scholarly journals Heterogeneous photocatalytic removal and reaction kinetics of Rhodamine-B dye with Au loaded TiO2 nanohybrid catalysts

2012 ◽  
Vol 14 (2) ◽  
pp. 42-48 ◽  
Author(s):  
Dongfang Zhang
Keyword(s):  
Reaction Kinetics ◽  
Rhodamine B ◽  
Diffuse Reflectance Spectroscopy ◽  
Degradation Kinetics ◽  
Chemical Reduction ◽  
Gold Deposition ◽  
Photocatalytic Removal ◽  
Rhodamine B Dye ◽  
Group Density ◽  
Kinetics Of

Heterogeneous photocatalytic removal and reaction kinetics of Rhodamine-B dye with Au loaded TiO2 nanohybrid catalysts Heterogeneous photocatalytic removal of Rhodamine-B (RhB) dye by metallic Au nanopatrticles deposited TiO2 photocatalyst was studied. For this study, a chemical reduction method by hydrazine hydrate for gold deposition was employed in order to synthesize Au/TiO2 nanocomposite system. For the characterization of the synthesized nanomaterials, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), the Fourier transformation infrared spectroscopy (FTIR) and photoluminescence spectroscopy (PLS) techniques were performed. The obtained results show that the deposition of gold onto TiO2 surface could effectively inhibit the recombination of the photoinduced electron and holes, improving the absorption capability for the visible light source and leading to the increased surface OH group density. The degradation experiment reveals that the efficiency of color removal from RhB aqueous solution containing Au/TiO2 powders for the photocatalytic bleaching of RhB dye is more efficient than that of bare TiO2 sample upon UV-vis light activation. In addition, degradation kinetics of RhB dye in aqueous suspensions can be well simulated by the Langmuir-Hinshelwood model and obeys the pseudo-first order law, with a decolorization rate of 0.0252 min-1 to the photocatalytic removal of RhB dye.

scholarly journals Degradation Kinetics of Anthocyanins in Shalgam Beverage

2019 ◽  
Vol 7 (2) ◽  
pp. 282
Author(s):  
Adnan Bozdoğan ◽  
Kurban Yaşar
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Half Life ◽  
Degradation Kinetics ◽  
Production Method ◽  
Order Reaction ◽  
Different Temperatures ◽  
Traditional Production ◽  
Effects Of Temperature ◽  
Kinetics Of

This research was performed to elucidate the effects of temperature on the degradation kinetics of anthocyanins in shalgam beverage. Shalgam beverage was produced according to traditional production method. Then, it was kept at three different temperatures (65°C, 75°C, and 85°C) for 12 hours, and the relevant quantities of anthocyanins were determined thereafter. The research revealed that degradation of the anthocyanins was well described with a 1st-order reaction kinetics model and the R2 values varied in the range of 0.9059-0.9715. Activation energy of the reaction was determined to be 48537 Joule/mole. The half-lives of anthocyanins at 65°C and 75° C, and 85°C were found to be 138.63, 136.72, and 51.57, respectively. Compared the half-life periods at different temperatures, anthocyanins were found to be more resistant at 65°C and 75°C than at 85°C.

A galvanic exchange process visualized on single silver nanoparticles via dark-field microscopy imaging

Nanoscale ◽  
2018 ◽  
Vol 10 (26) ◽  
pp. 12805-12812 ◽  
Author(s):  
Jun Zhou ◽  
Tong Yang ◽  
Wei He ◽  
Zi Yu Pan ◽  
Cheng Zhi Huang
Keyword(s):  
Silver Nanoparticles ◽  
Light Scattering ◽  
Reaction Kinetics ◽  
Removal Rate ◽  
Exchange Process ◽  
Dark Field ◽  
Gold Deposition ◽  
Microscopy Imaging ◽  
Dark Field Microscopy ◽  
Kinetics Of

A galvanic exchange (GE) process was visually monitored in real-time using light scattering dark-field microscopy imaging, through which the reaction kinetics of the GE process was visualized and the silver removal rate and gold deposition rate on single nanoparticles were revealed.

Simplified reaction kinetics, models and experiments for glyphosate degradation in water by the UV/H2O2process

2015 ◽  
Vol 14 (2) ◽  
pp. 366-377 ◽  
Author(s):  
Eduardo Vidal ◽  
Antonio Negro ◽  
Alberto Cassano ◽  
Cristina Zalazar
Keyword(s):  
Kinetic Model ◽  
Reaction Kinetics ◽  
Degradation Kinetics ◽  
Commercial Formulation ◽  
Kinetics Models ◽  
Glyphosate Degradation ◽  
Kinetics Of

This work reports the degradation kinetics of glyphosate in water employing the UV/H2O2process. The kinetic model was experimentally validated. Results compare the kinetics of the herbicide alone and a commercial formulation.

scholarly journals Effect of pH and concentration on the chemical stability and reaction kinetics of thiamine mononitrate and thiamine chloride hydrochloride in solution

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Adrienne L. Voelker ◽  
Lynne S. Taylor ◽  
Lisa J. Mauer
Keyword(s):  
Reaction Kinetics ◽  
High Performance ◽  
Degradation Kinetics ◽  
Degradation Pathway ◽  
Reaction Rate Constant ◽  
Solution Ph ◽  
Kinetics Of Degradation ◽  
One Year ◽  
Kinetics Of ◽  
Over Time

AbstractThiamine (vitamin B1) is an essential micronutrient in the human diet, found both naturally and as a fortification ingredient in many foods and supplements. However, it is susceptible to degradation due to heat, light, alkaline pH, and sulfites, among effects from other food matrix components, and its degradation has both nutritional and sensory implications as in foods. Thiamine storage stability in solution was monitored over time to determine the effect of solution pH and thiamine concentration on reaction kinetics of degradation without the use of buffers, which are known to affect thiamine stability independent of pH. The study directly compared thiamine stability in solutions prepared with different pHs (3 or 6), concentrations (1 or 20 mg/mL), and counterion in solution (NO3−, Cl−, or both), including both commercially available salt forms of thiamine (thiamine mononitrate and thiamine chloride hydrochloride). Solutions were stored at 25, 40, 60, and 80 °C for up to one year, and degradation was quantified by high-performance liquid chromatography (HPLC) over time, which was then used to calculate degradation kinetics. Thiamine was significantly more stable in pH 3 than in pH 6 solutions. In pH 6 solutions, stability was dependent on initial thiamine concentration, with the 20 mg/mL thiamine salt solutions having an increased reaction rate constant (kobs) compared to the 1 mg/mL solutions. In pH 3 solutions, kobs was not dependent on initial concentration, attributed to differences in degradation pathway dependent on pH. Activation energies of degradation (Ea) were higher in pH 3 solutions (21–27 kcal/mol) than in pH 6 solutions (18–21 kcal/mol), indicating a difference in stability and degradation pathway due to pH. The fundamental reaction kinetics of thiamine reported in this study provide a basis for understanding thiamine stability and therefore improving thiamine delivery in many foods containing both natural and fortified thiamine.

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