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1
Ding, Xiao Ou, Xiu Yi Hua, Fei Zhao, Zhi Yong Guo, Xing Song, and De Ming Dong. "Sorption and Desorption of DDTs to Natural Surface Coatings." Advanced Materials Research 322 (August 2011): 125–28. http://dx.doi.org/10.4028/www.scientific.net/amr.322.125.
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The sorption/desorption of DDTs to surface coatings were investigated using the bath equilibration technique. Freundlich isotherm was applied to describe the sorption/desorption of DDTs to surface coatings. The results showed that desorption of DDTs from surface coatings presented hysteresis which was described by hysteresis index (HI). Influences of pH values of solutions and the coexistence of Cu and Pb on sorption and desorption were also studied in the same method. The results indicated that the sorption of DDTs decreased and desorption increased when the values of pH increased from 5 to 9. The coexistence of Cu and Pb inhibited the sorption of DDTs, meanwhile had facility to desorption of DDTs.
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Kim, J. H., W. S. Shin, Y. H. Kim, S. J. Choi, Y. W. Jeon, and D. I. Song. "Sequential sorption and desorption of chlorinated phenols in organoclays." Water Science and Technology 47, no. 9 (May 1, 2003): 59–64. http://dx.doi.org/10.2166/wst.2003.0492.
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Effect of pH on the sorption and desorption of the chlorinated phenols (2-chlorophenol and 2,4-dichlorophenol) in HDTMA-montmorillonite organoclays was investigated using sequential batch experiments. 2,4-dichlorophenol exhibited higher affinity in both sorption and desorption than 2-chlorophenol at pH 4.85 and 9.15. For both chlorophenols, the protonated speciation (at pH 4.85) exhibited a higher affinity in both sorption and desorption than the predominant deprotonated speciation (about 80% and 95% of 2-chlorophenate and 2,4-dichlophenate anions at pH 9.15, respectively). Desorption of chlorinated phenols was strongly dependent on the current pH regardless of their speciation during the previous sorption stage. No appreciable desorption resistance of the chlorinated phenols was observed in organoclays after sequential desorptions. Affinity of both chlorophenols in bisolute competitive sorption and desorption was reduced compared to that in a single-solute system due to the competition between solutes. The ideal adsorbed solution theory coupled with the single-solute Freundlich model successfully predicted the bisolute competitive sorption and desorption equilibria.
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Gonzalez-Rodriguez, Sara, and Maria Luisa Fernandez-Marcos. "Sorption and Desorption of Vanadate, Arsenate and Chromate by Two Volcanic Soils of Equatorial Africa." Soil Systems 5, no. 2 (April 1, 2021): 22. http://dx.doi.org/10.3390/soilsystems5020022.
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Sorption of oxyanions by soils and mineral surfaces is of interest due to their role as nutrients or pollutants. Volcanic soils are variable charge soils, rich in active forms of aluminum and iron, and capable of sorbing anions. Sorption and desorption of vanadate, arsenate, and chromate by two African andosols was studied in laboratory experiments. Sorption isotherms were determined by equilibrating at 293 K soil samples with oxyanion solutions of concentrations between 0 and 100 mg L−1 V, As, or Cr, equivalent to 0−2.0 mmol V L−1, 0−1.3 mmol As L−1, and 0−1.9 mmol Cr L−1, in NaNO3; V, As, or Cr were determined by ICP-mass spectrometry in the equilibrium solution. After sorption, the soil samples were equilibrated with 0.02 M NaNO3 to study desorption. The isotherms were adjusted to mathematical models. After desorption with NaNO3, desorption experiments were carried out with a 1 mM phosphate. The sorption of vanadate and arsenate was greater than 90% of the amount added, while the chromate sorption was much lower (19–97%). The sorption by the Silandic Andosol is attributed to non-crystalline Fe and Al, while in the Vitric Andosol, crystalline iron species play a relevant role. The V and Cr sorption isotherms fitted to the Freundlich model, while the As sorption isotherms conformed to the Temkin model. For the highest concentrations of oxyanions in the equilibrating solution, the sorbed concentrations were 37–38 mmol V kg−1, 25 mmol As kg−1, and 7.2–8.8 mmol Cr kg−1. The desorption was low for V and As and high for Cr. The comparison of the sorption and desorption isotherms reveals a pronounced hysteresis for V in both andosols and for Cr in the Silandic Andosol. Phosphate induced almost no V desorption, moderate As desorption, and considerable Cr desorption.
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Amaria, Amaria, Suyono Suyono, Eko Sugiharto, and Anis N. Rohmah. "SORPTION OF Au(III) BY Saccharomyces cerevisiae BIOMASS." Indonesian Journal of Chemistry 10, no. 2 (July 8, 2010): 177–83. http://dx.doi.org/10.22146/ijc.21457.
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Au(III) sorption by S. cerevisiae biomass extracted from beer waste industry was investigated. Experimentally, the sorption was conducted in batch method. This research involved five steps: 1) identification the functional groups present in the S. cerevisiae biomass by infrared spectroscopic technique, 2) determination of optimum pH, 3) determination of the sorption capacity and energy, 4) determination of the sorption type by conducting desorption of sorbed Au(III) using specific eluents having different desorption capacity such as H2O (van der Waals), KNO3 (ion exchange), HNO3 (hydrogen bond), and tiourea (coordination bond), 5) determination of effective eluents in Au(III) desorption by partial desorption of sorbed Au(III) using thiourea, NaCN and KI. The remaining Au(III) concentrations in filtrate were analyzed using Atomic Absorption Spectrophotometer. The results showed that: 1) Functional groups of S. cerevisiae biomass that involved in the sorption processes were hydroxyl (-OH), carboxylate (-COO-) and amine (-NH2), 2) maximum sorption was occurred at pH 4, equal to 98.19% of total sorption, 3) The sorption capacity of biomass was 133.33 mg/g (6.7682E-04 mol/g) and was involved sorption energy 23.03 kJ mol-1, 4) Sorption type was dominated by coordination bond, 5) NaCN was effective eluent to strip Au(III) close to 100%. Keywords: sorption, desorption, S. cerevisiae biomass, Au(III)
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Matallo, M. B., D. A. S. Franco, S. D. B. Almeida, and A. L. Cerdeira. "Sorption and desorption of Suflafenacil in two soils in the state of São Paulo with different physical and chemical attributes." Planta Daninha 32, no. 2 (June 2014): 393–99. http://dx.doi.org/10.1590/s0100-83582014000200017.
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A study was conducted to evaluate the sorption and desorption of 14C herbicide saflufenacil (pyrimidinedione) in two soils in the State of São Paulo, classified as Red Yellow Latosol with clayey texture (LVA-1) and medium texture (LVA-2), using the batch method through isotherms. The soils were air dried and sieved a 2 mm mesh. The radioactivity was determined by liquid scintillation spectrometry in acclimatized room (25 ± 2 °C). Sorption isotherms were conducted for 5 concentrations of saflufenacil (5.0; 2.5; 1.0; 0.5 and 0.05 μg mL-1) and the results were adjusted to the Freundlich equation, thus obtaining the parameters of sorption followed by two extractions with 0.01 M CaCl2 to determine desorption parameters similarly to sorption. The results showed that saflufenacil sorption was low for both soils studied, being greater for the LVA with higher organic matter content. The desorption coefficients were greater than their sorption coefficients, suggesting the occurrence of hysteresis. The sorption and desorption isotherms (classified as type C isotherms), hysteresis and the t-test between the angular coefficient of the respective isotherms showed that both the sorption and desorption occur with equal intensity.
