model. The maximum sorption capacity was 41.1 mg/g at pH 5, which decreased slightly at pH 7. The efficiency of phosphate removal adsorption increased at lower pH values and by increasing the adsorbent dose. The maximum phosphate removal was 80% for pH 5 and decreased to 75% for pH 6, to 73% for pH 7 and to 70% for pH 8, for initial phosphate concentration at about 1 mg/L and for a dose of adsorbent 100 mg/L. The removal rate was increased with the increase of the adsorbent dose. For example, for initial phosphate concentration of 4 mg/L the removal rate increased from 40% to 80% by increasing the dose from 0.1 to 2.0 g/L at pH 7. The competitive anions adversely affected phosphate removal. Though they were also found to be removed to a certain extent. Their co-removal provided an adsorbent which might be very useful for treating waters with low-level multiple contaminant occurrence in natural or engineered aquatic systems.

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