Sodium chlorite – iodide – acetylacetone oscillation reaction investigated by UV-Vis spectrophotometry

2015 ◽  
Vol 93 (10) ◽  
pp. 1069-1075
Author(s):  
Jingjing Chen ◽  
Laishun Shi ◽  
Demei Li ◽  
Ying Wang ◽  
Shujie Lin ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Ph Value ◽  
Great Influence ◽  
Sodium Chlorite ◽  
Similar Reaction ◽  
Initial Concentration ◽  
Oscillation Reaction ◽  
Apparent Activation Energies ◽  
Two Stages ◽  
Induction Stage

A new sodium chlorite – iodide – acetylacetone chemical oscillatory reaction has been studied by the UV-Vis spectrophotometric method. The initial concentrations of acetylacetone, sodium chlorite, iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at a wavelength of 570 nm for the starch–triiodide complex. There is a pre-oscillatory or induction stage and the amplitude and number of oscillations depend on the initial concentration of the reactants. Equations for the starch–triiodide complex reaction rate change with reaction time and the initial concentrations in the oscillation stage were obtained. The induction time decreases linearly with the initial concentration of acetylacetone or sodium chlorite but increases linearly with the initial concentration of sulfuric acid. The oscillation reaction can be accelerated by increasing the reaction temperature. The apparent activation energies at the induction stage and the oscillation stage were 61.02 and 61.36 kJ/mol, respectively, indicating that the two stages have similar reaction mechanisms. Generating the enol isomer by keto–enol tautomerism is an important step to constrain the time of the induction period.

Modeling study for oscillatory reaction of chlorite – iodide – ethyl acetoacetate

2014 ◽  
Vol 92 (5) ◽  
pp. 417-425 ◽  
Author(s):  
Laishun Shi ◽  
Jian Gao ◽  
Jingjing Chen
Keyword(s):  
Chlorine Dioxide ◽  
Ethyl Acetoacetate ◽  
Ph Value ◽  
Great Influence ◽  
Iodine Concentration ◽  
Hydrogen Ion ◽  
Initial Concentration ◽  
Bifurcation Surface ◽  
Concentration Changes ◽  
Theoretical Evidence

Chlorine dioxide based chemical oscillating behavior was modeled by a simple scheme consisting of three component reactions. Furthermore, little is known about the influence of the pH value. In this study, four component reactions were used to model the chlorite – iodide – ethyl acetoacetate oscillating reaction by dynamic analysis software. The oscillatory phenomenon is observed for concentration changes of triiodide ion, chlorite ion, and hydrogen ion. The initial concentration of ethyl acetoacetate, chlorite ion, iodide ion, and hydrogen ion has great influence on oscillations. The amplitude and number of oscillations are associated with the initial reactant concentrations. The equation of the reaction rate of triiodide ion, chlorite ion, or hydrogen ion changing with reaction time and initial concentrations in the oscillation stage was obtained. The bifurcation surface between oscillatory and nonoscillatory behavior with different pH values was obtained. The spatial zone for the occurrence of oscillation is reduced with an increase in the pH value. The range of oscillation as concentrations of chlorine dioxide, iodine, and ethyl acetoacetate is well described by an equation. There is a lower limit on ethyl acetoacetate initial concentration for oscillation. However, there is a higher limit on chlorine dioxide and iodine concentration for oscillation. The concentrations of chlorine dioxide and iodine for oscillation decrease with an increase in the pH value. The results provide new theoretical evidence of the importance of pH value, which can affect the bifurcation surface between oscillatory and nonoscillatory behavior.

scholarly journals Chlorine Dioxide-Iodide-Methyl Acetoacetate Oscillation Reaction Investigated by UV-Vis and Online FTIR Spectrophotometric Method

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Laishun Shi ◽  
Xiaomei Wang ◽  
Na Li ◽  
Jie Liu ◽  
Chunying Yan
Keyword(s):  
Induction Period ◽  
Chlorine Dioxide ◽  
Spectrophotometric Method ◽  
Ph Value ◽  
Great Influence ◽  
Reaction System ◽  
Oscillatory Behavior ◽  
Methyl Acetoacetate ◽  
Oscillation Reaction ◽  
Online Ftir

