Metal Ions Mn Research Articles

Determination of Stability Constant of The Complexes of Metal Ion Fe(III), Mn(II) And Cr(III) With Some Substituted 2-Oxo-2H-Chromene-3-Carbohydrazide Derivatives at 0.1 M Ionic Strength at 42oC

Proton ligand and metal ligand stability constant are measured for Fe(III) and 1, 2-dihydroxy benzene and 1, 5-disulphonic acid complexes . Determination of stability constant of substituted of pyrazoles with rare earth metals form complexes are reported . Effect of temperature on formation constants of 2 acetylpyridine(N benzoyl)glycine hydrazone with lanthanide(III) ions at different ionic strengths are reported. Irving and Rossotti, Herson and Gilbert , Wilkins and Lewis and Rossotti and Rossotti have determined stability constant by Bjerrum-Calvin titration technique . Kabadi , Jahagirdar and Narwade have determined pK values of salicylaldehyde, salicylic acid and sulphonic acid respectively by similar procedure. The metal ligand stability constant of some β-diketones are reported . Stability constants have investigated for some substituted pyrazolines, isoxalline and diketone . The method most frequently applied for study of complex equilibria is pH-metric titration technique . Stepwise formation of mononuclear binary complexes is described by set of equilibrium constants. For pH-metric measurements an electrode must be selected. According to Bjerrum, Martell and Calvin , the formation of complex MLN is stepwise process and one has to deal with a series of equilibria of the type: Irving and Rossotti, Herson and Gilbert , Wilkins and Lewis and Rossotti and Rossotti have determined stability constant by Calvin-Bjerrum titration technique . The value of nA,n, pK, log K1 and log K2 are evaluated by Irving and Rossotti's equation. The stability constant and thermodynamic parameters of complexes containing lighter lanthanides , copper(II) , calcium and magnesium are reported. It is also important in environmental studies , medicinal and industrial chemistry . Effects of transition metal on stability constant of complexes have studied by pH metric method . Bendi , Janrao and Ramteke have studied stability constant of ligands with lanthanide metals complexes.The present work involves pH metric study of substituted 2-oxo-2H-chromene-3-carbohydrazide derivatives with metal ions Fe(III), Mn(II), Cr(III) and Ti(III) at temperature42oC. The Bjerrum-Calvin titration technique as modified by Irving and Rossotti has been employed in the present study. The following three sets of titrations are carried out in sequence.

Iron-Manganese Bimetallic-Organic Framework as A Photocatalyst for Degradation of Rhodamine B Organic Dye Under Visible Light

In recent years, there have been many research works on use of different methods to treat textile dyeing wastewater such as mechanical, biological and chemical methods (using oxidizing agents, such as: H2O2, O3, and H2O2/O3). However, some traditional textile dyeing wastewater treatment methods such as mechanical and biological methods have limitations in treating these pollutants thoroughly. To enhance the treatment efficiency, the use of photocatalysts combination with strong oxidizing agents, such as H2O2, has been extensively developed in recent years. In this study, the iron-centred bimetallic organic framework Fe-MOF has been synthesized by partial replacement of Fe3+ ions with Mn metal ions by solvent-thermal method. The analytical methods used to evaluate the structural characterization of the as-synthesized materials including Scanning Electron Microscope (SEM), Brunaurer-Emmett-Teller (BET), X-ray Diffraction (XRD), Fourier Transform Infra Red (FT-IR), and UV-Vis Diffuse Reflectance Spectroscopy (DRS). The experiments on the decomposition of organic pigment Rhodamine B were performed under varying conditions of pH, catalyst mass and RhB colorant concentration. Experiments with different electron capturers indicate that h+ plays a major role in the photochemical degradation of RhB. The stability and durability of the 0.1 Mn/Fe-MOF catalyst were evaluated through the leaching and recycle experiments, showing that the RhB degradation efficiency of the photocatalyst decreased modestly after five repetitions. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The Manganese Peroxidase Gene Family of Trametes trogii: Gene Identification and Expression Patterns Using Various Metal Ions under Different Culture Conditions.

