TRANSPORTABILITY OF IODIDE IN SOME ORGANIC SOIL MATERIALS FROM THE PRECAMBRIAN SHIELD OF ONTARIO

1987 ◽  
Vol 67 (2) ◽  
pp. 353-366 ◽  
Author(s):  
J. T. KOCH ◽  
B. D. KAY
Keyword(s):  
Rate Constant ◽  
Nuclear Power ◽  
Power Plants ◽  
Organic Soil ◽  
Zero Order ◽  
Organic Soils ◽  
Order Kinetic ◽  
Precambrian Shield ◽  
Zero Order Kinetics ◽  
Order Kinetic Model

Knowledge of the transportability of the long-lived and potentially hazardous nuclide 129I in organic soils is important for evaluating the concept of safely disposing of radioactive fuel waste from Canadian nuclear power plants. The current concept for the disposal of nuclear fuel waste in Canada involves its emplacement in a vault mined 500–1000 m deep in a stable plutonic rock formation in the Canadian Shield. Degradation over time of components of the vault could lead to the entry of 129I to organic soils from contaminated groundwater. Twelve samples from nine organic soils, widely different in degree of humification and in parent vegetation, were collected from the Precambrian Shield of Ontario. Batch reaction techniques were used to measure the kinetics of iodide loss from solution in the presence of the organic soil materials. All soil materials exhibited an initial constant rate of iodide loss from solution (zero-order kinetics). The rate constants for iodide loss for the different soil materials ranged from 1.44 to 36.0 mg iodide per kilogram soil per day. The natural I content for the organic soil samples was positively correlated to the measured rate constant. It is concluded that the rate constant for iodide, as measured in the laboratory, is related to the processes that operate in the field to immobilize I under natural conditions, and that a zero-order kinetic model is appropriate for describing the loss of iodide from the solution phase in an organic soil. Key words: Organic soils, iodide-129, groundwater, transport kinetics, immobilization

scholarly journals Novel Hydroxyapatite Beads for the Adsorption of Radionuclides from Decommissioned Nuclear Power Plant Sites

2021 ◽  
Vol 11 (4) ◽  
pp. 1746
Author(s):  
Thi Nhung Tran ◽  
Junho Kim ◽  
Joo-Sung Park ◽  
Youngkun Chung ◽  
Jaemun Han ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Polyvinyl Butyral ◽  
Order Kinetic ◽  
Practical Applications ◽  
Adsorption Mechanisms ◽  
Rate Limiting Step ◽  
Aqueous Environments ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Although a powdered form of hydroxyapatite (p-HdA) has been studied for the adsorption of heavy metals that contaminate the restoration sites of decommissioned nuclear power plants, most of the studies are limited in the laboratory due to the head loss and post-separation in practical applications. Herein, we fabricated a porous bead form of HdA (b-HdA) as a novel adsorbent for removing radionuclides from aqueous environments via a facile synthesis by mixing the p-HdA precursor and polyvinyl butyral (PVB) as a binder and added a sintering process for the final production of a porous structure. The spherical b-HdA with an approximate diameter of 2.0 mm was successfully fabricated. The effectiveness of the b-HdA at removing Co(II) was investigated via the adsorption equilibrium at various experimental temperatures. The b-HdA exhibited the adsorption capacity for Co(II) ions with a maximum of 7.73 and 11.35 mg/g at 293 K and 313 K, respectively. The experimental kinetic data were well described using a pseudo-second-order kinetic model, and the adsorption mechanisms of Co(II) onto the b-HdA were revealed to be a chemisorption process with intraparticle diffusion being the rate-limiting step. In addition, the competitive adsorption onto the b-HdA with the order of U(VI) > Co(II) > Ni(II) > Sr(II) > Cs(I) was also observed in the multi-radionuclides system. Considering the advantages of the size, applicability to the continuous-flow column, and the easy separation from treated water, the b-HdA can be an excellent absorbent with high potential for practical applications for removing radionuclides.

Browning Reaction Kinetics of High Hydrostatic Pressure-Treated Peach Puree during Storage

2011 ◽  
Vol 7 (4) ◽  
Author(s):  
Thamer Abdul Kadir Khalil ◽  
Mazin Ibrahem Al-Zubaidy ◽  
Omer Fawzi Abdulaziz
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Temperature Scale ◽  
Zero Order ◽  
Order Kinetic ◽  
Browning Reaction ◽  
Color Development ◽  
Order Kinetic Model ◽  
Pressure Scale ◽  
Kinetics Of