In order to study the chemical oscillatory behavior and mechanism of a new chlorine dioxide-iodide ion-methyl acetoacetate reaction system, a series of experiments were done by using UV-Vis and online FTIR spectrophotometric method. The initial concentrations of methyl acetoacetate, chlorine dioxide, potassium iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at wavelength of 289 nm. There is a preoscillatory or induction period, and the amplitude and the number of oscillations are associated with the initial concentration of reactants. The equations for the triiodide ion reaction rate changing with reaction time and the initial concentrations in the oscillation stage were obtained. Oscillation reaction can be accelerated by increasing temperature. The apparent activation energies in terms of the induction period and the oscillation period were 26.02 KJ/mol and 17.65 KJ/mol, respectively. The intermediates were detected by the online FTIR analysis. Based upon the experimental data in this work and in the literature, a plausible reaction mechanism was proposed for the oscillation reaction.

scholarly journals Oxidation of Citalopram with Sodium Hypochlorite and Chlorine Dioxide: Influencing Factors and NDMA Formation Kinetics

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3065
Author(s):  
Juan Lv ◽  
Yan Wang ◽  
Na Li
Keyword(s):  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Wastewater Treatment Plants ◽  
Ph Value ◽  
High Reactivity ◽  
Secondary Effluent ◽  
Water Matrix ◽  
Formation Kinetics ◽  
Operational Variables ◽  
Two Stages

The highly prescribed antidepressant, citalopram, as one of newly emerging pollutants, has been frequently detected in the aquatic environment. Citalopram oxidation was examined during sodium hypochlorite (NaOCl) and chlorine dioxide (ClO2) chlorination processes since conventional wastewater treatment plants cannot remove citalopram effectively. Citalopram has been demonstrated to form N-nitrosodimethylamine (NDMA) during chlorination in our previous study. Further investigation on NDMA formation kinetics was conducted in the present study. Influences of operational variables (disinfectant dose, pH value) and water matrix on citalopram degradation, as well as NDMA generation, were evaluated. The results indicated high reactivity of citalopram with NaOCl and ClO2. NDMA formation included two stages during CIT oxidation, which were linear related with reaction time. NaOCl was more beneficial to remove CIT, but it caused more NDMA formation. Increasing disinfectant dosage promoted citalopram removal and NDMA formation. However, no consistent correlation was found between citalopram removal and pH. Contrary to the situation of citalopram removal, NDMA generation was enhanced when citalopram was present in actual water matrices, especially in secondary effluent. DMA, as an intermediate of citalopram chlorination, contributed to NDMA formation, but not the only way.

Preparation of Sands Modified by Aluminous Salt and its Adsorption Capability of CD2+

2011 ◽  
Vol 130-134 ◽  
pp. 856-859
Author(s):  
Chun Sheng Ding ◽  
Yang Ping Fu ◽  
Qian Fen Zhu ◽  
Jing Fu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Influencing Factors ◽  
Removal Efficiency ◽  
Specific Surface Area ◽  
Quartz Sand ◽  
Ph Value ◽  
Alkaline Condition ◽  
Initial Concentration ◽  
Adsorption Capability

In this experiment quartz sand was chosen as a carrier to be coated by aluminous salt under alkaline condition, and then the specific surface area was tested, and the adsorption capability and Cd2+ removal influencing factors of modified sand were studied. The investigation results showed that the specific surface area of modified sand was 75.244m2/g which was 9.38 times of that of original sand; the removal efficiency of Cd2+ by aluminous salt modified sand reached 59% contrast to 39% of original sand with pH 7.00. It was also found that the removal efficiency of Cd2+ by the aluminous salt modified sand was reduced with the increase of initial concentration of Cd2+ solution, and was enhanced with the increase of pH value, the Cd2+ removal efficiency was almost 71% with pH 9.0.

