Kinetics of nonexchangeable potassium release from a Tropaquept as influenced by long-term cropping, fertilisation, and manuring

Soil Research ◽  
1999 ◽  
Vol 37 (2) ◽  
pp. 317 ◽  
Author(s):  
Ch. Srinivasa Rao ◽  
Anand Swarup ◽  
A. Subba Rao ◽  
V. Raja Gopal
Keyword(s):  
Rate Constants ◽  
Soil Samples ◽  
Continuous Cropping ◽  
Order Kinetic ◽  
Acid Media ◽  
First Order ◽  
Kinetics Of ◽  
K Release ◽  
Nonexchangeable Potassium

We studied the effect of long-term cropping, fertilisation, and manuring on kinetics of nonexchangeable potassium (K) release from a Tropaquept in 0·01 M CaCl2 and 0·01 M citric acid media under a rice–rice cropping system in an experiment started in 1971. Under continuous cropping, the cumulative K release from the soil decreased considerably in all treatments both with and without K application. The lowest K release from the nonexchangeable fraction of the soil was observed in the 100% optimum nitrogen+phosphorus (NP) treatment (55 and 34 mg/kg in 1980 and 1994, respectively), while the highest K release was in the 100% optimum NPK+farmyard manure (FYM) treatment (99 and 66 mg/kg in 1980 and 1994, respectively). Statistical analysis showed that a parabolic diffusion equation best described the K release from soil samples collected in 1980 (r = 0·989–0·992) and 1994 (r = 0·994–0·998), thereby indicating that the K release was a diffusion-controlled exchange. A first-order kinetic equation also explained K release behaviour from the soil samples in both years (r = 0·988 for 1980 and 0·971–0·988 for 1994 samples). The maximum and minimum values of rate constants were found for the 100% NPK+FYM and 100% NP treatments, respectively. A reduction in rate constants was observed with further cropping until 1994, with or without K supply, with the largest reduction being observed in the 100% NP treatment. Kinetic parameters of the first-order equation showed significant correlation with conventional measures of nonexchangeable K forms: 3 M H2SO4 and boiling 1 M HNO3 extractable K. From these results it is concluded that continuous cropping without K inputs through fertilisers or manure caused a decline in nonexchangeable K reserves and release rate while application of recommended NPK plus FYM maintained higher release rates.

Submerged upflow biotower operation and computer simulation

1994 ◽  
Vol 30 (11) ◽  
pp. 143-146
Author(s):  
Ronald D. Neufeld ◽  
Christopher A. Badali ◽  
Dennis Powers ◽  
Christopher Carson
Keyword(s):  
Computer Simulation ◽  
Benzoic Acid ◽  
Computer Model ◽  
Rate Constants ◽  
Batch Mode ◽  
Operational Conditions ◽  
First Order ◽  
Low Concentrations ◽  
Biological Transformation ◽  
Kinetics Of

A two step operation is proposed for the biodegradation of low concentrations (< 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.

Kinetics of bioactive compounds in functional spice Jiangpo during thermal processing

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Xiaoyan Dai ◽  
Chenhuan Yu ◽  
Qiaofeng Wu
Keyword(s):  
Kinetic Parameters ◽  
Bioactive Compounds ◽  
Thermal Processing ◽  
Order Rate Constant ◽  
Heat Processing ◽  
Order Kinetic ◽  
Time Intervals ◽  
First Order ◽  
Order Kinetic Model ◽  
Kinetics Of

Abstract Jiangpo is an increasingly popular East Asian spice which is made from Mangnolia officinalis bark and ginger juice. Since it induces bioactive compounds decomposition and has influence on final flavor and fragrance, cooking is regarded as the key operation in preparation of Jiangpo. To evaluate the bioactive compounds content changes of Jiangpo during thermal processing, kinetic parameters including reaction order, rate constant, T1/2 and activation energy of bioactive markers namely honokiol, magnolol and curcumin were determined. Cooking was set at temperatures 60, 90 and 120 °C for selected time intervals. Results displayed the thermal kinetic characteristics of the three compounds. Thermal degradation of Honokiol and magnolol both followed first order kinetic model and the loss of curcumin fitted second order. A mathematical model based on the obtained kinetic parameters has also been developed to predict the degradation of honokiol, magnolol and curcumin in non-isothermal state. All the information in this paper could contribute necessary information for optimizing the existing heat processing of Jiangpo.

