Interaction mechanism of Cu^(2+),Fe^(3+) ions and extracellular polymeric substances during bioleaching chalcopyrite by Acidithiobacillus ferrooxidans ATCC2370

The extracellular polymeric substances（EPS） of Acidithiobacillus ferrooxidans ATCC 23270,and iron and copper enclosed in EPS were extracted by ultrasonication and centrifugation methods to determine the interaction mechanism of Cu2＋,Fe3＋ and EPS during bioleaching chalcopyrite.Generally,Cu2＋ ions can stimulate bacteria to produce more EPS than Fe3＋ ions.The mass ratio of Fe3＋/Cu2＋ enclosed in EPS decreased gradually from about 4：1 to about 2：1 when the concentration of Cu2＋ ions increased from 0.01 to 0.04 mol/L.The amount of iron and copper bound together by EPS in ferrous-free 9K medium containing 1% chalcopyrite was about 2 times of that in 9K medium containing 0.04 mol/L Cu2＋ ions.It was inferred that the EPS with jarosites on the surface of chalcopyrite gradually acted as a weak diffusion barrier for Cu2＋,Fe3＋ ions transference during bioleaching chalcopyrite.

Topotactically constructed nickel-iron(oxy)hydroxide with abundant in-situ produced high-valent iron species for efficient water oxidation

The low efficiency of oxygen evolution reaction(OER) is regarded as one of the major roadblocks for metal-air batteries and water electrolysis.Herein,a high-performance OER catalyst of NiFe_(0.2)(oxy)hydroxide(NiFe_(0.2)-O_(x)H_(y)) was developed through topotactic transformation of a Prussian blue analogue in an alkaline solution,which exhibits a low overpotential of only 263 mV to reach a current density of 10 mA cm^(-2) and a small Tafel slope of 35 mV dec-1.Ex-situ/operando Raman spectroscopy results indicated that the phase structure of NiFe_(0.2)-O_(x)H_(y) was irreversibly transformed from the type of α-Ni(OH)_(2) to γ-NiOOH with applying an anodic potential,while ex-situ/operando 57Fe Mossbauer spectroscopic studies evidenced the in-situ production of abundant high-valent iron species under OER conditions,which effectively promoted the OER catalysis.Our work elucidates that the amount of high-valent iron species in-situ produced in the NiFe(oxy)hydroxide has a positive correlation with its water oxidation reaction performance,which further deepens the understanding of the mechanism of NiFe-based electrocatalysts.

Separation and Concentration of Indium from Leaching Solution Containing Indium, Antimony and Iron Ions

Processing conditions of effectively separating indium from the leaching solution of a smelting antimony slag were studied. For the leaching solution containing indium and antimony and iron ions, indium was separated by extracting with HDEHP kerosine solution, washing antimony and iron ions with oxalic acid solution and stripping indium with a dilute solution of hydrochloric acid. InCl 3 solution with purity above 90% is obtained. Indium can be enriched through a circulation of stripping with a dilute HCl solution. The concentration of InCl 3 solution is about 25～30 g/L.

Effect of iron transformation on Acidithiobacillus ferrooxidans bio-leaching of clay vanadium residue

The acid bio-leaching process of vanadium extraction from clay vanadium water-leached residue was studied and the effect of the performance of iron transformation was investigated.Acidithiobacillus ferrooxidans affects the dissolution of vanadium through the catalytic effect on Fe^3+/Fe^2+couple and material exchange.The passivation of iron settling correlates with ferrous ion content in bio-leaching solution.In medium containing A.ferrooxidans and Fe(Ⅲ),the increment in Fe(Ⅱ)concentration leads to the formation of jarosite,generating a decline in vanadium extraction efficiency.Analysis of cyclic voltammetry shows that Fe(Ⅱ)ion is apt to be oxidized and translated into precipitate by A.ferrooxidans,which strongly adsorbed to the surface of the residue.Fe(Ⅲ)ion promotes the vanadium extraction due to its oxidizing activity.Admixing A.ferrooxidans to Fe(Ⅲ)medium elevates the reduction of low valence state vanadium and facilitates the exchange of substance between minerals and solution.This motivates 3.8%and 21.8%increments in recovery ratio and leaching rate of vanadium compared to the Fe(Ⅲ)exclusive use,respectively.Moreover,Fe(Ⅱ)ion impacts vanadium extraction slightly in sterile medium but negatively influences vanadium leaching in the presence of bacteria.

