Removal of Anions from Solution by Calcined Hydrotalcite and Regeneration of Used Sorbent in Repeated Calcination-Rehydration-Anion Exchange Processes

1999 ◽  
Vol 64 (9) ◽  
pp. 1517-1528 ◽  
Author(s):  
František Kovanda ◽  
Eva Kovácsová ◽  
David Koloušek
Keyword(s):  
Anion Exchange ◽  
Sorption Capacity ◽  
Sorption Isotherms ◽  
Layered Crystal ◽  
Calcined Hydrotalcite ◽  
Capacity Evaluation ◽  
Exchange Processes ◽  
Sorption Ability ◽  
Subsequent Calcination ◽  
Rehydration Process

Synthetic hydrotalcite calcined at 350-550 °C was used for the removal of arsenate, chromate, and vanadate ions from water solutions. The initial anion concentrations were 0.002 mol l-1. The sorption isotherms were measured at 20 °C and at neutral pH. The Langmuir adsorption isotherm was used for the sorption capacity evaluation. The ability of the calcined hydrotalcite to remove the anions from solution decreased in the order of vanadate - arsenate - chromate. The hydrotalcite calcined at 450 °C exhibited the best sorption ability for all the anions. The sorbed anions were released by anion exchange in a carbonate-containing solution and the hydrotalcite after subsequent calcination was used again for the removal of anions. The repeating cycles calcination-rehydration-anion exchange gradually reduced the adsorption capacity of the hydrotalcite. The sorption capacity decreased by 50% after the first two cycles but it did not change significantly in the subsequent cycles. When chromate anions were adsorbed, the decrease in sorption capacity was not observed during repeated calcination-rehydration-anion exchange cycles. The change in the sorption capacity was influenced by the ability of calcined hydrotalcite to regenerate the layered crystal structure during the rehydration process.

The Influences of the Rank of Coal on Methane Sorption Capacity in Coals/Wpływ Rzędu Węgla Na Pojemność Sorpcyjną Metanu W Węglach

2014 ◽  
Vol 59 (2) ◽  
pp. 509-516
Author(s):  
Andrzej Olajossy
Keyword(s):  
Sorption Capacity ◽  
Coalbed Methane ◽  
Vitrinite Reflectance ◽  
Sorption Isotherms ◽  
Volatile Matter ◽  
Low Rank ◽  
Hard Coal ◽  
Petrographic Composition ◽  
Methane Sorption ◽  
Indian Coals

Abstract Methane sorption capacity is of significance in the issues of coalbed methane (CBM) and depends on various parameters, including mainly, on rank of coal and the maceral content in coals. However, in some of the World coals basins the influences of those parameters on methane sorption capacity is various and sometimes complicated. Usually the rank of coal is expressed by its vitrinite reflectance Ro. Moreover, in coals for which there is a high correlation between vitrinite reflectance and volatile matter Vdaf the rank of coal may also be represented by Vdaf. The influence of the rank of coal on methane sorption capacity for Polish coals is not well understood, hence the examination in the presented paper was undertaken. For the purpose of analysis there were chosen fourteen samples of hard coal originating from the Upper Silesian Basin and Lower Silesian Basin. The scope of the sorption capacity is: 15-42 cm3/g and the scope of vitrinite reflectance: 0,6-2,2%. Majority of those coals were of low rank, high volatile matter (HV), some were of middle rank, middle volatile matter (MV) and among them there was a small number of high rank, low volatile matter (LV) coals. The analysis was conducted on the basis of available from the literature results of research of petrographic composition and methane sorption isotherms. Some of those samples were in the form (shape) of grains and others - as cut out plates of coal. The high pressure isotherms previously obtained in the cited studies were analyzed here for the purpose of establishing their sorption capacity on the basis of Langmuire equation. As a result of this paper, it turned out that for low rank, HV coals the Langmuire volume VL slightly decreases with the increase of rank, reaching its minimum for the middle rank (MV) coal and then increases with the rise of the rank (LV). From the graphic illustrations presented with respect to this relation follows the similarity to the Indian coals and partially to the Australian coals.

scholarly journals Technical-economic comparison of chemical precipitation and ion exchange processes for the removal of phosphorus from wastewater

2020 ◽  
Vol 81 (7) ◽  
pp. 1329-1335
Author(s):  
Agostina Chiavola ◽  
Simona Bongirolami ◽  
Giorgia Di Francesco
Keyword(s):  
Ion Exchange ◽  
Anion Exchange ◽  
Ferric Chloride ◽  
Exchange Process ◽  
Chemical Precipitation ◽  
Ion Exchange Process ◽  
Aluminum Ions ◽  
Exchange Processes ◽  
Alternative Solutions ◽  
P Removal

