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1
Mokwenye, Ifesinachi I., Paul N. Diagboya, Bamidele I. Oluowolabi, Ikenna O. Anigbogu e Hilary I. Owamah. "Immobilization of toxic metal cations on goethite-amended soils: a remediation strategy". Journal of Applied Sciences and Environmental Management 20, n. 2 (25 luglio 2016): 436–43. http://dx.doi.org/10.4314/jasem.v20i2.26.
Testo completoAbstract (sommario):
The study investigates a simple and viable option to reduce toxic metals mobility and availability in four surface (0–30cm) soils with varying physicochemical properties amended by different percentages of goethite. Batch sorption experiments carried out to study the effectiveness of immobilizing Pb2+, Cu2+, Zn2+ and Cd2+ ions on these soils showed that goethite played vital role in the metals adsorption (≥10% increase in adsorption). Removal of soil iron oxides caused reduced Pb2+ adsorption on soils with high organic matter (≤ 10% decrease in adsorption) with no significant increase in adsorption upon amendment, while soils having low organic matter had enhanced adsorption with amendment. Cu2+ and Cd2+ adsorptions were not enhanced even at 10% goethite amendment. However, Zn2+ adsorption was interestingly different: the soils showed ≥55 % increases upon removal of inherent soil iron oxides without goethite amendment. Goethite amendments further enhanced Zn2+ adsorption on these soils. Generally, both whole and amended soils showed higher preference for Pb2+; the sorption trend is – Pb2+ >Cu2+ >Zn2+ >Cd2+. Goethite amendment of these soils improved Pb2+ and Zn2+ adsorption. Hence, goethite amendment may be an effective method for immobilizing Pb2+ and Zn2+ on these soils and thus reducing their availability to biota. The quantity of goethite required by a soil to attain maximum immobilization varies depending on the metal and the soil’s physicochemical properties; however, Cu2+ and Cd2+ may not be effectively immobilized using goethite amendment.Keywords: Soil; Goethite; Toxic metals; Adsorption, Remediation
2
Wang, Shiyu, Junnan Zhang, Fada Zhou, Cunzhen Liang, Liao He, Wentao Jiao e Wenyong Wu. "Adsorption of EDCs on Reclaimed Water-Irrigated Soils: A Comparative Analysis of a Branched Nonylphenol, Nonylphenol and Bisphenol A". Water 13, n. 18 (15 settembre 2021): 2532. http://dx.doi.org/10.3390/w13182532.
Testo completoAbstract (sommario):
Nonylphenol (NP) and bisphenol A (BPA) are two typical endocrine disrupter chemicals (EDCs) in reclaimed water. In this study, the adsorptions of NP, a branched NP (NP7) and BPA on reclaimed water-irrigated soils were studied by isothermal experiments, and the different environmental factors on their adsorptions were investigated. The results showed that the adsorptions of NP and NP7 on soils conformed to the Linear model, and the adsorption of BPA conformed to the Freundlich model. The adsorptions of NP, NP7 and BPA on soils decreased with increasing temperatures and pHs. Adsorption equilibrium constant (Kd or Kf) were maximum at pH = 3, temperature 25 °C and As(III)-soil, respectively. The adsorption capacity of NP, NP7 and BPA to soils under different cation valence were as follows: neutrally > divalent cations > mono-cations. Kd of NP7 on soil was less than that of NP under different pH and temperatures, while under different cation concentrations it was the inverse. Fourier Transform Infrared Spectrometer (FTIR) analysis showed alkyl chains of NP and BPA seemed to form van der Waals interactions with the cavity of soil. Results of this study will provide further comprehensive fundamental data for human health risk assessment of NP and BPA in soil.
3
Bao, Yanyu, Qixing Zhou e Yingying Wang. "Adsorption characteristics of tetracycline by two soils: assessing role of soil organic matter". Soil Research 47, n. 3 (2009): 286. http://dx.doi.org/10.1071/sr08112.
Testo completoAbstract (sommario):
The adsorption characteristics of tetracycline by 2 soils including a clay-rich soil (cinnamon soil) and an iron oxide-rich soil (red soil) were investigated as a function of soil organic matter (SOM). SOM is the main adsorbent for tetracycline in the soil environment. The results indicated that the adsorption kinetics of tetracycline by the different soils with or without organic matter was described by the Elovich equation and the exponent equation. The adsorption of tetracycline on red soil was quite rapid and equilibrium could be reached after 5 h. In contrast, the concentration of tetracycline in cinnamon soil reached equilibrium after 11 h. The difference in equilibrium time in cinnamon soil and red soil was caused by their dominant components for adsorption, including clays, organic matter, and Al/Fe hydrous oxides. It took longer for the penetration of tetracycline into the interlayers between clays and organic matter in cinnamon soil, but tetracycline needed less time for adsorption through surface complexation on oxide surfaces of red soil. Removing SOM from soil markedly shortened the equilibrium time (7 h) of adsorption and reduced the equilibrium concentration (Cs) in cinnamon soil, but not in red soil, because of different dominant components for adsorption in the 2 natural soils. In natural and SOM-free soils, >98% of tetracycline in solution could be sorbed. The adsorption of tetracycline on natural and SOM-free soils was well described by Freundlich adsorption isotherms. Batch adsorption experiments showed that the adsorption of tetracycline on natural red soil was stronger than that on natural cinnamon soil. Adsorption capacity (KF) decreased with an increase in SOM removed from soil, which is attributed to the effect of tetracycline sorbed by SOM in different soils. However, SOM affected the adsorption intensity (n) of different soils diversely; there was a decrease for red soil and an increase for cinnamon soil. In particular, red soil with high Al/Fe hydrous oxides had higher adsorption affinities than cinnamon soil.
4
Mejías, Carmen, Juan Luis Santos, Julia Martín, Irene Aparicio e Esteban Alonso. "Thermodynamic and Kinetic Investigation of the Adsorption and Desorption of Trimethoprim and Its Main Metabolites in Mediterranean Crop Soils". Molecules 28, n. 1 (3 gennaio 2023): 437. http://dx.doi.org/10.3390/molecules28010437.
Testo completoAbstract (sommario):
The adsorption–desorption processes of organic pollutants into the soil are one of the main factors influencing their potential environmental risks and distribution in the environment. In the present work, the adsorption–desorption behavior of an antibiotic, trimethoprim (TMP), and two of its main metabolites, 3-desmethyltrimethoprim (DM-TMP) and 4-hydroxytrimethoprim (OH-TMP), were assessed in three Mediterranean agricultural soils with different physicochemical characteristics. Results showed that the adsorption kinetic is performed in two steps: external sorption and intraparticle diffusion. The adsorptions of the studied compounds in soils were similar and fitted to the three models but were better fitted to a linear model. In the case of DM-TMP and OH-TMP, their adsorptions were positively correlated with the soil organic matter. In addition, desorption was higher in less organic matter soil (from 1.3 to 30.9%). Furthermore, the desorptions measured for the TMP metabolites were lower than those measured in the case of TMP (from 2.0 and 4.0% for OH-TMP and DM-TMP, respectively, to 9.0% for TMP).
5
Jaffri, Shaan Bibi, Khuram Shahzad Ahmad, Mehtabidah Ali e Shahid Iqbal. "Sorptive Interactions of Fungicidal 2-(4'-Thiazolyl) Benzimidazole with Soils of Divergent Physicochemical Composition". International Journal of Economic and Environmental Geology 10, n. 2 (4 settembre 2019): 97–104. http://dx.doi.org/10.46660/ijeeg.vol10.iss2.2019.268.
Testo completoAbstract (sommario):
Thiabendazole, 2-(4'-thiazolyl) Benzimidazole fungicide is rampantly used in Pakistan for controlling fungalgrowth in addition to combating various fungus driven diseases. Thiabendazole leaching and mobility patterns can beeasily predicted through investigation of Thiabendazole adsorption and desorption behavior in soils. Present work iscarried out by conducting a batch equilibration experiment for evaluation of Thiabendazole adsorption and desorption insoils from four diverse Pakistani climatological regions. Data revealed Thiabendazole had moderate to weak adsorption inselected soils with distribution co-efficient Kd(ads) ranging from 13.33 to 24.04 µg/ml in selected soils. The TBZ adsorptionin soils best fitted with Freundlich model (R2>0.87). The Freundlich adsorption coefficient (Kf(ads)) values ranged from4.51 to 8.90 µg/ml. Thiabendazole adsorption trends in the selected soils were positively influenced by the clay contentand soil organic matter while it was negatively influenced by soils’ pH. The Freundlich desorption coefficient (Kf(des))values spanned over a range of 1.03 to 6.43 µg/ml indicating decreased desorption from soils with creditable affinities forThiabendazole adsorption. The adsorptive interactions between Thiabendazole and selected soils were primarily physicalconfirmed through lower values of Gibbs free energy ∆G ≤ - 40kJ/mol. Thiabendazole desorption was highly hysterical inall soils with profound irreversibility. Thiabendazole possessed medium mobility patterns in selected soils. The loweradsorptive capability of Thiabendazole in selected soils points towards its lower application rates for combating long termenvironmentally perilous implications.
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Jaffri, Shaan Bibi, Khuram Shahzad Ahmad, Mehtabidah Ali e Shahid Iqbal. "Sorptive Interactions of Fungicidal 2-(4'-Thiazolyl) Benzimidazole with Soils of Divergent Physicochemical Composition". International Journal of Economic and Environmental Geology 10, n. 2 (4 settembre 2019): 97–104. http://dx.doi.org/10.46660/ojs.v10i2.268.
