Metal Ni2 Research Articles

Freestanding flexible Ni12P5 in bacteria based carbon @ reduced graphene oxides paper for lithium-ion anode

A freestanding flexible Ni12P5 – carbon @ reduced graphene oxides (RGO) paper was in-situ fabricated by using bacteria to absorb and encapsulate the metal Ni2+ completely. It presented excellent performances such as long cycle-life, high capacity, excellent coulombic efficiency and superior rate performance during charge/discharge processes. Specially, its high conductivity and robust mechanical flexibility may be used in wearable devices or other fields.

Investigation on the removal performances of heavy metal ions with the layer-by-layer assembled forward osmosis membranes

The removal performances of heavy metal ions with the layer-by-layer (LbL) assembled forward osmosis (FO) membranes were investigated in this study. The prepared FO membrane with the multi-layer polymer network was fabricated by assembling multiple polyethylenimine (PEI) and sodium alginate (SA) bilayers on a polydopamine-functionalized polyvinylidene fluoride (PVDF) supporting membrane. The prepared FO membrane possessed high rejection of five heavy metal ions, i.e., Cu2+, Ni2+, Pb2+, Zn2+ and Cd2+. The influences of different osmosis modes, number of bilayers, pH, time, temperature, regeneration as well as the concentration of feed and draw solutions on the heavy metal ion removal performances of the FO membrane were studied. Results showed that all the heavy metal ion rejections with the 3-layer assembled FO membranes exceeded 99.31% in AL-FS (the active layer facing the feed solution) mode when 1M MgCl2 was employed as the draw solution, and the rejection in AL-FS mode was higher than that in AL-DS (active layer facing the draw solution) mode. The experimental results revealed that the number of bilayers of the polyelectrolyte pairs, the hydrated radii of metal ions and the heavy metal ion adsorption all contributed to the high rejection of the heavy metal ions.

Effect of Metal (Ni2+, Fe3+, and Mo3+) Doping in TiO2 Thin Films on Antimicrobial Activity

Effect of Metal (Ni²⁺, Fe³⁺, and Mo³⁺) Doping in TiO₂ Thin Films on Antimicrobial Activity

Naked Eye Detection of Cr3+ and Co2+ Ions by Gold Nanoparticle Modified with Azomethine

This paper reports the synthesis of azomethine-modified gold nanoparticles with azomethine (azomethine-AuNPs) in aqueous media, which were characterized by FT-IR spectroscopy, ultraviolet–visible spectroscopy (UV-Vis), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The azomethine-AuNPs were employed as colorimetric for Cr3+ and Co2+ ions at pH 6.2–7.5 and 8.1–9.1, at room temperature in aqueous solution. In the presence of Cr3+ and Co2+, the azomethine-AuNPs induce aggregation of the nanoparticles. Upon aggregation, the surface plasmon absorption band red-shifts so that the nanoparticle solution appears a blue color. The sensitivity of azomethine-AuNPs towards other metal ions, Mg2+, Mn2+, Cr6+, Na+, Ni2+, Ag+, Al3+, Ca2+, Cd2+, Cu2+, Fe2+, Fe3+, Hg2+, Cd2+, K+, Co3+, Ni2+, Pb2+, and Zn2+ are negligible. This highly selective sensor allows a direct quantitative assay of Co2+ and Cr3+ with colorimetric detection limits of 83.22 and 108 nM, respectively.

Effects of Metal Ions on the Aluminum Electrodeposition from Ionic Liquids

In this study, we report on the effects of three common transition metal ions, i.e., Ni2+, Cu2+ and Fe3+ on the electrodeposition of aluminum from a chloroaluminate ionic liquid, evaluated by means of electrochemical and morphological investigation. Aiming at the determination of the morphological and chemical effects on the aluminum coatings, variable amounts of ions were introduced into the electroplating bath. Thick (about 20 μm) Al coatings were obtained by direct deposition (galvanostatic, 10 mA cm2, 2 h) on brass or carbon steel substrates (10 mm diameter disks), and their morphology was examined via rugosimetry, optical and electron microscopy. The chemical composition of the deposits was provided by EDX analysis. Nickel and iron resulted to have only moderate effects on the coatings properties, but copper affected the process even in tiny amounts being detected in the deposits for bath content as low as 10 ppm.