Preparation and photocatalytic properties of Fe-doped TiO_2 nanoparticles

Nanocrystalline Fe-doped TiO2 with size of 6070 nm was prepared by a sol-gel technique, followed by freeze-drying treatment for 2 h. Thermogravimetric and differential thermal analyses, X-ray diffraction, scanning （electron） microscope, laser diffraction particle size analyzer and UV-Vis spectrophotometer technologies were used to characterize the product. The photocatalytic activities of the samples were evaluated by the degradation of wastewater of paper-making. The effects of Fe ion implantation on the photocatalytic activity of TiO2 were also discussed. The results show that the iron content plays an essential role in affecting the photocatalytic activity of the Fe-doped TiO2 and the optimum content of Fe-doped is 0.05% （mass fraction）. The photocatalytic activity of samples with lower content of Fe-doped is higher than that of pure TiO2 in the treatment of paper-making wastewater. The photo-degradation effect of paper-making effluent is the best by means of Fe-doped TiO2 with 0.05% Fe.

Structure and Coordination Investigation of Iron-ion Tinting Principle in Ferreous Glass

The tinting phenomena of iron oxide contained glasses were studied from aspects of the electronic configuration, the iron ions coordination fields and the ions structure in glass. Several iron ion tinting forms at different redox or COD (chemical oxygen demand) conditions and their influential factors were given necessary explanations. The results reveal that the Fe^(3+)-O-Fe^(2+) structure is the real tinting reason of iron involved glasses, whereas the Si^(4+)-O-Fe^(3+) and Si^(4+)-O-Fe^(2+) formulations modify the glass colours. Under oxidizing melting condition, the amount of 4/6-coordinated Fe^(3+) increases and makes the glass colour yellowish. Conversely, reducing melting condition makes the 6-coordinated Fe^(2+) increased and gives much blue tint to the glass. The conventional tank furnace melting the very strong reducing condition, which is of high COD glass batch, is not suitable. The high ratio of ferrous/ferric in glass can be obtained with a new refining technology which contains no or little amount of refining agent.

3-Aminopropyltriethoxysilane Complexation with Iron Ion Modified Anode in Marine Sediment Microbial Fuel Cells with Enhanced Electrochemical Performance

Anode modification plays a key role in higher power output in marine sediment microbial fuel cells(MSMFCs).A low-molecular organosilicon compound(3-aminopropyltriethoxysilane)was grafted onto the surface of carbon felt using chemical method and a composite modified anode was prepared through organic ligands coordination Fe^(3+)for better electro-chemical per-formance.Results show that the biofilm resistance of the composite modified anode(2707Ω)is 1.3 times greater than that of the unmodified anode(2100Ω),and its biofilm capacitance also increases by 2.2 times,indicating that the composite modification pro-motes the growth and attachment of electroactive bacteria on the anode.Its specific capacitance(887.8 Fm^(−2))is 3.7 times higher than that of unmodified anode,generating a maximum current density of 1.5Am^(−2).In their Tafel curves,the composite modified anodic exchange current density(5.25×10^(−6)Acm^(−2))is 5.8 times bigger than that of unmodified anode,which suggests that the electro-chemical activity of redox,anti-polarization ability and electron transfer kinetic activity are significantly enhanced.The marine sediment microbial fuel cell with the composite modified anode generates the higher power densities than the blank(203.8mWm^(−2) versus 45.07mWm^(−2)),and its current also increases by 4.4 times.The free amino groups on the anode surface expands a creative idea that the modified anode ligates the natural Fe(Ⅲ)ion in sea water in the MSMFCs for its higher power output.

Amplified Detection of Iron Ion Based on Plasmon Enhanced Fluorescence and Subsequently Fluorescence Quenching

A facile and rapid approach for detecting low concentration of iron ion(Fe3+) with improved sensitivity was developed on the basis of plasmon enhanced fluorescence and subsequently amplified fluorescence quenching.Au1Ag4@Si O2 nanoparticles were synthesized and dispersed into fluorescein isothiocyanate(FITC) solution. The fluorescence of the FITC solution was improved due to plasmon enhanced fluorescence. However, efficient fluorescence quenching of the FITC/Au1Ag4@Si O2 solution was subsequently achieved when Fe3+, with a concentration ranging from17 n M to 3.4 l M, was added into the FITC/Au1Ag4@Si O2 solution, whereas almost no fluorescence quenching was observed for pure FITC solution under the same condition. FITC/Au1Ag4@Si O2 solution shows a better sensitivity for detecting low concentration of Fe3+compared to pure FITC solution. The quantized limit of detection toward Fe3+was improved from 4.6 l M for pure FITC solution to 20 n M for FITC/Au1Ag4@Si O2 solution.

