scholarly journals Optimization of opeation parameters for methylene blue degradation by UV/TiO2/H2O2 process in an annular reactor

2021 ◽  
Vol 10 (1) ◽  
pp. 40-47
Author(s):  
Chinh Pham Duc ◽  
Cuong Pham Manh ◽  
Thanh Le Phuong ◽  
Trang Nguyen Thi Thu ◽  
Tan Nguyen Minh
Keyword(s):  
Methylene Blue ◽  
Rate Constant ◽  
Reaction Rate ◽  
Great Influence ◽  
Reaction Rate Constant ◽  
Reaction Conditions ◽  
Methylene Blue Degradation ◽  
Annular Reactor ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

In this study, the degradation of methylene blue (MB) by UV/TiO2/ H2O2 process was ivestigated in an annular reactor. The effects of the factors: TiO2 concentration, H2O2 dosage, UV density, and hydrodynamic conditions on the reaction rate constant were evaluated by the response surface methodology. The results showed that TiO2concentration, H2O2dosage and UV density had a great influence on the kapp, hydrodynamics had a lower influence. Design Expert V.11 software is used to optimize the reaction conditions, the optimal apparent reaction rate constant is 0.168 min-1 under the following conditions: TiO2 concentration of 0.2 g/l, H2O2 dosage is 0.063 mol/l, UV density of 287  W/m2 and Re number is 10000.

scholarly journals Enhanced Heterogeneous Photodegradation of Organic Pollutants by a Visible Light Harvesting CoO@meso–CN@MoS2 Nanocomposites

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 722
Author(s):  
Linjer Chen ◽  
Thanh Binh Nguyen ◽  
Yi-Li Lin ◽  
Chung-Hsin Wu ◽  
Jih-Hsing Chang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Visible Light ◽  
Reaction Rate ◽  
Weight Ratio ◽  
Reaction Rate Constant ◽  
Pollutant Degradation ◽  
New Approach ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

Developing simple and effective synthetic strategies regarding the formation of heterostructure photocatalytic semiconductors remains an intense challenge in research matters. Uniform heterostructure cobalt oxide@meso–CN@MoS2 (CoO@meso–CN@MoS2) photocatalyst exhibits excellent photocatalytic redox performance for pollutant degradation under visible light. By adjusting the weight ratio of CoO@meso–CN and MoS2, we fabricated a CoO@meso–CN@MoS2 heterostructure photocatalyst, and the established heterostructure between CoO@meso–CN and MoS2 was indicated by various physicochemical and morphological characterizations. The photocatalytic response to the fabricated hybrid was determined by rodamine B (RhB), methylene blue (MB), and congo red (CR) degradation in aqueous solution under visible light, and the nanocomposites with a slight content consisting of CoO@meso–CN achieved better catalysis than pure MoS2. This finding confirmed the propriety of this heterostructure as a valuable photocatalyst. The experimental results demonstrated that the apparent reaction rate constant of the 3 wt% CoO@meso–CN modified MoS2 was about two times higher than that of pure MoS2. The present work serves as a new approach for designing highly efficient visible light-induced heterostructure-based photocatalysts for environmental applications in the future.

Influence of Reduction Time of SSI on Nitrite Removal from Wastewater

2012 ◽  
Vol 450-451 ◽  
pp. 667-671 ◽  
Author(s):  
Jun Guo Li ◽  
Shou Zhang Li ◽  
Wei Tian
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Direct Reduction ◽  
Nitrate Removal ◽  
Reaction Rate Constant ◽  
Pseudo First Order Reaction ◽  
Reduction Time ◽  
Nitrite Removal ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. To optimize the reduction technology of SSI and its removal ability for nitrate from wastewater, the influence of reduction time of SSI on nitrate removal percentage was investigated. Because the specific surface area was impact smartly by the reduction time of SSI, it was suggested that nitrate removal ability of SSI should declined with the increasing of reduction time once the reduction time longer than the optimized reduction time. When the reduction time was t1, nitrate removal percentage reached to the maximum. When the nitrate original concentration was 5mg-N/L, the reaction order was closed to 0.7 and the apparent reaction rate constant was 0.323 to 0.359 h-1. When nitrate original concentration increased to 50 mg-N/L, nitrate removal reaction appeared to be the pseudo-first-order reaction, and the apparent reaction rate constant was 0.314 to 0.248 h-1.