Synthesis and characterization of PAMAM/CNT nanocomposite as a super-capacity adsorbent for heavy metal (Ni2 +, Zn2 +, As3 +, Co2 +) removal from wastewater

The water cleaning applications of carbon nanotubes (CNT) have generated much research interest since their initial discovery. However, in the early stages of research, the efficiency of CNTs for the removal of heavy metal ions has been severely limited because of the intense agglomeration of CNTs and their deficiency of functional groups. In this research, a new method has been discovered for the preparation of dendrimer functionalized CNTs and a PAMAM/CNT nanocomposite was prepared. FTIR, SEM, TEM, Raman spectroscopy, zeta potential measurements, and dispersion observing methods have been employed for characterizing the synthetic nanocomposite and these techniques indicated that the dendrimer functionalized CNTs have been favorably synthesized. In addition, the uniquely high adsorption capacities properties of PAMAM/CNT nanocomposite for Ni2+, Zn2+, As3+, Co2+ were examined. The effects of several parameters including initial metal ion concentration, temperature, solution pH, the nanocomposite dosage and contact time were studied. The experimental data were analyzed using equilibrium isotherm relationships (Langmuir, Temkin and Freundlich) and the uniquely high adsorption capacities and rates were studied using (pseudo-first order, intraparticle diffusion and pseudo second-order) adsorption kinetics models. The results indicated that the maximum adsorption occurred at pH=8. With increasing nanocomposite dosage and increasing contact time, there was increased adsorption capacity. Analysis of the adsorption process demonstrated that the Langmuir isotherm and pseudo-second order kinetics are the most appropriate models for heavy metal ions adsorption onto PAMAM/CNT nanocomposite.

Purification and characterization of an alkaline chloride-tolerant laccase from a halotolerant bacterium, Bacillus sp. strain WT

Laccases are multicopper oxidases with various biotechnological applications that oxidize different aromatic or inorganic substrates. In present work, different bacterial strains isolated from Urmia lake, a hypersaline lake in northwest of Iran, were screened to find laccase-producing ones. Spore and an extracellular enzyme from a halotolerant spore-forming bacterium, Bacillus sp. strain WT, showed laccase activity toward typical laccase substrates: syringaldazine and 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate). The extracellular laccase (0.01UmL−1) decolorized sulphonyl green BLE up to 97% at pH 7.0 after two h incubation at 35°C, without any addition of mediators. This enzyme with apparent molecular mass of 180kDa was purified using ammonium sulfate precipitation method and anion exchange chromatography. The optimum laccase activity toward 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate) and syringaldazine was at 55°C and pH values of 5.0 and 8.0, respectively. One mM of metal ions, Na+ and Ni2+, increased the enzyme activity by 12%. The enzyme from Bacillus sp. strain WT could be able to tolerate up to 600–800mM NaCl (a very strong laccase inhibitor) and showed halotolerant nature with maximum activity at 100mM NaCl. One mM NaN3 (another potent laccase inhibitor) almost had no effect on the laccase activity; however, 1mM l-Cys reduced 87% of its original activity. KM values for the purified enzyme on 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate) and syringaldazine were determined to be 132.7 and 3.7μM, with corresponding kcat values of 309 and 51s−1, respectively. The present study is among the first studies on laccase activity of a halotolerant bacterial strain isolated from a hypersaline lake.

