Sharif Digital Repository

An easily synthesized fluorescent probe for detecting copper in aqueous samples, with a short response time and at neutral pH, has been investigated. Through the chelation of Cu2+ ions or by binding to CuO nanoparticles, the fluorescence emission of the 2-(aminomethyl)aniline derivative H2L is quenched by over 50%. Spectroscopic determination of the association constants of H2L with some metal ions showed that the ligand has a higher affinity toward Cu2+ than toward other d-block metal ions. The comparative bonding ability of the aniline-based fluorescent probe in d-block metal complexes was studied in solution by a combination of UV-Vis, 1H NMR and mass spectrometry analyses. Besides these,... 

In this report, the synthesis of a new bi-macrocycle tweezer linked through an azobenzene moiety, L was undertaken. The characterization of the tweezer was accomplished by employing IR, 1H and 13C NMR, UV–vis, fluorescence spectroscopy and CHN microanalysis while the UV–visible spectroscopy illustrated a trans ⇆ cis photo-isomerization for L. According to our preliminary fluorescence observations, a metal-ion chemosensing behavior was established for trans-L isomer towards Cr(III) ion among the library metal ions. The quenching of the respective trans ⇆ cis isomerization in the presence of Cr(III) ion suggested the preference of a strong interaction between Cr(III) ion with L, leading to... 

In the present study, a ratiometric fluorescent sensor array as an artificial tongue has been developed on a nanopaper platform for chemical discrimination applications. The bacterial cellulose (BC) nanopaper was utilized for the first time as a novel, flexible, and transparent substrate in the optical sensor arrays for developing high-performance artificial tongues. To fabricate this platform, the hydrophobic walls on the BC nanopaper substrates were successfully created using a laser printing technology. In addition, we have used the interesting photoluminescence (PL) properties of an immobilized ratiometric probe (carbon dot-Rhodamine B (CD-RhB) nanohybrids) on the nanopaper platform to... 

In this research, an adsorbent with manifold interplay sites for the adsorption of sulfur components is developed in a silver ion functionalized Cr3+ based metal-organic framework (MIL-101(Cr)-SO3Ag). The adsorption performance of MIL-101(Cr), MIL-101(Cr)-SO3H, and MIL-101(Cr)-SO3Ag was evaluated in dynamic adsorption system in terms of its adsorption capacity. MIL-101(Cr)-SO3Ag could interact with H2S through multiple ways which performed about 4 times higher adsorption capacity (96.75 mg/g) rather than MIL-101(Cr); further, the high adsorption capacity of MIL-101(Cr)-SO3Ag was almost unchanged after five successive adsorption–desorption cycles, making it a potential adsorbent for an... 

Zeolite-based micromotors were developed to eliminate the biological and chemical contamination of water in a fast and efficient way. The motors consist of a silver-exchanged zeolite core and a partial catalytic coating. These porous engines showed rapid killing of Pseudomonas aeruginosa bacteria cells in a very short time, less than 7.5 minutes. The heavy metal uptake of the zeolitic motors during the first 20 minutes of contact was considerably higher than that of zeolite particles by 23% for Pb2+, 19% for Co2+, and 16% for Ni2+. Also, the maximum removal efficiency of the motors (at room temperature and for 6 hours) for Pb2+, Co2+, and Ni2+ was 93%, 87%, and 78%, respectively, higher than... 

This study aims to elucidate the impact of salinity on the interactions governing the adsorption of polar aromatic oil compounds onto calcite. To this end, molecular dynamics simulations were employed to assess adsorption of a model polar organic molecule (deprotonated benzoic acid, benzoate) on the calcite surface in NaCl brines of different concentration levels, namely, deionized water (DW), low-salinity water (LS, 5000 ppm), and sea water (SW; 45,000 ppm). Calcite was found to be completely covered by several well-ordered water layers. The top hydration layer is very compact and prevents direct adsorption of benzoates onto the substrate. Instead, Na+ ions form a distinct positively... 