Reducing Sugar Production in Sweet Potatoes Heated by Electromagnetic Radiation

2009 ◽  
Vol 15 (1) ◽  
pp. 89-95 ◽  
Author(s):  
J. Sawai ◽  
T. Nakai ◽  
M. Shimizu
Keyword(s):  
Sweet Potato ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Reducing Sugar ◽  
Sugar Production ◽  
Sweet Potatoes ◽  
Experimental Values ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

The apparent reaction rate constant needed to generate reducing sugar was determined by heating a thin slice of sweet potato using thermal conductive heating. This value was used to predict reducing sugar production in sweet potatoes cooked by electromagnetic irradiation. The generation of reducing sugar in the thin slice was not observed at temperatures <65°C or >85°C, but it increased linearly during the early stage of heating. The Arrhenius plot had a peak of approximately 83°C, allowing determination of the values for activation energy and frequency factor. Then, using the values obtained for apparent reaction rate constant, the yields of reducing sugar in sweet potatoes cooked by infrared (IR) and microwave (MW) heating were calculated and compared with experimental data. Although the calculated values exceeded the experimental values in the early stages of electromagnetic irradiative heating, the calculated amounts of reducing sugar generally agreed with the experimental values. Moreover, when the time needed to heat the sweet potato from 65°C to 85 °C was longer than approximately 8 min, the yield of reducing sugar was maximized for both MW and IR heating. These results indicated that the yield of reducing sugar did not depend on the heat transfer mechanism and that the amount of reducing sugar produced in heat-treated sweet potatoes could be predicted.

Influence of Reduction Agent of SSI on its Cadmium Removal from Wastewater

2012 ◽  
Vol 251 ◽  
pp. 406-410
Author(s):  
Jun Guo Li ◽  
Yan Shi ◽  
Na Bi
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Order ◽  
Direct Reduction ◽  
Reaction Rate Constant ◽  
Cadmium Removal ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by charcoal or hydrogen. The capability of cadmium removal by SSI was investigated in. It was suggested that the reaction of SSI reduced by hydrogen was higher than that reduced by charcoal, and the increasing rate of pH and cadmium removal in solution by SSI reduced by hydrogen was higher than that reduced by charcoal. Moreover, cadmium removal percentage by SSI reduced with hydrogen was much higher than that reduced by charcoal. When the original concentration of cadmium was 50mg/L, cadmium removal by SSI appeared to be the pseudo-first-order reaction because the reaction order was from 0.861 to 0.984. The apparent reaction rate constant of cadmium removal by SSI reduced with charcoal was 0.586 h-1. While hydrogen was utilized as reduction agent, the apparent reaction rate constant of cadmium removal was increased by 7.3 and 13.7 times.

Influence of Reduction Temperature of SSI on Nitrate Removal from Wastewater

2012 ◽  
Vol 487 ◽  
pp. 682-686
Author(s):  
Jun Guo Li ◽  
Shou Zhang Li ◽  
Wei Tian
Keyword(s):  
Reaction Rate ◽  
Direct Reduction ◽  
Nitrate Removal ◽  
Reaction Rate Constant ◽  
Reduction Temperature ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Short Time ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. To optimize the reduction technology of SSI and its removal ability for nitrate from wastewater, the influence of reduction temperature of SSI on nitrate removal was investigated. It was suggested that nitrate removal ability of SSI increased to the summit and then declined with the increasing of reduction temperature. When the reduction temperature of was T4, nitrate removal percentage reached to the maximum. When the original concentration of nitrate was only 5 mg-N/L, the additive quantity of SSI could prove plenty of zero-valent iron in a short time, and reduction temperature of SSI has little influence on nitrate removal. Nitrate removal by SSI appeared to be the pseudo-first-order reaction despite of reduction temperature. While nitrate original concentration was elevated to 50mg-N/L, the reaction order declined to the range of from 0.534 to 0.629 which was closed to 0.5, and the apparent reaction rate constant was 1.411 to 1.773 h-1.

In situ photogalvanic acceleration of optofluidic kinetics: a new paradigm for advanced photocatalytic technologies

RSC Advances ◽  
2015 ◽  
Vol 5 (1) ◽  
pp. 791-796 ◽  
Author(s):  
Huizhi Wang ◽  
Xiaojiao Luo ◽  
Michael K. H. Leung ◽  
Dennis Y. C. Leung ◽  
Zhiyong Tang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
New Paradigm ◽  
Order Of Magnitude

A multiscale-designed optofluidic reactor is demonstrated, featuring an overall reaction rate constant of 1.32 s−1 for photocatalytic decolourization of methylene blue, which is an order of magnitude higher as compared to literature records.

