scholarly journals Liquid-Phase Exfoliation of Biochars in Green Solvents and Correlation with Solvent Parameters

2020 ◽  
Author(s):  
Juliana Vidal ◽  
Stephanie Gallant ◽  
Douglas Richards ◽  
Stephanie MacQuarrie ◽  
Francesca Kerton
Keyword(s):  
Liquid Phase ◽  
Thermochemical Treatment ◽  
Layered Materials ◽  
Green Solvents ◽  
Solvent Parameters ◽  
Biomass Residues ◽  
Transmission Electron ◽  
Before And After ◽  
Liquid Phase Exfoliation ◽  
Concentrated Dispersions

Liquid-phase exfoliation (LPE) is a process frequently used to yield small sheets of layered materials. These materials are prepared via direct or indirect sonication in an ideal solvent, and the sheets produced often present remarkable chemical and physical properties. Unfortunately, the preferred solvents for exfoliation processes are frequently toxic and possess several health risks. In this work, we show the use of LPE in green solvents to access nanostructures of biochar. Biochar is a material produced after thermochemical treatment of biomass residues and it is an important tool for the sequestration of greenhouse gases. Herein, hardwood and softwood biomass residues (e.g. sludge, bark, and sawdust) are used to prepare pristine and oxidized biochars which are then exfoliated in a range of solvents. Stable dispersions containing up to 75% by weight of exfoliated biochar could be obtained. A range of solvents were screened for LPE of biochars to identify ‘green' options that could afford highly concentrated dispersions. The properties of the biochar before and after exfoliation were evaluated using Raman spectroscopy and Transmission Electron Microscopy. Correlations between effective LPE of biochar in a solvent and different solvent parameters were established. For example, LPE of oxidized biochars is more efficient in hydrogen-bond accepting solvents due to the increased concentration of carboxylic acid and alcohol functional groups within this material, when compared with pristine biochars.<div><br></div>

scholarly journals Liquid-Phase Exfoliation of Biochars in Green Solvents and Correlation with Solvent Parameters

2020 ◽  
Author(s):  
Juliana Vidal ◽  
Stephanie Gallant ◽  
Douglas Richards ◽  
Stephanie MacQuarrie ◽  
Francesca Kerton
Keyword(s):  
Liquid Phase ◽  
Thermochemical Treatment ◽  
Layered Materials ◽  
Green Solvents ◽  
Solvent Parameters ◽  
Biomass Residues ◽  
Transmission Electron ◽  
Before And After ◽  
Liquid Phase Exfoliation ◽  
Concentrated Dispersions

Liquid-phase exfoliation (LPE) is a process frequently used to yield small sheets of layered materials. These materials are prepared via direct or indirect sonication in an ideal solvent, and the sheets produced often present remarkable chemical and physical properties. Unfortunately, the preferred solvents for exfoliation processes are frequently toxic and possess several health risks. In this work, we show the use of LPE in green solvents to access nanostructures of biochar. Biochar is a material produced after thermochemical treatment of biomass residues and it is an important tool for the sequestration of greenhouse gases. Herein, hardwood and softwood biomass residues (e.g. sludge, bark, and sawdust) are used to prepare pristine and oxidized biochars which are then exfoliated in a range of solvents. Stable dispersions containing up to 75% by weight of exfoliated biochar could be obtained. A range of solvents were screened for LPE of biochars to identify ‘green' options that could afford highly concentrated dispersions. The properties of the biochar before and after exfoliation were evaluated using Raman spectroscopy and Transmission Electron Microscopy. Correlations between effective LPE of biochar in a solvent and different solvent parameters were established. For example, LPE of oxidized biochars is more efficient in hydrogen-bond accepting solvents due to the increased concentration of carboxylic acid and alcohol functional groups within this material, when compared with pristine biochars.<div><br></div>

scholarly journals Liquid-Phase Exfoliation of Biochars in Green Solvents and Correlation with Solvent Parameters

2020 ◽  
Author(s):  
Juliana Vidal ◽  
Stephanie Gallant ◽  
Douglas Richards ◽  
Stephanie MacQuarrie ◽  
Francesca Kerton
Keyword(s):  
Liquid Phase ◽  
Thermochemical Treatment ◽  
Layered Materials ◽  
Green Solvents ◽  
Solvent Parameters ◽  
Biomass Residues ◽  
Transmission Electron ◽  
Before And After ◽  
Liquid Phase Exfoliation ◽  
Concentrated Dispersions