Adsorption of Sulfur Compounds from Diesel with Ion-Impregnated Activated Carbons

The adsorption of benzothiophene sulfone (BTO) and dibenzothiophene sulfone (DBTO) from model diesel fuel were evaluated using granular activated carbon (GAC) and modified activated carbon. Modified activated carbon was impregnated with metal ions, Cu2+, Fe3+, and Ni2+, and the effect on its adsorption characteristics was determined. Adsorption performance was investigated using batch process at room temperature and agitation speed of 120 rpm. Results indicated a significant increase in the adsorption capacity compared to that of the unmodified GAC. Increasing adsorption capacity followed the order Cu2+/AC 0.90. Adsorption process seemed to proceed in a two-step process. First, a very fast rate for the first few minutes, then a markedly reduced rate until equilibrium is reached. All the adsorbents use...

The performance of forward osmosis in treating high-salinity wastewater containing heavy metal Ni2+

In this study, the performance of forward osmosis (FO) in treating the high-salinity feed waters containing heavy metal Ni2+ with different salinities was investigated using two different FO membranes (cellulose triacetate (CTA) and polyamide-based thin-film composite (TFC) membrane). Moreover, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were selected to analyze the used membrane. The result showed that, heavy metals Ni2+ stimulated the formation of CP, and then decreased the water flux. However, this effect decreased with the increase of FS salinity and membrane hydrophilicity. Due to the amphiprotic characteristics, SDBS promoted the water permeation by increasing the hydrophilicity of the membrane surface. The effect of SDBS on CTA-FO membrane was greater than TFC-FO membrane for that CTA-FO membrane was weakly hydrophilic. However, the role decreased with the salinity increasing. Ni2+ removal efficiencies were more than 93%. Specifically, TFC-FO membrane was higher than CTA-FO membrane in high-salinity wastewater, and the FO mode maintained an advantage over the PRO mode. SDBS enhanced Ni2+ removal efficiency greatly at low salinity, and decreased it instead at high salinity. The SEM–EDS analysis supplied the technique support and reflected the role of Ni2+ and SDBS in the membrane directly.

Bioinspired Citrate–Apatite Nanocrystals Doped with Divalent Transition Metal Ions

Bioinspired citrate–carbonate–apatite (cAp) nanocrystals doped with divalent transition metal (M) ions, i.e., Mn2+, Co2+, and Ni2+, were prepared by batch thermal decomplexing of Ca2+/M/citrate/phosphate/carbonate solutions at 80 and 37 °C, with initial Ca2+/M molar ratios of 9:1 and 5:5, and at different crystallization times ranging from 1 to 96 h. A thorough chemical, crystallographic, and morphological characterization was carried out on the doped nanocrystals revealing that (i) using similar crystallization conditions the amount of incorporated M normally followed the order Mn2+ > Co2+ > Ni2+; (ii) the growth of nanocrystals was clearly enhanced at 80 °C and when a lower amount of M was incorporated in the crystal structure; (iii) the increase of the M content increased the aspect ratio (length/width) of the M-doped cAp nanocrystals compared to undoped ones, (iv) the incorporation of the 6.5 wt % of M is a threshold for the long-range order of the nanocrystal; in fact, with a higher M content, amorph...

A Schiff base derivative used as sensor of copper through colorimetric and surface plasmon resonance techniques

Organic molecular sensors have the advantage of being used through easy, fast, economical and reliable optical methods for detecting toxic metal ions in the environment. In this work, we present a simple but highly specific organic ligand 5-Chloro-2-[(1E,2E)-3-(4-(dimethylamino)phenyl)allylidene)amino)]phenol (S1) that works as a colorimetric sensor of copper ions in aqueous solutions. Binding interaction between S1 and various metal ions was established by UV–Vis spectroscopic measurements showing favorable coordination toward Cu2+ and practically no interference with the presence of other metal ions, i.e., Cd2+, Co2+, Cr2+, Fe3+, Mg2+, Ni2+, Hg2+, Pb2+, Mn2+, and Zn2+. S1 exhibited binding-induced color changes from yellow to pink with a detection limit of 1.25×10−7M measured by spectroscopic methods, while colorimetric changes could be observed at naked eye for concentrations as low as 2×10−6M. Furthermore, we also demonstrated that S1 can be useful for sensing copper ions through the use of surface plasmon resonance (SPR) technique. This technique allowed detecting the presence of Cu2+ in aqueous solutions at the concentration level of ca 1.5×10−6M due to changes in the refractive index.