A series of thiophene-based donor-acceptor-donor (D-A-D) oligomer substituted metalloporphyrins (MPors) with different 3d central metal-ions (M = Co, Ni, Cu, and Zn) were systematically investigated to screen efficient hybrid photocatalysts for CO2 reduction based on density functional theory (DFT) and time-dependent DFT simulations. Compared with base MPors, the newly designed hybrid photocatalysts have a lower bandgap energy, stronger and broader absorption spectra, and enhanced intermolecular charge transfer, exciton lifetime, and light-harvesting efficiency. Then, the introduction of D-A-D electron donor (ED) groups into the meso-positions of MPors is a promising method for the... 

Since compactness is a disadvantageous characteristic of chitosan-based membranes, two different methods were used to increase the porosity of the chitosan/poly(vinyl alcohol)/polyethyleneimine (CS/PVA/PEI) membrane, and its effect on copper ion adsorption was studied. In the first method, selective dissolution of poly(vinyl pyrrolidone) (PVP) induced porosity and for the second method, a mixed solvent system, which consists of a volatile solvent (acetone), was used to improve the porosity of the membrane. Different percentages of PVP showed inadequate performance, but acetone improved the operation efficiency of adsorption. The membranes were characterized by the analysis of FT-IR, SEM,... 

Ethylenediamine-functionalized Zr-based metal-organic framework (MOF, UiO-66-EDA) was prepared via Michael addition reaction to investigate its potential for adsorption of heavy metal ions from water. Specifically, the influence of agitation time, solution pH, the dosage of the adsorbent, initial metal ion concentration, temperature, and coexistence of other metal ions was investigated on the removal efficiency of UiO-66-EDA towards Pb(II), Cd(II), and Cu(II) metal ions. The pseudo-second-order kinetic model governed the adsorption of these ions onto the UiO-66-EDA. Langmuir isotherm model matched the experimental isotherm of adsorption with a maximum adsorption capacity of 243.90, 217.39,... 

Na3MnCO3PO4 (NMCP) is considered one of the promising cathode materials for sodium-ion batteries due to its high theoretical capacity. The hydrothermal method is an efficient, environmental-friendly, and simple route with low instrument cost to prepare active cathode materials such as NMCP. In this research, magnetic stirring was applied to promote the hydrothermal synthesis, and NMCP was produced by controlling different stirring times. This method results in the formation of pure NMCP upon only 45 min processing time. According to the ICP results, the Na to Mn ratio in the NMCP approached the stoichiometric value of 3 by prolonging the stirring time. By analyzing the charge-discharge... 

The present work is expressed to interpret the hydrodynamic parameters of rotation extraction columns in the reactive and non-reactive systems. The solvent extraction technique has been utilized for optimizing the transportation of molybdenum ions to the organic phase in two agitated columns (ORC and Kühni columns). Dispersed phase volume fraction, average droplet diameter, slip velocity, size distribution, and ions permeability of the aqueous phase have been investigated in terms of changing the operational variables including the agitation rate, flow rate of the inlet dispersed and continuous phases, column geometry, and reaction conditions. By considering the reactive and non-reactive... 

In this study, antibacterial activity, biocompatibility, and corrosion resistance of 316 LVM implants were improved using the development of HAp/GO/Ag nanocomposite coatings by the dip-coating method. The XRD and FTIR results confirmed the synthesis of HAp/GO/Ag nanocomposites. HAp/Ag nanoparticles (68 nm) bound to epoxy, hydroxyl, and carboxyl functional groups on GO sheets (size of GO sheets varies from 255 to 1480 nm) by electrostatic interaction. FESEM images showed that HAp/GO/Ag coatings had higher density and fewer micro-cracks than pure HAp coatings. In addition, HAp/GO/Ag coatings showed optimized nano-hardness (4.5 GPa) and elasticity modulus (123 GPa). The results of... 