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Hariyanti, Mimien. "KARAKTERISTIK SORPSI DAN DESORPSI FOSFAT PADA OXISOL DENGAN PENDEKATAN KINETIK." Jurnal Solum 7, no. 2 (July 1, 2010): 97. http://dx.doi.org/10.25077/js.7.2.97-109.2010.
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The phosphorous sorption and desorption characteristics were studied in Oxisols Padang Siantah West Sumatera. The amount of P (0, 20, 40, 80, 100, 200, 400, 800 g P) was added to 1 gram soil and incubated for 0.04 days (1 hour) , 0.125 days (3 h), 0.25 days (6 h), 0.375 days (9 h), 1,3, 6, 9, 18 dan 36 days. A completely factorial design in triple replication was set up. The results of P sorption and desorption experiment showed that Oxisol had very high sorption with time until 99 from added P. P desorption maximum at the time was 3 days with sorption value 1,67 % from added P.
Keywords : Oxisol, Fe and Al oksides, P sorption, P desorption, time of reaction.
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Pusino, Alba, M. Vittoria Pinna, and Carlo Gessa. "Azimsulfuron Sorption−Desorption on Soil." Journal of Agricultural and Food Chemistry 52, no. 11 (June 2004): 3462–66. http://dx.doi.org/10.1021/jf049971e.
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Burton, Edward D., Ian R. Phillips, Darryl W. Hawker, and Dane T. Lamb. "Copper behaviour in a Podosol. 2. Sorption reversibility, geochemical partitioning, and column leaching." Soil Research 43, no. 4 (2005): 503. http://dx.doi.org/10.1071/sr04118.
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The sorption–desorption and leaching behaviour of Cu in a Podosol from south-east Queensland, Australia, was examined. Copper sorption was described by a linear distribution coefficient at low sorption levels (KDCa→0) of 481 L/kg and a sorption capacity (CS,Max) of 382 mg/kg. Selective removal of soil organic matter reduced these values by approximately 95%, indicating that Cu was sorbed predominantly to soil organic matter. The KDCa→0 and CS,Max values from Cu desorption experiments were 934 L/kg and 516 mg/kg, respectively, which indicates that sorption was not fully reversible. This irreversibility was related to aqueous Cu speciation (modelled with MINTEQA2), showing that aqueous complexes between Cu and dissolved organic carbon (DOC) comprised 28.3–72.8% and 21.3–45.4% of aqueous Cu in the sorption and desorption experiment, respectively. Sorption irreversibility was not evident when the corresponding data was presented as free Cu2+ isotherms. Both sorption and desorption experiments with free Cu2+ <0.2 mg/L were described by a KDCa→0 value of approximately 3000 L/kg. Sequential extraction of sorbed Cu indicated that at low concentrations, sorption occurred primarily via specific interactions, with non-specific sorption becoming increasing important at higher concentrations. Desorption of Cu in a column leaching experiment was attributable to exchange of sorbed Cu2+ with Na+. Leaching with a DOC solution of pH 7 and 135 mg/L greatly enhanced Cu mobility due to the formation of aqueous Cu–DOC complexes.
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Kookana, RS, and LAG Aylmore. "Retention and release of diquat and paraquat herbicides in soils." Soil Research 31, no. 1 (1993): 97. http://dx.doi.org/10.1071/sr9930097.
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The sorption and desorption behaviour of diquat and paraquat, in the presence of different salt concentrations, has been studied in some Western Australian soils varying in physical and chemical properties. Sorption isotherms were found to be of the 'L' type according to the Giles classification with the data fitting well to the Langmuir equation. The sorption capacities of soils for diquat ranged from very high in clay soil (146 400 �mol kg-1) to very low in sand (1765 �mol kg-1) and followed the order of clay content in the soils. The clay soil also showed the highest value for the Langmuir coefficient representing bonding energy. The sorption capacities for the herbicides were less than the CEC of the soils. Both the type and content of clay minerals present in soil were important for sorption and subsequent desorption of the dipyridylium herbicides. An increase in the salt concentration of the soil solution (from 0.005 to 0.05 M CaCl2) resulted in decreases in sorption capacities for the herbicides ranging from some 17% to 40% in the different soils. Both Ca2+ and Na+ cations competed for the sorption sites with the herbicides, but Na+ was not as effective as Ca2+. Desorption of the herbicides was also significantly affected by the salt concentrations of the extractant. After five successive extractions with 0.005 m CaCl2, the total amounts of equilibrium sorption desorbed from the Bassendean surface soil were 13% and 7% for diquat and paraquat, respectively. The percentages of diquat removed by extractions decreased with increasing clay contents in the soils studied. Desorption of diquat was higher than that of paraquat at all salt concentrations. Hysteresis was evident between sorption and desorption isotherms.. As sorption increased, the desorption became easier, indicating that the herbicides were less strongly held. Sorption which occurred in the presence of higher ionic strength solutions of inorganic cations was relatively less susceptible to desorption.
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Jada, Amane, and Rachid Ait Akbour. "Transport, Sorption and Desorption of Organic Dye Through Quartz Sand Particles." International Journal of Thermal and Environmental Engineering 16, no. 2 (August 2018): 65–71. http://dx.doi.org/10.5383/ijtee.16.02.001.
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Gray, C. W., R. G. McLaren, A. H. C. Roberts, and L. M. Condron. "Sorption and desorption of cadmium from some New Zealand soils: effect of pH and contact time." Soil Research 36, no. 2 (1998): 199. http://dx.doi.org/10.1071/s97085.
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The effects of soil pH on the desorption of native soil cadmium (Cd), and on the sorption and desorption of added Cd at low concentrations, have been examined for 6 New Zealand soils ranging from pH 4·9 to 6·2. The effect of contact time with added Cd on subsequent desorption from soil has also been studied. Cadmium desorption was determined by repeated equilibrations in 0·01 М Ca(NO3)2 solution. Cadmium sorption ranged between 38% and 96% from an initial addition of 2 µg Cd/g soil. The effect of increasing soil pH was to increase substantially the amount of Cd sorbed. Sorption isotherms were all linear, with a negative intercept on the y-axis. Sorption data also fitted a linearised Freundlich sorption equation. Cadmium desorption was also very sensitive to pH, with a dramatic reduction in the amount of native Cd desorbed from the soil as pH increased, as was observed for samples where Cd was added. The cumulative amounts of native Cd desorbed represented only a relatively small proportion (0–22%) of total soil Cd concentrations. Added Cd desorption ranged between 22% and 99% of the Cd initially sorbed on the soil at varying pH. Organic matter appeared to be the most important soil component controlling both sorption and desorption in the soils studied. In the contact period experiment, the proportion of Cd desorbed was decreased by increasing initial contact time to 70 days before desorption for all 4 soils studied. Contact time had the greatest effect on Cd desorption in soils with the highest amounts of soil oxide components. Implications of the study are that, for the soils studied, soil pH, Cd contact time, and soil organic matter content are controlling factors on Cd desorption into soil solution, and are therefore likely to play an important role in Cd phytoavailability.
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Kašička, Václav, and Zdeněk Prusík. "Desorption isotachophoresis —quantitative characterization of sorption and desorption conditions." Journal of Chromatography A 320, no. 1 (February 1985): 75–80. http://dx.doi.org/10.1016/s0021-9673(01)90481-9.
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Petter, Fabiano André, Tamara Santos Ferreira, Adilson Paulo Sinhorin, Larissa Borges de Lima, Leidimar Alves de Morais, and Leandro Pereira Pacheco. "Sorption and desorption of diuron in Oxisol under biochar application." Bragantia 75, no. 4 (September 29, 2016): 487–96. http://dx.doi.org/10.1590/1678-4499.420.
