scholarly journals Sorption Characteristics and Fraction Distribution Changes of Selenite in Soil

2018 ◽  
Vol 10 (7) ◽  
pp. 2491 ◽  
Author(s):  
Jianxin Fan ◽  
Guoliang Zhao
Keyword(s):  
Linear Regression ◽  
Sequential Extraction ◽  
Multiple Linear Regression ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Lower State ◽  
Fraction Distribution ◽  
Pseudo Second Order ◽  
Sorption Parameters ◽  
Sorption Characteristics

Sorption properties play a key role in the mobility of selenium (Se) and fraction distribution changes, leading to the bioavailability of Se in the soil environment. Thus, the effect of soil physicochemical properties on the sorption of exogenous selenite was investigated to predict the rate and capacity of sorption. Correlation analysis and multiple linear regression were used to observe the relationship between sorption characteristics and soil properties. Sequential extraction was used to observe the fractions of Se at different ages in soil. Results indicated that sorption isotherms followed the Langmuir equation, and the sorption capacity ranged from 50.7 to 567 mg·kg−1 with pseudo-second-order sorption kinetics. The correlation and multiple linear regression analyses showed that sorption parameters were significantly positively correlated with dithionite–citrate–bicarbonate-extracted Fe (FeDCB), dithionite–citrate–bicarbonate-extracted Al (AlDCB), amorphous Fe (FeOX), and soil organic matter (SOM), whereas pH was negatively correlated. Sequential extraction analyses revealed that the fraction distribution of Se in soil varied with the age, and the content of elemental Se increased with prolonged aging. FeDCB, AlDCB, FeOX, pH, and SOM play important roles in selenite sorption onto soils. Selenite sorption onto soil can be reduced to a lower-state Se, such as elemental Se and selenides, during the aging process. This information on the environmental behavior of Se is used to develop agronomic strategies for increasing Se levels in food crops and improving human health.

Effects of decalcification on the phosphate sorption characteristics of eight calcareous soils

Soil Research ◽  
1990 ◽  
Vol 28 (6) ◽  
pp. 919 ◽  
Author(s):  
ICR Holford ◽  
M Chater ◽  
GEG Mattingly
Keyword(s):  
Calcareous Soils ◽  
Sorption Isotherms ◽  
Phosphate Sorption ◽  
Surface Equation ◽  
P Sorption ◽  
Surface Areas ◽  
Freundlich Equation ◽  
Sorption Parameters ◽  
Parameter Values ◽  
Sorption Characteristics

Phosphate sorption isotherms and parameter values were determined on eight calcareous soils which were carefully decalcified using a procedure which minimized changes in cation saturation. Calcite content of the original soils varied from 0.8 to 24 2% and calcite surface areas from 4 . 0 to 8.5 m2 g-1. Sorption parameters were derived from the Langmuir 'two-surface' equation. Decalcification increased phosphate sorption at low residual P concentrations (<0.8 mg L-1) but decreased it at higher concentrations. The higher P sorption was associated with an increase in affinity because the calculated sorption capacities of high-affinity surfaces were not increased. These sorption capacities were well correlated with iron oxide contents of the soils, so the increase in phosphate affinity of these surfaces was consistent with the decrease in pH (0.5 to 1.5 units) of the decalcified soils. The lower P sorption at higher concentrations was associated with a substantial decrease in sorption capacity of the postulated low-affinity surfaces. These latter decreases were quantitatively correlated with the calcite surface areas of the original soils. These and other changes in phosphate sorption characteristics support the utility of the Langmuir 'two-surface' equation in providing information, compatible with what would be expected from more complex mechanistic models, and which exceeds what one would expect from other simpler models such as the Freundlich equation. They also support an hypothesis that an important component of low-affinity surfaces of these calcareous soils is calcite on which organic anions are co-adsorbed.

scholarly journals Use of Garlic Processing By-Products to Remove Pollutants from Aqueous Media

2021 ◽  
Vol 12 (4) ◽  
pp. 4518-4528
Keyword(s):  
Activated Carbons ◽  
Aqueous Media ◽  
Order Model ◽  
Chemical Reagents ◽  
Adsorption Processes ◽  
Pseudo Second Order ◽  
Sorption Parameters ◽  
Kinetics Of ◽  
By Products ◽  
Sorption Characteristics

The paper summarized the literature data on using ground peels, outer leaves, and garlic roots (Allium sativum L.) as sorption materials to remove various metal ions, dyes, and antibiotics from aqueous media. This paper provides brief information on the amount of waste generated from processing garlic, its chemical composition, and ways of reuse. It gives the adsorption processes parameters and the values of sorption parameters for the studied pollutants. It was shown that garlic residue sorption characteristics for various pollutants could be increased by chemical modification with various chemical reagents. It was determined that the Langmuir model more accurately describes the pollutant’s adsorption isotherms in most cases, and the kinetics of the process more accurately describes the pseudo-second-order model. It was shown that garlic peels and steam are good precursors for activated carbons production.

