scholarly journals Evaluation of red sludge use efficiency for water purification from sulphates

2021 ◽  
pp. 55-62
Author(s):  
Mykola Gomelya ◽  
Yana Kryzhanovska ◽  
Tetiana Shabliy
Keyword(s):  
Water Purification ◽  
Sodium Aluminate ◽  
Residual Concentration ◽  
Initial Concentration ◽  
Sulfate Solutions ◽  
Calcium Aluminates ◽  
Use Efficiency ◽  
Lime Consumption ◽  
Degree Of Extraction ◽  
Red Sludge

In this work the reagent purification of aqueous solutions from sulfates with the use of red sludge of the Nikolaev alumina plant processes were investigated. This sludge, according to chemical analysis, contains a sufficiently large amount of alumina (up to 18 %) and calcium oxide (up to 10 %) and along with calcium silicate and iron oxides contains sodium and calcium aluminates. The ability of sodium aluminate to be deposited from a solution of sulfates in the form of calcium sulfoaluminates was used in the work to purify water from sulfate anions. The process takes place when treating the solution with sludge and lime suspension. It is shown that when red sludge is applied in the amount of 1–50 g/dm3 during magnesium sulfate solutions liming, water is purified from sulfate anions. The degree of water purification reaches 50–70 %. It was found that the efficiency of sulfate extraction is significantly dependent on the consumption of lime and increases slightly with increasing sludge consumption over 1 g/dm3. The dependence of the efficiency of sulfate extraction from water on their initial concentration is determined. It was found that at the initial concentration of sulfates up to 1000 mg/dm3 at the expense of lime 3–12 mg-eq/dm3 the residual concentration of sulfates decreases to 236–460 mg/dm3, and at the concentration of sulfate anions about 2000 mg/dm3 their concentration decreases to 550–830 mg/dm3 at a lime consumption of 30 mg-eq/dm3 regardless of the sludge consumption. The degree of extraction of sulfates from solutions reaches 40–73 %.

Simulations on Expansive Strain of Concrete Caused by Ettringite Growth under Sulfate Attack

2011 ◽  
Vol 250-253 ◽  
pp. 1906-1911 ◽  
Author(s):  
Xiao Bao Zuo ◽  
Wei Sun
Keyword(s):  
Sulfate Solution ◽  
Sulfate Attack ◽  
Diffusion Time ◽  
Diffusion Reaction ◽  
Sulfate Ion ◽  
Reaction Equation ◽  
Ettringite Formation ◽  
Sulfate Solutions ◽  
Calcium Aluminates ◽  
Strain Responses

In order to assess theoretically the expansive strain of concrete caused by the ettringite formation and growth under the sulfate attack, some models are proposed to investigate the strain responses of concrete exposed to the sulfate solutions. Firstly, an 1-D nonlinear and nonsteady diffusion-reaction equation of sulfate ion in concrete is proposed; Secondly, based on chemical reactions between sulfate and aluminates in concrete, the expansive strain is obtained due to the ettringite growth resulting in concrete expansion. Thirdly, numerical simulations are carried out to analyze the formation process of the concrete expansive strain under the sulfate solution, and results show that the models can be used to predict the concrete responses with the diffusion time, such as the distribution concentration of sulfate ion, dissipated concentration of the calcium aluminates, expansion strain of concrete due to the formation and growth of ettringite.

scholarly journals Efficient removal of arsenic from water by dielectrophoresis-assisted adsorption

2018 ◽  
Vol 19 (4) ◽  
pp. 1066-1072
Author(s):  
Q. H. Jin ◽  
C. Y. Cui ◽  
H. Y. Chen ◽  
Y. Wang ◽  
J. F. Geng ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Removal Efficiency ◽  
Solution Ph ◽  
Residual Concentration ◽  
Initial Concentration ◽  
Weight Percentage ◽  
Before And After ◽  
High Concentrations ◽  
Plant Ash ◽  
Adsorbent Dose

Abstract Adsorption (ADS) and dielectrophoresis (DEP) techniques were combined (ADS/DEP) to efficiently remove As(V) in industrial wastewater. Fly ash, activated carbon, corncob and plant ash were tested to determine the best adsorbent by their adsorption capacity. Plant ash showed the highest adsorption capacity compared with the others. Different parameters such as solution pH and adsorbent dose were explored. The maximum As(V) removal efficiency was 91.4% at the optimized conditions (pH 9.0, adsorbent dose 5 g/L) when the initial concentration of As(V) was 15 mg/L. With the ADS/DEP technique, the plant ash particles with adsorbed As(V) were trapped on the electrodes in a DEP device. The ADS/DEP process could increase the removal efficiency of As(V) to 94.7% at 14 V even when the initial concentration of As(V) was 15 mg/L. And the residual concentration of As(V) decreased to 0.34 mg/L after two series of the ADS/DEP process. The adsorbents before and after DEP were examined by scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis. After the DEP process, the weight percentage of As(V) on the adsorbent surface increased to 0.96% from 0.5%. The ADS/DEP process could be a new efficient way to remove arsenic pollutant at high concentrations.