Testo completoAbstract (sommario):
Thiabendazole, 2-(4'-thiazolyl) Benzimidazole fungicide is rampantly used in Pakistan for controlling fungalgrowth in addition to combating various fungus driven diseases. Thiabendazole leaching and mobility patterns can beeasily predicted through investigation of Thiabendazole adsorption and desorption behavior in soils. Present work iscarried out by conducting a batch equilibration experiment for evaluation of Thiabendazole adsorption and desorption insoils from four diverse Pakistani climatological regions. Data revealed Thiabendazole had moderate to weak adsorption inselected soils with distribution co-efficient Kd(ads) ranging from 13.33 to 24.04 µg/ml in selected soils. The TBZ adsorptionin soils best fitted with Freundlich model (R2>0.87). The Freundlich adsorption coefficient (Kf(ads)) values ranged from4.51 to 8.90 µg/ml. Thiabendazole adsorption trends in the selected soils were positively influenced by the clay contentand soil organic matter while it was negatively influenced by soils’ pH. The Freundlich desorption coefficient (Kf(des))values spanned over a range of 1.03 to 6.43 µg/ml indicating decreased desorption from soils with creditable affinities forThiabendazole adsorption. The adsorptive interactions between Thiabendazole and selected soils were primarily physicalconfirmed through lower values of Gibbs free energy ∆G ≤ - 40kJ/mol. Thiabendazole desorption was highly hysterical inall soils with profound irreversibility. Thiabendazole possessed medium mobility patterns in selected soils. The loweradsorptive capability of Thiabendazole in selected soils points towards its lower application rates for combating long termenvironmentally perilous implications.
7
Fouad, Mohamed Riad. "Physical characteristics and Freundlich model of adsorption and desorption isotherm for fipronil in six types of Egyptian soil". Current Chemistry Letters 12, n. 1 (2023): 207–16. http://dx.doi.org/10.5267/j.ccl.2022.8.003.
Testo completoAbstract (sommario):
The soil type and temperature are considered important parameters that can influence the rates and equilibria of different environmental processes. Therefore, the adsorption and desorption isotherms of fipronil in clay loam, clay, sandy loam, sandy clay loam, sand and loamy sand soils at 25 and 50˚C was studied. The amount of fipronil adsorbed and desorbed by different soils was significantly influenced by the temperature. Adsorption was higher in clay loam, clay, sandy clay loam and sandy soil at 25°C, while sand soil and loamy sand soil at 50°C. The non-desorbed amount was greater at 25°C in different types of soil except for clay loam soil. The negative ΔG˚ indicated that the adsorption/desorption in different types of soil was spontaneous at different temperatures. The value of standard enthalpy change (ΔH˚) was positive in clay soil, sandy loam soil, sandy clay loam soil and loamy sand soil for adsorption and sandy loam soil, sand soil and loamy sand soil for desorption. Moreover, the standard entropy change (ΔS˚) was negative in soils for adsorption and desorption isotherms except clay loam soil. Adsorption and desorption isotherms trends as well as the values of the correlation coefficients indicated that the adsorption and desorption isotherms of fipronil in tested soils were fitted to the Freundlich model because the correlation coefficient is very close to 0.999.
8
Jing, Sun, Ma Xiu Lan, Wang Wen, Zhang Jing, Zhang Hao e Wang Yu Jun. "Adsorption characteristics of atrazine on different soils in the presence of Cd(II)". Adsorption Science & Technology 38, n. 7-8 (5 giugno 2020): 225–39. http://dx.doi.org/10.1177/0263617420928845.
Testo completoAbstract (sommario):
In this study, the effects of temperature, pH, and biochar under cadmium stress on the adsorption characteristics of atrazine in soils in northeast China were studied by batch adsorption method. In the atrazine–Cd(II) coexistence system, the adsorption of atrazine by the soils reached equilibrium within 24 h, but there were some differences in sorption capacities of the three types of soil and the order of adsorption is albic soil > black soil > saline-alkaline soil. With the concentration of atrazine increased, the adsorption capacity of atrazine in the three types of soil gradually increased, the upward trend became more obvious with the ambient temperature of the solution decreased. The adsorption kinetics curves of atrazine in the three types of soil conform to the pseudo-second-order kinetic model and the adsorption isotherm follows the Langmuir model. When atrazine and Cd(II) coexist in soils, the decrease in atrazine adsorption in the soil may be due to the competitive interaction between the two chemicals. Cd(II) occupies part of the adsorption site of atrazine, thus saturating the active site in soils. Since atrazine is a weakly alkaline pesticide, the lower the pH of the soil, the higher the affinity of atrazine for the soil. After adding biochar to the soil, the functional groups in biochar can form π bond with atrazine, which promotes the fixation of atrazine in the soil. The results show that the prevention of atrazine and cadmium leaching can be achieved by appropriately adjusting the pH, temperature, clay content, and organic matter of the soils.
9
Petruzzelli, Gianniantonio, e Francesca Pedron. "Adsorption, Desorption and Bioavailability of Tungstate in Mediterranean Soils". Soil Systems 4, n. 3 (22 agosto 2020): 53. http://dx.doi.org/10.3390/soilsystems4030053.
Testo completoAbstract (sommario):
The adsorption and desorption process of the tungstate ion was studied in three soils characteristic of the Mediterranean area, with particularly reference to bioavailability pathways. In the three soils examined, the tungstate adsorption was described by a Langmuir-type equation, while the desorption process showed that not all the adsorbed tungstate was released, probably due to the formation of different bonds with the adsorbing soil surfaces. The pH was found to be the main soil property that regulates the adsorption/desorption: The maximum adsorption occurred in the soil with the acidic pH, and the maximum desorption in the most basic soil. In addition, the organic matter content played a fundamental role in the adsorption of tungstate by soils, being positively correlated with the maximum of adsorption. These results indicate that the lowest bioavailability should be expected in the acidic soil characterized by the highest adsorption capacity. This is confirmed by the trend of the maximum buffer capacity (MBC) of soils which is inversely related to bioavailability, and was the highest in the acidic soil and the lowest in the most basic soil. Our data could contribute in drafting environmental regulations for tungsten that are currently lacking for Mediterranean soils.
10
Xu, Ziwen, Shiquan Lv, Shuxiang Hu, Liang Chao, Fangxu Rong, Xin Wang, Mengyang Dong, Kai Liu, Mingyue Li e Aiju Liu. "Effect of Soil Solution Properties and Cu2+ Co-Existence on the Adsorption of Sulfadiazine onto Paddy Soil". International Journal of Environmental Research and Public Health 18, n. 24 (19 dicembre 2021): 13383. http://dx.doi.org/10.3390/ijerph182413383.
Testo completoAbstract (sommario):
Paddy soils are globally distributed and saturated with water long term, which is different from most terrestrial ecosystems. To better understand the environmental risks of antibiotics in paddy soils, this study chose sulfadiazine (SDZ) as a typical antibiotic. We investigated its adsorption behavior and the influence of soil solution properties, such as pH conditions, dissolved organic carbon (DOC), ionic concentrations (IC), and the co-existence of Cu2+. The results indicated that (1) changes in soil solution pH and IC lower the adsorption of SDZ in paddy soils. (2) Increase of DOC facilitated the adsorption of SDZ in paddy soils. (3) Cu2+ co-existence increased the adsorption of SDZ on organic components, but decreased the adsorption capacity of clay soil for SDZ. (4) Further FTIR and SEM analyses indicated that complexation may not be the only form of Cu2+ and SDZ co-adsorption in paddy soils. Based on the above results, it can be concluded that soil solution properties and co-existent cations determine the sorption behavior of SDZ in paddy soils.
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Rukh, Shah, Saleem Akhtar, Ayaz Mehmood, Sayed Hassan, Khalid Khan, Syed Naqvi e Muhammad Imran. "Arsenate and arsenite adsorption in relation with chemical properties of alluvial and loess soils". Journal of the Serbian Chemical Society 82, n. 7-8 (2017): 943–54. http://dx.doi.org/10.2298/jsc170209042r.
Testo completoAbstract (sommario):
Arsenic is one of the most toxic elements in the soil environment. Understanding of the arsenic adsorption chemistry is essential for evolving the extent of soil and groundwater contaminations. This research was conducted to determine the variation in adsorption behaviour of arsenite and arsenate with depth in different lithology soils. We sampled two parent materials at genetic horizons, and within a parent material, we selected two soils. Besides basic soil characterizations, a laboratory batch experiments were carried out to study the adsorption of arsenate and arsenite. Freundlich adsorption approaches were employed to investigate the adsorption of arsenate and arsenite in the soils. Freundlich isotherms fit arsenate and arsenite sorption data well with r2 values of 0.88?0.98 in most soils. Arsenate and arsenite adsorption varied with the soil properties, especially in clay composition and in the oxides of iron and aluminum. Arsenic adsorption parameters also varied with depth in parent materials, and loess derived soils had greater adsorption capacity as compared to alluvial soils in most of the adsorption parameters. This research concludes that the loess soils had higher arsenic adsorption capacity than the alluvial soils.
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El Boukili, Abdellah, Nidae Loudiyi, Ahmed El Bazaoui, Abderrahim El Hourch, M'Hamed Taibi e Abderrahman EL Boukili. "Adsorption and Desorption Behavior of Herbicide Mefenpyr-diethyl in the Agricultural Soils of Morocco". Mediterranean Journal of Chemistry 7, n. 5 (12 dicembre 2018): 386–95. http://dx.doi.org/10.13171/mjc7519111210255aeb.
Testo completoAbstract (sommario):
The present study was conducted in order to investigate the adsorption and desorption behavior of Mefenpyr-diethyl (MFD) using the batch equilibration technique in four soils, with different ranges of organic matter content, from different regions of Morocco orders of Benimellal (Soil 1), Settat (Soil 2), Sidi Bettach (Soil 3) and EL Hajeb (Soil 4). The adsorption isotherm models Langmuir, linear and Freundlich were used to compare the adsorption capacity of the soils. The results indicated that the Freundlich equation provided the best fit for all adsorption data. The values of KF and Kd ranged from 4.45 to 15.9 and 4.30 to 18.30 L.kg-1 , respectively. The calculated total percentage of desorption values from the Soil 1, Soil 2, Soil 3 and Soil 4 after the four desorption process were 59 %; 55,6 %; 37,5 % and 52,5%, respectively. Highest adsorption and desorption were observed in soil 1, and the lowest was in soil 3. According to the adsorption and desorption results, organic matter and clay seemed to be the most important factors influencing the adsorption capacity of MFD.