scholarly journals Kinetics of K release from soils of Brazilian coffee regions: effect of organic acids

2008 ◽  
Vol 32 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Vladimir Antônio Silva ◽  
Giuliano Marchi ◽  
Luiz Roberto Guimarães Guilherme ◽  
José Maria de Lima ◽  
Francisco Dias Nogueira ◽  
...  
Keyword(s):  
Release Kinetics ◽  
Kinetic Studies ◽  
Release Rates ◽  
First Order ◽  
Potassium Release ◽  
Minas Gerais State ◽  
Soil Clay ◽  
Extractant Solution ◽  
Kinetics Of ◽  
K Release

Kinetic studies on soil potassium release can contribute to a better understanding of K availability to plants. This study was conducted to evaluate K release rates from the whole soil, clay, silt, and sand fractions of B-horizon samples of a basalt-derived Oxisol and a sienite-derived Ultisol, both representative soils from coffee regions of Minas Gerais State, Brazil. Potassium was extracted from each fraction after eight different shaking time periods (0-665 h) with either 0.001 mol L-1 citrate or oxalate at a 1:10 solid:solution ratio. First-order, Elovich, zero-order, and parabolic diffusion equations were used to parameterize the time dependence of K release. For the Oxisol, the first-order equation fitted best to the experimental data of K release, with similar rates for all fractions and independent of the presence of citrate or oxalate in the extractant solution. For all studied Ultisol fractions, in which K release rates increased when extractions were performed with citrate solution, the Elovich model described K release kinetics most adequately. The highest potassium release rate of the Ultisol silt fraction was probably due to the transference of "non-exchangeable" K to the extractant solution, whereas in the Oxisol exchangeable potassium represented the main K source in all studied fractions.

scholarly journals Compounds of 6, 13-Diamino-6, 13-Dimethyl-1, 4, 8, 11 - Tetraazacyclotetradecane

2021 ◽  
Author(s):  
◽  
Asokamali Siriwardena
Keyword(s):  
Rate Constants ◽  
Magnetic Measurements ◽  
Order Rate Constant ◽  
Acidic Solutions ◽  
First Order ◽  
Order Rate ◽  
Pendant Arm ◽  
Nickel Copper ◽  
13C Nuclear Magnetic Resonance ◽  
Kinetics Of