Fe^(3+)/Fe^(2+) redox electrolyte for high-performance polyaniline/SnO_2 supercapacitors

The Fe3＋/Fe2＋ redox electrolyte for use in polyaniline/tin oxide （PANI/SnO2）supercapacitors was reported. The influences of redox electrolyte based on different Fe3＋/Fe2＋ ion pair concentrations in 1 mol/LH2SO4 solution on the pseudocapacitive behaviors of PANI/SnO2 supercapacitor were investigated. The electrochemical properties of the supercapacitor were studied by cyclic voltammetry （CV）, galvanostatic charge discharge （GCD）, and electrochemical impedance spectroscopy （EIS） techniques. It is found that the performance of the supercapacitor is the best when the Fe3＋/Fe2＋ concentrationis 0.4 mol/L and its initial specific capacitance is 1172 F/g at an applied current density of 1 A/g. The long-term cycling experiment shows good stability with the retention of initial capacitance values of 88% after 2000 galvanostatic cycles. The experimental results testify that using Fe3＋/Fe2＋ redox electrolyte has a good prospect for improving the performances of energy-storage devices.

甲硝唑注射液灭菌后混浊原因探讨

甲硝唑注射液为抗厌氧菌的首选药物。1990年正式收载入中国药典的甲硝唑注射液,每100ml 含甲硝唑0.5g,并以适量氯化钠作等渗调节剂。我厂在生产250ml 规格注射液时,曾发现灭菌后偶有混浊现象,且混浊机率随灭菌温度升高及受热时间增加而增大。在配滤工序发现,滤机渗出的药液接触不锈钢材料时间较长后,

Electric Conductivity Study of o-Substituted Phenoxo Iron （Ⅲ） Complexes

The coordination nature of a number of substituted sodiumphenoxides to iron （Ⅲ） ion has been studied. The o-nitrosodiumphenoxide was found to have different coordination behaviour from that the sodium salts of salicylic acid and methylsalicylate showed. The structure of the complexes, the number of the ligands being coordinated to the metal ion, has also been determined by titration, uv-vis spectroscopy, atomic absorption and the flame test. In addition, other sodium phenoxides were also involved in this study for comparison. An electric conductivity study on the resulting complexes was carried out and all complexes were found to be semiconductors.

Activated carbon supported TiO_2 -photocatalysis doped with Fe ions for continuous treatment of dye wastewater in a dynamic reactor

Fe-doped TiO 2 coated on activated carbon （Fe-TiO 2 /AC, FTA） composites were prepared by an improved sol-gel method and characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry, inductively coupled plasma mass spectrometry and BET surface area analysis. Obtained FTA composites were applied to the continuous treatment of dye wastewater in a dynamic reactor. The effects of Fe ion content, catalyst content, UV-lamp power and flowrate of the continuous treatment of dye wastewater on degradation efficiency were analyzed to determine the optimum operating conditions of dye wastewater degradation. Continuous photocatalytic experiments provided interesting results that FTA had a high chemical oxygen demand （COD） removal rate compared with TiO 2 , Fe doped TiO 2 （FT） and TiO 2 coated on activated carbon （TA）. In particular, when using the FTA catalyst with a Fe ion content of 0.33%, the kinetic content （k = 0.0376） of COD removal was more than the sum of both TA （0.0205） and 0.33% FT （0.0166）. FTA showed a high photoactivity because of a synergistic effect between Fe ions and AC on TiO 2 , which is higher than the individual effects of AC or Fe ions on TiO 2 . Additionally, for the photocatalytic degradation of dye wastewater, the optimum Fe ion content, catalyst content, UV-lamp power and flowrate were 0.33%, 6 g/L, 60 W （two lamps） and 300 mL/hr, respectively. An investigation of catalyst reuse revealed that the 0.33% FTA showed almost no deactivation in photocatalytic degradation of naturally treated wastewater.

