scholarly journals Organophosphorous pesticide removal from water by graphene-based materials - only adsorption or something else as well?

2021 ◽  
pp. 12-12
Author(s):  
Vladan Anicijevic ◽  
Marko Jelic ◽  
Aleksandar Jovanovic ◽  
Nebojsa Potkonjak ◽  
Igor Pasti ◽  
...  
Keyword(s):  
Point Defects ◽  
High Performance ◽  
Density Functional ◽  
Carbon Materials ◽  
Physical Factors ◽  
Toxic Compounds ◽  
Pesticide Removal ◽  
Chemical Agents ◽  
Organophosphorous Pesticide ◽  
Epoxy Groups

The extensive use of pesticides requires innovative approaches to remediate these compounds from the environment. Carbon materials are traditionally used as adsorbents for removing pesticides, and the development of new families of carbon materials allows more advanced approaches in environmental applications. Using Density Functional Calculations, we have predicted chemical reaction between the S(O)=P moieties of organophosphates with point defects in graphene - single vacancies, Stone-Wales defects and epoxy-groups. The reaction was confirmed using Ultra High Performance Chromatography for two graphene oxide samples and dimethoate as a representative of organophosphates. The exact reaction mechanism is still elusive, but it is unambiguously confirmed that no selective oxidation of dimethoate to more toxic oxo-analog occurs. Presented results can help develop novel systems for irreversible conversion of organophosphates to non-toxic compounds without using aggressive chemical agents or external physical factors like UV radiation.

Problems in Detoxifying Fresh Waters Polluted by Base Metal Minewaters

1971 ◽  
Vol 6 (1) ◽  
pp. 53-79
Author(s):  
Vaclav Kresta ◽  
Gerald B. Ward
Keyword(s):  
Chelating Agents ◽  
Toxicity Tests ◽  
Contaminated Water ◽  
Total Dosage ◽  
Toxic Compounds ◽  
Mining Sites ◽  
Know How ◽  
Chemical Agents ◽  
Copper And Zinc ◽  
Receiving Waters

Abstract At many mining sites process (milling) and drainage waters escape treatment and cause receiving waters to become contaminated above avoidance or even toxic levels for fish. The present know-how on chemical agents which can be used to complex with copper and zinc to form non-toxic compounds is limited to chelating agents such as NTA or EDTA. Preferential reaction with trivalent ions such as iron means that such ions must be tied up before complexation of copper and zinc can occur. As the amount of iron in contaminated water is usually two to eight times higher than that of copper and zinc, high dosages of chelating agents are usually required. In this project, the use of salts of anthranilic acid, especially calcium anthranilate, was investigated. The consumption of anthranilateions was found to be about the same as that of NTA or EDTA, i.e. four milligrams per milligram of copper or zinc. The total dosage to be applied to contaminated waters would be, however, several times lower as iron is not involved in the reactions and copper and zinc are complexed in that order. Toxicity tests to compare the efficiency and dasages of calcium anthranilate and NTA or EDTA are presently being carried out.

scholarly journals Strain Investigation on Spin-Dependent Transport Properties of γ-Graphyne Nanoribbon Between Gold Electrodes

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Li ◽  
Xiaobo Li ◽  
Shidong Zhang ◽  
Liemao Cao ◽  
Fangping Ouyang ◽  
...  
Keyword(s):  
Transport Properties ◽  
High Performance ◽  
Density Functional ◽  
Strain Engineering ◽  
Molecular Junctions ◽  
Spin Splitting ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Dependent Transport

AbstractStrain engineering has become one of the effective methods to tune the electronic structures of materials, which can be introduced into the molecular junction to induce some unique physical effects. The various γ-graphyne nanoribbons (γ-GYNRs) embedded between gold (Au) electrodes with strain controlling have been designed, involving the calculation of the spin-dependent transport properties by employing the density functional theory. Our calculated results exhibit that the presence of strain has a great effect on transport properties of molecular junctions, which can obviously enhance the coupling between the γ-GYNR and Au electrodes. We find that the current flowing through the strained nanojunction is larger than that of the unstrained one. What is more, the length and strained shape of the γ-GYNR serves as the important factors which affect the transport properties of molecular junctions. Simultaneously, the phenomenon of spin-splitting occurs after introducing strain into nanojunction, implying that strain engineering may be a new means to regulate the electron spin. Our work can provide theoretical basis for designing of high performance graphyne-based devices in the future.