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Goetz, Andrew J., Robert H. Walker, Glenn Wehtje e Ben F. Hajek. "Sorption and Mobility of Chlorimuron in Alabama Soils". Weed Science 37, n. 3 (maggio 1989): 428–33. http://dx.doi.org/10.1017/s0043174500072179.
Testo completoAbstract (sommario):
Soil thin-layer chromatography and a soil solution technique were used to evaluate chlorimuron adsorption and mobility in five Alabama soils. The order of adsorption was atrazine > metribuzin > chlorimuron; mobility was chlorimuron > metribuzin > atrazine. The order of adsorption of chlorimuron in the five soils was Sumter clay > Eutaw clay > Lucedale fine sandy loam > Decatur silt loam > Dothan sandy loam, and Rfvalues were 0.63, 0.73, 0.69, 0.76, and 0.80, respectively. Chlorimuron mobility and adsorption were not highly correlated to any one soil type. Adsorption of all herbicides was inversely related to soil pH. Maximum chlorimuron adsorption in the Hiwassee loam was attributed to the high hematite and gibbsite content of the soil.
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Shaw, David R., e Glen P. Murphy. "Adsorption and relative mobility of flumetsulam". Weed Science 45, n. 4 (agosto 1997): 573–78. http://dx.doi.org/10.1017/s0043174500088846.
Testo completoAbstract (sommario):
Laboratory studies were conducted to evaluate flumetsulam adsorption and mobility in seven Mississippi soils of different organic matter content, pH, and texture. Adsorption isotherms were determined for all soils using a 1:1 (soil: water) technique. In six of seven soils, Freundlichnconstants were close to unity, suggesting a partitioning-like adsorption mechanism for flumetsulam. Mobility was examined using packed soil columns.14C-flumetsulam recoveries in leachate ranged from 1 to 70% and were influenced by both organic matter content and soil pH. However, the effects of organic matter content and soil pH were not independent. Consequently, clear relationships between flumetsulam mobility and either organic matter content or soil pH were not established across all soils. However, among soils of similar pH (7.5 ± 0.3), mobility decreased linearly (R2= 0.75) as organic matter content increased from 0.7 to 3.6%. Across soils with similar organic matter content (3.9 ± 0.3%), mobility increased linearly (R2= 0.98) as soil pH increased from 5.3 to 7.2. Net adsorption constants (Kd) provided a more accurate assessment of flumetsulam mobility across all soils thanKoc.
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Shao, Xing Hua, e Jiang Zhong Zhang. "Effect of Flooding Time on Phosphate Adsorption Desorption Characteristics of Two Acid Soils". Applied Mechanics and Materials 195-196 (agosto 2012): 1288–93. http://dx.doi.org/10.4028/www.scientific.net/amm.195-196.1288.
Testo completoAbstract (sommario):
In a laboratory incubation study, two soils were treated with distilled water, and flooded for a period of 0 (contr-ol), 1, 2, 3, 4, 8 weeks. P adsorption desorption characteristics of two soils were measured at the end of the incubation period. P a-dsorption increased with increasing levels of added P in two soi-ls. P adsorption of Paddy soil was comparatively lower than that of upland red soil. P adsorption data was found to fit Langmuir isotherms for two soils. Soil P adsorption maxima obtained from Langmuir isotherm varied from 1190 to 672 mg/kg for upland r-ed soil, and varied from 708 to 530 mg/kg for paddy soil. Floodi-ng decreased P adsorption capacity of upland red soil,increased soluble P (in 0.01M CaCl2) and equilibrium P concentration. For paddy soil, there was a large increase in the P sorption capacity after one week flooding, and then P sorption capacity decreased. The more adsorption maxima is, and the more desorption maxi-ma (Dm) is. Desorption rate constant (Kd) and bonding energy (b) varied inconsistently in two soils.
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Li, Wanting, Ruifeng Shan, Yuna Fan e Xiaoyin Sun. "Effects of tall fescue biochar on the adsorption behavior of desethyl-atrazine in different types of soil". BioResources 16, n. 2 (29 marzo 2021): 3575–95. http://dx.doi.org/10.15376/biores.16.2.3575-3595.
Testo completoAbstract (sommario):
Desethyl-atrazine (DEA) is a metabolite of atrazine that exerts a considerable influence on the environment. In this study, tall fescue biochar was prepared by pyrolysis at 500 °C, and batch experiments were conducted to explore its effect on the adsorption behavior of DEA in red soil, brown soil, and black soil. The addition of biochar increased the equilibrium amount of DEA adsorption for the three soil types. A pseudo-second-order kinetic model most closely fit the DEA adsorption kinetics of the three soils with and without biochar, with a determination coefficient (R2) of 0.962 to 0.999. The isothermal DEA adsorption process of soils with and without biochar was optimally described by the Freundlich and Langmuir isothermal adsorption models with R2 values of 0.98 and above. The DEA adsorption process in the pristine soil involved an exothermic reaction, which became an endothermic reaction after the addition of biochar. Partitioning was dominant throughout the entire DEA adsorption process of the three pristine soils. Conversely, in soils with biochar, surface adsorption represented a greater contribution toward DEA adsorption under conditions of low equilibrium concentration. The overall results revealed that the tall fescue biochar was an effective adsorbent for DEA polluted soil.
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Yusran, Fadly Hairannoor. "The Relationship between Phosphate Adsorption and Soil Organic Carbon from Organic Matter Addition". JOURNAL OF TROPICAL SOILS 15, n. 1 (9 aprile 2018): 1. http://dx.doi.org/10.5400/jts.2010.v15i1.1-10.
Testo completoAbstract (sommario):
The Relationship between Phosphate Adsorption and Soil Organic Carbon from Organic Matter Addition (FH Yusran): The application of organic matter (OM) can increase soil phosphorus (P) availability via soil mineralisation. In lateritic soils, however, soluble organic carbon (OC) from OM may also reduce phosphate adsorption capacity, a process that also releases P in soil solution. In these soils, competitive adsorption could be dominant compared to mineralisation. The main objectives of this study were to study phosphate adsorption in three lateritic soils which have been treated with different types and amounts of organic amendment, and had intrinsic OC removed by combustion. The adsorption isotherms showed that OM addition could reduce phosphate adsorption and that this reduction could last up to nine months after application. Lucerne hay was more effective than peat and wheat straw additions in reducing phosphate adsorption capacity. The bicarbonate phosphorus (BP) release through mineralisation occurred despite the increase of phosphate adsorption capacity due to the combustion of soil samples. Peat treatment was predicted to be more effective in creating organo-metal complexes with Al and Fe. Overall, mineralisation from added organic amendment was effective in minimising P adsorption in lateritic soil.
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Bolton, K. A., e L. J. Evans. "Cadmium adsorption capacity of selected Ontario soils". Canadian Journal of Soil Science 76, n. 2 (1 maggio 1996): 183–89. http://dx.doi.org/10.4141/cjss96-025.
Testo completoAbstract (sommario):
The retention of Cd by selected Ontario soils with a range of soil properties was investigated. Batch adsorption experiments were carried out at the actual (unadjusted) PH of the soil and at a range of PH values adjusted by the addition of acid or base. For all soils, Cd adsorption increased with increasing pH and with increasing Cd solution concentration. The adsorption data was fitted, by a linear least squares technique, to the Langmuir adsorption isotherm. Maximum adsorption, qmax, at unadjusted soil pH values ranged from less than 8 mmol kg−1 for the Fox sandy soil to 64.8 mmol kg−1 for the Hanbury heavy clay soil. Calculated Cd adsorption maxima were regressed against measured soil properties to determine the most important properties involved in the adsorption of Cd. Multiple linear regression analysis revealed the best model to be qmax = 8.33 + 0.67 (organic carbon) + 4.37 (inorganic – poorly crystalline Fe, Fepc). Surface complexation modeling indicates that humic surfaces account for adsorption at pH values beginning at approximately 3.5 and that hydrous ferric oxide surfaces account for Cd adsorption at pH values greater than 7. Key words: Cadmium adsorption, Langmuir isotherm, surface complexation, soil contamination
19
Bao, Yan Jiao, Hong Sheng Ding e Yan Yu Bao. "Effects of Temperature on the Adsorption and Desorption of Tetracycline in Soils". Advanced Materials Research 726-731 (agosto 2013): 344–47. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.344.
Testo completoAbstract (sommario):
Batch experiments of OECD Guide were conducted to the adsorption and desorption of tetracycline in soils. The adsorption and desorption isotherms of tetracycline in cinnamon soil and red soil were expressed well by the Freundlich equation at 20, 25 and 35°C. According to lg Kf and 1/n values of fitting parameters, tetracycline was strongly adsorbed by two soils with adsorption capacity (lg Kf) values from 3.06 to 3.59. Temperature from 20 to 30°C had little effects on the tetracycline adsorption in two soils. Thermodynamic parameters depict the exothermic nature of adsorption, and the process was favorable and spontaneous. Hysteresis effect was observed. The maximum adsorption capacity and hysteresis index of tetracycline were found at 20°C for cinnamon soil and 30°C for red soil, so there was little risk of tetracycline remobilization with temperature lower than 25°C in cinnamon soil or higher than 25°C in red soil.