scholarly journals Evaluation and mechanism of ammonia nitrogen removal using sediments from a malodorous river

2018 ◽  
Vol 5 (3) ◽  
pp. 172257 ◽  
Author(s):  
Xing Chen ◽  
Xia Jiang ◽  
Wei Huang
Keyword(s):  
Removal Efficiency ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Ammonia Nitrogen ◽  
Main Function ◽  
N Removal ◽  
Maximum Sorption ◽  
Pseudo Second Order ◽  
Unpleasant Smell ◽  
Beijing China

Malodorous rivers are among the major environmental problems of cities in developing countries. In addition to the unpleasant smell, the sediments of such rivers can act as a sink for pollutants. The excessive amount of ammonia nitrogen (NH 3 −N) in rivers is the main factor that causes the malodour. Therefore, a suitable method is necessary for sediment disposition and NH 3 −N removal in malodorous rivers. The sediment in a malodorous river (PS) in Beijing, China was selected and modified via calcination (PS-D), Na + doping (PS-Na) and calcination–Na + doping (PS-DNa). The NH 3 −N removal efficiency using the four sediment materials was evaluated, and results indicated that the NH 3 −N removal efficiency using the modified sediment materials could reach over 60%. PS-DNa achieved the highest NH 3 −N removal efficiency (90.04%). The kinetics study showed that the pseudo-second-order model could effectively describe the sorption kinetics and that the exterior activated site had the main function of P sorption. The results of the sorption isotherms indicated that the maximum sorption capacities of PS-Na, PS-D and PS-DNa were 0.343, 0.831 and 1.113 mg g −1 , respectively, and a high temperature was favourable to sorption. The calculated thermodynamic parameters suggested that sorption was a feasible or spontaneous (Δ G  < 0), entropy-driven (Δ S  > 0), and endothermic (Δ H  > 0) reaction.

scholarly journals Sorption studies of Cd and Cu on Brazilian alluvial soils

2021 ◽  
Vol 16 (4) ◽  
pp. 1
Author(s):  
Vitor Hugo de Oliveira Barros ◽  
Artur Paiva Coutinho ◽  
Adriana Thays Araújo Alves ◽  
Severino Martins dos Santos Neto ◽  
Fernando Xavier de Assis ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Contaminant Transport ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Metal Mobility ◽  
Sorption Behavior ◽  
Transport Mechanisms ◽  
Alluvial Aquifers ◽  
Alluvial Sediment ◽  
Pseudo Second Order

The Local Production Arrangement, located in the Pernambuco’s Agreste state, has been significantly developing the region's economy. Despite its importance, industrial activity has caused relevant environmental concerns regarding the disposal of textile effluents, especially from industrial laundries. This waste is made up of many chemicals, and among them are various types of heavy metals. The evaluation of the sorption behavior of contaminant transport mechanisms such as heavy metals is essential to assess the risk of contamination of alluvial aquifers. This study evaluated the sorption of heavy metals (Cu and Cd) in an alluvial sediment deposit in the Capibaribe River. Kinetics and isotherm experiments allowed the analyses of Cu and Cd sorption. Kinetics sorption showed an equilibrium tendency after 16 h for Cu and 18 h for Cd and was better described by a pseudo-second order model. The isotherm data were adjusted to the Linear, Freundlich and Langmuir models. Both linear and Freundlich models satisfactorily described sorption isotherms for the two pollutants. The metals in the study represent a risk of contamination of the groundwater of alluvial aquifers, mainly due to physicochemical attributes of the soil, such as high sand content (85%), low MO (2.1 g kg-1) and alkaline pH (8.2). The environmental conditions decrease absorption and facilitate metal mobility, greatly increasing the environmental risks inherent in pollutant leaching. Cu showed a higher affinity with the soil studied in all assays performed compared with the results of the tests for Cd.

scholarly journals USE OF THE WALNUT SHELL (JUGLANS REGIA) AS A SORPTION MATERIAL TO REMOVE POLLUTANTS FROM NATURAL AND WASTE WATER

2020 ◽  
pp. 5-18
Author(s):  
Il'dar Gil'manovich Shaykhiyev ◽  
Svetlana Vasil'yevna Sverguzova ◽  
Karina Il'darovna Shaykhiyeva ◽  
Zhanna Anuarovna Sapronova
Keyword(s):  
Metal Ions ◽  
Juglans Regia ◽  
Aqueous Media ◽  
Sorption Isotherms ◽  
Walnut Shell ◽  
Order Model ◽  
Sorption Material ◽  
Pseudo Second Order ◽  
Dyes Adsorption ◽  
Sorption Characteristics