Manganese peroxidases (MnPs), gene family members of white-rot fungi, are necessary extracellular enzymes that degrade lignocellulose and xenobiotic aromatic pollutants. However, very little is known about the diversity and expression patterns of the MnP gene family in white-rot fungi, especially in contrast to laccases. Here, the gene and protein sequences of eight unique MnP genes of T. trogii S0301 were characterized. Based on the characteristics of gene sequence, all TtMnPs here belong to short-type hybrid MnP (type I) with an average protein length of 363 amino acids, 5–6 introns, and the presence of conserved cysteine residues. Furthermore, analysis of MnP activity showed that metal ions (Mn2+ and Cu2+) and static liquid culture significantly influenced MnP activity. A maximum MnP activity (>14.0 U/mL) toward 2,6-DMP was observed in static liquid culture after the addition of Mn2+ (1 mM) or Cu2+ (0.2 or 2 mM). Moreover, qPCR analysis showed that Mn2+ obviously upregulated the Group I MnP subfamily (T_trogii_09901, 09904, 09903, and 09906), while Cu2+ and H2O2, along with changing temperatures, mainly induced the Group II MnP subfamily (T_trogii_11984, 11971, 11985, and 11983), suggesting diverse functions of fungal MnPs in growth and development, stress response, etc. Our studies here systematically analyzed the gene structure, expression, and regulation of the TtMnP gene family in T. trogii, one of the important lignocellulose-degrading fungi, and these results extended our understanding of the diversity of the MnP gene family and helped to improve MnP production and appilications of Trametes strains and other white-rot fungi.

Screening of Alkaline Tolerant Xylanase Strains in Rhizomyidae Intestines and Study on Enzymatic Properties

In order to obtain xylanase with good acid and alkali resistance, to solve the application problem of xylanase in the actual industry. In this study, xylan was used as the sole carbon source. From the intestines and feces of Yibin bamboo rats, the Congo red fading method was used to determine the xylanase activity for re-screening, and one strain with alkaline xylan was screened. Carbohydrase activity strain JZF, 16SrDNA sequence analysis, identified as Bacillus mycoides, the growth curve of Bacillus mycoides JZF, the enzyme production curve and the enzymatic properties of alkaline xylanase explore. The results showed that the enzyme activity of this strain reached 15.17 U/mL after cultured at 37 ℃ and 180 r/min for 48 h; the amount of bacteria reached the maximum after 28 h, the xylanase activity reached the maximum after 72 h, and the most suitable reaction temperature for the produced xylanase was 50 ℃,and the optimum pH was 9.0; the relative enzyme activity could be maintained above 60% under the conditions of 40~60 ℃ and pH8.0~9.0. The metal ions Mn2+ and Ca2+ had obvious effects on the xylanase of this strain. The xylanase produced by the strain obtained in this study has good activity under alkaline conditions, which provides a source and data basis for the subsequent practical application of alkaline xylanase.

Synthesis and Discovery of Schiff Base Bearing Furopyrimidinone for Selective Recognition of Zn2+ and its Applications in Cell Imaging and Detection of Cu2.

A simplefuro [2,3-d]pyrimidinone-based Schiff base FPS was synthesized via aza-Wittig reaction and structure elucidation was carried out by spectroscopic studies FT-IR, 1H NMR, and 13C NMR and mass spectrometry. FPS showed weak fluorescence emission in methanol and the selectivity of FPS to different metal ions (Mn2+, Ca2+, Fe2+, Fe3+, Mg2+, Al3+, Ba2+, Ag+, Co2+, Na+, K+, Cu2+, Zn2+, Pb2+, Bi3+) were studied by absorption and fluorescence titration. The results show that FPS has selective fluorescence sensing behavior for Zn2+ ions and the limit of detection (LOD) was calculated to be 1.19 × 10–8 mol/L. Moreover, FPS-Zn2+ acts as a metal based highly selective and sensitive new chemosensor for Cu2+ ions and the LOD was calculated to be 2.25 × 10–7 mol/L. In accordance with the results and theoretical calculations, we suspected that the binding mechanisms of FPS to Zn2+ and Cu2+ were assigned to be the cooperative interaction of Zn2+(Cu2+)-N.