Kinetics of browning color development, described as browning index (BI), of peach puree subjected to high hydrostatic pressure (HHP) treatments (400, 500, and 600 MPa/1 and 3 min) during 6 weeks of storage at 4 and 20°C were investigated. This research was conducted to modify the use of pressure scale instead of temperature scale in calculating the kinetic parameters of BI values in peach puree samples. The increase in BI values followed the zero-order kinetic model. The highest activation energy (Ea) was experienced with HHP treatment (400, 500, and 600 MPa/3 min) of peach puree samples stored at 4°C.

scholarly journals CHARACTERISTICS OF ASCORBIC ACID RELEASE FROM TPP-CROSSLINKED CHITOSAN/ALGINATE POLYELECTROLYTE COMPLEX MEMBRANES

2018 ◽  
Vol XXIII ◽  
pp. 76-87 ◽  
Author(s):  
Magdalena Gierszewska ◽  
Jadwiga Ostrowska-Czubenko ◽  
Ewelina Chrzanowska
Keyword(s):  
Ascorbic Acid ◽  
Kinetic Model ◽  
Polyelectrolyte Complex ◽  
Zero Order ◽  
Order Kinetic ◽  
Initial Burst ◽  
First Order ◽  
Order Kinetic Model ◽  
Acid Release ◽  
Release Data

Chitosan/alginate polyelectrolyte complex membranes (Ch/Alg) additionally cross-linked with tripolyphosphate (TPP) and containing ascorbic acid (AA) were prepared. The dynamic swelling behaviour of Ch/Alg/TPP and ascorbic acid release from the membrane were characterised in different buffer solutions. It has been found that the pH of the buffer solution affects the swelling and release behaviour of AA. Ascorbic acid release, observed over a period of 360 min, exhibited a biphasic pattern, characterised by a fast initial burst release, followed by a slow, sustained release. Different mathematical models were used to study the kinetics and transport mechanism of AA from Ch/Alg/TPP hydrogels. Drug release data were fitted to the zero order kinetic model and first order kinetic model. To characterise the drug mechanism, the release data were fitted to the Higuchi and Korsmeyer-Peppas equations. The initial burst AA release followed zero order kinetics and was quasi-Fickian in nature. The second step of AA release followed first order kinetics.

scholarly journals Efecto del proceso de acidificación sobre el color de queso cottage

2017 ◽  
Vol 28 (3) ◽  
pp. 677 ◽  
Author(s):  
Ramiro Vargas-Uscategui ◽  
Anthony Arenas-Clavijo ◽  
Juan Sebastian Ramírez-Navas
Keyword(s):  
Linear Correlation ◽  
Color Change ◽  
Correlation Coefficients ◽  
Cottage Cheese ◽  
Order Kinetic ◽  
First Order ◽  
Zero Order Kinetics ◽  
Significant Difference ◽  
Order Kinetic Model ◽  
Kinetics Order

The objective of this study was to evaluate the color change of cottage cheese made with different processes of acidification (enzymatic and chemical) over time. The research was conducted at Universidad del Valle (Cali, Colombia) laboratories, between 2014 and 2015. Microbial rennet and lactic culture (CC) were used for enzymatic coagulation method (control cheese), and solutions of citric acid (CA) and phosphoric acid (PA) were used for the chemical method. The physicochemical properties were determined, and color behavior was analyzed over nine days of storage. Significant differences in acidity and moisture for the three coagulants were found. In the color plane, it was observed that the final and initial points of the coordinates a * and b * are close together; changes in color were mostly due to changes in brightness. The speed at which brightness decreased in the three cheeses matches kinetics order to zero and one. The first order kinetics displayed in higher values of linear correlation coefficients (R), AC: 0.8410 ± 0.0533; AF: 0.8390 ± 0.0847, and CC: 0.8717 ± 0.0256. The kinetics of change in color also adjusted correctly to zero and the first order kinetic model; that is, no significant difference (p <0.05) between these results. However, the speed of color change for the three cheeses had a slightly higher setting for zero order kinetics, as evidenced by the linear correlation coefficient (R) results, AC: 0.8800 ± 0.0205; AF: 0.8543 ± 0.0099, and CC: 0.7982 ± 0.0605.