Preparation and characterization of boron-doped corn straw biochar: Fe(Ⅱ) removal equilibrium and kinetics

Nowadays,iron ions as a ubiquitous heavy metal pollutant are gradually concerned and the convenient and quick removal of excessive iron ions in groundwater has become a major challenge for the safety of drinking water.In this study,boron-doped biochar(B-BC)was successfully prepared at various preparation conditions with the addition of boric acid.The as-prepared material has a more developed pore structure and a larger specific surface area(up to 897.97 m2/g).A series of characterization results shows that boric acid effectively activates biochar,and boron atoms are successfully doped on biochar.Compared with the ratio of raw materials,the pyrolysis temperature has a greater influence on the amount of boron doping.Based on Langmuir model,the maximum adsorption capacity of 800 B-BC1:2 at25℃,40℃,55℃ are 50.02 mg/g,95.09 mg/g,132.78 mg/g,respectively.Pseudo-second-order kinetic model can better describe the adsorption process,the adsorption process is mainly chemical adsorption.Chemical complexation,ions exchange,and co-precipitation may be the main mechanisms for Fe2+removal.

Adsorptive removal of iron and manganese ions from aqueous solutions with microporous chitosan/polyethylene glycol blend membrane

Microporous chitosan （CS） membranes were directly prepared by extraction of poly（ethylene glycol） （PEG） from CS/PEG blend membrane and were examined for iron and manganese ions removal from aqueous solutions. The different variables affecting the adsorption capacity of the membranes such as contact time, pH of the sorption medium, and initial metal ion concentration in the feed solution were investigated on a batch adsorption basis. The affinity of CS/PEG blend membrane to adsorb Fe（II） ions is higher than that of Mn（II） ions, with adsorption equilibrium achieved after 60 min for Fe（II） and Mn（II） ions. By increasing CS]PEG ratio in the blend membrane the adsorption capacity of metal ions increased. Among all parameters, pH has the most significant effect on the adsorption capacity, particularly in the range of 2.9-5.9. The increase in CS/PEG ratio was found to enhance the adsorption capacity of the membranes. The effects of initial concentration of metal ions on the extent of metal ions removal were investigated in detail. The experimental data were better fitted to Freundlich equation than Langmuir. In addition, it was found that the iron and manganese ions adsorbed on the membranes can be effectively desorbed in 0.1 mol/L HCl solution （up to 98% desorption efficiency） and the blend membranes can be reused almost without loss of the adsorption capacity for iron and manganese ions.

Boosting 5-ALA-based photodynamic therapy by a liposomal nanomedicine through intracellular iron ion regulation

5-Aminolevulinic acid(5-ALA)has been approved for clinical photodynamic therapy(PDT)due to its negligible photosensitive toxicity.However,the curative effect of 5-ALA is restricted by intracellular biotransformation inactivation of 5-ALA and potential DNA repair of tumor cells.Inspired by the crucial function of iron ions in 5-ALA transformation and DNA repair,a liposomal nanomedicine(MFLs@5-ALA/DFO)with intracellular iron ion regulation property was developed for boosting the PDT of 5-ALA,which was prepared by co-encapsulating 5-ALA and DFO(deferoxamine,a special iron chelator)into the membrane fusion liposomes(MFLs).MFLs@5-ALA/DFO showed an improved pharmaceutical behavior and rapidly fused with tumor cell membrane for 5-ALA and DFO co-delivery.MFLs@5-ALA/DFO could efficiently reduce iron ion,thus blocking the biotransformation of photosensitive protoporphyrin IX(Pp IX)to heme,realizing significant accumulation of photosensitivity.Meanwhile,the activity of DNA repair enzyme was also inhibited with the reduction of iron ion,resulting in the aggravated DNA damage in tumor cells.Our findings showed MFLs@5-ALA/DFO had potential to be applied for enhanced PDT of 5-ALA.

Synthesis,Crystal Structure and Its Application in Living Cells Imaging of Benz(c)acridine-1,2,3-triazole Derivatives

A highly selective iron ions fluorescent probe based on the benz(c)acridine-1,2,3-triazole derivatives was produced by multi-step reactions. 1-(7-Benz[c]acridinyl)-4-(4-methylphenyl)-1,2,3-triazole(4 a), C_(26)H_(18)N_(4), was structurally determined by single-crystal X-ray diffraction. It crystallizes in the trigonal system, space group R-3 with a = 36.230(10), b = 36.230(10), c = 7.993(3)Å, β = 90°, V = 9086(6)Å^(3), Z = 18, D_(c)= 1.271 g/cm^(3), F(000) = 3636, μ = 0.602 mm^(-1), the final R = 0.0865 and wR = 0.1619 for 3951 observed reflections(I > 2σ(I)). X-ray analysis indicated that all four rings of benz(c)acridine are in the same plane, and the 1,2,3-triazole ring and the corresponding linked benzene(C(1)–C(6)–C(7)–C(8)–C(9)–N(1)) are approximately perpendicular with a dihedral angle of 106.5°. The crystal packing of the compound was stabilized by two weak interactions between C(11)–H(10)…N(4) and C(18)–H(18)…N(1). In fluorescence spectra studies, compound 4 c was exhibited good selectivity and sensitivity towards iron ions in DMSO: mops buffer solution. Furthermore, 4 c was successfully used for imaging iron ions in living He La cervical cancer cells.