Removal of Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II), and Pb(II) from water solutions using activated carbon based on cherry kernel shell powder

In this work, a method for preparing activated carbon based on cherry kernel shell (AC-CKS) was investigated using two consecutive steps: chemical activation with H2SO4 agent and thermal activation in air. For the first time, AC-CKS product is used for the removal of numerous metal ions such Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II), and Pb(II) from water solutions. The AC-CKS was characterized using EA, FTIR, SEM, EDX, and XRF techniques. The AC-CKS obtained by heating at 600 °C showed product with higher iodine number and invariably micro-size pores compared to those obtained by heating at 55°C and 400°C. Adsorption capacity of AC-CKS600 was tested in removal of previously mentioned metal ions. The essential parameters affecting the removal of metal ions were studied. The results showed maximum adsorption of 99.0% for Cr(III), 91.7% for Fe(III), 62.0% for Cu(II), 59.3% for Pb(II), 42.0% for Zn(II), 28.0% for Ni(II), and 26.9% for Mn(II). The adsorption data of most metal ions fitted well with Langmuir model. The maximum adsorption capacity followed the sequence: Cr(10.75 mg/g)>Fe(10.15 mg/g)>Cu(7.58 mg/g)>Pb(7.36 mg/g)>Zn(6.08 mg/g)>Ni(2.83 mg/g)>Mn(2.29 mg/g). The adsorption kinetics was tested for the pseudo-first order and pseudo-second order. The rate constants of adsorption for all studied metal ions were calculated. Good correlation coefficients (R2>0.9972) were obtained for the pseudo-second order kinetic model showing that all metal ions uptake processes followed the pseudo-second order rate expression. Desorption studies showed the quantitative recovery of metal ions in the range from 89.4% for Pb(II) to 94% for Cr(III). According to the adsorption model applied in this work, AC-CKS600 product could be recommended for the removal of Cr(III), Fe(III), Cu(II), Pb(II), and Zn(II) from aqueous solutions.

Mapping heavy metals contamination and eco-risk along Mediterranean Sea coast, Egypt

The study was selected according to its variability in resources and its important location parallel to an important protectorate. This coastal zone is characterized by different land use/cover activities (water, industrial site, agricultural areas, bare land, vegetative areas, fish farms, and sabkha). Twelve sites were selected along this part of the Mediterranean deltaic coast, each distance between every site is nearly 5 km. water and sediment samples were collected for the determination of these metal ions (Fe, Mn, Zn, Cu, Ni, Pb, Cd, and Co). The average concentrations of heavy metals are 56.50, 2.53, 24.77, 4.28, 0.88, 18.37, 0.97 and 0.06 µg/l in water and 7284.58, 132.60, 13.52, 2.99, 8.36, 4.84, 0.36 and 4.32 µg/g in sediments for Fe, Mn, Zn, Cu, Ni, Pb, Cd, and Co, respectively. The concentrations of these metals (Zn, Cu, Ni, Pb, and Cd) are within the Australian guideline of marine sediments, but Zn, Cu, and Cd in water exceed these limits. Cadmium was the most abundant element in the coastal marine sediments. The heavy metal pollution index for marine water of the study area is within the normal limits except for site 12. The risk index of metals gives a low-risk category. The principal component analysis indicated that site 11 was related by dissolved Pb in seawater and Fe in sediments, this is maybe interpreted by the nature of sediment texture and different shipping activities. Mapping the spatial distribution of metals and their risk categories is an aid in monitoring environmental problems and quantifying their magnitudes.