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Zainol, Maznah, Halimah Muhamad, Ismail Bin Sahid e Idris Abu Seman. "Adsorption-Desorption of Hexaconazole in Soils with Respect to Soil Properties, Temperature, and pH". Turkish Journal of Agriculture - Food Science and Technology 4, n. 6 (15 giugno 2016): 493. http://dx.doi.org/10.24925/turjaf.v4i6.493-497.669.
Testo completoAbstract (sommario):
The effect of temperature and pH on adsorption-desorption of fungicide hexaconazole was studied in two Malaysian soil types; namely clay loam and sandy loam. The adsorption-desorption experiment was conducted using the batch equilibration technique and the residues of hexaconazole were analysed using the GC-ECD. The results showed that the adsorption-desorption isotherms of hexaconazole can be described with Freundlich equation. The Freundlich sorption coefficient (Kd) values were positively correlated to the clay and organic matter content in the soils. Hexaconazole attained the equilibrium phase within 24 h in both soil types studied. The adsorption coefficient (Kd) values obtained for clay loam soil and sandy loam soil were 2.54 mL/g and 2.27 mL/g, respectively, indicating that hexaconazole was weakly sorbed onto the soils due to the low organic content of the soils. Regarding thermodynamic parameters, the Gibb’s free energy change (ΔG) analysis showed that hexaconazole adsorption onto soil was spontaneous and exothermic, plus it exhibited positive hysteresis. A strong correlation was observed between the adsorption of hexaconazole and pH of the soil solution. However, temperature was found to have no effect on the adsorption of hexaconazole onto the soils; for the range tested.
21
Zhang, Zhongqing, Qiang Gao, Jingmin Yang, Yue Li, Jinhua Liu, Yujun Wang, Hongge Su, Yin Wang, Shaojie Wang e Guozhong Feng. "The adsorption and mechanism of the nitrification inhibitor nitrapyrin in different types of soils". Royal Society Open Science 7, n. 9 (settembre 2020): 200259. http://dx.doi.org/10.1098/rsos.200259.
Testo completoAbstract (sommario):
The nitrapyrin was easily adsorbed by soil, but most current studies have focused on comparing the effects of nitrapyrin application at different soil organic matter levels and in different soil types. The adsorption kinetics and isotherm adsorption of the nitrification inhibitor nitrapyrin in black soil, chernozem and planosol were studied in this paper. The adsorption kinetics were fitted by quasi-second-order kinetic equation ( R 2 ≥ 0.8907, p < 0.05) with a lower acting energy of adsorption ( E a < 8.0 kJ mol −1 ). The isotherm was fitted by the Langmuir equation ( R 2 ≥ 0.9400 * , p < 0.05). The adsorption mechanism was determined to involve a spontaneous endothermic reaction accompanied mainly by physical adsorption to the surface that belonged to the ‘ L ’ isotherm curve ( n > 1). Temperature promoted the adsorption of nitrapyrin in these three soils, and the maximum adsorption occurring at different temperatures following the order of black soil > planosol > chernozem. The adsorption capacity and rate decreased with decreasing soil organic matter. For the black soil, the nitrapyrin EC adsorption rate was more than seven times higher than that of nitrapyrin CS. The result would determine the dose of nitrapyrin required for availability in different types of soils and to provide a theoretical basis for elucidating the adsorption of nitrapyrin in the soil environment.
22
Galán-Pérez, Jose Antonio, Beatriz Gámiz, Ivana Pavlovic e Rafael Celis. "Enantiomer-Selective Characterization of the Adsorption, Dissipation, and Phytotoxicity of the Plant Monoterpene Pulegone in Soils". Plants 11, n. 10 (12 maggio 2022): 1296. http://dx.doi.org/10.3390/plants11101296.
Testo completoAbstract (sommario):
Plant monoterpenes have received attention for their ecological functions and as potential surrogates for synthetic herbicides, but very little is known about the processes that govern their behavior in the soil environment, and even less about the possible enantioselectivity in the functions and environmental behavior of chiral monoterpenes. We characterized the adsorption and dissipation of the two enantiomers of the chiral monoterpene pulegone in different soils, and their phytotoxicity to different plant species through Petri dish and soil bioassays. R- and S-pulegone displayed a low-to-moderate non-enantioselective adsorption on the soils that involved weak interaction mechanisms. Soil incubation experiments indicated that, once in the soil, R- and S-pulegone are expected to suffer rapid volatilization and scarcely enantioselective, biodegradation losses. In Petri dishes, the phytotoxicity of pulegone and its enantioselectivity to Lactuca sativa, Hordeum vulgare, and Eruca sativa was species-dependent. Lactuca sativa was the most sensitive species and showed higher susceptibility to S- than to R-pulegone. Biodegradation and volatilization losses greatly reduced the phytotoxic activity of S-pulegone applied to soil, but the addition of a highly-adsorptive organoclay stabilized the monoterpene and increased its phytotoxic effect. Stabilization by adsorption may represent an important mechanism by which the bioactivity of plant monoterpenes in soils can be increased.
23
Lu, Weisheng, Ying Liu, Huike Ye, Dasong Lin, Guijie Li, Yang Zhao, Ting Deng, Huaxing Li e Ruigang Wang. "Adsorption and Desorption Characteristics of Cadmium on Different Contaminated Paddy Soil Types: Kinetics, Isotherms, and the Effects of Soil Properties". Sustainability 13, n. 13 (23 giugno 2021): 7052. http://dx.doi.org/10.3390/su13137052.
Testo completoAbstract (sommario):
The adsorption and desorption characteristics of cadmium (Cd) in uncontaminated soils have been investigated in numerous studies. However, similar studies on Cd-polluted soils from different sources, which exhibit complex physicochemical characteristics and internal interactions between Cd and the soil particles, are scarce. Therefore, in order to elucidate the adsorption and desorption characteristics of Cd in Cd polluted soils, six representative Cd-contaminated paddy soil samples were collected from farmlands in the vicinity of a steel plant (Soil 1), a smelter (Soil 2), a thermal power plant (Soil 3), two mining areas (Soil 4, the Dabaoshan mine, Shaoguan; Soil 5, a lead-zinc mine located at Lechang), and a paddy field irrigated with sewage at Zhongshan (Soil 6) in Guangdong Province, China. The analysis of the six soil samples showed that Cd adsorption fitted well to pseudo-second order as well as pseudo-first order kinetics; however, the pseudo-second order equation showed a better fit (R2 = 0.860–0.962), while Elovich and intraparticle kinetic models fitted the adsorption kinetics poorly. Further, the adsorption isotherms fitted well to both the Langmuir and Freundlich models, with the Freundlich model showing a better fit (R2 = 0.96–0.98). The following order was observed for the Cd(II) adsorption amount and rate: S5 > S6 > S1 > S3 > S2 > S4; meanwhile, the desorption amount and rate followed the opposite trend. Furthermore, the pH and soil organic matter were identified as the soil characteristics with the most significant impact on the adsorption and desorption behaviors of Cd(II) in the Cd-polluted soils.
24
Kogan, Marcelo, Alejandra Metz e Rodrigo Ortega. "Adsorption of glyphosate in chilean soils and its relationship with unoccupied phosphate binding sites". Pesquisa Agropecuária Brasileira 38, n. 4 (aprile 2003): 513–19. http://dx.doi.org/10.1590/s0100-204x2003000400010.
Testo completoAbstract (sommario):
The objective of this work was to investigate glyphosate adsorption by soils and its relationship with unoccupied binding sites for phosphate adsorption. Soil samples of three Chilean soils series - Valdivia (Andisol), Clarillo (Inceptisol) and Chicureo (Vertisol) - were incubated with different herbicide concentrations. Glyphosate remaining in solution was determined by adjusting a HPLC method with a UV detector. Experimental maximum adsorption capacity were 15,000, 14,300 and 4,700 mg g¹ for Valdivia, Clarillo, and Chicureo soils, respectively. Linear, Freundlich, and Langmuir models were used to describe glyphosate adsorption. Isotherms describing glyphosate adsorption differed among soils. Maximum adjusted adsorption capacity with the Langmuir model was 231,884, 17,874 and 5,670 mg g-1 for Valdivia, Clarillo, and Chicureo soils, respectively. Glyphosate adsorption on the Valdivia soil showed a linear behavior at the range of concentrations used and none of the adjusted models became asymptotic. The high glyphosate adsorption capacity of the Valdivia soil was probably a result of its high exchangeable Al, extractable Fe, and alophan and imogolite clay type. Adsorption was very much related to phosphate dynamics in the Valdivia soil, which showed the larger unoccupied phosphate binding sites. However relationship between unoccupied phosphate binding sites and glyphosate adsorption in the other two soils (Clarillo and Chicureo) was not clear.
25
Golia, Evangelia E., Ourania-Despoina Kantzou, Maria-Anna Chartodiplomenou, Sotiria G. Papadimou e Nikolaos G. Tsiropoulos. "Study of Potentially Toxic Metal Adsorption in a Polluted Acid and Alkaline Soil: Influence of Soil Properties and Levels of Metal Concentration". Soil Systems 7, n. 1 (10 febbraio 2023): 16. http://dx.doi.org/10.3390/soilsystems7010016.
Testo completoAbstract (sommario):
In the present study, the adsorption of zinc (Zn), lead (Pb), copper (Cu), and cadmium (Cd) was studied in two already polluted urban soil samples with different pH values, an acidic and an alkaline one. The Langmuir and Freundlich adsorption isotherm equations were used to thoroughly study the adsorption of the metallic elements on the solid surface of the soils. Langmuir equation described the adsorption of each metal satisfactorily, with a slight predominance over Freundlich, in both soils, as the R2 value approached almost unity. Even though Zn and Cu were adsorbed on the soil phase, their adsorption was minimal compared to the adsorption of more harmful metals such as Pb and Cd. Using the values of the coefficients obtained from the equations of the mathematical models, we concluded that in alkaline soils, the retention of metals was much greater than in acidic soils. The simultaneous presence of metals during the addition of the single-element solutions of the metals to the already metal-contaminated soils caused competitive adsorption increasing the retention of the more toxic metals on the solid surface of the alkaline soil. Factors affecting soil sorption (such as soil pH and CaCO3 content) were studied to provide theoretical support for understanding the laws and causes of metal sorption in the soils of the survey.