Liquid-phase exfoliation (LPE) is a process frequently used to yield small sheets of layered materials. These materials are prepared via direct or indirect sonication in an ideal solvent, and the sheets produced often present remarkable chemical and physical properties. Unfortunately, the preferred solvents for exfoliation processes are frequently toxic and possess several health risks. In this work, we show the use of LPE in green solvents to access nanostructures of biochar. Biochar is a material produced after thermochemical treatment of biomass residues and it is an important tool for the sequestration of greenhouse gases. Herein, hardwood and softwood biomass residues (e.g. sludge, bark, and sawdust) are used to prepare pristine and oxidized biochars which are then exfoliated in a range of solvents. Stable dispersions containing up to 75% by weight of exfoliated biochar could be obtained. A range of solvents were screened for LPE of biochars to identify ‘green' options that could afford highly concentrated dispersions. The properties of the biochar before and after exfoliation were evaluated using Raman spectroscopy and Transmission Electron Microscopy. Correlations between effective LPE of biochar in a solvent and different solvent parameters were established. For example, LPE of oxidized biochars is more efficient in hydrogen-bond accepting solvents due to the increased concentration of carboxylic acid and alcohol functional groups within this material, when compared with pristine biochars.<div><br></div>

scholarly journals Liquid-Phase Exfoliation of Biochars in Green Solvents and Correlation with Solvent Parameters

2021 ◽  
Author(s):  
Juliana Vidal ◽  
Stephanie Gallant ◽  
Evan Connors ◽  
Douglas Richards ◽  
Stephanie MacQuarrie ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Dimethyl Carbonate ◽  
Layered Materials ◽  
Polyethylene Glycols ◽  
Green Solvents ◽  
Biomass Waste ◽  
Solvent Parameters ◽  
Benign Solvents ◽  
Liquid Phase Exfoliation ◽  
Concentrated Dispersions

<div> <div> <div> <div> <p>Liquid-phase exfoliation (LPE) is a process frequently used to overcome the interactions between layers in layered materials to produce small sheets of material, with remarkable properties and high value applications. Materials are prepared via direct or indirect sonication in a solvent that must be able to effectively disperse and stabilize the sheets produced. Unfortunately, the preferred solvents for exfoliation processes are often toxic and possess several health risks. In this work, we show that LPE in greener solvents can be used to access nanostructures of biochar and further improve the applications of this renewable and bio-based material. Herein, pristine and oxidized biochars prepared from hardwood and softwood biomass waste (e.g. sludge, bark, and sawdust) are exfoliated in a range of solvents to allow the identification of benign alternatives that could afford highly concentrated dispersions. The majority of biochar nanostructures produced after exfoliation are stacked nanosheets containing between 2-8 layers (average 15 nm thickness). Correlations between effective LPE of biochar in solvents and different solvent parameters, including Kamlet-Taft, were established and allowed greener solvents to be used. Surface modification of biochars (e.g. via oxidation) has potential to increase their dispersibility in more benign solvents. LPE of oxidized biochars is more efficient in hydrogen-bond accepting solvents due to the increased concentration of carboxylic acid and alcohol functional groups on the surface of particles, when compared to non- functionalized biochars. Dispersions containing 0.20-0.75 mg/mL exfoliated oxidized biochar were obtained in solvents such as polyethylene glycols, glycerol formal and e-caprolactone. Moreover, LPE of pristine biochars in dimethyl carbonate, ethyl acetate, and solketal gave similar yields to more commonly used solvent for this process, N-methyl-2-pyrrolidone (NMP) a known reprotoxic molecule. </p> </div> </div> </div><br></div>

Green Solvents for the Liquid-Phase Exfoliation of Biochars

2021 ◽  
Author(s):  
Juliana L. Vidal ◽  
Stephanie M. V. Gallant ◽  
Evan P. Connors ◽  
Douglas D. Richards ◽  
Stephanie L. MacQuarrie ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Green Solvents ◽  
Liquid Phase Exfoliation

scholarly journals Sustainable Liquid-Phase Exfoliation of Layered Materials with Nontoxic Polarclean Solvent