Influence of Reaction Temperature on Nitrate Removal from Water by SSI

2013 ◽  
Vol 634-638 ◽  
pp. 345-348
Author(s):  
Xing Fu Cai ◽  
Yan Shi ◽  
Fan Wang ◽  
Jun Guo Li
Keyword(s):  
Reaction Temperature ◽  
Reaction Rate ◽  
Reaction Order ◽  
Nitrate Concentration ◽  
Nitrate Removal ◽  
Reaction Rate Constant ◽  
Solution Ph ◽  
First Order ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

Spherical sponge iron (SSI) with high activity and intension could be could be utilized to remove nitrate from wastewater. Influence of reaction temperature on nitrate removal by SSI from wastewater was investigated. Because of erosion battery reaction of SSI in solution, pH in solution increased quickly once SSI was added in and then maintain above 10 despite of nitrate original concentration. The reaction temperature has certain influence under higher nitrate original concentration, while little influence under lower nitrate concentration. It was concluded that nitrate removal by SSI appeared to be the first-order reaction because most of the reaction order was 1. The apparent reaction rate constant of nitrate removal was change slightly with the reaction temperature. It was suggested that the limited key of nitrate reduction by SSI was the diffusion of reactant because the activity energy, which was 11.37 and 7.24kJ/mol, was lower than 30kJ/mol.

Influence of pH on Cadmium Removal from Wastewater by SSI

2012 ◽  
Vol 232 ◽  
pp. 935-938
Author(s):  
Jun Guo Li ◽  
Yan Shi ◽  
Na Bi ◽  
Yan Ping Feng
Keyword(s):  
Reaction Rate ◽  
Ph Value ◽  
Direct Reduction ◽  
Reaction Rate Constant ◽  
Cadmium Removal ◽  
First Order ◽  
Initial Ph ◽  
Apparent Reaction Rate Constant ◽  
Influence Of Ph ◽  
Apparent Reaction Rate

Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. pH value in solution increased despite initial pH because a large amount of H+ was depleted along with erosion battery reaction of SSI. It was suggested that initial pH has significant influence on pH value in solution and cadmium removal percentage by SSI. When the initial pH maintained at 2.03, cadmium removal percentages were only 10.17% and 22.00%, respectively, in 10min and 30min. While the initial pH was adjusted to 3.00, cadmium removal percentage could be elevated to 73.10% and 95.46% in similar libration time. Cadmium removal by SSI appeared to be the first-order reaction. When the initial pH was maintained at 2.03, the apparent reaction rate constant of cadmium removal by SSI was only 0.434 and 1.027 h-1, while which could be elevated to 5.882 and 5.249 h-1 when the initial pH was adjusted to 3.00.

Thermodynamics of Spherical Sponge Iron Reduced by Hydrogen

2012 ◽  
Vol 487 ◽  
pp. 677-681
Author(s):  
Jun Guo Li ◽  
Shou Zhang Li ◽  
Wei Tian
Keyword(s):  
Reaction Rate ◽  
Direct Reduction ◽  
Reduction Rate ◽  
Reaction Rate Constant ◽  
Sponge Iron ◽  
First Order ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Apparent Reaction Rate Constant ◽  
Apparent Reaction Rate

Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. To optimize the reduction technology, thermodynamics of SSI reduction was investigated. Oxygen residue ratio in SSI declined with the reaction time despite of reaction temperature. It was concluded that SSI reduced by hydrogen appeared to be the first-order reaction, and the apparent reaction rate constant k was 0.289 h-1 to 3.819 h-1. Activity energy of SSI reduction was 22.19 kJ•mol-1 and 81.58 kJ•mol-1 corresponding to the lower temperature and higher temperature. When the temperature was lower than T4, the reaction rate was lower. Consequently, the optimized temperature should be controlled more than T5 to elevate the reduction rate.

scholarly journals Determination of exothermic batch reactor specific model parameters

2019 ◽  
Vol 292 ◽  
pp. 01063
Author(s):  
Lubomír Macků
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Specific Model ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Model Parameters ◽  
Reactor Model ◽  
First Order

An alternative method of determining exothermic reactor model parameters which include first order reaction rate constant is described in this paper. The method is based on known in reactor temperature development and is suitable for processes with changing quality of input substances. This method allows us to evaluate the reaction substances composition change and is also capable of the reaction rate constant (parameters of the Arrhenius equation) determination. Method can be used in exothermic batch or semi- batch reactors running processes based on the first order reaction. An example of such process is given here and the problem is shown on its mathematical model with the help of simulations.

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