metallic ions
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2022 ◽  
Vol 16 (1) ◽  
pp. 137
Author(s):  
Thanabalan Pitchay ◽  
Ali H. Jawad ◽  
Ili Syazana Johari ◽  
Sumiyyah Sabar

Immobilised chitosan on glass plates was used as an adsorbent for metallic ions from aqueous solutions in a batch adsorption system. Experiments were carried out as a function of contact time and initial metallic ions concentration. The adsorption efficiency increased with increasing initial metallic ions concentration (5 – 20 mg L-1) and the observed trend was: Ag2+ > Cu2+ > Ni2+ > Fe3+ > Cd2+ > Zn2+. The experimental data were fitted to pseudo-first, pseudo-second-order, intra-particle, and liquid film diffusion kinetic models. The applicability of the pseudo-second-order kinetic model indicated that the adsorption behaviour was ascribed by chemisorption. Further data analysis by the diffusion kinetic models suggested that the metallic ions adsorption was controlled by more than one step; adsorption at the active sites, intra-particle, and liquid film diffusion.


Author(s):  
Usanee Pantulap ◽  
Marcela Arango-Ospina ◽  
Aldo R. Boccaccini

AbstractBioactive glasses (BGs) have been a focus of research for over five decades for several biomedical applications. Although their use in bone substitution and bone tissue regeneration has gained important attention, recent developments have also seen the expansion of BG applications to the field of soft tissue engineering. Hard and soft tissue repair therapies can benefit from the biological activity of metallic ions released from BGs. These metallic ions are incorporated in the BG network not only for their biological therapeutic effects but also in many cases for influencing the structure and processability of the glass and to impart extra functional properties. The “classical” elements in silicate BG compositions are silicon (Si), phosphorous (P), calcium (Ca), sodium (Na), and potassium (K). In addition, other well-recognized biologically active ions have been incorporated in BGs to provide osteogenic, angiogenic, anti-inflammatory, and antibacterial effects such as zinc (Zn), magnesium (Mg), silver (Ag), strontium (Sr), gallium (Ga), fluorine (F), iron (Fe), cobalt (Co), boron (B), lithium (Li), titanium (Ti), and copper (Cu). More recently, rare earth and other elements considered less common or, some of them, even “exotic” for biomedical applications, have found room as doping elements in BGs to enhance their biological and physical properties. For example, barium (Ba), bismuth (Bi), chlorine (Cl), chromium (Cr), dysprosium (Dy), europium (Eu), gadolinium (Gd), ytterbium (Yb), thulium (Tm), germanium (Ge), gold (Au), holmium (Ho), iodine (I), lanthanum (La), manganese (Mn), molybdenum (Mo), nickel (Ni), niobium (Nb), nitrogen (N), palladium (Pd), rubidium (Rb), samarium (Sm), selenium (Se), tantalum (Ta), tellurium (Te), terbium (Tb), erbium (Er), tin (Sn), tungsten (W), vanadium (V), yttrium (Y) as well as zirconium (Zr) have been included in BGs. These ions have been found to be particularly interesting for enhancing the biological performance of doped BGs in novel compositions for tissue repair (both hard and soft tissue) and for providing, in some cases, extra functionalities to the BG, for example fluorescence, luminescence, radiation shielding, anti-inflammatory, and antibacterial properties. This review summarizes the influence of incorporating such less-common elements in BGs with focus on tissue engineering applications, usually exploiting the bioactivity of the BG in combination with other functional properties imparted by the presence of the added elements.