26
Ke, Xin, Guang Zhen Xu, Lin Lin Niu, Xin Zhao, Run Dong Li e Yun Zhang. "Study on the Adsorption-Desorption Behavior of Cr in Soil as Affect by Zeolite". Advanced Materials Research 414 (dicembre 2011): 32–38. http://dx.doi.org/10.4028/www.scientific.net/amr.414.32.
Testo completoAbstract (sommario):
Under laboratory simulation experimental model, through adding exogenous chromium and CaCl2 solution, we research adsorption, desorption characteristics of Cr in soils with or without fixative (zeolite). Research shows that: The soil with zeolite can increase adsorption capacity of soil for Cr, it can also reduce the desorption quantity of Cr. In thermodynamics experiment, Freundlich equation is one of the best model to describe adsorption、desorption characteristics for Cr in soil with or without zeolite.; In kinetics experiment, adding zeolite to soil could increase adsorption rate for Cr and decrease the desorption rate for Cr ,we could use Elovich equation to describe adsorption、desorption characteristics of soils with or without zeolite for Cr.
27
Liu, Zhifeng, Xun Fang, Lingyuan Chen, Bo Tang, Fengmin Song e Wenbin Li. "Effect of Acid–Base Modified Biochar on Chlortetracycline Adsorption by Purple Soil". Sustainability 14, n. 10 (12 maggio 2022): 5892. http://dx.doi.org/10.3390/su14105892.
Testo completoAbstract (sommario):
We used three purple soil (Hechuan, Jialing, and Cangxi) samples from the Jialing River basin as the research objects and added different proportions of an acid–base modified Alternanthera philoxeroides biochar (Cm) to the purple soil to study the effect of Cm on the adsorption of chlortetracycline (CTC) in the purple soil. The results indicated the following: (1) At 30 °C and pH = 6, the soil adsorption capacity increased with an increasing initial concentration of CTC. The maximum adsorption amount of CTC for each tested sample was in the range of 2054.63–3631.21 mg/kg, and the adsorption capacity in different Cm amended soils was ranked in the order of 10% Cm > 5% Cm > 2% Cm > CK. The adsorption capacity of CTC increased with an increase in the proportion of Cm. Furthermore, under the same addition ratio of Cm, Hechuan soil was found to have a better adsorption effect for CTC than Jialing and Cangxi soil. (2) The Langmuir model was the most suitable for fitting the adsorption behavior of CTC on different purple soils, and the fitting coefficients were all greater than 0.9, indicating that the adsorption of CTC on each soil sample occurred via monolayer adsorption. The thermodynamic experiment results showed that an increase in temperature was beneficial to the process of CTC adsorption, which was a spontaneous, endothermic, and entropy-adding process. (3) At pH = 6, the ionic strength ranged from 0.01 to 0.5 mol/L and the adsorption capacity of CTC of the soil samples decreased with an increase in ionic strength. In the range of pH 2–10, the adsorption capacity of CTC in all the soil samples decreased with an increase in pH. The inhibition capacity of CTC in the soil samples under acidic conditions was notably higher than that under alkaline conditions.
28
Gerritse, RG, J. Beltran e F. Hernandez. "Adsorption of atrazine, simazine, and glyphosate in soils of the Gnangara Mound, Western Australia". Soil Research 34, n. 4 (1996): 599. http://dx.doi.org/10.1071/sr9960599.
Testo completoAbstract (sommario):
Sandy soils were sampled from second rotation sites of Pinus pinaster Ait. on the Gnangara Mound in Western Australia. Adsorption isotherms were measured for atrazine [6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine], simazine [6-chloro-N,N'-diethyl-1,3,5-triazine-2,4-diamine], and glyphosate [N-phosphonomethyl-aminoaceticacid]. Adsorption isotherms were also measured for degradation products of atrazine: hydroxyatrazine [6-hydroxy-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine] (HA), desethylatrazine [6-chloro-N-isopropyl-1,3,5-triazine-2,4-diamine] (DEA); and of glyphosate: aminomethylphosphonic acid (AMPA). The adsorption of the 2 triazines was proportional to soil organic carbon content and was not affected significantly by other soil parameters. The affinity for soil organic carbon was in the order atrazine = simazine = DEA > HA. Affinity of atrazine for the type of organic matter in the Gnangara Mound soils (expressed as Koc) was significantly greater than is commonly reported for other soils. The adsorption of glyphosate and AMPA increased strongly with iron and aluminium content of soils and decreased with increasing soil organic carbon content. This would indicate that glyphosate and AMPA are mainly adsorbed by clay minerals, while soil organic matter competes for adsorption sites and inhibits adsorption. Contrary to what is usually reported for batch adsorption of pesticides in soils, significant increases in adsorption of the triazines and glyphosate were measured after 1 day of equilibration.
29
Krishnasamy, R., e KK Krishnamoorthy. "Cationic interferences on zinc adsorption". Soil Research 29, n. 4 (1991): 527. http://dx.doi.org/10.1071/sr9910527.
Testo completoAbstract (sommario):
The effects of bivalent cations such as Mg2+, MN2+, FE2+ and Cu2+ on zinc adsorption in 16 surface soil samples (0-25 cm depth), representing major soil series of Tamil Nadu (India), and of the soil orders Vertisol and lnceptisol were studied. The study revealed that the interference of the four bivalent cations on zinc adsorption was in the order Cu2+ > Mn2+ > Me2 + > Mg2+. The effects of these ions on zinc adsorption could be explained on the basis of chemical properties such as magnetic moment value, kinetic classification, crystal field stabilization energy (CFSE) and kinetics of substitution. The variations in soil properties, particularly soil texture, also influenced zinc adsorption in these soils.
30
Wu, Caixia, Yungui Li, Mengjun Chen, Xiang Luo, Yuwei Chen, Nelson Belzile e Sheng Huang. "Adsorption of Cadmium on Degraded Soils Amended with Maize-Stalk-Derived Biochar". International Journal of Environmental Research and Public Health 15, n. 11 (23 ottobre 2018): 2331. http://dx.doi.org/10.3390/ijerph15112331.
Testo completoAbstract (sommario):
Biochar has been extensively proven to distinctively enhance the sorption capacity of both heavy metal and organic pollutants and reduce the related environmental risks. Soil pollution and degradation widely coexist, and the effect of biochar addition on adsorption behavior by degraded soils is not well understood. Four degraded soils with different degrees of degradation were amended with maize-stalk-derived biochar to investigate the adsorption of cadmium using batch methods. The maximum adsorption capacity (Qm) of degraded soil remarkably decreased in comparison with undegraded soil (5361 mg·kg−1→170 mg·kg−1), and the Qm of biochar increased with increasing pyrolysis temperature (22987 mg·kg−1→49016 mg·kg−1) which was much higher than that of soil. The addition of biochar can effectively improve the cadmium adsorption capacity of degraded soil (36–328%). The improving effect is stronger when increasing either the degradation level or the amount of added biochar, or the pyrolysis temperature of biochar. Contrary to the general soil–biochar system, adsorption of Cd was not enhanced but slightly suppressed (7.1–36.6%) when biochar was incorporated with degraded soils, and the adsorptivity attenuation degree was found to be negatively linear with SOM content in the degraded soil–biochar system. The results of the present study suggest that more attention on the adsorption inhibition and acceleration effect difference between the soil–biochar system and the degraded soil–biochar system is needed.
31
AbdulKadium, Safa Mahdi, e Hadi Yasir Abbood Al-Janabi. "Selenium Adsorption as Influenced by Different Anions in some Middle Euphrates Soils". IOP Conference Series: Earth and Environmental Science 1060, n. 1 (1 luglio 2022): 012004. http://dx.doi.org/10.1088/1755-1315/1060/1/012004.
Testo completoAbstract (sommario):
Abstract Adsorption Selenium (Se) levels in soils may be changed by a variety of variables. such as compecting anion. Investigated adsorption behavior for two top soil different properties, aiming to describe selenium adsorption in selected centrial Iraq soils. (Awfi) Samples were collected comprising clayed soil, Which Se adsorption tests were performed on the samples. After a 72-hour reaction with increasing concentrations of Se(0-400 µg mL-1) added as Na2SeO4, adsorption was measured. In the presence of Sulphate and Phosphate, which are usually applied in an inorganic form to soils. Soil properties affected adsorption capability of se, i.e. Se adsorped amount were higher for Awfi soils. The adsorption of Se on soils increased as the amount of Se supplied increased, both in the presence and absence of cometic anions. Se adsorption followed Langmuir’s and Freundlich’s equations. There are no competing anions in the absence of any, adsorption maxima of Se 87.719 μg g-1 The data from K and XM adequately reflected the adsorption of Se in the examined soils. This was ascribed to the existence of higher concentrations of competing anions, particularly sulphate and phosphate.
32
Lee, S. Z., L. Chang, C. M. Chen, Y. I. Tsai e M. C. Liu. "Predicting soil-water partition coefficients for Hg(II) from soil properties". Water Science and Technology 43, n. 2 (1 gennaio 2001): 187–96. http://dx.doi.org/10.2166/wst.2001.0089.