Note. Hydrolysis of Onion and Kinetics of Non-Enzymatic Browning of its Hydrolysate

2004 ◽  
Vol 10 (1) ◽  
pp. 41-44 ◽  
Author(s):  
J. M. Kim ◽  
K. S. Ra ◽  
H. J. Suh
Keyword(s):  
Zero Order ◽  
Total Sugar ◽  
Effect Of Temperature ◽  
Enzymatic Browning ◽  
Order Kinetic ◽  
Arrhenius Model ◽  
Browning Index ◽  
Order Kinetic Model ◽  
Kinetics Of ◽  
Hydrolysis Of

Enzymatic hydrolysis of onion was performed by three different commercial enzyme products (Econase, Rapidase and Viscozyme) for preparation of onion hydrolysates. The hydrolysis yield was determined through the analysis of reducing and total sugar contents in final hydrolysates. Total sugar contents after 2 h-hydrolysis with Econase, Rapidase and Viscozyme were 59.6, 64.1 and 62.2 mg/mL, respectively, and reducing sugar contents of 28.5, 42.7 and 35.9 mg/mL in the same order. According to these results Rapidase was more suitable for the hydrolysis of onion than the other enzymatic products. The effect of temperature on non-enzymatic browning reaction kinetics of the onion hydrolysate was determined. The browning index variation was adequately described by both the first- and the zero-order kinetic. However, the zero-order kinetic model was preferred because its fitting was higher. The values of kinetic constants were 0.081 (60 C), 0.185 (70 C), 0.270 (80 C) and 0.377 (90 C). According to the Arrhenius model, the activation energy for browning index in the range 60–90 C was 21.9 kJ/mol.

scholarly journals Nitrogen Removal in a Horizontal Subsurface Flow Constructed Wetland Estimated Using the First-Order Kinetic Model

2016 ◽  
Author(s):  
Lijuan Cui ◽  
Wei Li ◽  
Yaqiong Zhang ◽  
Jiaming Wei ◽  
Yinru Lei ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Rate Constant ◽  
Constructed Wetland ◽  
Rate Constants ◽  
Removal Rate ◽  
Order Kinetic ◽  
First Order ◽  
N Removal ◽  
Order Kinetic Model ◽  
Beijing China

We monitored the water quality and hydrological conditions of a horizontal subsurface constructed wetland (HSSF-CW) in Beijing, China, for 2 years. We simulated the area rate constant and the temperature coefficient with the first-order kinetic model. We examined the relationships between the nitrogen (N) removal rate, N load, seasonal variations in the N removal rate, and environmental factors, such as the area rate constant, temperature, and dissolved oxygen (DO). The effluent ammonia (NH4+-N) and nitrate (NO3&minus;-N) concentrations were significantly lower than the influent concentrations (p&lt;0.01, n=38). The NO3&minus;-N load was significantly correlated with the removal rate (R2=0.9566, p&lt;0.01), but the NH4+-N load was not correlated with the removal rate (R2=0.0187, p&gt;0.01). The area rate constants of NO3&minus;-N and NH4+-N at 20 &deg;C were 27.01&plusmn;26.49 and 16.63&plusmn;10.58 m∙yr&minus;1, respectively. The temperature coefficients for NO3&minus;-N and NH4+-N were estimated at 1.0042 and 0.9604, respectively. The area rate constants for NO3&minus;-N and NH4+-N were not correlated with temperature (p&gt;0.01). The NO3&minus;-N area rate constant was correlated with the corresponding load (R2=0.9625, p&lt;0.01). The NH4+-N area rate was correlated with DO (R2=0.6922, p&lt;0.01), suggesting that the factors that influenced the N removal rate in this wetland met Liebig's law of the minimum.

scholarly journals EFEKTIVITAS ADSORPSI LOGAM Pb2+ DAN Cd2+ MENGGUNAKAN MEDIA ADSORBEN CANGKANG TELUR AYAM

Konversi ◽  
2018 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Erna Wati Ibnu Hajar ◽  
Reny Suryani Sitorus ◽  
Novi Mulianingtias ◽  
Fransiska Jawa Welan
Keyword(s):  
Adsorption Kinetics ◽  
Metal Ion ◽  
Chemical Activation ◽  
Order Kinetic ◽  
Chicken Egg ◽  
Physical Chemical ◽  
Zero Order Kinetics ◽  
Order Kinetic Model ◽  
Egg Shells ◽  
The Difference