The role of metal ions in the behavior of bovine serum albumin molecules under physiological environment

Metal ions released from metallic implants can affect the conformation and structural stability of proteins in biological fluids, which eventually affects the biocompatibility of implants. The present study aimed at understanding the interactions between the metal ions (Mn2+, Fe2+, Fe3+, Co2+, Cu2+, and Zn2+) and bovine serum albumin (BSA) molecules in physiological context. The structural information of BSA molecules and the microenvironment of functional groups were investigated using UV, Raman, and circular dichroism spectroscopy. The results revealed that addition of Fe3+, Fe2+, and Cu2+ ions alters the tertiary structure of BSA molecules and exposes the aromatic heterocyclic hydrophobic group of BSA amino acid residues. The addition of Fe3+ and Cu2+ ions results in increased viscosity and decreased intensity of the water peak in the BSA solution. Furthermore, Fe3+ and Cu2+ ions evidently promote the α-helix to β-sheet transformation of BSA molecules due to decreased disulfide bond stability. Tryptophan residues of BSA and metal ions containing BSA (Me+/BSA) solutions were found to be in a hydrophilic environment. Moreover, the addition of metal ions to BSA results in several of tyrosine residues acting as hydrogen-bond donors. Coomassie brilliant blue staining revealed that the addition of Cu2+ ions promotes the aggregation of BSA molecules. The findings of this study will be helpful for evaluating the biocompatibility of metallic implants.

Manganese(II), cobalt(II) and nickel(II) complexes constructed from a pyridyloxy-functionalized hexapodal cyclophosphazene ligand: Structural and magnetic studies

Herein, the coordination behaviour of a hexapodal building block, 2,2,4,4,6,6-hexakis((6-methylpyridin-3-yl)oxy) cyclotriphosphazene (MeHPCP), towards divalent metal ions (Mn, Co and Ni) is described. Three new coordination compounds, namely the molecular complex [Mn(MeHPCP)(Cl)2(H2O)2] (1) and the one-dimensional (1D) zig-zag chain coordination polymers {Co2(MeHPCP)(Cl)4(H2O)2](MeCN)(H2O)3}n (2) and {[Ni(MeHPCP)(Cl)2(H2O)]}n (3), were structurally characterized by FT-IR spectroscopy and single crystal X-ray diffraction analysis. Thermogravimetric analyses show that all the compounds have high thermal stability (>350 °C). The magnetic properties of 2 and 3 were analyzed by electron spin resonance (ESR) and the physical properties measurement system (PPMS) technique and these complexes exhibited paramagnetic behavior.

Characterization and Application of a New β-Galactosidase Gal42 From Marine Bacterium Bacillus sp. BY02.

β-Galactosidase plays an important role in medicine and dairy industry. In this study, a new glycoside hydrolase family 42 (GH42) β-galactosidase-encoding gene, gal42, was cloned from a newly isolated marine bacterium Bacillus sp. BY02 and expressed in Escherichia coli. Structural characterization indicated that the encoding β-galactosidase, Gal42, is a homotrimer in solution, and homology modeling indicated that it retains the zinc binding sites of the Cys cluster. The reaction activity of Gal42 was significantly increased by Zn2+ (229.6%) and other divalent metal ions (Mn2+, Mg2+, and Co2+), while its activity was inhibited by EDTA (53.9%). Meanwhile, the thermo-stability of the Gal42 was also significantly enhanced by 5 and 10 mM of zinc ion supplement, which suggested that the “Cys-Zn” motif played important roles in both structural stability and catalytic function. Furthermore, Gal42 showed effective lactose hydrolysis activity, which makes the enzyme hydrolyze the lactose in milk effectively. These properties make Gal42 a potential candidate in food technology.

Purification and Characterization of a Novel Alginate Lyase from a Marine Streptomyces Species Isolated from Seaweed.

Alginate, a natural polysaccharide derived from brown seaweed, is finding multiple applications in biomedicine via its transformation through chemical, physical, and, increasingly, enzymatic processes. In this study a novel alginate lyase, AlyDS44, was purified and characterized from a marine actinobacterium, Streptomyces luridiscabiei, which was isolated from decomposing seaweed. The purified enzyme had a specific activity of 108.6 U/mg, with a molecular weight of 28.6 kDa, and was composed of 260 amino acid residues. AlyDS44 is a bifunctional alginate lyase, active on both polyguluronate and polymannuronate, though it preferentially degrades polyguluronate. The optimal pH of this enzyme is 8.5 and the optimal temperature is 45 °C. It is a salt-tolerant alginate lyase with an optimal activity at 0.6 M NaCl. Metal ions Mn2+, Co2+, and Fe2+ increased the alginate degrading activity, but it was inhibited in the presence of Zn2+ and Cu2+. The highly conserved regions of its amino acid sequences indicated that AlyDS44 belongs to the polysaccharide lyase family 7. The main breakdown products of the enzyme on alginate were disaccharides, trisaccharides, and tetrasaccharides, which demonstrated that this enzyme acted as an endo-type alginate lyase. AlyDS44 is a novel enzyme, with the potential for efficient production of alginate oligosaccharides with low degrees of polymerization.