Testo completoAbstract (sommario):
The metal adsorption characteristics for fifteen Taiwan soils by Hg(II), were evaluated using pH as the major variable. The soil samples were thoroughly characterized for their physical chemical properties and composition, particularly organic matter and metal oxides. The adsorption of Hg(II) increased with increasing pH between pH 2.5 and 5.5, whereas the adsorption significantly decreased above around pH 5.5. Below pH 5.5, greater adsorption was found for soils with a higher organic matter content at constant pH and metal concentration. To better understand the mechanism of adsorption, the experimental results for Hg (II) were tested in a partition coefficient model to relate the adsorption of the Hg(II) by the different soils with soil components: organic matter, iron oxide, aluminium oxide and manganese oxide. This model was not successful when applied to measurements at the differing natural soil pHs because of the importance of pH. At pH greater than 5.5 the model fails because of the complexation of Hg by the dissolved organic matter. However, partition coefficients obtained from experimental data were highly correlated with those calculated for a partition coefficient between mercury and organic matter alone at lower pH. Normalization of the partition coefficients, Kd, for the organic matter content of the soils, Kom, greatly improved the correlation between the partition coefficient and pH under pH 5.5 (R2 increased from 0.484 to 0.716). This suggests that the surficial adsorption sites are principally due to organic matter for pH less than 5.5. For the 24-hour equilibration period employed, diffusion of Hg through this superficial organic matter coating to underlying sorptive materials, including metal oxides, is not important in the partitioning of Hg. At pH above 5, a decrease of mercury adsorption with increasing solution pH was also found. This result may be explained in part by the complexation of mercury by soil dissolved organic matter whose concentration increased with increasing pH.
33
Li, Leiming, e Jun Wu. "Lead and Chromium Immobilization Process Subjected to Different Freeze-Thaw Treatments in Soils of the Northeastern Qinghai-Tibet Plateau". Journal of Chemistry 2021 (21 ottobre 2021): 1–11. http://dx.doi.org/10.1155/2021/5286278.
Testo completoAbstract (sommario):
The freeze-thaw cycle is one of the important processes that affected heavy metal behaviors in soil. However, information regarding the adsorption and desorption behavior of heavy metals in soils under different freeze-thaw conditions is relatively less. Therefore, different freeze-thaw conditions including unfrozen, 15 freeze-thaw cycles at 60% water content, and 15 freeze-thaw cycles at 100% water content were investigated. Then the adsorption and desorption behaviors of Pb and Cr in freeze-thaw soils were studied. Results showed the Pb and Cr adsorption amount mostly decreased with increasing water-soil ratio, and the soil performance of Pb and Cr adsorption at same water-soil ratios showed variation under different freeze-thaw conditions. The Pb isothermal adsorption was higher for most freeze-thaw treatments compared to the control. The soil performance of Cr isothermal adsorption showed variation under different freeze-thaw conditions. Most electrostatic binding of Pb and Cr were stronger under unfrozen and freeze-thaw conditions than unfrozen conditions. Most Pb and Cr adsorption kinetics patterns of freeze-thaw treated soils were rapid than unfrozen conditions. These results implied that freeze-thaw cycles could change the soil adsorption and desorption patterns of Pb and Cr. Therefore, further studies are urgently needed to investigate Pb and Cr immobilization mechanisms in soils during freeze-thaw cycles. Hence, these findings provided useful information on Pb and Cr immobilization process in soils that underwent freeze-thaw cycles to offer an additional insight into predicting Pb and Cr behaviors in cold and freezing environments.
34
Gonçalves, Deyvison Andrey Medrado, Gilson Sergio Bastos de Matos, Antonio Rodrigues Fernandes, Katiane Raquel Mendes Barros, Danielle do Socorro Nunes Campinas e Cristine Bastos do Amarante. "Adsorption of cadmium and copper in representative soils of Eastern Amazonia, Brazil". Semina: Ciências Agrárias 37, n. 5 (26 ottobre 2016): 3005. http://dx.doi.org/10.5433/1679-0359.2016v37n5p3005.
Testo completoAbstract (sommario):
Studies of heavy metals adsorption in soil play a key role in predicting environmental susceptibility to contamination by toxic elements. The objective of this study was to evaluate cadmium (Cd) and copper (Cu) adsorption in surface and subsurface soil. Samples of six soils: Xanthic Hapludox (XH1 and XH2), Typic Hapludox (TH), Typic Rhodudalf (TR), Typic Fluvaquent (TF), and Amazonian dark earths (ADE) from Eastern Amazonian, Brazil. The soils were selected for chemical, physical and mineralogical characterization and to determine the adsorption by Langmuir and Freundlich isotherms. All soils characterized as kaolinitic, and among them, XH1 and XH2 showed the lowest fertility. The Langmuir and Freundlich isotherms revealed a higher Cu (H curve) than Cd (L curve) adsorption. Parameters of Langmuir and Freundlich isotherms indicate that soils TR, TF and ADE has the greatest capacity and affinity for metal adsorption. Correlation between the curve adsorption parameters and the soil attributes indicates that the pH, CEC, OM and MnO variables had the best influence on metal retention. The Langmuir and Freundlich isotherms satisfactorily described Cu and Cd soil adsorption, where TR, TF and ADE has a lower vulnerability to metal input to the environment. Besides the pH, CEC and OM the MnO had a significant effect on Cu and Cd adsorption in Amazon soils.
35
Malvar, José Luis, Juan Luis Santos, Julia Martín, Irene Aparicio e Esteban Alonso. "Approach to the Dynamic of Carbamazepine and its Main Metabolites in Soil Contamination through the Reuse of Wastewater and Sewage Sludge". Molecules 25, n. 22 (13 novembre 2020): 5306. http://dx.doi.org/10.3390/molecules25225306.
Testo completoAbstract (sommario):
The release of pharmaceutically active compounds to the soils through the application of sewage sludge and the irrigation with wastewater, or even with surface water, is constant. The adsorption of these compounds onto the soil is one of the key factors affecting their fate in the environment and their potential environmental risks. In this work, the adsorption of carbamazepine (CBZ) and its metabolites, 3-hydroxy-carbamazepine (3OH-CBZ), carbamazepine-10,11-dihydro-10,11-epoxide (EP-CBZ), and 10,11-dihydro-10-hydroxycarbamazepine (10OH-CBZ), in three Mediterranean soils was evaluated using single-solute and four-solute experiments. The highest adsorptions were measured for 3OH-CBZ, followed by CBZ, EP-CBZ, and 10OH-CBZ, in that order. A high influence of the physicochemical characteristics of the compounds, pH, and soil characteristics in the adsorption of the studied compounds was observed and corroborated by the statistical analysis of the results. Moreover, a good fit was observed in the three isotherm models evaluated (linear, Freundlich, and Langmuir) in single-solute experiments (R2 > 0.90). However, a decrease of the measured adsorptions and a worse fit to the isotherm models were observed in the case of multiple-solute experiments. This could be mainly due to the competition established between the studied compounds for the active sites of the soils.
36
Cazanga, Marcia, Marlen Gutierrez, Mauricio Escudey, Gerardo Galindo, Antonio Reyes e Andrew C. Chang. "Adsorption isotherms of copper, lead, nickel, and zinc in two Chilean soils in single- and multi-component systems: sewage sludge impact on the adsorption isotherms of Diguillin soil". Soil Research 46, n. 1 (2008): 53. http://dx.doi.org/10.1071/sr07009.
Testo completoAbstract (sommario):
The potential impact of the addition of sewage sludge from domestic waste water treatment plants on agricultural soils is a worldwide concern. A proportion of heavy metals in sewage sludge will be present in the soil solution; their equilibria can be modified by the competitive interactions between them, changing not only their mobility but also their adsorption pattern. The competitive adsorption of heavy metals by soils has been studied by several authors in simple model substrates and synthetic minerals, and also in soils but restricted to binary adsorption. In the present paper the modification of the Cu, Pb, Ni, and Zn interactions with soils as a consequence of a competitive adsorption on the available adsorption sites on Andisols were determined.The single- and multi-component adsorption of Cu, Pb, Ni, and Zn were carried out at constant ionic strength (0.1 m KNO3). The adsorption was monitored by ICP-OES and the Langmuir model was applied to fit the adsorption isotherms.Competitive adsorption isotherms indicate a reduction of the adsorption in the control soils when compared to the single adsorption isotherms. The maximum adsorption constants for single- and multi-component isotherms for Diguillín soil were 38.2 and 33.3 mmol/kg for Cu, 48.1 and 30.0 mmol/kg for Pb, 5.4 and 2.1 mmol/kg for Ni, and 18.0 and 8.1 mmol/kg for Zinc, respectively. With Ralun soil, lower values were obtained, but the same tendency was observed.The maximum adsorption and the affinity constant increased for all cations, after the addition of sewage sludge to Diguillin soil.
37
Cichota, R., I. Vogeler, N. S. Bolan e B. E. Clothier. "Cation influence on sulfate leaching in allophanic soils". Soil Research 45, n. 1 (2007): 49. http://dx.doi.org/10.1071/sr06070.
Testo completoAbstract (sommario):
We have examined the influence of the ionic composition of the soil solution on the movement of sulfate and calcium in 2 New Zealand soils with differing allophane content. For this study, we have carried out a series of miscible displacement experiments using repacked and intact soil columns, in which sulfate was applied in the presence of either calcium or potassium as the accompanying cation. Our results showed that sulfate leaching was significantly retarded in the soil with higher allophane content when applied with calcium. On the other hand, no effects were observed for all studied soils when potassium was used as the accompanying cation. In addition, in soils with high allophane content, calcium also had its retention increased when sulfate was present. The increase in sulfate adsorption was accompanied by corresponding increase in calcium adsorption. These findings evidenced the presence of co-adsorption, or ion-pair adsorption (IPA), in allophane-containing soils. The extent of this adsorption is dependent on the soil pH, the accompanying cation, and the allophane content of the soil.
38
Ishiguro, Munehide, e Luuk K. Koopal. "Surfactant adsorption to soil components and soils". Advances in Colloid and Interface Science 231 (maggio 2016): 59–102. http://dx.doi.org/10.1016/j.cis.2016.01.006.