Zinc carbonate recovery from brass melting slag

2021 ◽  
Vol 98 ◽  
pp. 14-18
Author(s):  
Thao Nguyen Thi ◽  
◽  
Nam Pham Ky ◽  
Ngoc Tran Vu Diem
Keyword(s):  
Sulfuric Acid ◽  
High Purity ◽  
Room Temperature ◽  
Ph Value ◽  
Zinc Carbonate ◽  
Leaching Solution ◽  
Optimized Conditions ◽  
Melting Slag

Brass melting slag (20.38 wt.% Zn) was leached in sulfuric acid with concentration of (50 + 80) g/l H2SO4, leaching temperature of (30 + 60) °C for (30 + 120) min. The optimized conditions for 94.16% Zn extraction from brass melting slag were found as 70 g/l H2SO4, room temperature and 90 min. The leaching solution was purified by removal of Fe through Fe(OH)3 precipitation when adding ZnO to adjust pH value of 5. The solution was continuously cemented by Zn metal at 60 °C for 60 min to obtain Cu metal with high purity of 99 wt.% Cu. The purified solution with 37.64 g/l Zn was modified by Na2C03 to have pH value of about 6 and precipitation of ZnC03 (94.14 %).

The Influence of Heat and Two Stages Precipitation in the Process of Natural Polymer Purification from the Byproduct of Bioethanol Process Base on Empty Palm Fruit Bunch

2015 ◽  
Vol 1123 ◽  
pp. 177-181
Author(s):  
Achmad Hanafi ◽  
Harry Budiman ◽  
Fauzan Aulia
Keyword(s):  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Room Temperature ◽  
Black Liquor ◽  
Ash Content ◽  
Natural Polymer ◽  
Palm Fruit ◽  
Second Stage ◽  
Direct Precipitation ◽  
Two Stages

The biopolymer material, lignin, was recovered from the black liquor by acidification of the black liquor using sulfuric acid. Several purification techniques were carried out to produce the high purity of lignin such as gradual precipitation of lignin from black liquor (first stage: precipitation at pH 7, second stage: precipitation at pH 2) and the diluting of crude lignin by sodium hydroxide then followed by re-precipitation at different temperature. Subsequently, the impurities of lignin product resulted from each purification techniques was determined as ash content that analyzed using temperature program furnace; and the content of lignin was investigated using spectrophotometer UV-Vis. The result showed that the content of lignin of material produced from gradual precipitation was approximately 77.6%. It was higher than the content of lignin about 3.4% of material produced from direct precipitation to pH 2. In addition, the elevating of temperature from 40 to 60°C was no considerably affect to the content of lignin in precipitate produced from re-precipitation of crude lignin solution in sodium hydroxide. Nonetheless, the content of lignin of precipitate improved 15% when the temperature of re-precipitation of crude lignin solution in sodium hydroxide was raised from room temperature to 40-60°C.

Study on Decolorization of Wastewater Containing Acid Orange II by Adsorption on Expanded Graphite

2011 ◽  
Vol 183-185 ◽  
pp. 873-876
Author(s):  
Jun Jie Yue ◽  
Xing Long Jin ◽  
Zhao Hui Jin
Keyword(s):  
Ph Value ◽  
Expanded Graphite ◽  
Orange Ii ◽  
Dye Wastewater ◽  
Temperature Level ◽  
Initial Concentration ◽  
Acid Orange ◽  
Ph Values ◽  
Simulated Wastewater ◽  
Acid Orange Ii

In this paper, the adsorption and decolorization capability of expanded graphite (EG) on the simulated wastewater containing Acid Orange Ⅱwere studied. The experimental results show that the initial concentration of wastewater, the dosage of EG, the pH value and the temperature all have greater effects on the decolorization ratio of simulated Acid Orange Ⅱ wastewater. The dye- wastewater containing lower concentration(＜150 mg/L) of Acid Orange Ⅱ is more suitable to be treated by EG, and approximately 100 mg/L is the preferable concentration. The decolorization ratio increases with the increment of the dosage of EG and the temperature level, but the growth rate obviously decreases at the higher initial concentration. All the decolorization ratios under strong acidic (pH<5) and alkalic (pH>11) conditions are higher than that at the range of 5-11 pH values, the highest value even reaches over 94%, while the decolorization ratio under the latter conditions are only between 75% and 85%.

