含铁有色金属矿渣的除砷方法

用ICP-AES法初步研究了含铁的有色金属矿渣除砷的方法.采用以硝酸为主的低浓度浸取液,在不损失铁含量的前提下,除砷效果好,且成本较低、周期短、工艺简单.     

除锈剂对莲藕铁膜的去除效果研究

分别以采摘后的莲藕和水泥微池中种植的莲藕为材料,比较不同除锈剂对根状茎铁膜的去除效果,以期为莲藕根状茎铁膜的田间防除提供依据。在莲藕采后除铁膜实验中,抗坏血酸在较短时间内将莲藕根状茎上的铁膜完全去除干净,除锈效果好,其次是草酸和柠檬酸。抗坏血酸和柠檬酸混合除锈可提高除锈效率,0.000 87 mol/L柠檬酸和0.012 5 mol/L抗坏血酸共混合处理3 h、0.000 43 mol/L柠檬酸和0.012 5 mol/L抗坏血酸混合处理3 h,可提高除锈效率,减少除锈剂使用。可见将抗坏血酸和柠檬酸按一定比例混合施用对铁膜的去除效果更好,其成本较单独使用抗坏血酸或柠檬酸低。     

采用大孔型树脂除去照相明胶中微量Fe3+的研究

利用大孔树脂吸附和分离照相明胶中的微量铁，比较了6种树脂对微量铁的吸附效果，讨论了温度等因素对树脂吸附微量铁的影响．结果显示，D412大孔螯合树脂对铁的吸附效果较好；宜选用NaCl和络合剂EDTA混合溶液将树脂再生转化为Na型；采用D412大孔螯合型、732强硬型和711强碱型3种树脂的串联组合处理方式，除铁效率达50%-90％；容液pH值对Fe^3 在D412树脂上的吸附行为影响较小．     

Oxidation of activated carbon: application to vinegar decolorization

This article reports studies on the feasibility of increasing the decoloring capacity of a granular activated carbon (GAC) by using oxidation with air at 350 degrees C to modify its surface activity and porosity. The GAC, obtained from olive stones, had a maximum decolorization capacity of 92% for doses of 20 g/l, while the maximum decolorization capacity of the modified granular activated carbon (MGAC) was about 96% at a dose of 10 g/l. The increase in decoloring capacity is thought to be due to an increase in mesopore area (from 129 to 340 m2/g) in the MGAC. The maximum decoloring values and the doses needed to attain them are very close to values obtained in previous studies using coconut shell powder-activated carbon (94 and 98% for red and white vinegar for a dose of 10 g/l, respectively).     

Formation of iron complexes from trifluoroacetic acid based liquid chromatography mobile phases as interference ions in liquid chromatography/electrospray ionization mass spectrometric analysis

Two unexpected singly charged ions at m/z 1103 and 944 have been observed in mass spectra obtained from electrospray ionization mass spectrometric analysis of liquid chromatography effluents with mobile phases containing trifluoroacetic acid (TFA) that severely interfered with sample analysis. Accurate mass measurement and tandem mass spectrometry studies revealed that these two ions are composed of three components; clusters of trifluoroacetic acid, clusters of mass 159 and iron. Formation of these ions is inhibited by removing TFA from the mobile phases and using formic acid in its place, replacing the stainless steel union with a titanium union or by adding a small blank fused-silica capillary column between the chromatography column and the electrospray tip via a stainless steel union without any adverse effects to chromatographic separation, peak broadening or peptide identifications.     

纳米零价铁去除水中重金属离子的研究进展

重金属离子危害严重.本文综述了近几年纳米零价铁去除水中重金属离子的研究,总结了纳米零价铁去除水中重金属离子的机理,主要包括:纳米零价铁的表面吸附-配合、还原、吸附-还原,并对纳米零价铁在这一领域的应用进行了展望.     

Iron isotope fractionation between liquid and vapor phases of iron pentacarbonyl

Iron isotope fractionation between liquid and vapor iron pentacarbonyl was measured in a closed system at ∼0 and ∼21 °C to determine if Fe isotope analysis of iron pentacarbonyl vapor is viable using electron-impact, gas-source mass spectrometry. At the 2σ level, there is no significant Fe isotope fractionation between vapor and liquid under conditions thought to reflect equilibrium. Experiments at ∼0 °C indicate iron pentacarbonyl vapor is ∼0.05 per mil (‰) greater in ⁵⁶Fe/⁵⁴Fe than liquid iron pentacarbonyl, which is just resolvable at the 1σ level. Partial decomposition of iron pentacarbonyl vapor or liquid to an iron oxide or iron metal shows that significant isotopic fractionation occurs, where the decomposed product has a lower ⁵⁶Fe/⁵⁴Fe ratio as compared to the starting iron pentacarbonyl. It follows that methods to decompose iron pentacarbonyl must be quantitative to obtain accurate isotope values.     

