Effects of heavy metal ions on N-nitrosodimethylamine (NDMA) formation

RSC Advances ◽  
2016 ◽  
Vol 6 (74) ◽  
pp. 70474-70479
Author(s):  
Yameng Liu ◽  
Yongdong Liu ◽  
Rugang Zhong ◽  
Bin Peng ◽  
Henry F. Schaefer, III
Keyword(s):  
Density Functional Theory ◽  
Heavy Metal ◽  
Metal Ions ◽  
Metal Complexes ◽  
Heavy Metal Ions ◽  
Density Functional ◽  
Functional Theory

The mechanism of NDMA formation as affected by heavy metal complexes [MONO]+ (M = Cd, Pb, Hg) was investigated using density functional theory (DFT). Three possible NDMA formation pathways are discussed.

The adsorption of divalent heavy metal ions on (8,0) carbon nanotubes: The first-principles study

2020 ◽  
Vol 34 (32) ◽  
pp. 2050368
Author(s):  
Z. Zhu ◽  
L. An ◽  
T. Chen ◽  
X. Jia
Keyword(s):  
Carbon Nanotubes ◽  
Heavy Metal ◽  
Metal Ions ◽  
First Principles ◽  
Industrial Wastewater ◽  
Heavy Metal Ions ◽  
Density Functional ◽  
Physical Adsorption ◽  
Functional Theory ◽  
Sensing Material

In order to explore new ways to detect and remove heavy metal ions from industrial wastewater, the first-principles method based on density functional theory has been used to investigate the performance of carbon nanotubes (CNTs) in adsorbing divalent heavy metal ions which include Zn[Formula: see text], Cu[Formula: see text], Pb[Formula: see text] and Sn[Formula: see text]. Results show that the adsorption of Zn[Formula: see text] on CNTs is weak and only physical adsorption forms between them. However, for Cu[Formula: see text], Pb[Formula: see text] and Sn[Formula: see text], the final adsorption distance with CNTs is greatly decreased, and the adsorption energy and charge transfer amount with CNTs are significantly increased. In addition, the charge density of Cu[Formula: see text], Pb[Formula: see text] and Sn[Formula: see text] overlaps effectively with that of CNTs. These indicate the formation of strong chemisorption between these ions and CNTs. Therefore, CNTs could be used as a sensing material to detect and remove Cu[Formula: see text], Pb[Formula: see text] and Sn[Formula: see text] from wastewater. The research provides theoretical guidance for the application of CNTs in heavy metal ions treatment.

scholarly journals Zn2+ -Schiff’s base Complex as an “On-Off-On” Molecular Switch and a Fluorescence Probe for the Cu2+ and Ag+ ions

2021 ◽  
Author(s):  
Shaaban Elroby ◽  
Bashair Abdullah Banaser ◽  
Saadullah G Aziz ◽  
Abdesslem Jedidi ◽  
Walid I Hassan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Metal Ions ◽  
Metal Complexes ◽  
Density Functional ◽  
Molecular Switch ◽  
Basis Set ◽  
Schiff’S Base ◽  
Functional Theory ◽  
B3lyp Functional ◽  
Cis Isomer

Abstract The present study presents a thorough theoretical analysis of the electronic structure and conformational preference of the Schiff’s base ligand N,N-bis(2-hydroxybenzilidene)-2,4,6-trimethyl benzene-1,3-diamine (H2L) and its metal complexes with Zn2+, Cu2+ and Ag+ ions. The study aims to investigate the behavior of H2L and the binuclear Zn2+ complex (1), as fluorescent probes for the detection of metal ions (Zn2+, Cu2+ and Ag+) using Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TDDFT). The six conformers of the H2L ligand were optimized using B3LYP/6-311++G** level of theory, while the L-2-metal complexes were optimized by applying B3LYP functional with LANL2DZ/6-311++G** mixed basis set. The gas-phase and solvated Enol-cis isomer (E-cis) was found to be the most stable species. The absorption spectra of E-cis isomer and its metal complexes were simulated using B3LYP, CAM-B3LYP, M06-2X and ωB97X functionals with a 6-311++G** basis set for C, O, N and H atoms and LANL2DZ basis set for the metal ions (Zn2+, Cu2+ and Ag+). The computational results of B3LYP functional were in excellent agreement with the experimental ones. Hence, it has been adopted for performing the emission calculations. The results indicated that, the metal complex (1) can act as a fluorescent chemosensor, for the detection of Ag+ and Cu2+ ions through the mechanism of the Intermolecular Charge Transfer (ICT) and as a molecular switch “On-Off-On” via the replacement of Cu2+ by Ag+ ions, as proved experimentally.

A DFT-BASED ANALYSIS OF ADSORPTION PERFORMANCE OF CU2+ AND ZN2+ ON DEFECTIVE GRAPHENE FOR THE APPLICATION OF POLLUTING METAL IONS TREATMENT

2021 ◽  
pp. 2150061
Author(s):  
TAO CHEN ◽  
LIBAO AN ◽  
YAN ZHANG ◽  
XIAOTONG JIA
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Density Functional ◽  
Chemical Adsorption ◽  
Functional Theory ◽  
Adsorption Performance ◽  
The Density Functional Theory ◽  
Orbit Analysis ◽  
Defective Graphene

The density functional theory has been used to study the adsorption performance of polluting Cu[Formula: see text] and Zn[Formula: see text] ions on defective graphene. Compared to intrinsic graphene, the adsorption distance between defective graphene and Cu[Formula: see text]/Zn[Formula: see text] decreases greatly, and the adsorption energy and charge transfer amount increases significantly. The calculation of charge density demonstrates that clear hybridization happens between defective graphene and Cu[Formula: see text]/Zn[Formula: see text] ions, suggesting the formation of chemical adsorption. The frontier orbit analysis shows that defective graphene has greater electrical sensitivity after adsorbing Cu[Formula: see text]/Zn[Formula: see text] ions. Therefore, defective graphene could be a potential material for the treatment of contaminating heavy metal ions.

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