scholarly journals Sorption of Polycyclic Musks on Soil Components of Different Aggregate Sizes: The Effect of Organic-mineral Interactions

2021 ◽  
Author(s):  
Qingwei Bu ◽  
Hongmei Cao ◽  
Dongkui Wu ◽  
Ming Zhou
Keyword(s):  
Sorption Process ◽  
Potential Ecological Risk ◽  
Batch Experiments ◽  
Valuable Contribution ◽  
Dual Effect ◽  
Aggregate Fraction ◽  
Polycyclic Musks ◽  
Organic Mineral ◽  
Aggregate Fractions ◽  
Soil Components

Abstract Polycyclic musks (PCMs) in soil environments have been of increasing concern because of their potential characteristic of persistence, bioaccumulation, and potential ecological risk. However, little is known about their fate process in soil environments. Here, we selected two PCMs as sorbates, namely galaxolide (HHCB) and tonalite (AHTN), to explore their sorption process in soils. Sorption batch experiments with six nature soils and their different aggregate fractions were carried out to elucidate the effect of organic–mineral interactions in different aggregate sizes on sorption of these two PCMs. The possible causes of variation in the organic carbon-normalized partition coefficient (Koc) for HHCB and AHTN have been investigated. The results indicated that the sorption contribution to different aggregate fractions to the overall sorption was dependent on both Koc and content of each aggregate fraction. The strong influence of organic–mineral interactions on Koc was evidenced by the large variation in Koc on HF-treatment for both bulk soils and their different aggregate fractions. This study verified the dual effect of organic–mineral interactions among selected soils. By comparing the measured and theoretical overlay ∆ Koc values, it was indicated that the interaction between particles of different size fractions will also affect Koc variation. This study represents a valuable contribution to the understanding of the fate processes and behaviors of PCMs in soil and its implication on the risk assessment.

Total extracellular surfactant is increased but abnormal in a rat model of gram-negative bacterial pneumonia

2002 ◽  
Vol 283 (3) ◽  
pp. L655-L663 ◽  
Author(s):  
Thomas A. Russo ◽  
Lori A. Bartholomew ◽  
Bruce A. Davidson ◽  
Jadwiga D. Helinski ◽  
Ulrike B. Carlino ◽  
...  
Keyword(s):  
Rat Model ◽  
Lung Surfactant ◽  
Surfactant Protein ◽  
Phospholipid Content ◽  
Aggregate Fraction ◽  
Protein Levels ◽  
Pulmonary Damage ◽  
Aggregate Fractions

An in vivo rat model was used to evaluate the effects of Escherichia coli pneumonia on lung function and surfactant in bronchoalveolar lavage (BAL). Total extracellular surfactant was increased in infected rats compared with controls. BAL phospholipid content in infected rats correlated with the severity of alveolar-capillary leak as reflected in lavage protein levels ( R2= 0.908, P < 0.0001). Western blotting showed that levels of surfactant protein (SP)-A and SP-D in BAL were significantly increased in both large and small aggregate fractions at 2 and 6 h postinstillation of E. coli. SP-B was also increased at these times in the large aggregate fraction of BAL, whereas SP-C levels were increased at 2 h and decreased at 6 h relative to controls. The small-to-large (S/L) aggregate ratio (a marker inversely proportional to surfactant function) was increased in infected rats with >50 mg total BAL protein. There was a significant correlation ( R2= 0.885, P < 0.0001) between increasing S/L ratio in BAL and pulmonary damage assessed by total protein. Pulmonary volumes, compliance, and oxygen exchange were significantly decreased in infected rats with >50 mg of total BAL protein, consistent with surfactant dysfunction. In vitro surface cycling studies with calf lung surfactant extract suggested that bacterially derived factors may have contributed in part to the surfactant alterations seen in vivo.

Kinetics and equilibria of Metribuzin sorption on model soil components

2000 ◽  
Vol 80 (2) ◽  
pp. 301-307 ◽  
Author(s):  
R. Sha'ato ◽  
E. Buncel ◽  
D. G. Gamble ◽  
G. W. vanLoon
Keyword(s):  
Humic Acid ◽  
Clay Minerals ◽  
Organic Contaminants ◽  
Solid Phase ◽  
Sorption Process ◽  
Model Soil ◽  
Hydrous Oxides ◽  
Soils And Sediments ◽  
Soil Components ◽  
Ultimate Fate

Sorption to solid phase materials is known to significantly affect the transport, bioavailability and ultimate fate of organic contaminants in soils and sediments. In order to develop a complete description of the fate of these compounds, it is necessary to understand both equilibrium interactions and rates and mechanisms of the sorption processes. The object of the present study was to investigate both these factors with respect to the sorption of metribuzin on model soil components, including the clay minerals kaolinite and montmorillonite, amorphous iron and aluminum hydrous oxides and humic acid. In all cases, uptake followed a similar course; there was a very rapid initial sorption process followed by continued uptake at a much slower rate. Rate constants for the slow sorption were smallest for the clay minerals, intermediate for the hydrous oxides and greatest for humic acid. Labile sorption capacities for metribuzin on the humic acid and clay minerals were also determined; the organic material had the largest capacity, and montmorillonite had a greater capacity than kaolinite. Key words: Metribuzin, sorption, clay minerals, humic material

scholarly journals Sepiolite functionalized with N-[3-(trimethoxysilyl)propyl]-ethylenediamine triacetic acid trisodium salt. Part II: Sorption of Ni2+ from aqueous solutions