Testo completo
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Wang, Yong, Jun Jiang, Ren-kou Xu e Diwakar Tiwari. "Phosphate adsorption at variable charge soil/water interfaces as influenced by ionic strength". Soil Research 47, n. 5 (2009): 529. http://dx.doi.org/10.1071/sr08181.
Testo completoAbstract (sommario):
The effect of phosphate adsorption on zeta potential of the colloids of variable charge soils and the effect of ionic strength on phosphate adsorption by the soils were investigated using batch experimental method. The presence of phosphate resulted in the decrease in zeta potential and isoelectric point (IEP) of the colloids of the soils, which further suggested that the phosphate was adsorbed specifically by these soils. The effect of phosphate adsorption on zeta potential was correlated with the content of free Fe/Al oxides in the soils; the higher the content of Fe/Al oxides in a soil the greater was the decrease in zeta potential and IEP of the soil colloids. The intersection of phosphate adsorption–pH curves at different ionic strengths (a characteristic pH) was obtained for 2 Oxisols. Above this pH, the adsorption of phosphate increased with increasing ionic strength, whereas below it the reverse trend occurred. The intersect pH was 4.60 for the Oxisol from Guangdong and 4.55 for the Oxisol from Yunnan, which was lower than the values of PZSE (point of zero salt effect) of these soils, but near the PZNC (point of zero net charge) of the soils. The effects of ionic strength and pH on phosphate adsorption by these soils were interpreted with the help of an adsorption model developed previously by Bowden et al. The results of zeta potential suggested that the potential in an adsorption plane became less negative with increasing ionic strength above the soil PZNC and decreased with increasing ionic strength below the soil PZNC. These results support the hypothesis of the adsorption model that the potential in the adsorption plane changed with ionic strength with an opposite trend to the surface charge of these soils. The phosphate adsorption by these soils was related not only to the ionic strength but also to the types of electrolytes present. K+ induced a greater increase in phosphate adsorption than Na+ due to the greater affinity of the soils to K+ than Na+.
40
Nakayama, Chieko, e Yoshinori Tanaka. "Adsorption of nitrate as a groundwater pollutant by soil particles". Journal of Nepal Geological Society 34 (9 ottobre 2006): 141–46. http://dx.doi.org/10.3126/jngs.v34i0.31890.
Testo completoAbstract (sommario):
This study discusses nitrogen adsorption in several soil samples of the Kanto loam collected from two locations in the Kanto plain. Their chemical properties were assessed on each of the soil samples as well as on pure allophane clay by instrumental analysis using batch and soil column tests.
Nitrogen-nitrate adsorption by soil samples was determined by a 10-hour batch test using a nitric acid solution of 0.14 mmol. A saturation column test was conducted to obtain a breakthrough curve and calculate the coefficients of dispersion and retardation. The extent of nitrate adsorption in soil samples was confirmed by percolation with 0.14 mmol nitric acid through columns packed with the soil sample and silicate sand.
In the batch test, it was found that the amount of nitrate adsorption was greater in allophane-rich volcanic ash soils with the amount of nitrate adsorption increasing under conditions of low pH. The breakthrough curve determined by the column test showed that the coefficient of retardation increased in allophane-rich soils.
Adsorption of nitrates by Kanto loam soils was thus found to be dependent upon the content of allophane and amorphous material in the soil. Since the positive charge of allophane has the potential to reduce the nitrate content in groundwater, it can be effectively applied to reduce nitrate contamination in groundwater.
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Shi, Zhenqing, Herbert E. Allen, Dominic M. Di Toro, Suen-Zone Lee e James B. Harsh. "Predicting PbII adsorption on soils: the roles of soil organic matter, cation competition and iron (hydr)oxides". Environmental Chemistry 10, n. 6 (2013): 465. http://dx.doi.org/10.1071/en13153.
Testo completoAbstract (sommario):
Environmental context Lead is a common and persistent soil and water contaminant. This study provides a unique set of parameters for chemical models that can be used for predicting Pb adsorption by soil. The suggested modelling approach can be used to quantitatively predict Pb retention and release in soils with changing environmental conditions. Abstract Lead (PbII) adsorption on 14 non-calcareous New Jersey soils was studied with a batch method. Both adsorption edge and adsorption isotherm experiments were conducted covering a wide range of soil compositions, Pb concentrations and solution pHs. Visual MINTEQ was used to calculate the Pb adsorption equilibrium by coupling the Stockholm Humic Model, the CD-MUSIC model, a diffuse layer model and a cation exchange model for Pb reactions with soil organic matter (SOM), Fe (hydr)oxides, Al hydroxides and clay minerals. For model predictions, reactive organic matter (ROM), the fraction of SOM responsible for Pb binding, and reactive Al and FeIII in soils were quantified. The models predicted Pb adsorption to soils reasonably well with varying SOM and mineral content at various pHs and Pb concentrations. For 3.0<pH<6.0, the log partition coefficient root mean square error was 0.34. However at higher pHs the models were less successful. Both ROM and Al competition had a significant effect on model predictions. ROM was the dominant adsorption phase at pHs between 3.0 and 5.0. For pH>5.0, Pb adsorption to Fe (hydr)oxides became significant. The modelling approach presented in this study can be used to understand and quantitatively predict Pb adsorption on soil.
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Campillo-Cora, Claudia, Manuel Conde-Cid, Manuel Arias-Estévez, David Fernández-Calviño e Flora Alonso-Vega. "Specific Adsorption of Heavy Metals in Soils: Individual and Competitive Experiments". Agronomy 10, n. 8 (1 agosto 2020): 1113. http://dx.doi.org/10.3390/agronomy10081113.
Testo completoAbstract (sommario):
The partitioning between the soil solid phase and the soil solution determines the mobility of pollutants like heavy metals. If nonspecific sorption takes place, the reactions are easily reversible and heavy metals are released to soil solution increasing the probability of leaching through soil profile. Mobility and leaching are also favoured if other metals are in the system and competition for specific adsorption sites takes place. In this study, desorption equilibrium experiments were conducted after adsorption ones. The specific adsorption was evaluated through the amounts of the still adsorbed Cu, Pb, Cr, Ni and Zn after desorption experiments in ten different soils. In addition, competition adsorption and desorption binary experiments were conducted for evaluating the metal competition in three of the soils. Pb and Cu are the metals adsorbed and retained in higher amounts in all the studied soils. In slightly neutral soils, Cr is retained in lesser amounts while in acidic soils Zn is the metal less retained. Results showed that despite the high and variable amounts of organic matter in the soils, soil pH is the most important variable in neutral soils. In acidic soils, soil properties different than pH play important roles and specific sorption of Pb is related to the cationic exchange capacity of the soils while that of Zn to the clay content. Instead, the release of Cu during desorption experiments is probably due to the more soluble organic fraction of the soils. The individual retention of Cu, Zn, Ni and Pb is higher than when they are in competition, except if Cr is present. In this case, the amount of those four metals and that of Cr increased. Therefore, the presence of Cr together with cationic heavy metals favoured the adsorption of those metals in multi-metal polluted areas. Specific adsorption is also important during competition as soil affinities increase during competition experiments.
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Singh, Dhirendra. "Effect of Different Factors on the Adsorption of Phosphamidon on Two Different Types of Indian Soil". Adsorption Science & Technology 16, n. 8 (settembre 1998): 583–94. http://dx.doi.org/10.1177/026361749801600801.
Testo completoAbstract (sommario):
The effect of exchangeable cations (H+ and Na+). autoclaving, organic matter, anionic surfactants and temperature on the adsorption of phosphamidon on two different types of Indian soil was studied. The adsorption isotherms for all the effects/treatments were in close agreement with the Freundlich equation and yielded S-shaped isotherms. The amount of phosphamidon adsorbed in all cases was higher in medium black (silt loam) soil than alluvial soil (sandy loam) and was related to the organic matter content, clay content, CaCO3 content, surface area and cation-exchange capacity of the soils. The adsorption on both types of soil follows the order H+-soil > Na+-soil > natural soil at 10°C > natural soil at 20°C > autoclaved soil > organic matter-removed soil > anionic surfactant > natural soil at 40°C, which was in accordance with the Freundlich constant, KF, and distribution coefficient, Kd, values. The adsorption capacity of phosphamidon for organic matter and clay content for both the soils was evaluated by calculating the Kom and Kc values when it was found that phosphamidon adsorption was better correlated with the clay content than with the orgnic matter content on the basis of adsorption isotherms. Various thermodynamic parameters such as the thermodynamic equilibrium constant (K0), the standard free energy (ΔG0), the standard enthalpy (ΔH0) and the standard entropy (ΔS0) changes have been calculated as a means of predicting the nature of the isotherms.
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Araujo, Anderson Mendes, Josimar Henrique de Lima Lessa, Liniker André Ferreira, Luiz Roberto Guimarães Guilherme e Guilherme Lopes. "Soil management and ionic strength on selenite retention in oxidic soils". Ciência e Agrotecnologia 42, n. 4 (agosto 2018): 395–407. http://dx.doi.org/10.1590/1413-70542018424007318.
Testo completoAbstract (sommario):
ABSTRACT Sorption of selenium (Se) on soils may be influenced by factors that are changed though agricultural practices usually performed for crop production, such as soil pH, competing anion and organic matter contents, among others. This study aimed to evaluate the influence of soil management and ionic strength (IS) on Se retention in Brazilian soils, which is important to predict Se availability in both systems, native and cultivated soils. For that, adsorption and desorption reactions of Se were evaluated in 16 soil samples (eight from cultivated soils and eight from native soils), using solutions containing 100 and 500 µg L-1 Se in the form of sodium selenate and in two IS, 15 and 150 mM. Se adsorption varied as a function of IS for most soils, which may indicate that the adsorption mechanism by outer-sphere complex is important for selenate retention in the studied soils, but future studies involving other techniques, such as spectroscopic studies, are needed to more clearly confirm the adsorption mechanism. In general, adsorption varied in relation to soil characteristics, and native soils adsorbed larger Se amounts than the cultivated soils. In terms of desorption, soils which had larger Se adsorbed amounts also presented larger desorbed amounts. Finally, IS and soil management influenced the availability of selenate in the studied soils.