Development of Cotton Linter Nanocellulose for Complexation of Ca, Fe, Mg and Mn in Effluent Organic Matter

Effluent organic matter (EfOM) is present in different domestic and industrial effluents, and its capacity to hold metallic ions can interfere in the wastewater treatment process. Due to the low quality of water, new sustainable technologies for this purpose have become extremely important, with the development of renewable-source nanomaterials standing out in the literature. Nanocellulose (NC) deserves to be highlighted in this context due to its physicochemical characteristics and its natural and abundant origin. In this context, the interactions between NC extracted from cotton linter, organic matter fraction (humic substances) and metal ions have been evaluated. Free metal ions (Ca, Fe, Mg and Mn) were separated by ultrafiltration and quantified by atomic absorption spectrometry. The nanomaterial obtained showed potential for the treatment of effluents containing iron even in the presence of organic matter. The probable interaction of organic matter with NC prevents the efficient removal of calcium, magnesium and manganese. For these elements, it is desirable to increase the interaction between metal and NC by modifying the surface of the nanomaterial.

Bioleaching Coal Gangue with a Mixed Culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans

A mixed culture of A. ferrooxidans and A. thiooxidans isolated from a coal gangue dump was used to bioleach coal gangue in a column reactor to investigate the leaching of elements. The changes of metal ions (Fe, Mn and Cr) and sulfate in the leaching solution, elemental composition, mineral components and sulfur speciation of the coal gangue before and after bioleaching were analyzed by atomic absorption, anion chromatography, XRF, XRD and XPS. The results show that the mixed culture could promote the release of metal ions in coal gangue, with a leaching concentration of Fe > Mn > Cr. EC and Eh have significantly increased with the increase of metal ion concentrations in the leaching solution. XRF analyses show that the contents of Fe, Mn and S decreased in coal gangue after bioleaching. XRD results suggest that the bioleaching has impacts on minerals in coal gangue, particularly the Fe-containing components. XPS analyses show that sulfur speciation in the raw gangue samples was associated with sulfate, dibenzothiophene and pyrite sulfur. After continuous leaching by the mixed culture, the total sulfur, pyrite sulfur and sulfate sulfur in coal gangue decreased from 2.06% to 1.18%, 0.66% to 0.14% and 1.02% to 0.52%. The desulfurization rates of the pyrite and sulfate were 78.79% and 49.02 %. It is concluded that the mixed culture of these two microorganisms could effectively leach metals from coal gangue coupling with the oxidation of sulfide to sulfate. This study has provided fundamental information as a potential application in the recovery of valuable metals from coal gangue or environmental remediation related to gangue in the future.

Stability constants and thermodynamic behaviour of the complex formation of two crown ethers with zinc (II) and copper (II) ions in water + acetonitrile mixed solvent: a conductivity measurement study

ABSTRACT We have investigated the behaviour of change of molar conductivity of mixtures of two crown ethers (CE) (18-Crown-6; 18C6 and 24-Crown-8; 24C8) and metal ions (Mn+) (Zn2+ and Cu2+) and the complexation between CE and Mn+ in water + acetonitrile binary solvent system (20, 40, 60 and 80%; v/v) at 298.15 K to 328.15 K by conductometric technique. K f values for all complexes were found to be decreased with enhancement of temperature. Complexes associated with Zn2+ exhibit a trend of K f: 24C8 + Zn2+ > 18C6 + Zn2+ in 20% solvent composition (water-acetonitrile) and order of 18C6 + Zn2+ > 24C8 + Zn2+ was found for 80% solvent composition. However, logarithm values of K f for the Cu2+ complexes were found to obey the order of 24C8 > 18C6 almost for all compositions except with a few exceptions. was found to be negative indicating spontaneous complexation between CE and Mn+.