2020 ◽  
Vol 8 (51) ◽  
pp. 18830-18840
Author(s):  
Valentina Paolucci ◽  
Gianluca D’Olimpio ◽  
Luca Lozzi ◽  
Antonio M. Mio ◽  
Luca Ottaviano ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Layered Materials ◽  
Liquid Phase Exfoliation

scholarly journals Optical trapping and optical force positioning of two-dimensional materials

Nanoscale ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 1245-1255 ◽  
Author(s):  
M. G. Donato ◽  
E. Messina ◽  
A. Foti ◽  
T. J. Smart ◽  
P. H. Jones ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Optical Trapping ◽  
Layered Materials ◽  
Optical Force ◽  
Two Dimensional ◽  
Optical Forces ◽  
Two Dimensional Materials ◽  
Liquid Phase Exfoliation

Optical forces are used for trapping, characterization, and positioning of layered materials (hBN, MoS2, and WS2) obtained by liquid phase exfoliation.

Toward Understanding the Efficient Exfoliation of Layered Materials by Water-Assisted Cosolvent Liquid-Phase Exfoliation

2016 ◽  
Vol 28 (21) ◽  
pp. 7586-7593 ◽  
Author(s):  
Kausik Manna ◽  
Huin-Ning Huang ◽  
Wei-Ting Li ◽  
Yao-Huang Ho ◽  
Wei-Hung Chiang
Keyword(s):  
Liquid Phase ◽  
Layered Materials ◽  
Liquid Phase Exfoliation

scholarly journals Higher Ultrasonic Frequency Liquid Phase Exfoliation Leads to Larger and Monolayer to Few-Layer Flakes of 2D Layered Materials

Langmuir ◽  
2021 ◽  
Author(s):  
Madina Telkhozhayeva ◽  
Eti Teblum ◽  
Rajashree Konar ◽  
Olga Girshevitz ◽  
Ilana Perelshtein ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Layered Materials ◽  
Ultrasonic Frequency ◽  
2D Layered Materials ◽  
Liquid Phase Exfoliation

INFLUENCE OF LIQUID-PHASE OXIDATIVE TREATMENTS ON STRUCTURE AND HYDROPHILITY OF CARBON NANOTUBES

2019 ◽  
Vol 62 (11) ◽  
pp. 133-137
Author(s):  
Lyudmila V. Tabulina ◽  
Ivan V. Komissarov ◽  
Tamara G. Rusalskaya ◽  
Boris G. Shulitsky ◽  
Yuri P. Shaman ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Phase ◽  
Chemical Deposition ◽  
Volume Ratio ◽  
Structural Features ◽  
Destructive Effect ◽  
X Ray ◽  
Aqueous Suspensions ◽  
Transmission Electron ◽  
Before And After

Carbon nanotubes (CNTs) were synthesized by gas phase chemical deposition (CVD) using methane as a hydrocarbon reagent and using a catalyst of iron oxide deposited on fine aluminum oxide, as well as the same catalyst with the addition of molybdenum oxide deposited on fine magnesium oxide. The synthesized materials were treated with concentrated nitric acid (HNO3) or a mixture of concentrated nitric and sulfuric acids (HNO3 / H2SO4) in a volume ratio of 2: 1, at a temperature of 110-120 ° C for 1 h. Some of them were subjected to peroxide action (H2O2) before oxidative acid treatments for 1-2 h at a temperature of 100-110 ° C. Structural features, elemental compositions of synthesized CNTs were investigated before and after liquid-phase oxidative treatments by methods such as transmission electron microscopy, Raman spectroscopy, X-ray energy dispersive spectroscopy, X-ray phase analysis. In this work, the ability of CNTs that were undergone treatment in various oxidizing environments to form stable concentrated aqueous suspensions was studied. It was established that the initial defectity of the CNT molecules significantly affects the hydrophilic properties of oxidized CNT modifications. This causes their different ability to form concentrated, stable aqueous suspensions, predetermines the choice of combinations of oxidizing liquid-phase treatments that most contributing to this. It was revealed that HNO3 and HNO3 / H2SO4 mixture at the used temperature conditions of treatments and their duration do not have a strong destructive effect on the structure of CNT. The oxidative effect of these reagents on the molecules of this material is manifested mainly in defective places. The cleaning of the catalytic components of the synthesis from the catalytic components contributes to the more efficient purification of HNO3 / H2SO4 with the formation of stable aqueous suspensions from the molecules of this material, and this does not depend on the characteristics of the synthesis of the CNTs.

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