Citric acid was polymerized onto the surface of functionalized multiwall carbon nanotubes (MWCNTCOOH) and MWCNT-graft-poly(citric acid) (MWCNTg-PCA) hybrid materials were obtained. Due to the grafted poly(citric acid) branches, MWCNT-g-PCA hybrid materials not only were soluble in water but also were able to trap water soluble metal ions. Reduction of trapped metal ions in the polymeric shell of MWCNT-g-PCA hybrid materials by reducing agents such as sodium borohydride led to encapsulated metal nanoparticles on the surface of MWCNT. Herein palladium nanoparticles were encapsulated and transported by MWCNT-g-PCA hybrid materials (MWCNT-g-PCA-EPN) and their application as nanocatalyst toward... 

Interaction of the DNA thymine base with Cu+ and Zn3+ was studied to explore: a) The metal binding energy (MIA) of thymine with Cu+ and Zn2+ and b) The possible correlation between charge transfer and MIAs. The gas-phase Cu+ and Zn2+ affinities of thymine, as well as the Mulliken charges, on the complexed metal cations were both determined at the same computational level, including the density functional level and employing the hybrid B3LYP exchange correlation potential in connection with the 6-311++G (d,p) basis set. All the molecular complexes were obtained by interaction between the most stable tautomer of thymine and two transition mono and divalent (Cu+, Zn2+) metal ions. To probe all... 

Here, the carboxamide ligand N-(thiazole-2-yl) picolinamide (L) was synthesized in an ionic liquid tetrabutylammonium bromide (TBAB) as the benign reaction medium. The sensitivity of L towards different metal-ions was investigated, and a comprehensive, logical optical investigation was conducted for the IIB transition metal ions, Hg2+, Cd2+ and Zn2+, based on off-on switch sensor protocols. In the absence of these metal ions, L showed weak emission only, but fluorescence intensity increased considerably upon their addition to a sensitivity range of 10-6 M. This phenomenon was enhanced significantly in the presence of Zn2+ compared to other metal ions, likely due to the coordination of... 

Polyaniline/graphene oxide (PANI/GO) co-doped with Zn2+ and Fe3+ was synthesized via a simple and low cost one-step chronoamperometry method on stainless steel (SS) as the substrate. The Fe3+-Zn2+-PANI/GO nanocomposite is characterized using X-ray diffraction as well as Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. Also, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy are used to study the electrochemical performance of the as-prepared electrode materials. Significantly, the Fe3+-Zn2+-PANI/GO nanocomposite exhibits a specific... 

Polyaniline/graphene oxide (PANI/GO) co-doped with Zn2+ and Fe3+ was synthesized via a simple and low cost one-step chronoamperometry method on stainless steel (SS) as the substrate. The Fe3+-Zn2+-PANI/GO nanocomposite is characterized using X-ray diffraction as well as Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. Also, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy are used to study the electrochemical performance of the as-prepared electrode materials. Significantly, the Fe3+-Zn2+-PANI/GO nanocomposite exhibits a specific... 

Density functional theory (DFT) calculations were performed at the B3LYP level with a 6-311++G(d,p) basis set to systematically explore the geometrical multiplicity and binding strength for complexes formed by Li+, Na+, and K+ with cytidine and 2′-deoxycytidine. All computational studies indicate that the metal ion affinity (MIA) decreases from Li+ to Na+ and K+ for cytosine nucleosides. For example, for cytidine the affinity for the above metal ions are 79.5, 55.2, and 41.8 and for 2′-deoxycytidine, 82.8, 57.4, and 42.2 kcal/mol, respectively. It is also interesting to mention that linear correlations between calculated MIA values and the atomic numbers (Z) of the above metal ions were... 

The binding of Mg 2+, Ca 2+, Zn 2+ and Cu + metal cations to 2′-deoxyguanosine has been analyzed, using the hybrid B3LYP, Density Functional Theory (DFT) method and 6311++G(d,p) orbital basis sets. Coordination geometries, absolute metal ion affinities, and free energies for the most stable complexes formed by Mg 2+, Ca 2+, Zn 2+ and Cu + with the nucleoside, 2′-deoxyguanosine, have been determined. Furthermore, the influences of metal cationization on the strength of the N-glycosidic bond, torsion angles and angle of Pseudorotation (P) have been studied. With respect to the results, it has been found that metal binding significantly changes the values of the phase angle of Pseudorotation...