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ABSTRACT The objective of this study was to verify the kinetics of sorption and desorption of diuron in an Oxisol under application of biochar. The samples were collected in a field experiment conducted in randomized design blocks consisted of 2 base fertilization levels (0 and 400 kg∙ha−1 NPK 00-20-20 fertilizer formula) and 3 doses of biochar (0, 8 and 16 Mg∙ha−1). In the evaluation of sorption and desorption, Batch Equilibrium method was used. The kinetics of sorption and desorption of diuron, total organic carbon, fulvic acid, humic acid and humin, pH and partition coefficient to organic carbon were evaluated. The Freundlich isotherm was adjusted appropriately to describe diuron sorption kinetics in all the studied treatments. The application of biochar provided increment in the sorption (Kf) and reduction in the desorption of diuron in 64 and 44%, respectively. This effect is attributed to the biochar contribution to the total organic carbon and C-humin and of these to diuron through hydrophobic interactions and hydrogen bonds. The positive correlation between the partition coefficient to organic carbon and Kf confirms the importance of soil organic compartment in the sorption of diuron. There was no competition of NPK fertilizer for the same sorption site of diuron. The increase and reduction in sorption and desorption, respectively, show that the application of biochar is an important alternative for the remediation of soil leaching of diuron, especially in sandy soils.
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Santosa, Sri Juari, Narsito Narsito, and Aldes Lesbani. "SORPTION-DESORPTION MECHANISM OF Zn(II) AND Cd(II) ON CHITIN." Indonesian Journal of Chemistry 6, no. 1 (June 13, 2010): 47–51. http://dx.doi.org/10.22146/ijc.21772.
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This study reports the results of the elucidation of the sorption-desorption mechanism of Zn(II) and Cd(II) on chitin through the determination of capacity, energy, and rate constant of sorption as well as the investigation of their desorption properties in NaCl and Na2EDTA solutions. The chitin was isolated through deproteination followed by demineralization of crab (Portunus pelagicus Linn) shell using NaOH solutions. The sorption of both metal ions followed the Langmuir isotherm model, resulting the sorption capacities of 3.2 x 10-4 and 2.8 x 10-4 mol g-1 for Zn(II) and Cd(II), respectively, and sorption energies of 15.1 kJ mol-1 for Zn(II) and 17.9 kJ mol-1 for Cd(II). It was also observed that Zn(II) was sorbed slightly faster than Cd(II) with first order sorption rate constants of 2.82 x 10-3 min-1 for Zn(II) and 2.61 x 10-3 min-1 for Cd(II). The result of the desorption experiment showed that Cd(II) and especially Zn(II) could only be exchanged by Na(I) after desorbing those metal ions by strong chelating agent of EDTA2-. The easier desorption of Zn(II) than Cd(II) by EDTA2- must be attributed by the smaller sorption energy of Zn(II) and by harder acid property of Zn(II) than Cd(II) as EDTA2- contained hard electron donor elements. Keywords: sorption, desorption, chitin, Zn(II), Cd(II)
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Al-Kanani, T., and A. F. MacKenzie. "Sorption and desorption of orthophosphate and pyrophosphate by mineral fractions of soils, goethite, and kaolinite." Canadian Journal of Soil Science 71, no. 3 (August 1, 1991): 327–38. http://dx.doi.org/10.4141/cjss91-032.
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Sorption-desorption reactions of orthophosphate (OP) and pyrophosphate (PP) were studied in two size fractions of Quebec soils (St. Bernard and Dalhousie) and minerals (goethite and kaolinite). Soil and mineral samples were fractionated into two separates (20.0–2.0 μm and 2.0–0.2 μm). The soils had similar mineral suites, but the St. Bernard have more vermiculite, chlorite, and quartz in the coarser fraction than the Dalhousie soil, perhaps an indication of different origin of parent material. Soil and goethite samples sorbed more OP than PP whereas kaolinite sorbed small but similar amounts of PP and OP. The PP and OP sorption was found to be significantly correlated with acid ammonium oxalate extractable Fe, but not with dithionite extractable Fe. Kaolinite desorbed similar amounts of OP and PP whereas more OP than PP was desorbed from soil and goethite samples. The degree of subsequent desorption seemed to be related to degree of sorption. The lack of similarity between sorption and desorption isotherms may indicate that sorption isotherms are of limited value in P fertilizer studies especially with regard to the estimation of subsequent P release in fertilized soils. Smaller particle sizes and their larger specific surface area resulted in higher OP and PP sorption compared with the coarser particle sizes. For OP sorption, the Langmuir equation yielded the closest fit in comparison to Freundlich and Temkin equations; the Freundlich equation gave the closest fit for PP sorption data. The Langmuir equation failed to fit desorption data. Key words: Orthophosphate, pyrophosphate, sorption, desorption
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Elbana, Tamer A., and H. Magdi Selim. "Multireaction Modeling of Lead (Pb) and Copper (Cu) Sorption/Desorption Kinetics in Different Soils." Soil Systems 3, no. 2 (May 31, 2019): 38. http://dx.doi.org/10.3390/soilsystems3020038.
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Batch kinetic experiments were carried out to quantify and describe the sorption/desorption of Cu and Pb in ten soils that exhibited a wide range of properties. Sorption isotherms were quantified using the Langmuir equation, whereas modeling of sorption/desorption kinetics was described using multireaction model (MRM). Results revealed the nonlinear sorption behavior of Cu and Pb in all soils. The ten soils exhibited higher affinity to Pb (6.4 to 36.5 mmol kg−1) in comparison to Cu (3.6 to 22.4 mmol kg−1). Simulation of Cu and Pb kinetic data indicated that the rate of sorption reaction was two orders of magnitude higher than the rate of release. Considering one irreversible site in addition to one-reversible kinetic site improved the estimation of rates of reaction for both Cu and Pb in acidic and alkaline soils. All soils exhibited sorption/desorption hysteresis where Pb-releases ranged between <0.2% and 14.4% of the total sorbed. The respective Cu releases ranged from <0.85% and 23.4%. The multireaction model, which was successful in describing Cu and Pb for all ten soils, provided insight into the processes of sorption/desorption of Cu and Pb in all soils.
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Mousa, Noor Edin, Claudia Maria Simonescu, Rodica Elena Patescu, Vasile Lavric, and Daniela C. Culita. "Regeneration of Calcium Alginate and Chitosan Coated Calcium Alginate Sorbents to be Reused for Lead (II) Removal from Aqueous Solutions." Revista de Chimie 68, no. 9 (October 15, 2017): 1992–96. http://dx.doi.org/10.37358/rc.17.9.5808.
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The application of biopolymer-based sorbents in solving some environmental problems such as the removal and recovery of heavy metals from natural polluted water and wastewater has received lately a lot of attention due to their unique characteristics. The fundamental properties that recommend the usage of biopolymers-based sorbents for environmental remediation are: high selectivity and sorption capacity, renewability, safe manipulation, sorption capacity increase through simple physical and chemical methods, easy separation from treated water, and easy regeneration and reuse for repetitive sorption-desorption cycles. Accordingly, this research study has as purpose to present the results related to the usage of two types of alginate sorbents (calcium alginate and chitosan coated calcium alginate) in four repetitive lead(II) ions sorption-desorption cycles and to examine the influence of desorption agents on structural sorbent�s characteristics. The results obtained showed that both calcium alginate and chitosan coated calcium alginate are good stable sorbents to be used in lead(II) ions sorption-desorption cycles.
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Nursapina, Nurgul, Fatima Meiirman, Gulsana Amanova, and Ilona Matveyeva. "Study of effectiveness of strongly basic anion exchange resins in the process of uranium extraction from the underground leaching productive solution." Chemical Bulletin of Kazakh National University, no. 4 (December 28, 2018): 10–15. http://dx.doi.org/10.15328/cb979.