Studies on the optimum conditions using acid-washed zero-valent iron/aluminum mixtures in permeable reactive barriers for the removal of different heavy metal ions from wastewater

The method of permeable reactive barriers (PRBs) is considered as one of the most practicable approaches in treating heavy metals contaminated surface and groundwater. The mixture of acid-washed zero-valent iron (ZVI) and zero-valent aluminum (ZVAl) as reactive medium in PRBs to treat heavy metal wastewater containing Cr(VI), Cd2+, Ni2+, Cu2+, and Zn2+ was investigated. The performance of column filled with the mixture of acid-washed ZVI and ZVAl was much better than the column filled with ZVI or ZVAl alone. At initial pH 5.4 and flow rates of 1.0mL/min, the time that the removal efficiencies of Cr(VI), Cd2+, Ni2+, Cu2+, and Zn2+ were all above 99.5% can keep about 300h using 80g/40g acid-washed ZVI/ZVAl when treating wastewater containing each heavy metal ions (Cr(VI), Cd2+, Ni2+, Cu2+, and Zn2+) concentration of 20.0mg/L. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize ZVI/ZVAl before and after reaction and the reaction mechanism of the heavy metal ions with ZVI/ZVAl was discussed.

Bifunctional composite from spent “Cyprus coffee” for tetracycline removal and phenol degradation: Solar-Fenton process and artificial neural network

Removals of tetracycline and photocatalytic degradation of phenol by Fe3O4/coffee residue (MCC) were investigated. Brunauer–Emmett–Teller (BET), vibrating sample magnetometer (VSM) and Boehm titration were employed to characterize MCC. Artificial neural network (ANN) model was developed to predict the tetracycline (TC) concentration in the column effluent. Maximum tetracycline adsorption capacity of 285.6mg/g was observed in a batch system. High removal efficiency (87%) was obtained at 3.3mL/min flow rate, 8.0cm bed height and 50mg/L influent TC concentration in a column system. Complete degradation of phenol by solar-Fenton was attained at 60min irradiation time. Total organic carbon (TOC) removal increased to 63.3% in the presence of 1.0g/L MCC, 1.2g/L H2O2 and solar irradiation. MCC showed remarkable potential to remove antibiotics from wastewater even in the presence of heavy metal (Ni2+) via magnetic separation.

The thermodynamics and biodegradability of chelating agents upon metal extraction

Chelation technology, one of emerging green approaches, has shown its potential to extract metals from industrial waste; however, the stability of metal–chelate complexes and the biodegradability of chelating agents are opposing aspects which need to be balanced carefully in order to develop a sustainable metal extraction process. In present study, stability of transition metal (Ni2+, Co2+, Rh3+, Mo6+) complexes with different aminopolycarboxylic chelating ligands (EDTA, EDDS, NTA) was investigated using density functional theory (DFT) calculations and the results were compared to previous experimental studies (Chauhan et al., 2012, 2013b; Cruywagen et al., 1994; Smith and Sawyer, 1968a;Marcus, 1985). Desolvation and complexation processes were examined to rationalize the thermodynamics of ligand substitution reactions using generalized gradient approximations (GGA) and hybrid DFT methods. A combination of explicit metal–water complexation and implicit solvation treatment was used to calculate the free energies of desolvation and chelation. Standard state corrections were also included for solvation free energies to enable a direct comparison with literature values. Thermodynamic analysis was performed in order to estimate the metal–ligand binding free energies at room and elevated process temperatures. Existence of different Rh3+ species in solution and in complexes was also explored and the most stable complex was identified. Differences in the coordination chemistry associated with Mo6+ were observed which motivated to perform free energy calculations upon MoO3 as a central coordination unit for different metal-to-ligand complexes (1:1, 2:1) in order to characterize the thermodynamically most stable complex at optimum reaction pH. In general, the metal–chelate ligand complexes followed the stability trend i.e. (EDTA)>(EDDS)>(NTA). The high stability of EDTA4− ligand with a favorable minimal strain can be the reason for its inherent resistance to degradation; it is therefore reckoned to consider the environmental impact of chelate assisted metal extraction processes by assessing ligand degradation pathways also. Possible pathways for the biodegradability of the chelating agents were investigated by calculating the bond dissociation energies of the ligands.