Abstrak-Cangkang telur merupakan bagian terluar dari telur yang berfungsi memberikan perlindungan bagi komponen-komponen isi telur dari kerusakan secara fisik, kimia maupun mikrobiologis. Setiap cangkang telur memiliki 10.000-20.000 pori-pori sehingga diperkirakan dapat menyerap suatu solute dan dapat digunakan sebagai adsorben untuk menjerap logam seperti Pb2+ dan Cd2+. Tujuan dari penelitian ini untuk mengetahui efektivitas cangkang telur ayam sebagai adsorben dengan variasi waktu kontak yaitu 15, 30, 45 menit dan perbedaan massa adsorben yaitu 3, 6, dan 9 gram, serta untuk mengetahui model kinetika adsorpsi yang tepat pada penjerapan logam Pb2+ dan Cd2+. Penelitian ini diawali dengan pengecilan ukuran cangkang telur ayam menjadi 200 mesh, kemudian dilakukan aktivasi kimia dengan merendam cangkang telur ayam dengan larutan HCl 0,1 M. Selanjutnya dilakukan proses adsorpsi dengan mengontakkan adsorben dengan larutan sampel berdasarkan perbedaan waktu dan massa adsorben, konsentrasi larutan hasil adsorpsi kemudian dianalisa dengan menggunakan AAS. Hasil penelitian menunjukkan bahwa % efektivitas penjerapan Pb2+ tertinggi yang dapat dihasilkan dari adsorben cangkang telur ayam yaitu 91,1242% pada berat adsorben 9 gram dengan waktu pengontakan 15 menit, sedangkan pada penjerapan Cd2+ yang dapat dihasilkan dari adsorben cangkang telur ayam yaitu 99,9515% pada berat adsorben 9 gram dengan waktu pengontakan 15 menit. Kinetika adsorpsi penjerapan Pb2+ pada 3, 6, dan 9 gram mengikuti model kinetika orde 2, sedangkan kinetika adsorpsi penjerapan Cd2+ pada 3 gram mengikuti model kinetika orde 0. Kata kunci: Cangkang Telur Ayam, Efektivitas, Kinetika Adsorpsi Abstract-An egg shells is the part of the egg which serves to provide protection for the components of the egg contents from damage because of physical, chemical and microbiological activity. Egg shells has 10,000-20,000 pores that are expected to absorb a solute and can be used as adsorbent to adsorb metals ion such as Pb2+ and Cd2+. The aims of this study were to examine the effectivity of chicken egg shells as adsorbent by variation of contacting time ie 15, 30, 45 mins and the difference in mass of adsorbent which are 3, 6  and 9 grams, as well as to determine the kinetics model of adsorption on metal ion of Pb2+ and Cd2+. This study begins with downsizing the size of chicken egg shells become to 200 mesh, then was performed a chemical activation by soaking the chicken egg shells with 0.1 M HCl. The adsorption was performed by contacting the adsorbent with a solution of the sample is based on the contacting time and mass of adsorbent, the concentration of the resulting solution adsorption then analyzed by AAS. The results showed that the % effectiveness adsorption of the Pb2+ highest that can be produced from chicken egg shells adsorbent that is 91.1242% by weight of 9 gram adsorbent by contacting time 15 mins, while on the adsorption Cd2+ can be produced from chicken egg shells adsorbent is 99.9515% on the weight of the adsorbent 9 grams with time contacting the 15 minutes. Pb2+ adsorption kinetics at 3, 6  and 9 grams following the second-order kinetic model, whereas the adsorption Cd2+ adsorption kinetics at 3 grams following the model zero-order kinetics. Keywords: Chicken Egg Shells, Effectiveness, Adsorption Kinetics

MICROBIAL PARTICIPATION IN IODIDE REMOVAL FROM SOLUTION BY ORGANIC SOILS

1989 ◽  
Vol 69 (1) ◽  
pp. 127-135 ◽  
Author(s):  
J. T. KOCH ◽  
D. B. RACHAR ◽  
B. D. KAY
Keyword(s):  
Gamma Irradiation ◽  
Key Words ◽  
Microbial Activity ◽  
Nuclear Fuel ◽  
Organic Soil ◽  
Organic Soils ◽  
Γ Radiation ◽  
Precambrian Shield ◽  
Biological Removal ◽  
Nuclear Fuel Waste

The migration of the long-lived nuclide 129I in the biosphere may be changed if the nuclide passes through an organic soil (organic soils often occur in topographical depressions where groundwater generally enters the biosphere). The reactivity of I and, hence, its transportability may be altered in organic soils by processes in which microorganisms participate. The aim of this study, therefore, was to test for microbial participation in these processes. Twelve samples of nine organic soils, varying widely in degree of humification and in parent vegetation, were used in this study and were collected mainly on the Precambrian Shield of Ontario. Experiments were conducted using glucose, thymol, and γ radiation (60Co) to stimulate or suppress microbial activity in the soils. The presence of glucose generally increased I− removal from solution whereas thymol depressed removal. Gamma irradiation of the soils decreased I− removal from solution in all samples, but 100 kGy terminated I− removal in only one sample. If the removal of I− from solution after exposing the soils to 100 kGy of γ radiation is termed nonbiological, the biological removal of I− from solution exceeded the non-biological in all samples but one. The natural I content of the soils was directly related to both the biologically and the nonbiologically mediated processes of I− removal from solution. We conclude that microorganisms play an important role in the processes of I− removal from solution in organic soils of the Precambrian Shield of Ontario. Key words: Nuclear fuel waste, 129I, groundwater, microorganisms, enzymes, mobility

Sign in / Sign up

Export Citation Format

Share Document