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The process of uranium sorption is one of the important stages in the production of uranium. This stage affects uranium extraction effectiveness from productive solutions. The sorption and desorption characteristic of anion exchange resins in dynamic condition were investigated in order to study the effectiveness of resins, which were used for extraction of uranium from sulfuric acid productive solution. The sorption and desorption of uranium from the productive solution on anion exchange resins AB-17 and DOWEX 1X8 200 was carried out in laboratory conditions. The sorption characteristics were investigated. The determined sorption capacities of the resins were 1.47 and 14.4 mg/mL, respectively. The most efficient anion exchanger is DOWEX 1X8 200 that has a high sorption capacity as well as good desorption characteristics, which make it possible to obtain solutions having 23 times higher uranium concentrations than in productive solutions.
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Trickovic, Jelena, Ivana Ivancev-Tumbas, Marijana Kragulj, Miljana Prica, Dejan Krcmar, Aleksandar Nikolic, and Bozo Dalmacija. "Lindane sorption and desorption behaviour on sediment organic matter." Journal of the Serbian Chemical Society 78, no. 6 (2013): 883–95. http://dx.doi.org/10.2298/jsc120706104t.
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The work is concerned with the sorption and desorption behaviour of lindane on four humic acid fractions (HAs) and two humin fractions, sequentially extracted from Ludas lake sediment. All sorption isotherms, fitted to a Freundlich model, were nonlinear. The isotherm linearity increased from 0.757 for the first extracted HA to 0.944 for the ninth HA showing a positive correlation with atomic H/C ratio, while a negative correlation between sorption coefficient and aliphaticity of the isolated HAs was observed. It has been shown that the sorption processes may be strongly influenced by the physical conformation of and accessibility to sediment organic matter (SOM), as demonstrated by high Koc and low n values of humin samples. Despite exhibiting the most nonlinear sorption isotherms, humin samples did not show a pronounced sorption-desorption hysteresis, while the most significant hysteresis was observed for three HA samples. These results support the hypothesis that the aromatic domains in SOM influence strongly the sorption and desorption behaviour of lindane. Our findings may be helpful in understanding the distribution, transport and fate of lindane in soils and sediments.
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Arévalo, R., and R. E. Hernández. "Influence of Moisture Sorption on Swelling of Mahogany (Swietenia macrophylla King) Wood." Holzforschung 55, no. 6 (November 6, 2001): 590–94. http://dx.doi.org/10.1515/hf.2001.096.
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Summary Samples of mahogany wood (Swietenia macrophylla King) from Peru were used for moisture sorption tests associated with swelling tests at 25°C. Seven adsorption and five desorption moisture conditions were investigated to study the differences in swelling between adsorption and desorption curves at a given equilibrium moisture content. The results demonstrated that dimensional changes in the tangential direction and in volume were greater for desorption than for adsorption. The presence of these second order effects of moisture sorption in mahogany wood were not detected in the radial direction. Finally, the tangential/radial swelling ratio of this wood was lower in both states of sorption, and was lower in adsorption than in the desorption state.
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Khodaverdiloo, H., and A. Samadi. "Batch equilibrium study on sorption, desorption, and immobilisation of cadmium in some semi-arid zone soils as affected by soil properties." Soil Research 49, no. 5 (2011): 444. http://dx.doi.org/10.1071/sr10156.
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Little information is available for cadmium (Cd) sorption/desorption behaviour in soils with relatively variable CaCO3 content. The objectives of this study were to: (i) parameterise the sorption and desorption of Cd and the hysteretic behaviour of Cd sorbed to soils with varying CaCO3 content; and (ii) correlate sorption, desorption, and retention parameters with physicochemical characteristics of the soils. Twenty soil samples of different physico-chemical properties were taken from agricultural regions of Western Azerbijan province, Iran. A batch equilibrium experiment was conducted to construct sorption/desorption curves of Cd. The linear, Langmuir, and Freundlich isotherm equations were fitted to the experimental data of Cd sorption and retention, using either linear regression procedure or nonlinear least square optimisation (LSO). Both the Freundlich and Langmuir approaches described the Cd sorption and retention data well. A strong and irreversible binding of Cd in the soils was recorded, using a desorption approach. In the case of Cd sorption, a significant positive correlation (r = 0.38, P ≤ 0.05) was found between the Freundlich constant (Kf) and active CaCO3 equivalent (ACCE). The Freundlich n was positively correlated with cation exchange capacity (r = 0.49, P ≤ 0.05) and clay (r = 0.61, P ≤ 0.01) and negatively with ACCE (r = –0.60, P ≤ 0.01). The soil partition coefficient (KSD) showed a positive correlation with ACCE. The sorption maxima (b) were much less than the cation exchange capacity of soils. However, the relatively high pH (7.0–8.0) of the experimental soils and presence of relatively high values of free and active carbonate in the soils, along with the large sorption capacity of the soils, suggest the possibility of solid-phase precipitation as octavite (CdCO3). Parameter b, when fitted through LSO, showed a negative correlation with clay (r = –0.51, P ≤ 0.05) and a positive correlation with ACCE (r = 0.63, P ≤ 0.01). Langmuir K (Kl) showed a positive correlation with clay (r = 0.52, P ≤ 0.05) and a negative relationship with pH (r = –0.58, P ≤ 0.05) and ACCE (r = –0.65, P ≤ 0.01). Sorption of Cd showed a positive correlation (r ≥ 0.54, P ≤ 0.05) and its desorption a high negative correlation (r ≤ –0.61, P ≤ 0.05), with ACCE. It can be concluded that the ACCE is the important soil property controlling the sorption and retention of Cd in the studied soils.
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Korovin, Vadym, Oleksandr Valiaiev, Oleksandr Zontov, Larysa Zontova, Volodymyr Pilchyk, and Borys Pysmennyi. "Uranium (VI) sorption from sulphuric solutions by AM-p-2 anionite." E3S Web of Conferences 109 (2019): 00039. http://dx.doi.org/10.1051/e3sconf/201910900039.
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Research results were presented for equilibrium and kinetics of uranium sorption by AM-p-2 strong-base anionite from model sulphuric solution. Kinetic experimental data agreed with the pseudo second-order model while equilibrium ones – with the modified Langmuir-Freundlich equation. Testing of the anionite including sorption-desorption process operations used at uranium-mining industrial facilities showed that the resin had high sorption-desorption characteristics.
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Sato, Shinjiro, and Nicholas Brian Comerford. "Influence of soil pH on inorganic phosphorus sorption and desorption in a humid brazilian Ultisol." Revista Brasileira de Ciência do Solo 29, no. 5 (October 2005): 685–94. http://dx.doi.org/10.1590/s0100-06832005000500004.
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Liming is a common practice to raise soil pH and increase phosphorus (P) bioavailability in tropical regions. However, reports on the effect of liming on P sorption and bioavailability are controversial. The process of phosphorus desorption is more important than P sorption for defining P bioavailability. However few studies on the relationship between soil pH and P desorption are available, and even fewer in the tropical soils. The effects of soil pH on P sorption and desorption in an Ultisol from Bahia, Brazil, were investigated in this study. Phosphorus sorption decreased by up to 21 and 34 % with pH increases from 4.7 to 5.9 and 7.0, respectively. Decreasing Langmuir K parameter and decreasing partition coefficients (Kd) with increasing pH supported this trend. Phosphorus desorption was positively affected by increased soil pH by both the total amount of P desorbed and the ratio of desorbed P to initially sorbed P. A decreased K parameter and increased Kd value, particularly at the highest pH value and highest P-addition level, endorsed this phenomenon. Liming the soil had the double effect of reducing P sorption (up to 4.5 kg ha-1 of remaining P in solution) and enhancing P desorption (up to 2.7 kg ha-1 of additionally released P into solution).