scholarly journals SORPTION EXTRACTION OF PLATINUM METALS FROM CHLORIDE – SULFATE AND SULFATE ACIDIC SOLUTIONS BY POLYACRYLONITRILE FIBERS FIBAN

2019 ◽  
Vol 62 (11) ◽  
pp. 117-125
Author(s):  
Svetlana V. Drogobuzhskaya ◽  
Anna A. Shirokaya ◽  
Sergey A. Solov’ev
Keyword(s):  
Sulfuric Acid ◽  
Electronic Spectra ◽  
Chloride Ion ◽  
Platinum Group Metals ◽  
Platinum Metals ◽  
Sulfate Solutions ◽  
Acidic Chloride ◽  
Chloride Sulfate ◽  
Platinum Group ◽  
Degree Of Extraction

The sorption of platinum group metals by fibers FIBAN AK-22 and A-5 from acidic chloride-sulfate and sulfate solutions was studied under static conditions. FIBAN contains primary, secondary and tertiary amino groups. The degree of extraction of platinum metals is calculated. The optimal conditions of sorption from the model solutions are determined. The influence of the temperature regime on the sorption process is established. It is shown, that all platinum group metals are quantitatively extracted from acidic chloride-sulfate solutions by fiber FIBAN AK-22 regardless of the concentration of chloride ions, H2SO4 and temperature absorption. Extraction exceeds 96% at a concentration of sulfuric acid up to 3 mol/dm3 and chloride ion up to 1 mol/dm3. Extraction of osmium is maximum at a concentration of sulfuric acid and chloride ion 3 mol/dm3. The degree of extraction of platinum group metals on FIBAN A-5 is from 50 to 85% and is maximum at elevated temperature and concentrations of H2SO4 and chloride ion 1 mol/dm3 and decreases with increasing concentration of sulfuric acid. Electronic spectra of platinum metal solutions were obtained and the state of platinum metals in chloride and chloride-sulfate solutions was estimated. After the introduction of sulfuric acid into the system, changes in the electronic spectra of platinum (IV), ruthenium and osmium solutions were noted. The spectra of palladium, rhodium and iridium solutions have not changed. When extracting platinum metals from production sulfate solutions of complex composition with a high content of macro components (Ni, Cu, Fe, Te and Se), the efficiency of fiber AK-22 is shown. The advantages of fiber FIBAN AK-22 over FIBAN A-5 are noted.

scholarly journals Degradation of Chlorobenzenes at Nanomolar Concentrations byBurkholderia sp. Strain PS14 in Liquid Cultures and in Soil

1999 ◽  
Vol 65 (6) ◽  
pp. 2547-2552 ◽  
Author(s):  
Peter Rapp ◽  
Kenneth N. Timmis
Keyword(s):  
Incubation Period ◽  
Detection Limits ◽  
Batch Experiments ◽  
Sorptive Capacity ◽  
Residual Concentration ◽  
Soil Microcosms ◽  
Initial Concentration ◽  
High Affinity ◽  
Low Cell Density ◽  
Very High

ABSTRACT The utilization of 1,2,4,5-tetrachloro-, 1,2,4-trichloro-, the three isomeric dichlorobenzenes and fructose as the sole carbon and energy sources at nanomolar concentrations was studied in batch experiments with Burkholderia sp. strain PS14. In liquid culture, all chlorobenzenes were metabolized within 1 h from their initial concentration of 500 nM to below their detection limits of 0.5 nM for 1,2,4,5-tetrachloro- and 1,2,4-trichlorobenzene and 7.5 nM for the three dichlorobenzene isomers, with 63% mineralization of the tetra- and trichloroisomers. Fructose at the same initial concentration was, in contrast, metabolized over a 4-h incubation period down to a residual concentration of approximately 125 nM with 38% mineralization during this time. In soil microcosms, Burkholderia sp. strain PS14 metabolized tetrachlorobenzene present at 64.8 ppb and trichlorobenzene present at 54.4 ppb over a 72-h incubation period to below the detection limits of 0.108 and 0.09 ppb, respectively, with approximately 80% mineralization. A high sorptive capacity ofBurkholderia sp. strain PS14 for 1,2,4,5-tetrachlorobenzene was found at very low cell density. The results demonstrate thatBurkholderia sp. strain PS14 exhibits a very high affinity for chlorobenzenes at nanomolar concentrations.

