Assessment the leaching characteristics and long-term leaching behavior of some radionuclides from synthesized zeolite cement matrix

2021 ◽  
Vol 143 ◽  
pp. 106357
Author(s):  
N.M. Sami ◽  
O.A. Abdel Moamen ◽  
M.I. El-Dessouky ◽  
A.M. El-Kamash
Keyword(s):  
Cement Matrix ◽  
Leaching Behavior ◽  
Leaching Characteristics

scholarly journals Sorption and leaching characteristics of pesticides in volcanic ash soils of Jeju Island, Korea

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Won-Pyo Park ◽  
Kong-Man Chang ◽  
Hae-Nam Hyun ◽  
Kyung-Hwan Boo ◽  
Bon-Jun Koo
Keyword(s):  
Volcanic Ash ◽  
Agricultural Soils ◽  
Distribution Coefficients ◽  
The Other ◽  
Jeju Island ◽  
European Standard ◽  
Leaching Behavior ◽  
Mobility Assessment ◽  
Leaching Characteristics ◽  
Volcanic Ash Soils

Abstract It is important to evaluate leaching behavior in agricultural soils to prevent the pollution of groundwater by pesticides. We identified the distribution coefficients (Kd) of ten pesticides with different physicochemical properties and compared their leaching characteristics using wick lysimeters from three distinct soil types on Jeju Island. The Kd values varied by pesticide and soil, but were within the range of 1.2 to 4231 L kg−1. Based on the European standard (Kd < 10 L kg−1), six pesticides (alachlor, ethoprophos, carbofuran, napropamide, tebuconazole, and etridiazole) were mobile in at least one tested soil, and their soil organic carbon affinity was ≤ 5.811. This value differed greatly from the other pesticides (16.533 and higher). The solubility of the six mobile pesticides was ≥ 32 mg L−1, which substantially differed from the other pesticides (≤ 0.71 mg L−1). Thus, we conclude that our mobility assessment, which is based on Kd values, can be used to predict the leaching of pesticides in the volcanic ash soils of Jeju Island. The use of pesticides should be strictly controlled to reduce the possibility of groundwater contamination.

scholarly journals An Evaluation of the Long-term Leaching Behavior of Heavy Metals from Granulated Incineration Ash

2020 ◽  
Vol 15 (3) ◽  
pp. 471-478
Author(s):  
Satoshi SHINOHARA ◽  
Tatsushi KAWAI ◽  
Daisuke ISHIGAMI ◽  
Junichi KAWABATA ◽  
Takeshi SATO ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Leaching Behavior

scholarly journals Changes in thermal stability of lignocelluloses waste aggregates long-term incorporated in composite

2021 ◽  
Vol 900 (1) ◽  
pp. 012042
Author(s):  
N Stevulova ◽  
A Estokova
Keyword(s):  
Thermal Stability ◽  
Alkaline Treatment ◽  
Cement Matrix ◽  
Scanning Calorimetry ◽  
Alkali Ions ◽  
Thermal Gravimetry ◽  
Pre Treatment ◽  
Surface Modified ◽  
Thermal Stability Of

Abstract This paper is addressed to comparative study of changes in thermal stability of surface-modified hemp-hurds aggregates long-term incorporated in bio-aggregate-based composites with the original ones before their integration into alternative binder matrix. In this study, the effectiveness of alkaline treatment of hemp hurds compared to the raw bio-aggregates as well as in relation to their behaviour when they are long-term incorporated in the MgO-cement environment is investigated. The differences in the thermal behaviour of the samples are explained by the changed structure of hemp hurds constituents due to the pre-treatment and long-term action of the alternative binder components on the bio-aggregates. Alkaline treatment increases thermal stability of hemp hurds compared to raw sample. Also long-term incorporation of hemp hurds in MgO-cement matrix had a similar effect in case of alkaline modified bio-aggregates. The more alkali ions present in the structure of hemp hurdssamples, the more ash is formed during their thermal decomposition studied by thermal gravimetry (TG) and differential scanning calorimetry (DSC).

scholarly journals Long-Term Leaching Behavior of Marine Sediment by a Large Column Percolation Test

2020 ◽  
Vol 69 (1) ◽  
pp. 53-56
Author(s):  
Toru INUI ◽  
Mutsumi HORI ◽  
Takeshi KATSUMI ◽  
Atsushi TAKAI
Keyword(s):  
Marine Sediment ◽  
Leaching Behavior ◽  
Percolation Test

Prediction of the Deterioration Depth of Concrete by Accelerating Calcium Leaching Test

2011 ◽  
Vol 365 ◽  
pp. 3-7 ◽  
Author(s):  
An Cheng ◽  
Sao Jeng Chao ◽  
Wei Ting Lin ◽  
Jia Liang Chang
Keyword(s):  
Nitrate Solution ◽  
Leaching Behavior ◽  
Calcium Leaching ◽  
Ammonium Nitrate Solution ◽  
Binder Ratio ◽  
Two Stages ◽  
Strength And Durability ◽  
Calcium Ion Leaching ◽  
Water Binder Ratio