<p>The reaction of bis-(diaminoethane)nickel(II) chloride, ([Ni(en)2]Cl2 in methanol with formaldehyde and nitroethane in the presence of triethylamine proceeds readily to produce (6, 13-dimethyl-6, 13-dinitro-1, 4, 8, 11-tetraazacyclotetradecane)nickel(II) chloride, [Ni(dini)] - Cl2. Reduction of the nitro groups of this compound by catalytic hydrogenation yields three isomers of the pendant arm macrocyclic complex (6, 13-diamino-6, 13-dimethyl-1, 4, 8, 11-tetraazachyclotetradecane)nickel(II) chloride, designated a-, b- and c-[Ni(diam)]Cl2. These were separated by fractional crystallization. The aisomer was observed to isomerizes slowly in solution to the b- form. A parallel dissociation reaction of the a- isomer was also observed. The demetallation of a- and b- isomers of the diam complex of nickel by reaction with cyanide or concentrated acid at 140 degrees C produces the macrocycle meso-(6, 13-diamino-6, 13-dimethyl-1, 4, 8, 11-tetraazacyclotetra-decane), diam. A variety of hexamine, pentamine and tetramine complexes of diam with nickel(II), copper(II), cobalt(II) and (III), chromium(III), palladium(II), rhodium(III), zinc(II) and cadmium(II) were prepared. Hexamine and tetramine forms of labile metal complexes could be rapidly and reversibly interconverted by altering the pH. The hexamine cobalt(III) cation, [Co(diam)]3+ was by far the most inert of the prepared cobalt(III) complexes, remaining unaffected in hot acidic solutions. In contrast, a single pendant arm of the hexamine [Cr(diam)]3+ cation could be dissociated in acid. (Two possibly triamine complexes of lead were also prepared). These compounds were characterized by elemental analysis, magnetic measurements, electronic, infrared, 1H and 13C nuclear magnetic resonance spectra. The pendant arm protonation constants (log K) of diam and selected complexes of nickel, copper and palladium were calculated from potentiometric titration measurements at 25 degrees C. The log K values for diam at 25 degrees C (I = 0.1 M NaclO4) were 11.15, 9.7, 6.2 and 5.3. Kinetics of the parallel isomerization and dissociation of a-[Ni(dimH2)]4+ in HCl/NaCl solutions were monitored spectrophotometrically at 50 degrees C. The rate of reaction in acidic solutions showed a non-linear dependency on acid concentration. The observed first order rate constant (kobs) for disappearance of a-[Ni(diamH2)]4+ (by isomerization and dissociation) in 2.0 M HCl, 0.1 M NaOH and 2.0 M NaCl were 3.05 x 10-4, 2.0(3) x 10-2 and 5.0 x 10-5 s-1 respectively. The rate of the dissociation component of the reaction of a-[Ni(diamH2)]4+ in 2.0 M HCl at 50 degrees C was 1.82 x 10-7 s-1. Acid bydrolysis kinetics of (Cu[diamH2])(ClO4)4 in hydrochloric acid and perchloric acid at 50 and 70 degrees C were studied spectrophotometrically. The reactions were slow and the observed first order rate constants were to a first approximation independent of the particular acid or its concentration. The observed first order rate constants were 1 x 10-9 and 8 x 10-9 s-1 at 50 and 70 degrees C respectively. Questions about the nature of the reaction being followed have been raised.</p>

scholarly journals KINETICS OF OZONE REACTIONS WITH ADENINE AND CYTOSINE IN AQUEOUS SOLUTIONS

2020 ◽  
Vol 63 (10) ◽  
pp. 17-22
Author(s):  
Aigul A. Maksyutova ◽  
Elvina R. Khaynasova ◽  
Yuriy S. Zimin
Keyword(s):  
Aqueous Solutions ◽  
Rate Constants ◽  
Correlation Coefficients ◽  
Activation Parameters ◽  
Second Order ◽  
Order Kinetic ◽  
Temperature Dependences ◽  
Ozone Reactivity ◽  
Kinetics Of ◽  
Ozone Reactions

The ultraviolet spectroscopy method has been applied to study the kinetics of the ozone reactions with nitrogenous bases (NB), namely adenine and cytosine in aqueous solutions. At the first research stage, the range of NB working concentrations has been determined. It was found that linear dependences between optical densities and concentrations of nitrogenous bases aqueous solutions are quite reliable, with correlation coefficients r ≥ 0.998, are satisfied up to [NB] = 2.3 ∙ 10–4 mol/l. According to the Bouguer-Lambert-Beer law, adenine and cytosine extinction coefficients in aqueous solutions were determined and subsequently used to calculate their residual concentrations. At the next stage, the kinetics of nitrogenous bases ozonized oxidation was studied with equal initial concentrations of the starting substances ([NB]0 = [О3]0). The results revealed that the kinetic consumption curves of the starting reagents are fairly well linearized (r ≥ 0.996) in the second-order reaction equation coordinates. As found with the bubbling installation, 1 mol of the absorbed ozone falls on 1 mol of the used NB. Thus, the reactions of ozone with adenine and cytosine explicitly proceed according to the second-order kinetic laws (the first – according to О3 and the first – according to NB). The rate constants were calculated by the integral reaction equations, the values of which indicate a higher ozone reactivity in relation to nitrogen bases. The temperature dependences of the second-order rate constants was studied ranging 285-309 K, and the activation parameters (pre-exponential factors and activation energies) of the ozone reactions with adenine and cytosine in aqueous solutions were determined.