Author(s):  
Yi Shen ◽  
Yongfang Zhou ◽  
Hongying Li

Abstract The presence of metallic impurities in the electrolyte greatly affects electrocatalytic performance. A systematic study on this topic can not only provide guidance for rigorous practices on electrochemical measurements, but also in-depth fundamental understanding on the mechanisms of the electrochemical reactions. Herein, nine types of metallic ions including Cu2+, Ni2+, Fe3+, Fe2+, Co2+, Mn2+, Zn2+, Ce3+ and Al3+ are intentionally introduced into the electrolytes with a controlled manner and their effects on electro-oxidation of water, 5-hydroxymethylfurfural (HMF) and glycerol are investigated in details. Among these metal ions, Co2+ has the most pronounced effects on H2O electro-oxidation while Cu2+ species displays superior activity toward HMF and glycerol electro-oxidation, but negligible effects on H2O electro-oxidation. Such a unique feature of Cu2+ can also be noted from electro-oxidation of other small molecules, such as ethylene glycol, ethanol and furfural. More importantly, the effects of metallic impurities are independent of the composition of the electrodes, only rely on the pH of the electrolytes. In-situ electrochemical Raman spectroscopy, control electrochemical experiments and X-ray photoelectron spectroscopy analyses reveal that the origin of impurity effects is attributed to the formation of hydroxides during the electrochemical measurements.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Yang Xie ◽  
Lin Yu ◽  
Yuna Fu ◽  
Heng Sun ◽  
Jianhua Wang

Abstract Background Excessive aggregation of β-amyloid peptides (Aβ) is regarded as the hallmark of Alzheimer’s disease. Exploring the underlying mechanism regulating Aβ aggregation remains challenging and investigating aggregation events of Aβ in the presence and absence of metallic ions at molecular level would be meaningful in elucidating the role of metal cations on interactions between Aβ molecules. In this study, chemical self-assembled monolayer (SAM) method was employed to fabricate monolayer of β-amyloid peptides Aβ42 on gold substrate with a bolaamphiphile named 16-Mercaptohexadecanoic acid (MHA). Firstly, the samples of gold substrate (blank control), the MHA-modified substrate, and the Aβ42-modified substrate were detected by X-ray photoelectron spectroscopy (XPS) to track the self-assembly process. Aggregation behaviors of Aβ42 before and after metallic ions (Zn2+, Ca2+, Al3+) treatment were monitored by atomic force microscopy (AFM) and the interaction between Aβ42 and metallic ions (Zn2+, Ca2+, Al3+) was investigated by surface-enhanced Raman Scattering (SERS). Results The XPS spectra of binding energy of gold substrate (blank control), the MHA-modified substrate, and the Aβ42-modified substrate are well fitted with the corresponding monolayer’s composition, which indicates that Aβ42 monolayer is well formed. The recorded surface morphology of different experimental groups obtained by AFM showed markedly different nanostructures, indicating occurrence of aggregation events between Aβ42 molecules after adding metal ions to the solution. Compared to the control group, the presence of metallic ions resulted in the increased size of surface structures on the observed 3D topography. Besides, the intermolecular rupture force of Aβ42 increased with the addition of metallic ions. Further study by SERS showed that the Raman strength of Aβ42 changes significantly after the metal cation treatment. A considerable part of the amide bonds interacts with metal cations, leading to a structural change, which is characterized by the weakened β-fold Raman peak. Conclusion The AFM imaging results suggest that aggregation events occurred between Aβ42 molecules with the addition of metal cations. In addition, the results of force tests indicate that the presence of metallic ions could promote adhesion between Aβ42 molecules, which is likely to be the trigger for aggregation behavior of Aβ42. Furthermore, the effect of metallic cations on the conformational change of Aβ42 studied by SERS supported the results obtained by AFM. Taken together, the results showed that the presence of substoichiometric metal cations promotes aggregation behavior between Aβ42 molecules on the substrate at pH 7.4.