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Ruan, H. D., and R. J. Gilkes. "Kinetics of phosphate sorption and desorption by synthetic aluminous goethite before and after thermal transformation to hematite." Clay Minerals 31, no. 1 (March 1996): 63–74. http://dx.doi.org/10.1180/claymin.1996.031.1.06.
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AbstractGoethite is an important component of many soils and its transformation to hematite by fire may affect phosphate retention. This study deals with the kinetics of phosphate sorption and desorption by synthetic aluminous goethites and their dehydroxylated products. Phosphate sorption and subsequent desorption were measured for periods up to 128 h. Phosphate sorption increased with equilibrium solution concentration, Al substitution and surface area, and decreased with increasing crystal size. The trend in amount of phosphate sorbed was: partially dehydroxylated goethite > hematite > goethite. Sorption and desorption kinetics are well described by the modified Elovich equation. Desorption of a minor proportion of the sorbed P was rapid and this was sometimes followed by minor resorption. The amount of P desorbed directly reflected the amount that was initially sorbed. Acid dissolution of the Fe oxides with sorbed phosphate suggested that most phosphate was present at the crystal surface and not in relatively poorly accessible micropores.
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Hiller, E., Ľ. Jurkovič, and M. Bartaľ. "Effect of temperature on the distribution of polycyclic aromatic hydrocarbons in soil and sediment." Soil and Water Research 3, No. 4 (December 15, 2008): 231–40. http://dx.doi.org/10.17221/28/2008-swr.
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The knowledge of sorption-desorption processes of polycyclic aromatic hydrocarbons (PAHs) in natural solids is essential to predict the fate, transport, and environmental risks of these pollutants. In this study, the effect was investigated of temperature on the sorption-desorption of three PAHs (naphthalene, phenanthrene, and pyrene) in two natural solids with different organic carbon contents. In all cases, the sorption isotherms obtained could be well described by the linear sorption model. The analysis based on the measured isotherms and the corresponding equilibrium partition coefficients (Kp) revealed that (1) the sorption of PAHs increased with organic carbon content of the solid and PAH hydrophobicity in the order: sediment < soil and naphthalene < phenanthrene < pyrene, respectively, and (2) the extent of PAH sorption decreased with increasing temperature from 4°C to 27°C on average by 27.3, 17.0, and 27.4% for naphthalene, phenanthrene, and pyrene, respectively. The enthalpies of sorption (δHs) calculated by van’t Hoff equation were negative, relatively small, and in the range of weak forces such as van der Waals forces (0–9 kJ/mol), consistent with hydrophobic interactions and partitioning of the PAHs into soil/sediment organic matter. The desorption of naphthalene and phenanthrene showed significant hysteresis, i.e. great fraction of PAHs was resistant to desorption and somewhat increased with temperature.
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Singh, D., R. G. McLaren, and K. C. Cameron. "Desorption of native and added zinc from a range of New Zealand soils in relation to soil properties." Soil Research 35, no. 6 (1997): 1253. http://dx.doi.org/10.1071/s97059.
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Compared with zinc (Zn) sorption, there is very little information on the effect of soil properties on Zn desorption from soils. In this study, desorption of native and added Zn from 7 Canterbury (NZ) soils was determined using a technique involving repeated equilibration of soil in 0·01 M Ca(NO3)2. The concentrations and patterns of desorption of both native and added Zn varied between the different soils. Greater concentrations of native Zn were desorbed from surface soils than from subsoils, and greater concentrations of added Zn were desorbed from subsoils than from their corresponding surface horizons. Correlation analysis showed that cation exchange capacity (CEC) and organic carbon (C) were the dominant soil variables contributing towards sorption or desorption of Zn. However, simple linear regressions involving CEC or organic C explained only 48–62% of the total variation in Zn sorption or desorption from the different soils. Multiple regression analysis indicated that cumulative native Zn desorption (expressed as percentage of DTPA-extractable Zn) was strongly related to CEC and the content of Mn oxides, which in combination explained 80% of the variability between soils. Regression analysis also showed that CEC plus Mn oxides and pH explained 91% of the variability in Zn sorption between the soils; whereas for added Zn desorbed (%), CEC plus pH and crystalline Al oxides explained 93% of variability in added Zn desorption.
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Olchawa, Andrzej, and Jerzy Terlikowski. "Application of sorption tests to estimate selected properties of alluvial soils in Żuławy Elbląskie." Journal of Water and Land Development 15, no. 1 (December 1, 2011): 167–77. http://dx.doi.org/10.2478/v10025-012-0015-y.
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Application of sorption tests to estimate selected properties of alluvial soils in Żuławy Elbląskie The specific surface area and hence the sorption or desorption moisture at constant water vapour pressure will increase with increasing content of humus and clay fraction in soils. Adopting such an assumption, preliminary experimental studies were performed to assess the possibility of using sorption/desorption tests to determine some features of alluvial soils from Żuławy such as cation exchange capacity CEC and the specific external surface area Se. Results of the sorption tests were compared with the analyses of the same soil properties determined with standard methods to evaluate the usefulness of the former. Preliminary studies showed a high similarity in the determination of CEC and Se with both methods. Confirmed usefulness of sorption/desorption methods for determination of the specific surface area of mineral soil particles and particularly for analyses of cation exchange capacity would bring a significant simplification of studies and a possibility of their dissemination due to the ease of such analyses. Determination of the specific surface area with the sorption and desorption method does not require sophisticated equipment and laborious and costly preliminary procedures. Dissemination of this method and recognition it as a reference one would, however, need further studies on various soil types.
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Peek, Daniel C., and V. V. Volk. "Fluoride Sorption and Desorption in Soils." Soil Science Society of America Journal 49, no. 3 (May 1985): 583–86. http://dx.doi.org/10.2136/sssaj1985.03615995004900030010x.
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Barba, C., M. Martí, J. Carilla, A. M. Manich, and L. Coderch. "Moisture sorption/desorption of protein fibres." Thermochimica Acta 552 (January 2013): 70–76. http://dx.doi.org/10.1016/j.tca.2012.11.001.
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Berglöf, Tomas, Tran Van Dung, Henrik Kylin, and Ingvar Nilsson. "Carbendazim sorption–desorption in Vietnamese soils." Chemosphere 48, no. 3 (July 2002): 267–73. http://dx.doi.org/10.1016/s0045-6535(02)00096-6.
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Duarte Zaragoza, Victor M., Rogelio Carrillo, and Carmen M. Gutierrez Castorena. "Lead sorption–desorption from organic residues." Environmental Technology 32, no. 4 (March 2011): 353–61. http://dx.doi.org/10.1080/09593330.2010.491133.
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Jansson, Mats, Mats Jonsson, and Joel Mohlén. "Kinetic evaluation of sorption and desorption." Adsorption 16, no. 3 (February 12, 2010): 155–59. http://dx.doi.org/10.1007/s10450-010-9208-3.
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Pacheco, G., G. Nava-Galve, P. Bosch, and S. Bulbulian. "60Co sorption-desorption in Mexican montmorillonites." Journal of Radioanalytical and Nuclear Chemistry Letters 200, no. 3 (June 1995): 259–64. http://dx.doi.org/10.1007/bf02164088.
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Cao, Xiaoyan, He Wang, Min Lu, Chengfeng Ge, Limin Zhou, and Guipeng Yang. "Evaluation study for phosphorus mobilisation-release behaviour on different marine sediments: focus on phosphate sorption characteristics." Environmental Chemistry 16, no. 3 (2019): 179. http://dx.doi.org/10.1071/en18176.