Effect of Oxidant on the Leaching Rate of Indium from Water Quenching Slag

2013 ◽  
Vol 591 ◽  
pp. 122-125
Author(s):  
Li Jiao Yang ◽  
Si Chen ◽  
Yan Zhang ◽  
Nan Chun Chen ◽  
Jun Gao ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Sulfuric Acid ◽  
Potassium Permanganate ◽  
Crystal Violet ◽  
Acid Leaching ◽  
Water Quenching ◽  
Test Results ◽  
Leaching Rate ◽  
Initial Concentration ◽  
Solid Ratio

Extracting indium from water quenching slag, which contains poor indium, by two process of leaching, the effect of different oxidants and dosages on the leaching rate of indium in water quenching slag were studied. The leaching conditions: temperature 80 °C, leaching time 2 h, the liquid to solid ratio of neutral leaching 8︰1, the liquid to solid ratio of acid leaching 2︰1, initial concentration of sulfuric acid 500 g·L-1, adding different oxidants, the concentration was detected by crystal violet spectrophotometry. Test results showed that the leaching rate of indium was significantly improved by adding hydrogen peroxide and potassium permanganate. Compared with the effect of different oxidants, the effect of potassium permanganate was significantly higher than that of hydrogen peroxide on the leaching rate of indium.

scholarly journals Degradation of methylene blue by natural manganese oxides: kinetics and transformation products

2019 ◽  
Vol 6 (7) ◽  
pp. 190351 ◽  
Author(s):  
Shuangxi Zhou ◽  
Zhiling Du ◽  
Xiuwen Li ◽  
Yunhai Zhang ◽  
Yide He ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Manganese Oxides ◽  
Ph Value ◽  
Low Cost ◽  
Reaction System ◽  
Transformation Products ◽  
Low Ph ◽  
Initial Concentration ◽  
Environmental Material ◽  
High Redox Potential

In this study, natural manganese oxides (MnO x ), an environmental material with high redox potential, were used as a promising low-cost oxidant to degrade the widely used dyestuff methylene blue (MB) in aqueous solution. Although the surface area of MnO x was only 7.17 m 2 g −1 , it performed well in the degradation of MB with a removal percentage of 85.6% at pH 4. It was found that MB was chemically degraded in a low-pH reaction system and the degradation efficiency correlated negatively with the pH value (4–8) and initial concentration of MB (10–50 mg l −1 ), but positively with the dosage of MnO x (1–5 g l −1 ). The degradation of MB fitted well with the second-order kinetics. Mathematical models were also built for the correlation of the kinetic constants with the pH value, the initial concentration of MB and the dosage of MnO x . Furthermore, several transformation products of MB were identified with HPLC-MS, which was linked with the bond energy theory to reveal that the degradation was initiated with demethylation.

Nanoparticle Fe3O4 magnetized activated carbon from Armeniaca sibirica shell for the adsorption of Hg(II) ions

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6100-6120
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Qingwei Du ◽  
Xudong Li ◽  
Ximing Wang
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Initial Concentration

Armeniaca sibirica shell activated carbon (ASSAC) magnetized by nanoparticle Fe3O4 prepared from Armeniaca sibirica shell was investigated to determine its adsorption for Hg2+ from wastewater. Fe3O4/ASSAC was characterized using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and BET (Brunauer–Emmett–Teller). Optimum adsorption parameters were determined based on the initial concentration of Hg2+, reaction time, reaction temperature, and pH value in adsorption studies. The experiment results demonstrated that the specific surface area of ASSAC decreased after magnetization; however the adsorption capacity and removal rate of Hg2+ increased 0.656 mg/g and 0.630%, respectively. When the initial concentration of Hg2+ solution was 250 mg/L and the pH value was 2, the adsorption time was 180 min and the temperature was 30 °C, and with the Fe3O4/ASSAC at 0.05 g, the adsorption reaching 97.1 mg/g, and the removal efficiency was 99.6%. The adsorption capacity of Fe3O4/ASSAC to Hg2+ was in accord with Freundlich isotherm models, and a pseudo-second-order kinetic equation was used to fit the adsorption best. The Gibbs free energy ΔGo < 0，enthalpy change ΔHo < 0, and entropy change ΔSo < 0 which manifested the adsorption was a spontaneous and exothermic process.

Sign in / Sign up

Export Citation Format

Share Document