Abstract Chemical precipitation with the addition of ferric chloride is commonly used to remove phosphorus from wastewater. However, since its application also involves several disadvantages, alternative solutions are required. The present paper shows the results of a full-scale experimental work aimed at evaluating the efficiency of the ion exchange process using a polymeric anion exchange resin impregnated with aluminum ions in the removal of phosphorus from wastewater. The study compared the results obtained through this process with chemical precipitation, considering both technical and economic issues. At the same dosage of 6 L/hour and influent concentration (about 6 mg/L), total removal efficiency of 95% and 78% (including also that occurring in the mechanical and biological processes) was achieved by means of the anion exchange process and chemical precipitation, respectively. However, in the latter case, this value was insufficient to ensure consistent compliance with the limit of 2 mg/L Ptot set on the effluent; to achieve this goal, the ferric chloride dosage had to be raised to 12 L/hour, thus increasing the related costs. Furthermore, the anion exchange process generated a lower sludge production. Therefore, the ion exchange process represents a valid alternative to chemical precipitation for P removal from wastewater.

scholarly journals Sorption of V and VI group metalloids (As, Sb, Te) on modified peat sorbents

2016 ◽  
Vol 14 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Linda Ansone-Bertina ◽  
Maris Klavins
Keyword(s):  
Sorption Capacity ◽  
Batch Tests ◽  
Physical Sorption ◽  
Sorption Ability ◽  
A Minor ◽  
Competing Ions ◽  
Optimal Ph ◽  
Sorption Time

AbstractThe present work investigates arsenic, antimony and tellurium sorption using iron modified peat. The results were obtained using batch tests and the sorption was studied as a function of initial metalloid concentration, pH and sorption time, as well as the presence of competing substances. The obtained results indicate that modification of peat with Fe compounds significantly enhances the sorption capacity of the sorbents used for sorption of arsenic, antimony and tellurium. The optimal pH interval for the sorption of Sb(III) is 6.5–9 and for As(V) and Sb(V) – 3–6, while As(III) and tellurium sorption using Fe-modified peat is favourable in a wider interval of 3–9. The presence of competing ions as well as HA affect sorption of metalloids on Fe-modified peat. A minor impact on the reduction of metalloid sorption was detected in the presence of nitrate, sulphate, carbonate and tartrate ions, while in the presence of phosphate and HA the sorption ability of metalloids can be considerably reduced. The obtained results of kinetic experiments indicate that sorption of metalloids on Fe-modified peat mainly occurs relying on mechanisms of physical sorption processes.

scholarly journals Synthesis of Nitrogen-Rich Polymers by Click Polymerization Reaction and Gas Sorption Property

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1732 ◽  
Author(s):  
Jing-Ru Song ◽  
Wen-Gui Duan ◽  
Dian-Peng Li
Keyword(s):  
Surface Area ◽  
Sorption Property ◽  
Sorption Isotherms ◽  
Magic Angle Spinning ◽  
Polymerization Reaction ◽  
Magic Angle ◽  
Gas Sorption ◽  
Click Polymerization ◽  
Sorption Ability ◽  
Angle Spinning

Microporous organic polymers (MOPs) are promising materials for gas sorption because of their intrinsic and permanent porosity, designable framework, and low density. The introduction of nitrogen-rich building block in MOPs will greatly enhance the gas sorption capacity. Here, we report the synthesis of MOPs from the 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine unit and aromatic azides linkers by click polymerization reaction. Fourier transform infrared (FTIR) and solid-state 13C CP-MAS (Cross Polarization-Magic Angle Spinning) NMR confirm the formation of the polymers. CMOP-1 and CMOP-2 exhibit microporous networks with a BET (Brunauer–Emmett–Teller) surface area of 431 m2·g−1 and 406 m2·g−1 and a narrow pore size distribution under 1.2 nm. Gas sorption isotherms including CO2 and H2 were measured. CMOP-1 stores a superior CO2 level of 1.85 mmol·g−1 at 273 K/1.0 bar, and an H2 uptake of up to 2.94 mmol·g−1 at 77 K/1.0 bar, while CMOP-2, with its smaller surface area, shows a lower CO2 adsorption capacity of 1.64 mmol·g−1 and an H2 uptake of 2.48 mmol·g−1. In addition, I2 vapor adsorption was tested at 353 K. CMOP-1 shows a higher gravimetric load of 160 wt%. Despite the moderate surface area, the CMOPs display excellent sorption ability for CO2 and I2 due to the nitrogen-rich content in the polymers.