11-Mercaptoundecanoic acid functionalized gold nanoclusters as fluorescent probes for the sensitive detection of Cu^(2＋) and Fe^(3＋) ions

Metal ions are physiologically essential,but excessive metal ions may cause severe risk to plants and animals.Here,we prepared gold nanoclusters（Au NCs） protected by 11-mercaptoundecanoic acid（11-MUA）,which have excellent fluorescence properties for the detection of metal ions.The results showed that the copper ions（Cu^（2＋）） and iron ions（Fe^（3＋）） in the solution have obvious quenching effect on the fluorescence intensity of Au NCs.The detection range of Fe^（3＋） was 0.8-4.5 mmol/L（R^2= 0.992） and 4.5-11.0 mmol/L（R^2= 0.997）.And Cu^（2＋） has a lower linear range（0.1-1.0 mmol/L,R2= 0.993）.When EDTA was added into the reaction system,it was observed that the quenching effect of Cu^（2＋） and Fe^（3＋）on Au NCs showed different phenomenon.Then,the effect of metal ions on the fluorescence of Au NCs was investigated.The selective detection of Cu（2＋） was achieved by EDTA masking of Fe^（3＋）.In addition,we realized the metal ions detection application of Au NCs in the serum

Preparation of highly luminescent nitrogen and sulfur co-doped carbon nanoparticles for iron(Ⅲ)ions detection and cell imaging

Highly photoluminescent nitrogen and sulfur co-doped carbon nanoparticles（CNPs） ca. 56 nm have been prepared through a green one-step hydrothermal synthesis route by using millet powder as carbon sources, in which the nitrogen and sulfur co-doping improves the photoluminescent efficiency of the CNPs. The as-prepared CNPs display excellent fluorescent properties and low biotoxicity with a relatively high quantum yield of 30.4%, which have been applied for bioimaging and highly sensitive and selective detection of iron（III） ions.

Anion/Cation (H_2PO_4^- and Fe^(3+)) induced dual luminescence quenching effect based on terbium solid sensor

An investigation on the photophysical properties of the newly designed terbium imidazole-4,5-dicarboxylic acid complex encapsulated in the inert matrices (tetraethoxysilane, TEOS) was performed. The composite material was very stable and showed strong green emission in pure water. Interestingly, we discovered that the luminescence of hybrid material was selectively responsive to H2PO4-. 1H-NMR and fluorescence spectra supported that the receptor had strong affinity to dihydrogen phosphate. Meanwhile, the luminescence was quenched by Fe3+ when adding different metal ions such as Fe3+, Pd2+, Cd2+, Co2+ and Mn2+ concomitantly. Moreover, thin film was successfully pre-pared by the same materials and it also exhibited selective recognition behavior to the above two ions.

A novel phosphorus oxide quantum dots as an emissive nanomaterial for inorganic ions screening and bioimaging

In this work,a novel blue-green fluorescence phosphorous oxide quantum dots(PO QDs)was synthesized by solvothermal method in N-methyl-2-pyrrolidone(NMP)solution without any protection treatment during synthesis.Upon excitation at 400 nm,PO QDs emitted blue-green fluorescence with quantum yield of 0.28.PO QDs exhibited the high inertness to air or moisture,the excellent water solubility,and stable emission intensity in a wide pH range and in high ionic strength solution.Interestingly,PO QDs could give the positive optical response to iron ions(Fe^(3+))and iodine ion(I^(-)).The photoluminescence(PL)of PO QDs could be directly quenched by Fe^(3+).While I^(-)quenched the PO QDs PL by means of Ag^(+)-mediated PO QDs system via the internal filtration effects(IFE)induced by the formation of AgI.Moreover,the biocompatibility and low toxicity of PO QDs verified in bean sprout and Hela cells indicated the promising application of PO QDs in medicine related fields.Furthermore,PO QDs could also be utilized in luminescent composite film for various application scenarios.