2016 ◽  
Vol 81 (2) ◽  
pp. 197-208
Author(s):  
Slavica Lazarevic ◽  
Ivona Jankovic-Castvan ◽  
Bojan Jokic ◽  
Djordje Janackovic ◽  
Rada Petrovic
Keyword(s):  
Ph Value ◽  
Sorption Isotherms ◽  
Sorption Process ◽  
Equilibration Time ◽  
Batch Experiments ◽  
Temperature Dependent ◽  
Sorption Equilibrium ◽  
Covalent Grafting ◽  
Pseudo Second Order ◽  
Trisodium Salt

sorption of Ni2+ on the sepiolite functionalized by covalent grafting of N-[3-(trimethoxysilyl)propyl]ethylenediamine triacetic acid trisodium salt, MSEAS, was studied in batch experiments as a function of the initial metal concentration, the equilibration time, pH value, and temperature. The modification of sepiolite resulted in an enhanced Ni2+ retention with a capacity of 0.261 mmol/g at 298 K. The retention of Ni2+ ions occurred dominantly by specific sorption and exchange of Mg2+ ions from the sepiolite structure. The sorption process followed pseudo-second-order kinetics. The sorption equilibrium results were best described by the non-linear form of the Langmuir Sorption Equation. The values of the thermodynamic parameters (enthalpy, free energy and entropy) were calculated from temperature dependent sorption isotherms and these values showed that the sorption of Ni2+ onto modified sepiolite was endothermic.

scholarly journals Use of La-, Ce-, Y-, Fe- bentonites for Removing Phosphate Ions from Aqueous Media

2017 ◽  
Vol 61 (1) ◽  
pp. 27 ◽  
Author(s):  
Dóra Buzetzky ◽  
Noémi M. Nagy ◽  
József Kónya
Keyword(s):  
Activation Energy ◽  
Ion Exchange ◽  
Aqueous Media ◽  
Sorption Process ◽  
Similar Amount ◽  
Batch Experiments ◽  
Phosphate Sorption ◽  
Phosphate Ions ◽  
Exchange Adsorption

Clays play an important role in the environment. By removing cations and anions either through ion exchange, adsorption and precipitation, or all these combined, they can act as natural decontaminating agents of numerous pollutants. In this study, four modified bentonites (La-, Ce-, Y-, Fe-bentonite) were prepared and characterized, and their phosphate sorption capabilities were measured in batch experiments. Equilibrium times were also examined. The activation energy of the sorption process was calculated. The La- , Ce- and Y-bentonite can bind similar amount of phosphate ions, while iron-bentonite can bind only half of it compared to La-, Ce- and Y-bentonite.

scholarly journals Lightweight concrete with copper slag waste as sand substitution

2018 ◽  
Vol 163 ◽  
pp. 03006 ◽  
Author(s):  
Roman Jaskulski ◽  
Wojciech Kubissa
Keyword(s):  
Compressive Strength ◽  
Lightweight Concrete ◽  
Cement Content ◽  
Copper Slag ◽  
Fine Aggregate ◽  
River Sand ◽  
Aggregate Fraction ◽  
Aggregate Fractions ◽  
Hydrostatic Weighing ◽  
Slag Waste

The paper presents results of tests of lightweight concrete made with copper slag waste material as fine aggregate (fraction 0 – 2 mm) and two types of light aggregate (fractions > 2 mm). Six series of concrete with three w/c ratios (0.50, 0.55 and 0.60) and two variants of cement content (200 kg/m3 and 300 kg/m3) were manufactured. Reference concretes were also prepared in which copper slag waste was replaced by the same mass of river sand. To maintain similar densities of mixtures with copper slag in comparison to those with sand mutual proportions of both lightweight aggregates were modified. On concrete specimens compressive strength was tested as well as the open porosity was determined by drying to stable mass at 65°C. The concrete bulk density in saturated and dried state was also determined using hydrostatic weighing. The obtained results were compared with the results of the reference concrete tests. Results have shown that replacing sand with copper slag waste in lightweight concrete does not negatively affect their strength but may slightly increase their porosity.