Characterization of Iron Metal Corrosion in Liquid Smoke Coagulant

Latex coagulant is one of important factors on natural rubber processing because it will determine the quality of rubber end products. One of the coagulants that produce good quality natural rubber is liquid smoke. The use of liquid smoke as coagulant is thought to cause corrosion in processing equipment commonly made of iron or steel. The objectives of this study were to identify and to study the characteristic of iron metal corrosion in the solution of liquid smoke coagulant. The treatment of liquid smoke as corrosion media consisted of 100% pure liquid smoke (AC100), 10% pure liquid smoke (AC10), 100% liquid smoke formula (FA100) and 10% liquid smoke formula (FA10). The method used was weight loss method with the planned interval test. The removal of corrosion products on the metal specimen was done by pickling method based on ASTM G1-81. The results showed that corrosion rate of the liquid smoke and its formula was around 0.05-0.23 mm per years. Corrosion resistance of iron metal in liquid smoke coagulant was categorized as good level. This analysis indicated that liquid smoke coagulant and its formula has very low corrosivity level. The visualization with 10x magnification showed that the corrosion attack was clearly visible on the iron metal surface.     

Assessment of a new method for the differential pulse polarographic determination of silicon in steel

A procedure is described by which silicon in steel may be determined by differential pulse polarography after removal of iron. Silicomolybdic acid is formed within 20 min by reaction of the silicon with molybdate in the presence of methyl ethyl ketone: subsequent addition of citrate buffer prevents interference from phosphate and excess of molybdate. At the levels present in high-purity iron ( approximately 0.002%) the precision for silicon is better than that usually quoted for the molybdenum blue method. The steel is dissolved by standard procedures but iron must be removed before the silicon is determined. The lower limit imposed by the polarography is about 10(-5)% silicon, but the practical lower limit is probably set by the difficulty of removing the last traces of iron.     

Spectrophotometric determination of iron in process samples from the chemical cleaning of coal

Iron is removed during the desulphurization and demineralization of coal by a chemical cleaning process utilizing a mixture of molten sodium hydroxide and potassium hydroxide. When 1,10-phenanthroline is used for spectrophotometric determination of the iron in the various caustic, aqueous and acidic process streams, organic materials leached from the coal by the molten caustic interfere with the colour-forming reaction. Pre-oxidation of the samples with potassium persulphate has proved to be an effective means of removing the interfering organic material before the iron determination.     

Interaction between dispersed photochromic compound and polymer matrix

Thin films containing photochromatic spiropyran (SP) was prepared from polymethyl methacrylate (PMMA), polyethyl methacrylate (PEMA), poly(n-butyl methacrylate) (PnBMA), and styrene-butadiene-styrene copolymer (SBS). The thin films were illuminated with the ultraviolet light (365 nm) under various temperatures. The photochromic response was monitored with a multichannel photodetector. The results show that the photocoloring rate of SP was faster in PMMA, while the thermal decoloring rate was faster in SBS. In addition, the decoloring rate was higher in a polymer matrix with lower T_g.     

Ion Exchange Treatment of Cobalt Acetate Solutions to Remove Iron(III) Impurity

Russian Journal of Applied Chemistry - The possibility of removing an iron(III) impurity from cobalt acetate solutions by sorption was examined. Among a number of tested ion exchange resins with...     

Macroscopic Graphene Fibers Directly Assembled from CVD‐Grown Fiber‐Shaped Hollow Graphene Tubes

Using a copper wire as the substrate for the CVD growth of a hollow multilayer graphene tube, we prepared a macroscopic porous graphene fiber by removing the copper in an aqueous mixture solution of iron chloride (FeCl₃, 1 M ) and hydrochloric acid (HCl, 3 M ) and continuously drawing the newly released graphene tube out of the liquid. The length of the macroscopic graphene fiber thus produced is determined mainly by the length of the copper wire used. The resultant macroscopic graphene fiber with the integrated graphene structure exhibited a high electrical conductivity (127.3 S cm^?1) and good flexibility over thousands bending cycles, showing great promise as flexible electrodes for wearable optoelectronics and energy devices—exemplified by its use as a flexible conductive wire for lighting a LED and a cathode in a fiber‐shaped dye‐sensitized solar cell (DSSC) with one of the highest energy conversion efficiencies (3.25 %) among fiber‐shaped DSSCs.     