Potentiometric determination of stability constants of ternary complexes of first row transition metal ions with ditopic azelaic acid dihydrazide and aspartic acid in aqueous medium

A Chemical speciation study of ternary complexes containing transition metal ions (Mn2+,Co2+,Ni2+, Cu2+ and Zn2+) with a ditopic novel ligand L ​= ​Azelaic acid dihydrazide (AZDH) and X ​= ​l-Aspartic acid of type [MmLlX xHh], (where m ​= ​1, 2; l ​= ​1; x ​= ​1, 2 and h ​= ​−2 to 5) in different ratios of M:L:X ​= ​1:1:1, 1:2:1, 2:1:1and 2:1:2 was carried out using pH -potentiometric method of data acquisition and applied to chemometric modelling methods of analysis. MINIQUAD-75 program was used for the resolution of the plausible species and their corresponding formation constants at 303 ​± ​0.1 ​K, and 0.01 ​M ionic strength. Species concentration distribution diagrams were generated using HySS program. Best-fit chemical models were selected on the basis of statistical parameters like Standard deviation (SD), U (sum of the squares of the residuals in mass balance equations), and chi-square test etc. Relatively stable ternary complexes were evaluated quantitatively using Δlog K formulation. All the formation constants for the species were compared for Irving-Williams order of stability.

Analysis of the effect of doped metal ions in the tricalcium phosphate bioceramic

Calcium phosphate bioceramics such as hydroxyapatite (HA) and tricalcium phosphate (TCP) were successfully used in medical fields such as dentistry, orthopedics, and facial surgery due to their resorption and bioactivity characteristics. This work aims to obtain an osteoinductive ceramic matrix doped with metal ions. First, TCP doped with 10 mol.% of MgO was selected for the initial matrix due to the increased of HA content, microstructure densification (90%), and mechanical strength (27 MPa). Second, the addition of others metal ions (Zn, Mn, and Fe), at most 5 mol.%, to this initial matrix was evaluated by means of statistical analysis applying design of experiments (DOE). The presence of metal ions was studied by XRD and SEM-EDX analysis. The trace plots and equations were obtained for apparent and relative densities, apparent porosity, and diametral compression resistance, all for a 95% confidence interval and maximum error of p < 0,05. The results show a strong dependency between the addition of these metal ions and all studied properties.

Hypergolic coordination compounds as modifiers for ionic liquid propulsion

Ionic liquids (ILs) have been regarded as green hypergolic materials since 2008, and hundreds of hypergolic ionic liquids have been reported thus far. However, only few have been proved to meet practical applications, due to their complex preparation technology and long hypergolic ignition delay (ID). Herein, to improve the properties of hypergolic ignition of ILs, we demonstrate a new design strategy of hypergolic coordination compounds (HCCs). Eight HCCs were synthesized based on two commonly used hypergolic ILs components (imidazolium = IM, dicyanamide = DCA) and four transition metal ions (Mn, Co, Ni, Cu) and were characterized through infrared spectroscopy, X-ray powder diffraction, and single-crystal X-ray diffraction. The experimental results showed that these HCCs exhibited excellent hypergolic ignition properties, and the ignition and combustion properties could be modulated by changing the metal, ligand, and anion. Additionally, the effects of HCCs on the ignition and combustion of organic hypergolic IL were investigated. The Cu-based HCCs showed the best performance among these new hypergolic materials. Compared with the HCCs-free IL, the IL system with 5% of [Cu(AIM)4](DCA)2 exhibited a sharp reduction in the ID time of 1-allyl-3-methylimidazolium dicyanamide (AMIMDCA) (6 ms vs. 45 ms).