The literature data on the crushed walnut shells usageas a sorption material for metal ions, dyes and some organic compounds removal from aqueous media are summarized. Trees of the Juglans regia species are widespread in Russia; their shells are natural annually replenished material that is of industrial importance and can be used as sorption material for the extraction of many pollutants from aquatic environments. The paper gives a characteristic of the walnut shell, shows the indicators of the main substances that make up the shell (cellulose, lignin, hemicellululose), indicates the approximate specific surface area for BET and the content of functional groups. The results of studies of the adsorption of metal ions and and some dyes adsorption by walnut shellsare considered. The values of sorption indices for the studied pollutants are given. It is shown that it is possible to increase the sorption characteristics by chemical modification of the Juglans regia shell. It is determined that sorption isotherms in most cases are more fully described by the Langmuir model, and the process kinetics in all cases obeys the pseudo-second order model.

scholarly journals Radionuclides distribution and its sorption behavior in the Kara sea bottom sediments surface layer

2019 ◽  
Vol 64 (11) ◽  
pp. 1187-1195
Author(s):  
N. V. Kuzmenkova ◽  
V. V. Krupskaya ◽  
E. V. Duriagina ◽  
I. N. Semenkov ◽  
S. E. Vinokurov
Keyword(s):  
Bottom Sediments ◽  
Sea Water ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Kara Sea ◽  
Sorption Behavior ◽  
Freundlich Equation ◽  
Sea Bottom ◽  
Complexation Mechanism ◽  
Sorption Characteristics

The sorption characteristics of the Kara sea bottom sediments were investigated. The sediments were collected during scientific expedition of the R/V Akademik Mstislav Keldysh (Cruise AMK-66). The mineral and fraction composition of sediments was determined. It has been found that 137Cs sorbed predominantly by an ion exchange mechanism because of the clay minerals presence in the sediments. At the same time, 243Am and 90Sr sorbed from seawater by the surface complexation mechanism. The sorption kinetics for 243Am was established: about 20 hours, 137Cs: 2 hours, 90Sr: less than an hour. The sorption isotherms shows Cs and Am in experiments on marine and distilled water are described by the Henry equation. The Sr behavior in deionized water is described by the Langmuir equation, in the case of sea water, by the Freundlich equation.

Agar-agar impregnated on porous activated carbon as a new adsorbent for Pb(II) removal

2019 ◽  
Vol 79 (7) ◽  
pp. 1316-1326 ◽  
Author(s):  
Sabrine Saidi ◽  
Farouk Boudrahem ◽  
Idris Yahiaoui ◽  
Farida Aissani-Benissad
Keyword(s):  
Activated Carbon ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Second Order ◽  
Sorption Properties ◽  
Point Of Zero Charge ◽  
Impregnation Ratio ◽  
Pseudo Second Order ◽  
Liquid Displacement ◽  
Porous Activated Carbon

Abstract This paper presents a new sorbent, agar-agar (AA), impregnated on porous activated carbon (AC) – and its Pb(II) sorption properties. The influence of impregnation ratio (AA/AC) on the Pb(II) ion sorption properties is studied in order to optimize this parameter. The developed AC-AA shows substantial capability to sorb Pb(II) ions from aqueous solutions and 75% represents the optimal impregnation ratio. The AC-AA sorbent with impregnation ratio of 75% was characterized by a liquid displacement method, point of zero charge pH (pHPZC), scanning electron microscopy and Fourier transform infrared spectroscopy. The effect of parameters such as sorbent dosage, pH, agitation time and initial Pb(II) concentration on Pb(II) removal were examined. In addition, sorption kinetics and sorption isotherms were determined. The maximum uptake of Pb(II) was about 242 mg/g at 25 °C, pH 5 and initial Pb(II) concentration of 100 mg/L. The kinetic data were fitted to the models of pseudo-first-order and pseudo-second-order, and the experimental results follow closely the pseudo-second-order model. The results also reveal that the experimental equilibrium is very close to those predicted by the Freundlich model. The developed AC-AA exhibits high Pb(II) sorption capacity, offering possibilities for future practical use.

scholarly journals Review of Almond (Prunus Dulcis) Shell Use to Remove Pollutants from Aquatic Environments

2021 ◽  
Vol 11 (6) ◽  
pp. 14866-14880
Keyword(s):  
Activated Carbons ◽  
Aqueous Media ◽  
Prunus Dulcis ◽  
Order Model ◽  
Chemical Reagents ◽  
Adsorption Processes ◽  
Pseudo Second Order ◽  
Sorption Parameters ◽  
Kinetics Of ◽  
Sorption Characteristics

We summarized the literature data on using ground almond (Prunus dulcis) green hull and shell as sorption materials to remove various metal ions, dyes, and some organic compounds from aqueous media. This paper provides brief information on the amount of waste generated from processing almonds, their chemical composition, and ways of reuse. It gives the adsorption processes parameters and the values of sorption parameters for the studied pollutants. It was shown that almond shells’ sorption characteristics for various pollutants could be increased by chemical modification with various chemical reagents. It was determined that the Langmuir model more accurately describes the pollutants adsorption isotherms in most cases, and the kinetics of the process in all cases follows the pseudo-second-order model. It was shown that almond hulls and shells are a good precursor for activated carbons production.

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