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Teixeira, Juliana Brito da Silva, Rogério Oliveira de Sousa e Marcos Lima Campos do Vale. "Phosphorus adsorption after drainage in two soil classes". Revista Ceres 65, n. 2 (marzo 2018): 196–203. http://dx.doi.org/10.1590/0034-737x201865020012.
Testo completoAbstract (sommario):
ABSTRACT Lowland soils, seasonally flooded for rice cultivation, feature alternate oxidation and reduction conditions, which determine intense modifications in the soil mineral solid phase and in the dynamics of highly reactive elements, such as phosphorus. This study aimed to evaluate the effect of drainage of two lowland soils (Albaqualf and Argiaquoll) after a flooding period on the maximum phosphorus adsorption capacity (MPAC). The experiment was conducted in a greenhouse, and the system factor was composed of two levels: 1) flooded soil for 63 days, followed by drainage, and then humidity remained at 16% for 184 days; 2) soil moisture maintained at 16% throughout the trial period. After drainage, soil samples were collected at 0, 36, 96 and, 184 days for MPAC determination, which was performed by the adjustment of adsorption isotherms according to the Langmuir model. The behavior of MPAC after soil drainage was different for both soil classes evaluated. An immediate reduction of maximum phosphorus adsorption capacity was seen after drainage in the case of Albaqualf, while for Argiaquoll, there was a tendency to maintain higher values of MPAC after drainage, with subsequent reduction. Soil drainage after a flooding period increases de maximum phosphorus adsorption capacity, and this effect remains for approximately 163 days in Argiaquoll and 121 days in Albaqualf soils.
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Baskaran, S., NS Bolan, A. Rahman, RW Tillman e AN MacGregor. "Effect of drying of soils on the adsorption and leaching of phosphate and 2,4-dichlorophenoxyacetic acid". Soil Research 32, n. 3 (1994): 491. http://dx.doi.org/10.1071/sr9940491.
Testo completoAbstract (sommario):
Surface samples of an allophanic (Patua silt loam) and a non-allophanic (Tokomaru silt loam) soil were used to examine the effects of drying on the adsorption and leaching of phosphate and 2,4-dichlorophenoxyacetic acid (2,4-D). Phosphate and 2,4-D adsorption isotherms and adsorption kinetics were determined for field-moist, air-dried and oven-dried soil samples using KH2PO4 and 14C labelled 2,4-D. In a separate experiment, the leaching of a pulse of phosphate or 2,4-D was examined using soil columns. The Patua silt loam adsorbed 4-7 times more phosphate and 2,4-D than the Tokomaru silt loam. Compared with field-moist soil, both air-dried and oven-dried soil increased (2-5 times) the adsorption of phosphate, and oven-dried soil decreased the adsorption of 2,4-D. The adsorption kinetics indicated that there was no effect of drying on the rate of adsorption of either phosphate or 2,4-D. In column experiments, there was less leaching of phosphate and 2,4-D from the Patua soil than from the Tokomaru soil. In both soils, there was no effect of drying on the leaching of phosphate, whereas oven-drying increased the leaching of 2,4-D. Solubilization of organic matter during drying increased the accessibility of P to adsorption sites on the mineral surface and thereby increased the adsorption, whereas the water-soluble organic matter bound 2,4-D and thereby decreased the apparent adsorption onto soil and increased leaching
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Wang, Fangting, Ke Bao, Changsheng Huang, Xinwen Zhao, Wenjing Han e Zhibin Yin. "Adsorption and pH Values Determine the Distribution of Cadmium in Terrestrial and Marine Soils in the Nansha Area, Pearl River Delta". International Journal of Environmental Research and Public Health 19, n. 2 (11 gennaio 2022): 793. http://dx.doi.org/10.3390/ijerph19020793.
Testo completoAbstract (sommario):
Cadmium is a toxic element with a half-life of several decades, which can accumulate in the human body by entering the food chain and seriously harm health. The cadmium adsorption and desorption processes in the soil directly affect the migration, transformation, bioavailability, and ecotoxicity of this element in soil-plant systems. Coastal zones are located in the transitional zone between land and sea, and large amounts of terrigenous material input have important environmental effects on this ecosystem. The pH, hydrodynamic conditions, soil organic matter (SOM), and other factors defining the sea-land interaction within the sedimentary environment are significantly different from those defining land facies. In order to study the key factors affecting cadmium adsorption in soils at the sea-land interface in the Nansha area of the Pearl River Delta, a test was conducted on a column of undisturbed soil. The results showed that the adsorption constant KF and the Cd2+ adsorption capacity of marine soils were higher than those of terrestrial soils. However, the saturation adsorption of cadmium in terrestrial sediments was higher than in marine sediments. Soil pH was an important factor affecting cadmium adsorption capacity in both terrestrial and ma-rine sediments. Neutral and alkaline topsoil conditions inhibited the vertical migration of cadmium, while the acidic environment favored it. The higher the clay and SOM were, the stronger the Cd2+ adsorption capacity of the soil was. These findings suggest that the distribution of cadmium in marine and continental sedimentary soils is not only related to adsorption, but also to the physical and chemical processes occurring in different sedimentary environments.
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Mueller, Thomas C., e Philip A. Banks. "Flurtamone Adsorption and Mobility in Three Georgia Soils". Weed Science 39, n. 2 (giugno 1991): 275–79. http://dx.doi.org/10.1017/s0043174500071605.
Testo completoAbstract (sommario):
Flurtamone and atrazine adsorption to soil was examined using a batch equilibrium method. Flurtamone mobility in packed soil columns under saturated flow conditions was also evaluated. Adsorption was greater for flurtamone than atrazine in the three soils, and the order of adsorption to soil for both herbicides was Greenville sandy clay loam > Cecil loam > Dothan loamy sand. Greater adsorption of each herbicide corresponded to soils with greater organic matter and clay content. The14C–flurtamone movement under saturated flow conditions in 28–cm soil–packed columns was limited to 16 cm, with no flurtamone leaching from any soil column after the addition of two pore volumes of water. Seventy–five percent of the applied14C–flurtamone remained in the 0– to 4–cm soil depth in the Greenville sandy clay loam, with less than 5 percent moving to a depth > 4 cm. Flurtamone movement was greater in the Cecil loam and the Dothan loamy sand, with movement in each soil to a depth of 16 and 12 cm, respectively.
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Nagodavithane, Chamali Laksala, Balwant Singh e Yunying Fang. "Effect of ageing on surface charge characteristics and adsorption behaviour of cadmium and arsenate in two contrasting soils amended with biochar". Soil Research 52, n. 2 (2014): 155. http://dx.doi.org/10.1071/sr13187.
Testo completoAbstract (sommario):
Biochar has been recognised as an effective amendment for the remediation of contaminated soils; however, there is limited knowledge on the effects of biochar ageing in soil on its adsorption behaviour for cationic and anionic species. Biochars are considered to develop negative charge from oxidation with ageing, which may create additional interaction mechanisms for adsorption processes. In the present study, surface charge characteristics and cadmium (Cd) and arsenate (AsO43–) adsorption behaviour of aged biochar were investigated in two soils with variable charge, an Oxisol and an Inceptisol, by comparing (i) unamended soils, and soils amended with (ii) fresh biochar (450°C) and (iii) biochar (450°C) aged for 12 months, applied at a rate of 2% w/w. Surface charge characteristics were assessed using the ‘index’ ion adsorption method, with a LiCl electrolyte. Batch adsorption studies were conducted using fresh and aged soil–biochar mixtures. In contrast to previous studies, the results provided no evidence of an increase in cation exchange capacity as a consequence of biochar ageing. There was an increase in Cd adsorption in the presence of aged biochar in both soil types compared with unamended soils and soils amended with fresh biochar. Results also indicated an increase in AsO43– adsorption in the Inceptisol amended with aged biochar, whereas a decrease in AsO43– adsorption was observed in the Oxisol amended with aged biochar. Overall, the study has highlighted that adsorption behaviour of aged biochar varies depending on the ion it interacts with, soil properties and solution pH.
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Suwardji, Suwardji, e I Made Sudantha. "The Fate of Glyphosate in Soil and Water: A Review". Jurnal Penelitian Pendidikan IPA 7, SpecialIssue (31 dicembre 2021): 389–99. http://dx.doi.org/10.29303/jppipa.v7ispecialissue.971.
Testo completoAbstract (sommario):
The fate of glyphosate in soil and water is dependent on the properties of glyphosate and its envoronement. Behaviour of glyphosate in soil, sediment and water is strongly influenced the way by which it can be adsorbed by soils, sediments, and suspended material in water. The role of soil organic matter, clay mineral, and amorphous minerals on the adsorption of glyphosate depends primarily on the nature and properties of the soil itself and the properties of glyphosate. Environmental factors have some influence on sorption and degradation of glyphosate. Glyphosate is rapidly inactivated in soil, is in part due to adsorption. Some soil properties have been identified strongly influence adsorption of glyphosate, such as clay minerals, composition of cations in exchangeable site of clay and organic matter, unoccupied phosphate adsorption site, degree of humification, and soil pH. Adsorption limits the availability of glyposate for microbial degradation. The sorbed glyphosate is not directly available to microorganisms in soil. Evidence also suggests that not only a strongly sorbed compound such as paraquat but also weakly sorbed compounds such as flumetsulam and picloram can persist for long periods when they are sorbed by soil constituents. This suggests that the interaction between sorption and biodegradation should be considered in predicting the fate of pesticides in soils and sediments.