Adsorption of Metal Ion Manganese (Mn) in Sodium Silicate Solution using Chitosan

High purity Silica precipitate is very potential materials which can be utilized for many applications for high grade silicon, filler, photovoltaic, catalytic chemical, etc. Indonesia has abundant natural resources including quartz sand as raw materials for making high purity silica precipitate. Silica precipitate is made by roasting quartz sand forming sodium silicate solution. In order to obtain high purity silica precipitate, purification of sodium silicate solution is needed. In this study, purification of sodium silicate solution is performed by adsorption process of metal ion manganese (Mn) using chitosan as adsorbent. The experiment was done using batch technique. The variation of adsorption process was performed to get optimum conditions such as sample concentration, adsorbent mass, contact time, pH and temperature. The adsorption of metal ions of Mn was analyzed by atomic adsorption spectroscopy. The result of experiment shows that the best mass of chitosan for Mn adsorption process is 0.2 grams which gives percentage adsorption of 56.63%. The optimum contact time is 30 minutes, it results percentage adsorption of 52.5%. The optimum pH 3 gives adsorption percentage of 58.67%. And the best temperature for adsorption is at 60 °C with the percentage adsorption of 65.72%. Adsorption mechanism of metal ion Mn follow the isotherm model of langmuir and freundlich with the linearity value of R2 = 0.99 and 0.98 respectively.

Naphthalimide-phenanthroimidazole incorporated new fluorescent sensor for “turn-on” Cu2+ detection in living cancer cells

In recent years, fluorescent sensors have emerged as attractive imaging probes due to their distinct responses toward bio-relevant metal ions. However, the bioimaging application main barrier is the ‘turn-off’ response toward paramagnetic metal ions such as Cu2+ under physiological conditions. Herein, we report a new sensor (2-methyl(4-bromo-N-ethylpiperazinyl-1,8-naphthalimido)-4-(1H-phenanthro[9,10-d]imidazole-2-yl) phenol)NPP with multifunctional (Naphthalimide, Piperazine, Phenanthroimidazole) units for fluorescent and colourimetric detection of Cu2+ in an aqueous medium. Both absorption and fluorescence spectral titration strategies were used to monitor the Cu2+-sensing property of NPP. The NPP displays a weak emission at ca. 455 nm, which remarkably enhances (⁓3.2-fold) upon selective binding of Cu2+ over a range of metal ions, including other paramagnetic metal ions (Mn2+, Fe3+, Co2+). The stoichiometry, binding constant (Ka) and the LOD (limit of detection) of NPP toward Cu2+ ions were found to be 1:1, 5.0 (± 0.2) × 104 M−1 and 6.5 (± 0.4) × 10−7 M, respectively. We have also used NPP as a fluorescent probe to detect Cu2+ in live (human cervical HeLa) cancer cells. The emission intensity of NPP was almost recovered in HeLa cells by incubating ‘in situ’ the derived Cu2+ complex (NPP-Cu2+) in the presence of a benchmark chelating agent such as EDTA (ethylenediaminetetraacetate). The fluorescent emission of NPP was reverted significantly in each cycle upon sequencial addition of Cu2+ and EDTA to the NPP solution. Overall, NPP is a novel, simple, economic and portable sensor that can detect Cu2+ in biological and environmental scenarios.

Effect of transition metal Mn2+ ion doping on the structural, spectral and photoluminescent properties of NaSrVO4 prepared by combustion synthesis

The paper presents a simplistic way to synthesize NaSr(1−x)VO4:xMn2+ nanophosphors with 0.25 ≤ x ≤ 3.0 mol% by using combustion synthesis route in which urea is used as an organic fuel. The structural, spectral and optical properties were examined using XRD, UV–Vis spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Photoluminescence (PL) spectroscopy. Doping the host with Mn2+ ions created the mid gap absorption phenomenon. Initially, a red shift is observed in the band gap for low amount of the transition metal ion Mn2+ in NaSrVO4 host which is followed by an augment in the band gap values for higher concentrations. Photoluminescence properties shows that under excitation at 380 nm, sample possess two prominent emissions peaking at 434 nm and 523 nm. This phosphor material may possibly be considered of as a new material to be excited by UVA emitting InGaN LEDs.