scholarly journals Ultrafast mode-locking in highly stacked Ti3C2Tx MXenes for 1.9-μm infrared femtosecond pulsed lasers

Nanophotonics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1741-1751
Author(s):  
Young In Jhon ◽  
Jinho Lee ◽  
Young Min Jhon ◽  
Ju Han Lee
Keyword(s):  
High Performance ◽  
Density Functional ◽  
2D Materials ◽  
Density Functional Theory Calculations ◽  
Mode Locking ◽  
Infrared Range ◽  
Saturable Absorption ◽  
Pulsed Lasers ◽  
Saturable Absorbers ◽  
Layer Stacking

Abstract Metallic 2D materials can be promising saturable absorbers for ultrashort pulsed laser production in the long wavelength regime. However, preparing and manipulating their 2D structures without layer stacking have been nontrivial. Using a combined experimental and theoretical approach, we demonstrate here that a metallic titanium carbide (Ti3C2Tx), the most popular MXene 2D material, can have excellent nonlinear saturable absorption properties even in a highly stacked state due to its intrinsically existing surface termination, and thus can produce mode-locked femtosecond pulsed lasers in the 1.9-μm infrared range. Density functional theory calculations reveal that the electronic and optical properties of Ti3C2Tx MXene can be well preserved against significant layer stacking. Indeed, it is experimentally shown that 1.914-μm femtosecond pulsed lasers with a duration of 897 fs are readily generated within a fiber cavity using hundreds-of-layer stacked Ti3C2Tx MXene saturable absorbers, not only being much easier to manufacture than mono- or few-layered ones, but also offering character-conserved tightly-assembled 2D materials for advanced performance. This work strongly suggests that as-obtained highly stacked Ti3C2Tx MXenes can serve as superb material platforms for versatile nanophotonic applications, paving the way toward cost-effective, high-performance photonic devices based on MXenes.

scholarly journals Alloying effect on the order–disorder transformation in tetragonal FeNi

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-Yun Tian ◽  
Oliver Gutfleisch ◽  
Olle Eriksson ◽  
Levente Vitos
Keyword(s):  
Transition Temperature ◽  
High Performance ◽  
Density Functional ◽  
Permanent Magnets ◽  
Positive Impact ◽  
Design Strategies ◽  
Alloying Effect ◽  
Functional Theory ◽  
Disorder Transition ◽  
Disorder Transition Temperature

AbstractTetragonal ($${\hbox{L1}}_{0}$$ L1 0 ) FeNi is a promising material for high-performance rare-earth-free permanent magnets. Pure tetragonal FeNi is very difficult to synthesize due to its low chemical order–disorder transition temperature ($$\approx {593}$$ ≈ 593  K), and thus one must consider alternative non-equilibrium processing routes and alloy design strategies that make the formation of tetragonal FeNi feasible. In this paper, we investigate by density functional theory as implemented in the exact muffin-tin orbitals method whether alloying FeNi with a suitable element can have a positive impact on the phase formation and ordering properties while largely maintaining its attractive intrinsic magnetic properties. We find that small amount of non-magnetic (Al and Ti) or magnetic (Cr and Co) elements increase the order–disorder transition temperature. Adding Mo to the Co-doped system further enhances the ordering temperature while the Curie temperature is decreased only by a few degrees. Our results show that alloying is a viable route to stabilizing the ordered tetragonal phase of FeNi.

scholarly journals Three-dimensional tellurium and nitrogen Co-doped mesoporous carbons for high performance supercapacitors

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8628-8635
Author(s):  
Chang Ki Kim ◽  
Jung-Min Ji ◽  
M. Aftabuzzaman ◽  
Hwan Kyu Kim
Keyword(s):  
High Performance ◽  
Carbon Materials ◽  
Synergetic Effect ◽  
Three Dimensional ◽  
Mesoporous Carbons ◽  
Capacitive Performance ◽  
Nitrogen Doped ◽  
Carbon Based Nanomaterials ◽  
Nitrogen Doped Carbon ◽  
Co Doped

The incorporation of the Te element into nitrogen-doped carbon-based nanomaterials is a good strategy to improve the capacitive performance of carbon materials and the incorporation of two types of atoms improves the overall capacitive performance of the materials due to a synergetic effect.

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