The concrete is a solid and porous composite materials, when the concrete exposure to moisture environment for a long-term, the pore water will penetrate into concrete cause hydration products leaching. Leaching of calcium ions increase in porosity and resulting in harmful ions ingress into concrete to reduce strength and durability of concrete. The purpose of this study is to evaluate the effect of water-binder ratio on calcium ion leaching behavior of cement-based material. The ammonium nitrate solution was used to accelerate leaching process. Leaching duration was 56 days, 91 days and 140 days, respectively. The leaching depth and compressive strength were measured. The results showed that leaching resistance increased with a decrease in water/binder ratio. The leaching depth showed that leaching behavior of the specimens without minerals admixtures can be divided into two stages, the first stage was leaching of calcium hydroxide and than the C-S-H gel were leaching.

Nd- and Ce-doped ceramic-glass composites: chemical durability under aqueous conditions and Surface alteration in a moist clay medium at 90°C

2000 ◽  
Vol 663 ◽  
Author(s):  
P.J. Mcglinn ◽  
T. Advocat ◽  
E. Loi ◽  
G. Leturcq ◽  
J.P. Mestre
Keyword(s):  
Chemical Durability ◽  
Powdered Sample ◽  
Leaching Behavior ◽  
Glass Composites ◽  
Geological Repository ◽  
Trivalent Actinides ◽  
Surface Alteration ◽  
Ceramic Glass ◽  
Aqueous Conditions

ABSTRACTZirconolite-glass and sphene -glass specimens, doped with REE as simulants for trivalent actinides, were leached under two conditions. The first was a solubility test using a powdered sample in deionized water at an SA/V ratio of 200 cm−1, to examine the long-term leaching behavior of the composite materials. The other test was carried out in the presence of moist clay, to assess the degree of surface alteration of the composites in the presence of potential geological repository materials. Both tests were carried out at 90°C.

Modifying Brushite Cement Degradation Using Calcium Alginate Beads

2007 ◽  
Vol 361-363 ◽  
pp. 311-314 ◽  
Author(s):  
Liam M. Grover ◽  
Sarika Patel ◽  
Y. Hu ◽  
Uwe Gbureck ◽  
J.E. Barralet
Keyword(s):  
Calcium Alginate ◽  
Alginate Beads ◽  
The Body ◽  
Cement Matrix ◽  
Calcium Alginate Beads ◽  
Long Term Stability ◽  
The Matrix ◽  
Implant Degradation

The hydrolysis of brushite in calcium phosphate cements to form hydroxyapatite is known to result in the long term stability of the material in the body. It has previously been established that this hydrolysis reaction can be influenced by implant volume, media refreshment rate and media composition. In this study, the effect of macroporosity on the rate of degradation of the material is investigated. Macroporosity was incorporated into the material using calcium alginate beads mixed into the cement paste. The inclusion of the calcium alginate beads did not influence the degree of conversion of the material and allowed the incorporation of porosity at up to maximum of 57%. The macroporosity weakened the cement matrix (from 46.5 to 3.2 MPa). When aged the brushite in the macroporous cement dissolved completely from the matrix resulting in a weight loss of 60wt% in a period of 28 days. This suggests that the controlled incorporation of calcium alginate beads into brushite cements in vivo can be used to control implant degradation rate.

scholarly journals A REVIEW ON MECHANICAL PROPERTIES OF NATURAL FIBRE REINFORCED CONCRETE FOR RIGID PAVEMENTS

2021 ◽  
pp. 266-270
Author(s):  
M.Venkata Naga Prasad ◽  
Dr.J.Sridhar
Keyword(s):  
Low Cost ◽  
Natural Fibers ◽  
Natural Fibre ◽  
Cement Matrix ◽  
Rigid Pavements ◽  
Steel Bars ◽  
Coconut Coir ◽  
The Impact ◽  
Coconut Fibers

This study focuses on fiber reinforcement, specifically the use of jute and coir as a fiber reinforcing material in concrete. Natural fibers have been used to provide substantial toughness and strength in a very fragile cement matrix composite. It is necessary to make effective changes in this regard. Uses a very alkaline cement matrix to achieve durability. It is preferable to have a chemical composition that is clear. Reinforce the cement and change the surface of the fibers composite. The usage of jute fiber in this article is discussed. Concrete and the impact it has on the characteristics of the concrete it produces, for example this is an attempt to review the work that has just been completed. In the discipline, as well as to establish a foundation for future study in that case. It is critical to create low-cost building and reinforcing techniques that are suited for developing countries. If agricultural by-products like coconut coir can be used to replace steel bars as reinforcement, building costs can be reduced. Down significantly the purpose of this study is to evaluate the characteristics of coconut fibers. Species produced in India and their uses in many fields of engineering, notably civil engineering enhancing the long-term durability of concrete and mortar using engineering as a building material with the addition of coconut fibers the overall objective is to look into the possibility of utilizing domestic resources. Wastes for construction on a tiny scale a review of several researchers’ experiences utilizing is presented in this publication. The performance of coconut coir as a reinforcing component is explored in depth.

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