Author(s):  
Festus Chioma

Background and Objectives: The resistance of microbes against anti-bacteriological drugs leading to countless deaths and terminal ailments remains a basis for concern. Hence, the main interest of this study was to design, synthesize and report unusual compounds with basic hydrophilic moieties plus hydrophobic functions for anti-bacteriological studies. Materials and Methods: Analytical (melting points, micro-analysis (C. H.N.S) magnetic susceptibility (µeff), molar conductance plus solubility test) methods; spectral (Fourier Transform Infrared(FTIR)), electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance (1H- plus 13C-NMR), electronic(UV-Vis)) measurements; theoretical (DFT) evaluations were utilized for the characterization of the chelator and its chelates. All synthesized compounds were examined for antimicrobial and antioxidant potentials while the chelator was singly evaluated for solvent extractive capacity. Results: A nitrogenous based chelator-ligand, (E)-1-(((4,6-dimethylpyrimidin-2-yl)imino)methyl) naphthalen-2-ol(LH) synthesized through reflux-condensation reaction of 2-amino-4,6-dimethylpyrimidine with 2-hydroxy-1-napthaldehyde was acquired. Further reflux of the chelator-ligand with bivalent ions of iron-sulphate and zinc-acetate salts plus 2,2’-bipyridine resulted into separate bivalent-heteroleptic metallic chelates. The deprotonated nitrogen of the amine moiety and carbon of the carbonyl gave rise to the chelator-ligand with N2O2 chromophore detected around the metallic atom in the chelates. The µeff data plus UV-Vis spectral values of the chelates conformed to 6-coordinate octahedral geometry. All the chelates were high spin and non-ionic in dimethylsulfoxide (DMSO). The antimicrobial and antioxidant screening of the compounds presented moderate to fantastic results, while the metallic extractive proficiency of the chelator showed outstanding extractability for Fe2+ and Zn2+ions with an efficiency of 79.34% and 51.92% correspondingly. Conclusion: All the synthesized compounds are novel and demonstrated prospective biological, plus metallic ions’ extractive potentials required for designs plus isolation of products also for such actions.


2021 ◽  
Author(s):  
Yang Xie ◽  
Lin Yu ◽  
Yuna Fu ◽  
Heng Sun ◽  
Jianhua Wang

Abstract Background: Excessive aggregation of β-amyloid peptides (Aβ) is regarded as the hallmark of Alzheimer’s disease. Exploring the underlying mechanism regulating Aβ aggregation remains challenging and investigating aggregation events of Aβ in the presence and absence of metal ions at molecular level would be meaningful in elucidating the role of metal cations on interactions between Aβ molecules. In this study, chemical self-assembled monolayer (SAM) method was employed to fabricate monolayer of β-amyloid peptides Aβ42 on gold substrate with a bolaamphiphile named 16-Mercaptohexadecanoic acid (MHA). Firstly, the samples of gold substrate (blank control), the MHA-modified substrate and the Aβ42-modified substrate were detected by X-ray photoelectron spectroscopy (XPS) to track the self-assembly process. Aggregation behaviors of Aβ42 before and after metallic ions (Zn2+、Ca2+、Al3+) treated were monitored by atomic force microscopy (AFM) and the interaction between Aβ42 and metallic ions (Zn2+、Ca2+、Al3+) was investigated by surface-enhanced Raman Scattering (SERS), respectively.Results: The XPS spectra of binding energy of gold substrate (blank control), the MHA-modified substrate and the Aβ42-modified substrate are well fitted with the corresponding monolayer’s composition, which indicates that Aβ42 monolayer is well formed. The recorded surface morphology of different experimental groups obtained by AFM showed markedly different nanostructures, indicating occurrence of aggregation events between Aβ42 molecules after adding metal ions to the solution. Compared to the control group, the presence of metal ions resulted in the increased size of surface structures on the observed 3D topography. Further study by SERS showed that the Raman strength of Aβ42 changes significantly after the metal cation treatment. A considerable part of the amide bonds interacts with metal cations, leading to a structural change, which is characterized by the weakened β-fold Raman peak.Conclusion: The AFM imaging results suggest that aggregation events occurred between Aβ42 molecules with the addition of metal cations. Furthermore, the effect of metallic cations on the conformational change of Aβ42 studied by SERS supported the results obtained by AFM imaging. Taken together, the results showed that the presence of substoichiometric metal cations promotes aggregation behavior between Aβ42 molecules on the substrate at pH 7.4.


