scholarly journals Synthesis, Characterization and Ecotoxicity Evaluation of Biochar-Derived Carbon Dots from Spruce Tree, Purple Moor-Grass and African Oil Palm

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1095
Author(s):  
Kaory Barrientos ◽  
Maria I. Gaviria ◽  
Juan Pablo Arango ◽  
Jersson Placido ◽  
Sandra Bustamante ◽  
...  
Keyword(s):  
Optical Properties ◽  
Elaeis Guineensis ◽  
Hydrothermal Process ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Optical Biosensors ◽  
High Toxicity ◽  
Molinia Caerulea ◽  
Ecotoxicity Tests ◽  
African Oil Palm

Biochar-derived C-Dots from Picea, Molinia caerulea and Elaeis guineensis were synthesized through a hydrothermal process, and their physicochemical and optical characteristics and environmental effects were compared. These C-Dots were characterized by techniques such as Attenuated Total Reflection–Fourier Transform Infrared (ATR-FTIR), UV-Vis spectrophotometry, fluorescence spectroscopy, dynamic light scattering (DLS), Z potential, and High-Resolution Transmission Electronical Microscopy (HR-TEM). The ecotoxicity tests were performed using the Microtox™ test, making this study one of the few that use this method. The C-Dots from Molinia caerulea showed the best quantum yield (QY) of 8.39% and moderate ecotoxicity, while Elaeis guineensis has the lowest QY (2.31%) but with zero toxicity. Furthermore, the C-Dots from Picea presents good optical properties but showed high toxicity and limits its use. Finally, all C-Dots showed functional groups that could be biofunctionalized with biomolecules, especially C-Dots from Molinia caerulea and Elaeis guineensis show potential for use in the development of optical biosensors.

Optical properties of silver island films in the attenuated-total-reflection geometry

1986 ◽  
Vol 25 (20) ◽  
pp. 3635 ◽  
Author(s):  
T. Inagaki ◽  
J. P. Goudonnet ◽  
P. Royer ◽  
E. T. Arakawa
Keyword(s):  
Optical Properties ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Silver Island Films ◽  
Silver Island ◽  
Reflection Geometry ◽  
Island Films

scholarly journals Structure and Optical Properties of Spiropyran LB Ultrathin Films Using Attenuated Total Reflection Method

1996 ◽  
Vol 116 (1) ◽  
pp. 55-61
Author(s):  
Takashi Wakamatsu ◽  
Hisashi Okuchi ◽  
Hitoshi Saiki ◽  
Kazunari Shinbo ◽  
Keizo Kato ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ultrathin Films ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Reflection Method

Gas Cell Infrared and Attenuated Total Reflection Infrared Spectroscopic Studies for Organic–Inorganic Interactions in Adsorption of Fulvic Acid on the Goethite Surface Generating Carbon Dioxide

2021 ◽  
pp. 000370282199121
Author(s):  
Yuki Nakaya ◽  
Satoru Nakashima ◽  
Takahiro Otsuka
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Fulvic Acid ◽  
Spectroscopic Studies ◽  
Reaction Model ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Gas Cell ◽  
Rate Determining Step ◽  
Ir Spectroscopic

The generation of carbon dioxide (CO2) from Nordic fulvic acid (FA) solution in the presence of goethite (α-FeOOH) was observed in FA–goethite interaction experiments at 25–80 ℃. CO2 generation processes observed by gas cell infrared (IR) spectroscopy indicated two steps: the zeroth order slower CO2 generation from FA solution commonly occurring in the heating experiments of the FA in the presence and absence of goethite (activation energy: 16–19 kJ mol–1), and the first order faster CO2 generation from FA solution with goethite (activation energy: 14 kJ mol–1). This CO2 generation from FA is possibly related to redox reactions between FA and goethite. In situ attenuated total reflection infrared (ATR-IR) spectroscopic measurements indicated rapid increases with time in IR bands due to COOH and COO– of FA on the goethite surface. These are considered to be due to adsorption of FA on the goethite surface possibly driven by electrostatic attraction between the positively charged goethite surface and negatively charged deprotonated carboxylates (COO–) in FA. Changes in concentration of the FA adsorbed on the goethite surface were well reproduced by the second order reaction model giving an activation energy around 13 kJ mol–1. This process was faster than the CO2 generation and was not its rate-determining step. The CO2 generation from FA solution with goethite is faster than the experimental thermal decoloration of stable structures of Nordic FA in our previous report possibly due to partial degradations of redox-sensitive labile structures in FA.

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