Potentiometric studies on ternary complexes involving some divalent transition metal ions, gallic acid and biologically abundant aliphatic dicarboxylic acids in aqueous solutions

Formation of binary and ternary complexes of the divalent transition metal ions, Cu2+, Ni2+, Co2+ and Zn2+ with gallic acid and the biologically important aliphatic dicarboxylic acids (adipic, succinic, malic, malonic, maleic, tartaric and oxalic acids) were investigated by means of the potentiometric technique at 25 °C and I = 0.10 mol dm−3 NaNO3. The acid-base properties of the ligands were investigated and discussed. The acidity constants of gallic acid and aliphatic dicarboxylic acids were determined and used for determining the stability constants of the binary and ternary complexes formed in the aqueous medium under the above experimental conditions. The formation of the different 1:1 and 1:2 binary complexes and 1:1:1 ternary complexes are inferred from the corresponding potentiometric pH-metric titration curves. The ternary complex formation was found to occur in a stepwise manner. The stability constants of these binary and ternary systems were calculated. The values of Δ log K, percentage of relative stabilization (%R.S.) and log X were evaluated and discussed. The concentration distribution of the various complex species formed in solution was evaluated and discussed. The mode of chelation of ternary complexes formed was ascertained by conductivity measurements.

Microwave Induced Center-Doping of Transition Metals Ions in Aqueous CdS NCs with Special Optical Properties

Under microwave irradiation, we systematically studied the formation of transition metal ions (TM), Ag+, Mn2+, Cu2+, Fe2+, Co2+ and Ni2+, doped CdS semiconductor nanocrystals in a pure water solution. The center-doping strategy is essential for achieving efficient internal-doping to improve the optical properties and stability of doped nanocrystals. The resulting TM doped nanocrystals have a high photoluminescence quantum yield (~ 60%) and an amazingly large range of the visible spectrum (480 ~ 650 nm). For Mn2+ doped CdS nanocrystals, significant high photoluminescence quantum yield, between 20% and 50% even at more than 600 nm, was achieved and there is potential for them to be directly used as a consummate toner for multicolor sensing and encoding without ligand exchange. Highly emissive-doped nanocrystals synthesized under designed conditions have been found to have excellent stability; samples could be stored for months without precipitation. In practice, this approach has great potential to promote the metal doping of various semiconductor nanocrystals to realize the specific advantages of doped nanocrystals in water solution. Keywords: CdS, doping, microwave, nanocrystals, transition metal ions.

Cloning and Characterization of Physarum Endo-Beta-1,3-1,4-Glucanase-1 Expression in E. coli and Trichoderma reesei