scholarly journals ADSORPTION OF PHOSPHATE IONS ON RED SLUDGE

2017 ◽  
Vol 60 (8) ◽  
pp. 80
Author(s):  
Svetlana M. Kramer ◽  
Mariya V. Terekhova ◽  
Inna V. Artamonova
Keyword(s):  
Hydrochloric Acid ◽  
Experimental Studies ◽  
Aluminum Production ◽  
Quantitative Composition ◽  
Experimental Conditions ◽  
Initial Concentration ◽  
Phosphate Ions ◽  
Frumkin’S Isotherm ◽  
Ph Range ◽  
Red Sludge

In work the possibility of red sludge (waste of aluminum production by Bayer's method) to adsorb phosphate ions from water solutions at various concentration of ions and in the pH range from 3 to 10 is studied. Relevance of use of red sludge for receiving on its basis of sorbents is reasoned. For identification of the studied object the qualitative and quantitative composition of red sludge was established by the method of the X-ray phase analysis. The technique of red slage activation by hydrochloric acid, and also an adsorption technique of phosphate ions on the red sludge surface is described. Experimental studies of adsorption of phosphate ions on the surface of the red slage activated by hydrochloric acid depending on рН and concentration of initial solution were conducted. The dependence of adsorption phosphate ions on the red slage activated by НСl on рН and on the initial concentration of phosphate ions in solution is presented. These dependences of a relative fraction of distribution of various ions of phosphoric acid on рН are given in work. The form of ion phosphate having the greatest adsorptive activity on the red slage activated by hydrochloric acid in experimental conditions is revealed. Experimental data on dependence of adsorption of phosphate ions on their initial concentration in solution are described by Frumkin's isotherm. The constant of the adsorptive balance, limit adsorption, the parameter of intermolecular interaction of the adsorbed particles are calculated. Optimum conditions for adsorption of phosphate ions on red slage are established.Forcitation:Kramer S.M., Terekhova M.V., Artamonova I.V. Adsorption of phosphate ions on red sludge. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 80-83.

scholarly journals Special features of elimination of phosphorus compounds in aeration tanks

2020 ◽  
Vol 163 ◽  
pp. 05016
Author(s):  
Nina Zaletova
Keyword(s):  
Total Phosphorus ◽  
Sewage Treatment ◽  
Phosphorus Compounds ◽  
Residual Concentration ◽  
Wastewater Treatment Process ◽  
Initial Concentration ◽  
Organic Mineral ◽  
Complex Forms ◽  
The Impact ◽  
Active Dose

In the sewage treatment plants, phosphorus compounds presented constantly, due to the sources of their appearance. In urban wastewater, phosphorus stays in various compounds – dissolved, insoluble, organic, mineral, simple and complex forms. Only phosphates and total phosphorus are monitored in wastewater chemicals laboratories. The data on phosphorus compounds containing in the wastewater of a number of cities is analyzed in the study. The impact of the biological wastewater treatment process on the efficiency of phosphorus removal was assessed. The research was carried out on an experimental technological installation. It is shown that in the original wastewater not only the concentration of total phosphorus and phosphates is constantly varying, but also their ratio. In the process of biological treatment, a number of complex biochemical and physical-chemical processes are parallel: assimilation, hydrolysis, and adsorption. The effectiveness of these processes is influenced by the magnitude of the initial concentration of total phosphorus and the amount of active dose of sludge. It has been recognized that the increased efficiency of the removal of total phosphorus has an effect on both the increase in the active dose of sludge and the size of the initial concentration of total phosphorus. However, the residual concentration of total phosphorus is affected by its original content, while the initial content of the total phosphorus is affected insignificantly.