Effect of operating conditions and potassium content on Fischer-Tropsch liquid products produced by potassium-promoted iron catalysts

The dependencies of Fischer-Tropsch synthesis liquid hydrocarbon product distribution on operating pressure and temperature have been studied over three potassium-promoted iron catalysts with increasing potassium molar content. The study followed an experimental planning and the results were analyzed based on surface response methodology. The effects of different operating conditions and potassium contents on the liquid product distribution were compared based on number average carbon number and dispersion. Results showed that high pressures （25 to 30 arm） favored the production of waxes that could be converted into liquid fuels through hydrocracking, while greater direct selectivity towards diesel was favored by low pressure （20 arm） using catalysts with low potassium to iron molar ratios. The liquid product distribution produced using an iron catalyst with high potassium content presented higher number-average number of carbons when compared to the distribution obtained using an iron catalyst with low potassium content.     

选矿废水中铜铁含量连续滴定

本文针对选矿废水中的铜离子和铁离子,在滴定铜离子含量的基础上,向滴定液中继续加入三氯化铝溶液作为解蔽剂将铁离子解蔽,此时溶液呈深棕色,以硫代硫酸钠标准溶液继续滴定铁,溶液深棕色消失转为奶白色即为滴定终点,本法避免了单独滴定铜铁含量的麻烦,且在滴定铁离子含量时无需除铜。经实验验证,应用本法对选矿废水中铁含量进行滴定与重铬酸钾滴定铁含量的结果一致,相对误差小于2.03%,加标回收率在95.80%-101.9%之间,相对标准偏差(RSD,n=10)在0.48%-1.52%之间。本方法精密度高,重现性好,简便快捷,可以满足选矿废水中铜、铁含量的滴定要求。     

Metal oxides immobilized fabrics by radiation induced graft polymerization

Radiation induced graft polymerization is effective for adding a new functionality to various forms of existing polymers. Ion-exchange nonwoven fabrics by gamma radiation induced graft polymerization have been used as filters in air and liquid. However, these materials have no capability for removing non-ionic species, such as volatile organic compound and ozone. Manganese oxides immobilized fabrics were developed for removing ozone. In addition, these materials were capable of removing formaldehyde and arsenic. Fine particles of manganese oxides were observed on the fibers. New materials produced by radiation induced graft polymerization and metal immobilization were applicable for purification of contaminants in environment. Manufacturing process is applicable for immobilization of the other metal oxides.     

An investigation into the use of platinum ware for silicate analysis

The amount of platinum dissolved from platinum apparatus used for dissolving silicate materials to obtain solutions for analysis has been determined. The study included apparatus made from an alloy containing 95 % platinum and 5 % gold. The affinity of iron and platinum was investigated, together with the problem of removing iron from platinum after the latter has been contaminated during fusions. The behaviour of platinum in a classical scheme for the analysis of silicate materials was investigated and the distribution of the platinum in various precipitates established. Platinum has been found to interfere in commonly used methods for the determination of silica, aluminium, iron, titanium, calcium and magnesium.     

Imprinted polymer particles for iron uptake: Synthesis, characterization and analytical applications

This work reports the preparation of molecularly imprinted polymer particles for selective extraction and determination of iron ions from aqueous media. The polymer particles were synthesized from Fe(NO₃)₃, morin, 4-vinylpyridine, ethyleneglycoldimethacrylate, and 2,2′-azobisisobutyronitrile and characterized by IR and DSC both prior to and after removing the Fe-morin complex by leaching with HCl. The effect of different parameters, such as pH, adsorption and desorption time, type and minimum amount of eluent for removing the complex from polymer was evaluated and optimized. The proposed method is characterized by the detection limit of 3.1 µg l^?1 anddynamic linear range of 25 to 200 µg l^?1, with the relative standard deviation less than 8.8%. The method was applied to the recovery and determination of iron ions in a few real samples.     

纳米尺寸材料的结构和性质III：铁纳米粒子的结构和性质

Molecular dynamics computer simulation has been carded out to study the structure and physical properties of iron nanoparticles with 331 to 2133 Fe atoms or with diameter from 2.3 to 4.3 nm. The core of liquid nanodroplets has the similar structure of the bulk molten iron liquid that has an average coordination number around 10.5 and the packing density around 0.45, although the closest Fe-Fe distance is slightly longer in the bulk liquid. Most of the iron nanoparticles formed from the cooling of molten nanodroplets have the same body center cubic crystal structure as it was observed in the bulk under the normal temperature and pressure. Lattice contraction was observed for iron nanoparticles. An amorphous solid and an HCP like solid were obtained accidentally during the quenching runs on Fe331 nanoparticles. The physical properties of iron nanoparticles such as molar volume, density, thermal expansion coefficient, melting point, heat of fusion, heat capacity and diffusion coefficient were estimated based on the results obtained from this simulation. The dependence of physical properties on the nanoparticle sizes was addressed.     

Chemical behaviour of microamount of radium transferred from liquid to solid phase

Some results of tests on removing radium from liquid phase by adsorption on barytes are described. The paper demonstrates the mechanism for removal of radium, which is basically a chemical exchange between radium and barium ions on solid surface.