Author(s):  
Florina Cristiana Căpriță ◽  
Antoaneta Ene

In this article, it will be presented the results obtained from research conducted in order to reduce the concentrations of metals in industrial wastewater resulted from heavy metal polluting industries, especially the metallurgical industry. Most of the world's water sources are profoundly negatively affected by human activities, and the population faces critical water supply and drinking water quality problems. Millions of people develop various diseases from drinking water from unsafe or poor quality sources, creating a global public health problem. Due to massive industrialisation, current water treatment methods are outdated, which is why water treatment and purification laws, regulations, and controls need to be updated to minimise and stop contamination of the food chain. It is the responsibility of the researchers to make the public aware of the dangers to which they are exposed due to their own negligence and to offer possible solutions to these problems. New, reliable, viable, cheap, and sustainable technologies must be developed to improve drinking water quality. One such technology that can be developed and implemented is using the biological method of biosorption. Stranded seaweed on the Romanian Black Sea coast is currently treated as waste, but it could be exploited as biomass in the biosorption process. The research aimed to investigate the possibility of valorification of macrophyte seaweed species in this direction. Five different species of stranded macrophyte seaweed were collected and used to remove selected metallic ions (Cr, Fe, Zn, Cu) from a source of wastewater resulted from the metallurgical industry processes. The wastewater samples were analyzed before and after the application of the biosorption technique using the spectrophotometric method.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 1140
Author(s):  
IKHOU Djamila ◽  
M'hamed Kaid ◽  
ZIANI Hanane ◽  
Didier Villemein

This study has investigated the solvent extraction of cadmium and lead ions from an aqueous solution in nitrate medium using aminooctyldiphosphonic acid (AODPA) as extractant in chloroform. In order to establish spectrophotometrically the concentration of metal ion in the aqueous phase before and after extraction, the Arsenazo III method was used. The effects of several extraction parameters on the extraction of these metals ions  including volume ratio between the aqueous and organic phases (1–5), extraction kinetic time (0–30 min), molar ratio Q (1–5), addition of HNO3 (pH =2–6), addition of KNO3 (0.01 – 1M), temperature (10–40°C) and the synergetic effect by adding TOPO (solvating agent) were evaluated. Thermodynamic parameters including the Gibbs free energy (ΔG0),enthalpy (ΔH0), and entropy (ΔS0) were calculated. Performed experiments showed that Pb (II) can be extracted till 73% when Cd (II) can be recovered completely after two cycles. The extraction of both metallic ions was spontaneous, endothermic and with a slight randomness.  Positive synergetic effect was observed at  a chelating agent/TOPO ratio of 3. It is a very encouraging result which can lead us to recover cadmium and lower the concentration of lead from wastewater.


2021 ◽  
Vol 11 (21) ◽  
pp. 10404
Author(s):  
Berta Alcalde ◽  
Enriqueta Anticó ◽  
Clàudia Fontàs

Metal speciation studies are of great importance in assessing metal bioavailability in aquatic environments. Functionalized membranes are a simple tool to perform metal chemical speciation. In this study, we have prepared and tested a polymer inclusion membrane (PIM) made of the polymer cellulose triacetate (CTA), the extractant di-(2-ethylhexyl) phosphoric acid (D2EHPA), and the plasticizer 2-nitrophenyloctyl ether (NPOE) as a sensor for Zn and Cu complexation studies. This PIM, incorporated in a device with an 0.01 M HNO3 receiving solution, is shown to effectively transport free metal ions, and it is demonstrated that the presence of ligands that form stable complexes with divalent metallic ions, such as ethylenediaminetetraacetic acid (EDTA) and humic acid (HA), greatly influences the accumulation of the metals in the receiving phase due to the increasing metal fraction complexed in the feed phase. Moreover, the effect of major ions found in natural waters has been investigated, and it is found that the presence of calcium did not decrease the accumulation of either Zn or Cu. Finally, the PIM sensor has been used successfully to evaluate metal complexation in a river water affected by Zn pollution.


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