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Environmental contextPhosphorus is a key nutrient element associated with eutrophication in aquatic ecosystems. We studied phosphate sorption processes, which play a key role in phosphorus cycling, in sediments collected from 23 sites including estuary, coastal sea and aquaculture areas in China. The results show the influence of sediment type on phosphorus buffering capacity and allow better interpretation of phosphorus migration in aquatic ecosystems. AbstractPhosphorus is well known as an important nutrient element associated with eutrophication in the marine ecosystem, and its sorption on sediments plays a key role in its immobilisation in the bio-geochemical cycle. In this paper, the sorption behaviour of phosphorus onto sediments collected from 23 different sites in estuary, coastal sea and aquaculture areas of China was studied. The main aim is to determine the phosphorus sorption characteristics of these sediments thereby assessing their phosphorus buffering capacities. Both kinetic and equilibrium isotherms of the sorption and desorption of phosphorus were assessed. The resultant sorption and desorption kinetic curves fit well to a two-compartment first-order equation. The equilibration time was considered as 48h. The isotherms agreed well with the Freundlich and Langmuir equations. The hysteresis coefficient values showed an obvious sorption-desorption hysteresis. Decreasing salinity was favourable for the sorption ability in the range from 30 to 3. The mean values of the phosphorus sorption-desorption equilibrium concentration and the maximum phosphorus sorption capacity were 0.098mgL−1 and 0.086mgg−1 for sediments in the Changjiang Estuary and East China Sea shelf, and 0.138mgL−1 and 0.067mgg−1 for the sediments in the aquaculture area. The fractions of clay, calcite and organic matter influenced the sorption and retention abilities and the effects were different for sediments obtained from different origins.
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Yang, Ji Feng. "Influence of Rice Residue-Derived Charcoal on Sorption and Desorption Behaviors of a Nonionic Pesticide Carbofuran in a Soil." Advanced Materials Research 236-238 (May 2011): 417–21. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.417.
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We investigated the influence of amendment of charcoals derived from rice residues at 250, 450 and 850 °C on the sorption and desorption behaviors of carbofuran in a soil using a batch equilibrium method. The crop residues derived charcoals at 850 °C had higher sorption capacity than those prepared at 250 and 450 °C. Amendment of the charcoal material (<1%) prepared at 250 °C had no obvious effects on pesticide sorption in soils. The soils amended with the charcoal materials had higher sorption capacity than the original soil, and the nonlinearity of sorption of carbofuran on the amended soils increased with the content of charcoal, especially for those amended with the charcoal obtained at 850 °C. Sorption-desorption hysteresis occurred for all treatments including the control.
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Ekundayo, Jamiu M., and Reza Rezaee. "Numerical Simulation of Gas Production from Gas Shale Reservoirs—Influence of Gas Sorption Hysteresis." Energies 12, no. 18 (September 4, 2019): 3405. http://dx.doi.org/10.3390/en12183405.
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The true contribution of gas desorption to shale gas production is often overshadowed by the use of adsorption isotherms for desorbed gas calculations on the assumption that both processes are identical under high pressure, high temperature conditions. In this study, three shale samples were used to study the adsorption and desorption isotherms of methane at a temperature of 80 °C, using volumetric method. The resulting isotherms were modeled using the Langmuir model, following the conversion of measured excess amounts to absolute values. All three samples exhibited significant hysteresis between the sorption processes and the desorption isotherms gave lower Langmuir parameters than the corresponding adsorption isotherms. Langmuir volume showed positive correlation with total organic carbon (TOC) content for both sorption processes. A compositional three-dimensional (3D), dual-porosity model was then developed in GEM® (a product of the Computer Modelling Group (CMG) Ltd., Calgary, AB, Canada) to test the effect of the observed hysteresis on shale gas production. For each sample, a base scenario, corresponding to a “no-sorption” case was compared against two other cases; one with adsorption Langmuir parameters (adsorption case) and the other with desorption Langmuir parameters (desorption case). The simulation results showed that while gas production can be significantly under-predicted if gas sorption is not considered, the use of adsorption isotherms in lieu of desorption can lead to over-prediction of gas production performances.
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Tatarková, V., E. Hiller, and R. Halko. "Retention characteristics of acetochlor in soils collected from different depths in relation to soil properties (Žitný ostrov area, SW Slovakia)." Soil and Water Research 9, No. 2 (April 25, 2014): 58–65. http://dx.doi.org/10.17221/98/2013-swr.
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Determination of the sorption-desorption of herbicides within soil profile is one of the first steps in predicting their leaching potential. Batch experiments were performed to evaluate the influence of soil properties on acetochlor retention. Soil samples were taken from horizons A, B, and C of three soil types representative of the Žitný ostrov area. The sorption and desorption isotherms were fitted to the Freundlich equation. The Freundlich sorption coefficient (K<sub>fs</sub>) values ranged from 0.71 to 6.58 mg<sup>(1–1/n)</sup>.l<sup>(1/n)</sup>/kg and were correlated positively with soil organic carbon, humic and fulvic acid carbons, amorphous aluminum oxides, and negatively with soil pH. The Freundlich desorption coefficient (K<sub>fd</sub>) values were greater than those for sorption, showing that not all acetochlor sorbed was desorbed after four washing steps. The percentage of acetochlor desorbed ranged from 7.80 to 54.5% with decreased desorption from soil horizons B and C. The higher sorption capacity of surficial soil horizons in the three soils may be a limiting factor for penetration of acetochlor through soil profiles into groundwater.
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Assis, E. C., A. A. Silva, L. C. Barbosa, M. E. L. R. Queiroz, L. D'Antonino, and L. S. Cruz. "Sorption and desorption of picloram in soils under pastures in Brazil." Planta Daninha 29, no. 4 (December 2011): 893–99. http://dx.doi.org/10.1590/s0100-83582011000400020.
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The objective of this work was to determine the coefficients of sorption and desorption of picloram in Ultisol (PVA) and Oxisol (LVA), displaying different physical and chemical characteristics. Samples of soil were collected at the 0 20 cm depth in degraded pasture areas in Viçosa-MG. Firstly, the equilibrium time between the herbicide in solution and the herbicide which was sorbed in the soil was determined by the Batch Equilibrium method. The time required was 24 hours. Sorption and desorption studies were carried out under controlled laboratory conditions; the sorption evaluation consisted in adding 10.0 mL of herbicide solutions at different concentrations to tubes containing 2.00 g of soil, with vertical rotary agitation being maintained during the pre-determined equilibrium time. After centrifugation, supernatant extract cleaning and filtration, herbicide concentration was determined by high performance liquid chromatography (HPLC) with UV detection at 254 nm. Desorption was evaluated using the samples in the tubes after the sorption tests. The Freundlich model was used for interpretation of the sorption process. Ultisol showed higher adsorption coefficient (Kf a) compared with Oxisol, which may be attributed to the lower pH of the soil and its higher organic matter content. Desorption process occurred in both soils; the LVA allowed greater release of the previously sorbed molecules.
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Langaro, Ana Cláudia, Matheus de Freitas Souza, Gustavo Antônio Mendes Pereira, João Pedro Ambrósio Barros, Antonio Alberto da Silva, Daniel Valadão Silva, Ana Beatriz Rocha de Jesus Passos, and Vander Mendonça. "Influence of Glyphosate Formulations on the Behavior of Sulfentrazone in Soil in Mixed Applications." Toxics 8, no. 4 (December 17, 2020): 123. http://dx.doi.org/10.3390/toxics8040123.