New Asthma Drug Has Dual Effect, Expert Says

2007 ◽  
Vol 41 (5) ◽  
pp. 57
Author(s):  
TIMOTHY F. KIRN
Keyword(s):  
Dual Effect ◽  
Asthma Drug

Study Of Structure Formation Of Organic-Mineral Compositions With Fibrous Filler By Electron Microscopy Method

2019 ◽  
pp. 41-47
Keyword(s):  
Electron Microscopy ◽  
Structure Formation ◽  
Mineral Composition ◽  
Bending Strength ◽  
Cement Stone ◽  
Hydrated Cement ◽  
Fibrous Filler ◽  
Organic Mineral ◽  
Microscopy Method ◽  
Mineral Compositions

The article presents the study of processes of structure formation of cement stone and products of hardening of organic-mineral compositions with fibrous filler (shavings) by the electronic scanning microscopy method. It is established that the additive-free cement stone at the age of 28 days has a dense and homogeneous structure, consists of calcium hydro-silicates, Portlandite and calcite - newgrowths characteristic for cement systems. Cellulose fibers, which make up the bulk of the substance of shavings, are sufficiently active, which determines the high adhesion of the hydration products of the cement binder to their surface. It is shown that the introduction of shavings into the organo-mineral composition leads to inhibition of cement hydration processes. Organo-mineral compositions with different shavings content (two compositions) were analyzed. The first composition is characterized by a fairly dense structure, the cement stone consists of globular nanoscale nuclei of hydrosilicates, Portlandite and calcite. The second composition has a loose porous structure, cement stone consists of non-hydrated cement grains, newgrowths are represented by calcite and vaterite. The structure of the contact zone "osprey fiber-cement stone" in the organo-mineral composition of the first composition indicates a good adhesion of the filler surface with the phases of hydrated cement. The use of shavings as a fibrous filler (the first composition) increases the tensile and bending strength, as well as the wear resistance of organo-mineral compositions. The data obtained by scanning electron microscopy are confirmed by the results of studying the processes of structure formation of cement stone by quantitative x-ray phase analysis.

Dynamics of CO2 emission from chernozems under agricultural use

2017 ◽  
Vol 4 (3) ◽  
pp. 43-49
Author(s):  
M. Miroshnychenko ◽  
O. Siabruk
Keyword(s):  
Carbon Dioxide ◽  
Agricultural Practices ◽  
Growing Season ◽  
Warm Period ◽  
Direct Seeding ◽  
Soil Tillage ◽  
Plant Residues ◽  
Hydrothermal Conditions ◽  
Organic Mineral ◽  
Mineral System

Aim. The comparison of the effect of hydrothermal conditions and various agricultural practices on the emission of CO 2 from chernozems in the Left-Bank Forest-Steppe of Ukraine. Methods. The dynamics of the intensity of carbon dioxide emissions from chernozem calcic (typical chernozem – in Ukrainian classifi cation) was studied during the growing season of 2011–2012. The observations were based on two fi eld experiments with various methods of soil till- age (6–7 years from the beginning of the experiment) and fertilization systems (21–22 years from the beginning of the experiment). Particularly, plowing at 20–22 cm, disking at 10–12 cm, cultivation at 6–8 cm and direct seeding using Great Plains drill were studied among the soil tillage methods. Mineral system (N 45 P 50 K 45 ), organic system (manure 8 t/ha) and combined organic-mineral system (manure 8 t/ha + N 45 P 50 K 45 ) were studied among fertilization systems. The intensity of CO 2 fl ux was determined using the non-stationary respiratory chambers by the alkaline absorption method, with averaging of the results during the day and the frequency of once a month. Results. During the warm period, the emission of carbon dioxide from the soil changes dynamically depending on temperature and humidity. The maximum of emission coincides with the periods of warm summer showers in June-July, the minimum values are characteristic for the late autumn period. The total emission losses of carbon in chernozems over the vegetation period ranged from 480 to 910 kg/ha and varied depending on the methods of tillage ± (4.0–6.0) % and fertilization systems ± (3.8–7.1) %. The changes in the intensity of CO 2 emission from the soil under different methods of soil tillage are associated with hydrothermal regime and the depth of crop residues location. The biggest difference is observed im- mediately after tillage, but in the spring period the differences are only 12–25 %, and after drying of the top layer of soil become even less. Direct seeding technology provides the greatest emission of CO 2 from chernozem, which is fa- cilitated by better water regime and more complete mineralization of plant residues on the soil surface. Annual losses of carbon are the least under disking of soil at 10–12 cm. The changes in the intensity of CO 2 emission from the soil under different fertilization systems are associated with the involvement of the additional organic matter from plant residues and manure to the microbiological decomposition. The greatest emission was observed under the organic- mineral fertilization system, which increased the loss of carbon by 7–8 % in comparison with the mineral system in the unfavorable hydrothermal year and by 11–15 % in the more favorable year. These differences are observed mainly during the fi rst half of the growing season when there is a clear tendency to increase the intensity of soil respiration. Conclusions. The hydrothermal conditions of the warm period of the year are decisive in the formation of the CO 2 emission fl ow from chernozems. Due to the improvement of agricultural practices, emissions might be reduced but not more that by 15 % of natural factor contribution.

DAG Accumulation due to Type 1 DGK Inhibition Has Contradictory Dual Effect on Ca2+Signaling in Pancreatic ß Cells

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 328-OR
Author(s):  
TOSHIAKI SAWATANI ◽  
YUKIKO K. KANEKO ◽  
TOMOHISA ISHIKAWA
Keyword(s):  
Dual Effect
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