The endo-β-1,3-1,4-glucanases have been found widely in bacteria, fungi, algae and plants, and have been applied to the hydrolysis of barley β-1,3-1,4-glucans in the beer brewing industry. Here, we report a novel endo-β-1,3- 1,4-glucanase gene (PEGase1) isolated from Physarum polycephalum and expressed in E. coli, and Trichoderma reesei. The molecular weights of the proteins are 34 and 66 kDa respectively by SDS-PAGE analysis. Enzymatic assays show that recombinant PEGase1 expressed by T. reesei was more efficient when hydrolyzing barley β-1,3- 1,4-glucans specifically, suggesting that modifications have a dramatic effect on the activity of PEGase1. We found that recombinant PEGase1 can be enriched by 40-70% ammonium sulfate precipitation and purified by HiTrapTM CaptoTM Q ion-exchange chromatography. Measurements of the enzymatic activity of purified PEGase1 under a range of conditions show that its optimal pH is around 5.5, and its optimal temperature is 55°C, with Km = 0.882 mg/ ml. PEGase1 activity is more stable in acidic solution and at low temperatures than it is in alkaline solution and at high temperatures. Metal ions and their concentration are able to affect the enzymatic activity, some metal ions, for example, Cu2+, Ni2+, Zn2+, Fe2+, Ba2+, Mg2+ and Ca2+ can enhance the enzymatic activity at 1 mmol/L concentration and inhabit the activity at 5 mmol/L concentration, but metal ion Mo2+and Co2+show inhabit the enzymatic activity at both concentration.

Removal of Toxic Metal Ions from Water Using Chelating Terpolymer Resin as a Function of Different Concentration Time and pH

Terpolymer resin 4-ASAUF was synthesized by the condensation of 4-aminosalicylic acid (4-ASA) and urea (U) with formaldehyde (F) in the presence of 2 N hydrochloric acid. The structure of the resin was characterized by various spectral techniques like infrared (FTIR) and nuclear magnetic resonance (1H and 13C-NMR) spectroscopy. The empirical formula and empirical weight of the resin were determined by elemental analysis. The physiochemical properties of terpolymer resin were determined. The morphological feature of the 4-ASAUF terpolymer resin was studied by scanning electron microscopy (SEM). The chelating ion-exchange property of this copolymer was studied for eight metal ions, namely, Fe3+, Cu2+, Ni2+, Co2+, Hg2+, Zn2+, Cd2+, and Pb2+ ions by using batch equilibrium method. The chelating ion-exchange study was carried out over a wide pH range at different time intervals using different electrolyte of various ionic strengths.

Chemical substitution-induced exceptional emitting-wavelength tuning in transition metal Ni2+-doped ferroelectric oxides with ultrabroadband near-infrared luminescence

Simultaneous ferroelectric and optical properties are present in transition metal Ni2+-doped perovskites BaxSr1−xTiO3. Large tuning of near-infrared (NIR) photoluminescence is achieved by chemical substitution due to the variation in the crystal field acting on Ni2+ doping ions. The prepared materials show ultrabroadband NIR luminescence, from 1100 nm to over 1600 nm. The peak position of the NIR emission can be finely tuned, and a total shift of 269 nm was observed. The mechanism behind the observation is discussed; the interestingly tunable luminescence originates from a change in the specific structure of the ferroelectric matrix.

Removal of oxidized sulfur compounds using different types of activated carbon, aluminum oxide, and chitosan-coated bentonite

The adsorption of benzothiophene sulfone and dibenzothiophene sulfone from diesel using six different types of adsorbents were investigated. Adsorbents used were commercial adsorbents granular-activated carbon (GAC), aluminum oxide (ALU), novel adsorbents chitosan-coated bentonite (CHB), and metal-ion impregnated activated carbons, where there types of metal ions, Cu2+, Fe3+, and Ni2+, were loaded (Cu2+/AC, Fe3+/AC, Ni2+/AC). Kinetic studies conducted showed that the adsorption process followed a pseudo-second-order kinetics. Equilibrium studies indicated that the heterogeneous and homogenous monolayer adsorption and are present in the process. Moreover, based on the results of sulfone removal using the synthetic diesel fuel, increasing removal efficiencies of Benzothiophene sulfone followed the order of ALU < GAC < Cu2+/AC < < Fe3+/AC < CHB, while for dibenzothiophene sulfone (DBTO) removal, increasing DBTO removed efficiencies followed the order of GAC < CHB < ALU < Cu2+/AC ≈ Fe3+/AC ≈ Ni2+/AC.