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The selection of weed biotypes that are resistant to glyphosate has increased the demand for its use mixed with other herbicides, such as sulfentrazone. However, when chemical molecules are mixed, interactions may occur, modifying the behavior of these molecules in the environment, such as the sorption and desorption in soil. In this study, we hypothesized that the presence of glyphosate-formulated products might increase the sorption or decrease the desorption of sulfentrazone, thereby increasing the risk of the contamination of water resources. Therefore, our work aimed to evaluate the sorption, desorption, and leaching of sulfentrazone in the soil in an isolated and mixed application with different glyphosate formulations. The sorption coefficients (Kfs) for the sulfentrazone, sulfentrazone + Roundup Ready, sulfentrazone + Roundup Ultra, and sulfentrazone + Zapp Qi foram were 1.3, 2.1, 2.3, and 1.9, respectively. The desorption coefficients (Kfd) for the sulfentrazone, sulfentrazone + Roundup Ready, sulfentrazone + Roundup Ultra, and sulfentrazone + Zapp Qi foram were 65.7, 125.2, 733.3 and 239.8, respectively. The experiments demonstrated that the sorption and desorption of sulfentrazone in combination with the other formulated glyphosate products are altered, supporting the hypothesis suggested by this work, i.e., that the presence of other molecules is a factor that affects the behavior of herbicides in the soil. This phenomenon altered the vertical mobility of sulfentrazone. Situations involving mixtures of pesticides should be evaluated in order to improve our understanding of the dynamics of these molecules and thus avoid environmental contamination.
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Ugrina, Marin, Nediljka Vukojević Medvidović, Jelena Perić, and Marina Trgo. "A study of kinetics and successive sorption/desorption of Zn and Cd uptake onto iron-modified zeolite." Clay Minerals 50, no. 1 (March 2015): 117–32. http://dx.doi.org/10.1180/claymin.2015.050.1.11.
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AbstractThe sorption properties of iron-modified zeolite (IMZ) and the kinetics of zinc and cadmium uptake by the IMZ were investigated by the batch method. Two kinetic stages were observed, fast uptake up to 240 min, followed by slow uptake up to equilibrium. Kinetic results were fitted to the reaction and diffusion kinetic models, which indicated that intra-particle diffusion was the rate-limiting step. The Vermeulen’s approximation model was used to predict the quantity of Zn and Cd ions removed per gram of IMZ. The results of the successive sorption and desorption of Zn and Cd ions, with different electrolyte solutions, showed the best desorption efficiency with sodium salt solutions. Four successive repetitions of the sorption/desorption cycles showed a small difference between the amount of sorbed and desorbed Zn and Cd ions from the second to the fourth cycle. This indicates excellent sorption/regeneration properties of the IMZ.
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Reddy, Krishna N., and Martin A. Locke. "Sulfentrazone sorption, desorption, and mineralization in soils from two tillage systems." Weed Science 46, no. 4 (August 1998): 494–500. http://dx.doi.org/10.1017/s0043174500090950.
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Sulfentrazone sorption kinetics, desorption, and mineralization were evaluated in surface 7.5 cm of soils collected from long-term conventional-till (CT) and no-till (NT) plots. The soils used were Miami silt loam and Drummer silty clay loam from Illinois and Dundee silt loam from Mississippi. Sulfentrazone sorption kinetics in Dundee silt loam CT and NT soils were adequately described by a simple two-site equilibrium/kinetic model. Rapid initial sorption (within 1 h) was followed by a slower sorption and equilibrium, largely achieved by 72 h of shaking, with a negligible increase in sorption thereafter. The sorptionKfranged from 1.02 to 3.44 among the six CT and NT soils. TheKfvalues were greater for NT compared to their respective CT soils. Overall,Kfvalues were higher in Drummer silty clay loam followed by Dundee silt loam and Miami silt loam soil. TheNvalues were less than unity in all soils indicating nonlinear sorption. Sulfentrazone desorption was hysteretic with a very low rate of desorption. The total amount desorbed in four desorptions ranged from 58 to 72% of that sorbed. Less than 2.1% of applied14C-sulfentrazone was mineralized to14CO2 in Dundee silt loam CT and NT soils during a 77–d incubation. Relatively low mineralization of sulfentrazone suggests poor adaptability of native microbial populations that have not been exposed to this herbicide. Higher sorption and lower desorption of sulfentrazone in NT soils compared to CT soils suggest that NT systems (which tend to increase plant residues) may prolong sulfentrazone residence time in soil.
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Park, Jeong-Hun, Yucheng Feng, Pingsheng Ji, Thomas C. Voice, and Stephen A. Boyd. "Assessment of Bioavailability of Soil-Sorbed Atrazine." Applied and Environmental Microbiology 69, no. 6 (June 2003): 3288–98. http://dx.doi.org/10.1128/aem.69.6.3288-3298.2003.
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ABSTRACT Bioavailability of pesticides sorbed to soils is an important determinant of their environmental fate and impact. Mineralization of sorbed atrazine was studied in soil and clay slurries, and a desorption-biodegradation-mineralization (DBM) model was developed to quantitatively evaluate the bioavailability of sorbed atrazine. Three atrazine-degrading bacteria that utilized atrazine as a sole N source (Pseudomonas sp. strain ADP, Agrobacterium radiobacter strain J14a, and Ralstonia sp. strain M91-3) were used in the bioavailability assays. Assays involved establishing sorption equilibrium in sterile soil slurries, inoculating the system with organisms, and measuring the CO2 production over time. Sorption and desorption isotherm analyses were performed to evaluate distribution coefficients and desorption parameters, which consisted of three desorption site fractions and desorption rate coefficients. Atrazine sorption isotherms were linear for mineral and organic soils but displayed some nonlinearity for K-saturated montmorillonite. The desorption profiles were well described by the three-site desorption model. In many instances, the mineralization of atrazine was accurately predicted by the DBM model, which accounts for the extents and rates of sorption/desorption processes and assumes biodegradation of liquid-phase, but not sorbed, atrazine. However, for the Houghton muck soil, which manifested the highest sorbed atrazine concentrations, enhanced mineralization rates, i.e., greater than those expected on the basis of aqueous-phase atrazine concentration, were observed. Even the assumption of instantaneous desorption could not account for the elevated rates. A plausible explanation for enhanced bioavailability is that bacteria access the localized regions where atrazine is sorbed and that the concentrations found support higher mineralization rates than predicted on the basis of aqueous-phase concentrations. Characteristics of high sorbed-phase concentration, chemotaxis, and attachment of cells to soil particles seem to contribute to the bioavailability of soil-sorbed atrazine.
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Arsenijevic, Zorana, Bosko Grbic, Nenad Radic, Radmila Garic-Grulovic, and Zeljko Grbavcic. "Ethylene oxide removal by sorption on aluminium oxide." Chemical Industry 63, no. 4 (2009): 337–43. http://dx.doi.org/10.2298/hemind0904337a.
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The dynamics of ethylene oxide sorption and desorption on Al2O3 sorbent were investigated. The investigations of ethylene oxide sorption on Al2O3 show that significant sorption appeared above 125?C. The removal of sorbed ethylene oxide from Al2O3 was achieved by continuous increasing of the temperature up to 450?C in air stream. The analysis of desorbed products show that 90% of adsorbed ethylene oxide is converted to CO2 and the rest consists of the three derivatives of ethylene oxide. The exact composition of desorbed organic products will be determined in further investigation. The desorption temperature profiles point out the presence of two exothermic picks, as was confirmed by detection of CO2 and derivates of ethylene oxide at these temperatures. Investigation of textural characteristics and thermal stability of Al2O3 sorbent show that there are no changes of any characteristics of Al2O3 in sorption/desorption operating temperatures regimes. Only at 700?C the specific surface area of Al2O3 decreases of about 10%. This indicates that the investigated Al2O3 is convenient material for removal of ethylene oxide by sorption.