Kinetik der Reaktion von 2.4-Dinitrofluorbenzol mit Imidazol-, SH- und Imidazol-SH-Verbindungen / Kinetics of the Reaction of 2,4-dinitro-1-fluorobenzene with Imidazole-, SH- and Imidazole-SH-compounds

1971 ◽  
Vol 26 (10) ◽  
pp. 1010-1016 ◽  
Author(s):  
Renate Voigt ◽  
Helmut Wenck ◽  
Friedhelm Schneider
Keyword(s):  
Temperature Dependence ◽  
Rate Constants ◽  
Reaction Rate ◽  
Ph Dependence ◽  
First Order ◽  
Molecular Transfer ◽  
Thiolate Anion ◽  
Nucleophilic Reactivity ◽  
Kinetics Of ◽  
Lindley Equation

First order rate constants of the reaction of a series of SH-, imidazole- and imidazole/SH-compounds with FDNB as well as their pH- and temperature dependence were determined. Some of the tested imidazole/SH-compounds exhibit a higher nucleophilic reactivity as is expected on the basis of their pKSH-values. This enhanced reactivity is caused by an activation of the SH-groups by a neighbouring imidazole residue. The pH-independent rate constants were calculated using the Lindley equation.The kinetics of DNP-transfer from DNP-imidazole to SH-compounds were investigated. The pH-dependence of the reaction displays a maximum curve. Donor in this reaction is the DNP-imidazolecation and acceptor the thiolate anion.The reaction rate of FDNB with imidazole derivatives is two to three orders of magnitude slower than with SH-compounds.No inter- or intra-molecular transfer of the DNP-residue from sulfure to imidazole takes place.

Evidence for the formation of lignin-hexenuronic acid-xylan complexes during modified kraft pulping processes

Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 137-142 ◽  
Author(s):  
Zhi-Hua Jiang ◽  
Jean Bouchard ◽  
Richard Berry
Keyword(s):  
Acid Hydrolysis ◽  
Kraft Pulp ◽  
Kraft Pulping ◽  
Order Kinetic ◽  
Kraft Pulps ◽  
First Order ◽  
Pseudo First Order ◽  
Hexenuronic Acid ◽  
Kinetics Of ◽  
Hydrolysis Of

Abstract The finding that hexenuronic acid (HexA) groups can be selectively removed from kraft pulps by acid hydrolysis has provided an opportunity to reduce bleaching chemicals. However, there is evidence that the acid hydrolysis is not uniform. In this report, we evaluate the kinetics of acid hydrolysis of HexA in a xylan sample enriched with HexA, a conventional kraft pulp, and three modified kraft pulps: anthraquinone pulp (Kraft-AQ), polysulfide pulp (PS), and polysulfide-anthraquinone pulp (PS-AQ). We found that HexA present in the xylan and conventional kraft pulp behaved similarly toward the acid hydrolysis throughout. On the other hand, HexA present in the Kraft-AQ, PS-AQ and PS pulps was heterogeneous toward acid hydrolysis and the reaction can be separated into two pseudo-first-order kinetic phases, each of which has a different rate constant. The kinetic data provide evidence for the formation of lignin-HexA-xylan complexes during modified kraft pulping processes.

Kinetics of the Ozonation of Tetrabromobisphenol-A in Wastewater

2011 ◽  
Vol 383-390 ◽  
pp. 2945-2950 ◽  
Author(s):  
Jie Zhang ◽  
Shi Long He ◽  
Mei Feng Hou ◽  
Li Ping Wang ◽  
Li Jiang Tian
Keyword(s):  
Rate Constants ◽  
Apparent Rate Constant ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Kinetic Studies ◽  
Tetrabromobisphenol A ◽  
First Order ◽  
Reaction Rate Constants ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of TBBPA degradation by ozonation in semi-batch reactor was studied. The reaction rate constants of TBBPA with O3 and •OH were measured by means of direct ozone attack and competition kinetics, and the values of which were 6.10 l/(mol•s), 4.8×109 l/(mol•s), respectively. Results of kinetic studies showed that TBBPA degradation by ozonation under the different conditions tested followed the pseudo-first-order. The values of apparent rate constant of TBBPA degradation increased with the increase of ozone dosage and pH, but decreased with the increase of initial TBBPA concentration.

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