scholarly journals Defluoridation with Locally Produced Thai Bone Char

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Yothin Mutchimadilok ◽  
Sunisa Smittakorn ◽  
Surat Mongkolnchai-arunya ◽  
Deanna Durnford
Keyword(s):  
Sorption Isotherms ◽  
Sorption Properties ◽  
Social Constraints ◽  
Contaminated Water ◽  
Bone Char ◽  
Groundwater Samples ◽  
Sorption Ability ◽  
Synthetic Solution ◽  
Rural Thailand

The fluoride sorption ability of a locally available bone char is quantified. Both a synthetic solution and natural groundwater samples from several sites are studied and compared to Indian bone char, which is widely accepted and used successfully in India and elsewhere. The Freundlich and Langmuir sorption isotherms were used to quantify sorption properties. Results show that the Thai bone char is as effective as the Indian bone char for removing fluoride from contaminated water, despite the more rigid physical and social constraints found in rural Thailand. Sorption studies with fluoride-contaminated natural groundwater samples also show that chlorides, nitrates, and sulfates had little effect on the removal of fluoride by the homemade bone char.

Synthesis of kaolinite/iron oxide magnetic composites and their use in the removal of Cd(II) from aqueous solutions

2013 ◽  
Vol 67 (7) ◽  
pp. 1642-1649 ◽  
Author(s):  
Pengfei Zong ◽  
Shoufang Wang ◽  
Chaohui He
Keyword(s):  
Iron Oxide ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Sorption Capacity ◽  
Sorption Isotherms ◽  
Entropy Change ◽  
Solution Chemistry ◽  
Standard Entropy ◽  
Iron Oxide Particles ◽  
Magnetic Composites

Kaolinite/iron oxide magnetic composites (kaolinite/MCs) were used as adsorbent for the removal of Cd(II) from aqueous solutions. The influences of pH, ionic strength, solid/liquid ratio and temperature on Cd(II) sorption on kaolinite/MCs were evaluated. The results showed that the removal of Cd(II) on kaolinite/MCs was strongly dependent on pH and ionic strength. An optimal kaolinite/MCs concentration mass per volume for removal of Cd(II) from aqueous solutions was 1.4 g L–1. The Langmuir and Freundlich models were used to simulate sorption isotherms of Cd(II) at three different temperatures of 293, 313 and 333 K. The sorption of Cd(II) on kaolinite/MCs increased with increasing temperature, and thermodynamic parameters (standard entropy change, enthalpy change and Gibbs free energy change) illustrated that this sorption process was spontaneous and endothermic. The sorption behaviors of Cd(II) were mainly dependent on surface properties of kaolinite/MCs and solution chemistry conditions. The sorption capacity of Cd(II) on kaolinite/MCs was lower than that on kaolinite, because iron oxide particles decreased surface charge of kaolinite leading to less sorption capacity. Due to high magnetism, kaolinite/MCs could be easily separated with an external magnetic field. Kaolinite/MCs could therefore be used as potential adsorbent for preconcentration and immobilization of Cd(II) ions from large volumes of aqueous solutions.

scholarly journals Time changeability model of the bog ore sorption ability

2014 ◽  
Vol 21 (1) ◽  
pp. 113-123
Author(s):  
Kazimierz Gaj ◽  
Hanna Cybulska-Szulc
Keyword(s):  
Statistical Analysis ◽  
Regression Model ◽  
Sorption Capacity ◽  
Time Variation ◽  
Iron Ore ◽  
Theoretical Calculations ◽  
Sorption Ability ◽  
Laboratory Examinations

Abstract Basing on long-standing cyclic measurements of sludge-originated biogas composition and considering statistical analysis of their results, a regression model describing time variation of biogas desulfurization using bog iron ore has been developed. The model was verified by theoretical calculations and results from laboratory examinations of the sorbent. It was also used to estimate the depletion time and sorption capacity of the bed and to determine the demand index for bog ore.

scholarly journals Sorption of medical preparations by chitosan

2020 ◽  
Vol 164 ◽  
pp. 06025
Author(s):  
Anna Beliaeva ◽  
Galina Nianikova
Keyword(s):  
Quantitative Determination ◽  
Sorption Capacity ◽  
Maximum Degree ◽  
Sorption Isotherms ◽  
Sorption Process ◽  
Sorption Properties ◽  
Before And After ◽  
Static Conditions ◽  
Degree Of Sorption

The article provides information about sorption properties of crab chitosan in relation to Analgin, Aspirin, Quamatel, Mydocalm, Paracetamol, Tsifran and Phtalazol. Quantitative determination of medicines’ amount before and after sorption was performed by HPLC-MS method with the preliminary plotting of calibration curves. The sorption capacity of chitosan taken in different concentrations was determined. Sorption isotherms and kinetic curves of medications’ sorption by chitosan were plotted. It has been shown that the maximum degree of sorption in static conditions for all studied medicines was achieved within an hour after the beginning of the sorption process.

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