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Skorokhoda, Volodymyr, Yuriy Melnyk, Natalia Semenyuk, Nataliya Ortynska, and Oleh Suberlyak. "FILM HYDROGELS ON THE BASIS OF POLYVINYLPYRROLIDONE COPOLYMERS WITH REGULATED SORPTION-DESORPTION CHARACTERISTICS." Chemistry & Chemical Technology 11, no. 2 (June 15, 2017): 171–74. http://dx.doi.org/10.23939/chcht11.02.171.
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Takigami, H., N. Taniguchi, and Y. Shimizu. "Sorption and desorption of 17β-estradiol to natural sediment." Water Science and Technology 64, no. 7 (October 1, 2011): 1473–78. http://dx.doi.org/10.2166/wst.2011.527.
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The sorption and desorption of 17β-estradiol (E2) to various natural sediment were investigated. First, the quantitative solvent–water partition indices were measured. Significant differences were found between the n-octanol–water partition coefficient (KOW) and the n-hexane–water partition coefficient (KHW) of E2. The value of KHW (Log KHW = 0.07) is lower than those of two to four ring polyaromatic hydrocarbons (PAHs), while the value of KOW (Log KOW = 3.99) and that of organic matter–water partition coefficient (KOC) onto humic acid (Log KOC = 4.30) were similar to those of the PAHs. Five natural sediments of various characteristics and origins were selected for sorption and desorption experiments. Linear isotherms were obtained for sorption and desorption. The equilibrium partitioning coefficients of E2 were well-correlated with their values of weight fraction of organic carbon in sediments (fOC). Results suggest that E2 is sorbed mainly onto the organic portion of sediments and that its sorption coefficient can be estimated from KOW and fOC, as in the case of non-polar PAHs. However, because of its polarity, the sorption mechanism of E2 onto sediments cannot be explained solely by the hydrophobic interaction.
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Gamble, Donald S., and Shahamat U. Khan. "Atrazine in mineral soil: chemical species and catalysed hydrolysis." Canadian Journal of Chemistry 70, no. 6 (June 1, 1992): 1597–603. http://dx.doi.org/10.1139/v92-197.
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Equilibrium and kinetics parameters have been evaluated at 25.0 °C for the heterogeneous catalysis of atrazine hydrolysis in slurries of a chemically characterized mineral soil. The fraction of acidic sites that accounts for sorption capacity, and the sorption equilibrium function resemble those for humic acid and organic soil. Sorption and desorption half-lives increased with increasing coverage of sorption sites. The sorption half-lives ranged from 3.6 to 735 days. The desorption half-lives ranged from 1 to 11 days. The hydrolysis half-lives ranged from 9.6 to 168 days and are consistent with Brönsted acid catalysis theory. The relationship of independent variables to data scatter has been analyzed. The information obtained should be useful for water and solute transport models.
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Langová, Jitka, Donludee Jaisut, Ratiya Thuwapanichayanan, Charotorn Phowong, Jiří Štencl, Danijela Jovanovic, Jiří Fryč, and Václav Vlášek. "Modelling the moisture sorption isotherms of Roselle (Hibiscus sabdariffa L.) in the temperature range of 5–35 °C." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 61, no. 6 (2013): 1769–77. http://dx.doi.org/10.11118/actaun201361061769.
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Water sorption tests of Roselle (Hibiscus sabdariffa L.) carried out under laboratory conditions are presented together with mathematical analyses of the moisture sorption isotherms (MSI’s). Moisture equilibrium data for adsorption and desorption of water from Roselle powder were investigated at near ambient air temperatures in the range of 5 and 35 °C and water activity (Aw) ranging from 0.11 to 0.97. The manometric method has been used for water sorption tests. Models for MSI’s are exponential equations. Coefficients of determination are 0.998 and 0.996 (for adsorption and desorption at 5 °C, respectively), 0.998 and 0.999 (for adsorption and desorption at 20 °C, respectively), and 0.998 and 0.999 (for adsorption and desorption at 35 °C, respectively). The equilibrium moisture content (EMC) of Roselle samples increased with an increase of Aw at a constant temperature both for adsorption and desorption. Adsorption curve equates to desorption curve at higher temperatures of tests carried out. Critical values of EMC of samples tested corresponding to the Aw equal to 0.6 were between 13.401% moisture content wet basis (MC w.b.) and 15.934% MC (w.b.) for moisture adsorption and desorption, respectively. These values are useful for storing conditions optimisation from point of view microorganisms grow and structural changes analyses. Crystal structure changes were observed during adsorption and desorption in the microscope, too. It was found out glass transition in dependence on the water content of samples tested.
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Liu, Wenzhi, Guihua Liu, Siyue Li, and Quanfa Zhang. "Phosphorus sorption and desorption characteristics of wetland soils from a subtropical reservoir." Marine and Freshwater Research 61, no. 5 (2010): 507. http://dx.doi.org/10.1071/mf09013.
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Water-level regulation results in alternating exposure and inundation of soils in reservoir fluctuation zones, which may significantly influence the phosphorus sorption and desorption processes in the soil. The present study investigated the phosphorus sorption and desorption properties of wetland soils in China's Danjiangkou Reservoir using a batch equilibrium technique. Results showed that the maximum phosphorus sorption ranged from 435 to 1429 mg kg−1, with an average of 771 mg kg−1. The maximum phosphorus sorption was found to be significantly related to amorphous iron (r = 0.883, P < 0.01) and pH (r = −0.333, P < 0.05), and the binding constant k was strongly correlated with the amorphous iron (r = 0.475, P < 0.01) and organic matter (r = −0.455, P < 0.01). The phosphorus desorption percentage varied from 8 to 44%, with a mean value of 24%. The present study implies that short-term inundation in reservoir fluctuation zones would result in soil phosphorus desorption to some extent, in spite of the considerable absorption ability in the exposure period. These results are useful for assessing the phosphorus retention capacity of wetland soils and optimising management strategies for water conservation in reservoir regions.
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Ермоченков and Mihail Ermochenkov. "Kinetics of drying and moistering of wood." Forestry Engineering Journal 6, no. 4 (May 3, 2017): 161–67. http://dx.doi.org/10.12737/23451.
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The article presents the results of experimental and computational studies of the kinetics of drying of different types of wood in a helium environment. Wood is considered as a multi-component composite, one component of which is free and bound moisture. A model describing the removal of bound moisture, as a set of direct (desorption) and reverse (sorption) processes is described. The experimental-computational method for determining the kinetic parameters of sorption is suggested. They are determined from the condition that the rate of sorption and desorption is equal with equilibrium moisture content of wood.
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Kastelan-Macan, Marija, and Mira Petrovic. "The role of fulvic acids in phosphorus sorption and release from mineral particles." Water Science and Technology 34, no. 7-8 (October 1, 1996): 259–65. http://dx.doi.org/10.2166/wst.1996.0630.
Full textAbstract:
The competitive sorption of phosphates and marine fulvic acids on mineral particles (sand, calcite, bentonite and hematite) has been studied under simulated estuarine conditions. Afterwards, the release and desorption of bound phosphates by solutions containing dissolved fulvic acids was determined. It was found out that due to the favorable sorption of fulvic acids onto minerals studied binding of phosphate was significantly decreased. Desorption experiments showed that fulvic acids, present at high concentration level, similar to that in interstitial water of an oxygenated sediment, increase phosphate desorption by 10-20%.