RESEARCH ON ELECTROCHEMICAL METHODS TO REMOVE FLUORIDE FROM WATER

2017 ◽  
Vol 126 (2B) ◽  
Author(s):  
Võ Anh Khuê
Keyword(s):  
Optimal Condition ◽  
Removal Efficiency ◽  
Water Solution ◽  
Electrochemical Methods ◽  
Fluoride Ion ◽  
Residual Concentration ◽  
Initial Concentration ◽  
Iron Electrodes ◽  
Aluminum Electrodes

<p>The use of electrochemical methods such as micro-electrolysis, electrocoagulation, and micro-electrolysis combined with electrocoagulation to remove fluoride from water were studied in this paper. The results indicated that the micro-electrolysis (using Fe/C particles) and the electrocoagulation (using iron electrodes) are not suitable for removal of fluoride from water solution. The electrocoagulation method with aluminum electrodes for removal efficiency of fluoride is very good. But it is not as good as the micro-electrolysis (using Fe/C particles) combined with the electrocoagulation method (using aluminum electrodes). At the optimal condition of the micro-electrolysis (using Fe/C particles) combined with the electrocoagulation method (using aluminum electrodes) and the initial concentration of fluoride ion of 50 mg/L, the removal efficiency of fluoride ion is 94.03% and the residual concentration is 2.986 mg/L.</p>

scholarly journals Optimization of Nitrogen Fertilizer Application with Climate-Smart Agriculture in the North China Plain

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3415
Author(s):  
Jinsai Chen ◽  
Guangshuai Wang ◽  
Abdoul Kader Mounkaila Hamani ◽  
Abubakar Sunusi Amin ◽  
Weihao Sun ◽  
...  
Keyword(s):  
Nitrogen Use Efficiency ◽  
Nitrogen Fertilizer ◽  
Maize Yield ◽  
Application Rate ◽  
N2o Emissions ◽  
Nitrogen Application ◽  
Residual Concentration ◽  
Nitrogen Use ◽  
N Application ◽  
Use Efficiency

Long−term excessive nitrogen fertilizer input has resulted in several environmental problems, including an increase in N2O emissions and the aggravation of nitrate leaching; monitoring nitrogen fertilizer is crucial for maize with high yield. This study aimed to optimize the amount of nitrogen applied to maize by Climate−Smart Agriculture (CSA) so as to continuously improve agricultural productivity and reduce or eliminate N2O emissions as much as possible. Field experiments with a completely randomized design were conducted to examine the effects of six nitrogen treatments (N application levels of 0, 120, 180, 240, 300, 360 kg·ha−1, respectively) on N2O emissions, residual concentration of nitrate and ammonium nitrogen, maize yield, and nitrogen utilization efficiency in 2018 and 2019. The results indicated that the residual concentration of nitrate nitrogen (NO3-−N) in the two seasons significantly increased; N2O emissions significantly increased, and the nitrogen fertilizer agronomic efficiency and partial productivity of maize fell dramatically as the nitrogen application rate increased. The maize grain yield rose when the N application amount was raised (N application amount <300 kg·ha−1) but decreased when the N application amount > 300 kg·ha−1. An increase in the nitrogen application rate can decrease nitrogen use efficiency, increase soil NO3-−N residual, and N2O emissions. Reasonable nitrogen application can increase maize yield and reduce N2O emissions and be conducive to improving nitrogen use efficiency. By considering summer maize yield, nitrogen use efficiency, and farmland ecological environment, 173.94~178.34 kg N kg·ha−1 could be utilized as the nitrogen threshold for summer maize in the North China Plain.

scholarly journals Suitability of Lemna Trisulca (Duckweed) in Water Purification

2017 ◽  
Vol 2 (3) ◽  
pp. 11 ◽  
Author(s):  
Terlumun Joseph Utsev ◽  
Uungwa Shachia Jude ◽  
Peter Okah
Keyword(s):  
Water Sample ◽  
Water Purification ◽  
Laboratory Experiments ◽  
Suspended Solid ◽  
Residential Area ◽  
Optimum Conditions ◽  
Initial Concentration ◽  
Load Removal ◽  
Water And Wastewater ◽  
Percentage Removal

The research was aimed at studying the effectiveness of duckweed as a coagulant/disinfectant in the treatment of water and wastewater. Water sample was obtained from River Benue and duckweed was harvested near a residential area in Makurdi Town, Nigeria. Laboratory experiments were carried out using dosage, pH, temperature, initial concentration and Flocculating Speed as variables for both disinfection and coagulation. Results obtained revealed that, the optimum conditions with respect to disinfection (bacteria load removal) were; Dosage=0.4ml, pH=9, Temperature=30°C, Initial concentration=300µm and Flocculating speed=90rev/min, with highest percentage removal of 91% and 82% for the filtrate and powder respectively. For coagulation (turbidity and suspended solid removal), the optimum conditions were; Dosage=0.2ml, pH=5, Temperature=30°C, Initial concentration=633FTU and Flocculating Speed=90rev/min with the highest percentage removal at 84.3% and 80.4% for duckweed filtrate and powder respectively. It is recommended that, duckweed filtrate and powder should be used in water purification for drinking and greywater respectively.

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