Removal of rubidium from brine by an integrated film of sulfonated polysulfone/graphene/potassium copper ferricyanide

A novel integrated film of sulfonated polysulfone/graphene/potassium copper ferricyanide(KCuFC/SPSG)was used for selectively extracting rubidium ion(Rb^(+))from brine.To form KCuFC/SPSG,the precursor film of sulfonated polysulfone/graphene(SPSG)was synthesized by phase conversion process,which was alternately immersed in 0.1 mol·L^(-1)CuSO_(4)/K_(4)[Fe(CN)_(6)]by in-situ adsorption coupled co-precipitation method.Various data such as nuclear magnetic resonance spectrometer,Fourier transform infrared spectroscope,X-ray photoelectron spectroscope,X-ray diffraction,scanning electron microscope,and energy dispersive spectroscopy all verified that abundant KCuFC were uniformly located on the film.The resulting KCuFC/SPSG was used in film separation system.As the solution was fed into the system,the Rb^(+)could be selectively adsorption by KCuFC/SPSG.After the saturation adsorption,0.5 mol·L^(-1)NH_(4)Cl/HCl was fed into the film cell,Rb^(+)could be quickly desorbed by ion-exchange between Rb^(+)and NH_(4)^(+)in the lattice of KCuFC.The purpose of separating and recovering Rb^(+)from the brine can be achieved after the repeated operation.The effects of pH,adsorption time,and interferential ions on the adsorption capacity of Rb^(+)were investigated by batch experiments.The adsorption behavior fits the pseudo-second order kinetic process,while KCuFC has a higher adsorption capacity(Langmuir maximum sorption 165.4 mg·g^(-1)).In addition,KCuFC/SPSG shows excellent selectivity for Rb^(+)even in complex brine systems.KCuFC/SPSG could maintain 93.5%extraction efficiency after five adsorption/desorption cycles.

Application of potassium ferricyanide in the spectrophotometric determination of captopril

A novel method for the determination of captopril by spectrophotometer is described in this paper. The experiment is based on the fact that Fe（Ⅲ） is reduced to Fe（Ⅱ） by captopril, then the in sire formed Fe（Ⅱ） reacts with potassium ferricyanide to give the soluble prussian blue at pH 4.00, and its maximal adsorption wavelength （λmax） is 735 nm. Good linear relationship is obtained between the absorbance and the concentration of captopril in the wide range of 0.05-20 μg/mL. The linear regression equation is A = -0.04314 ＋ 0.11423C （μg/mL） with a correlation coefficient R = 0.9998. The detection limit （3σ/k） is 0.04 μg/mL, the molar absorption coefficient is 2.5×10^4 L/mol cm. By mensurating the absorbance of soluble prussian blue, the indirect determination of captopril can be obtained. This method has been successfully applied to determination of captopril in pharmaceutical samples. Analytical results obtained are satisfactory.

Flow injection spectrophotometric determination of vitamin E in pharmaceuticals,milk powder and blood serum using potassium ferricyanide-Fe(Ⅲ) detection system

A simple and sensitive flow injection spectrophotometric method is reported for the determination of vitamin E using potassium ferricyanide-Fe(Ⅲ) detection system.In the presence of vitamin E,Fe(Ⅲ)/ferricyanide reduces.The in situ reduced ions are then reacted with unreduced portion of ferricyanide/Fe(Ⅲ) to make soluble Prussian blue,which is monitored at absorption wavelength of 735 nm.Linear calibration graph was obtained in the concentration range of 0.1-40μg mL^(-1).The relative standard deviations (n=4) were in the range of 1.1-3.6%,with limits of detection(3 s blank) of 0.04μg mL^(-1).The proposed method allowed 12 injections h^(-1).The method is applied to determine vitamin E in pharmaceuticals,infant milk and blood serum samples using hexane extraction with the recoveries in the range of 93±3 to 97.5±4%.The method is validated using certified reference materials SRM 968c for blood serum samples.

Flow-injection Determination of Cysteine,N-Acetyl Cysteine and Glutathione in Pharmaceuticals via Potassium Ferricyanide-Fe(Ⅲ) Spectrophotometric System

A simple flow injection spectrophotometric method is reported for the determination of cysteine,N-acetyl cysteine and glutathione based on the reduction of Fe（Ⅲ）/ferricyanide,the in situ reduced ions are reacted with unreduced portion of ferricyanide/Fe（Ⅲ） to form soluble Prussian blue,which is monitored at 735 nm.The calibration graphs are linear in the concentration ranges of（1―100）×10-6 mol/L for cysteine and N-acetyl cysteine,and（1―50）×10-6 mol/L for glutathione.The relative standard deviations of 1.8%,2.5% and 1.9% were found for eleven replicate analyses of 5×10-6 mol/L cysteine,N-acetyl cysteine and glutathione.The limits of detection（3σ blank） at 5×10-7 mol/L for cysteine,and 3×10-7 mol/L for N-acetyl cysteine and glutathione were obtained.The proposed method allowed 60 injections/h.The effects of common substances present in pharmaceuticals and human physiological fluids were examined.The method was applied to determining cysteine in pharmaceutical formulations with the recoveries in a range of 97% to 106% and the results obtained are agreed well with labeled values.

Removal of radioactive cesium from solutions by zinc ferrocyanide

Adsorption of ^(134)Cs from aqueous solution by zinc fcrrocyanide,and the effect of experimental conditions on the adsorption were investigated.Preliminary results showed that zinc ferrocyanide was very efficient as an absorbent.Over 98% of ^(134)Cs could be removed by zinc ferrocyanide of 0.33 g·L^(-1) from ^(134)Cs solution (Co) of 3.2～160.0 kBq·L^(-1),with adsorption capacities (Q) of 9.6～463.0 kBq·g^(-1).The adsorption equilibrium time was within one hour and the suitable pH ranged 1～10.No significant differences on ^(134)Cs adsorption were observed at 0～50℃,or in solutions containing Ca^(2+),Fe^(3+),Mg^(2+),HCO_3^-,CO_3^(2-),Cl and SO_4^(2-),even though they are 1000 times higher than the anions or cations in groundwater.However,the adsorption rates decreased when solutions contained K^+ or Na^+.The adsorption process could be described by Frcundlich and Langmuir adsorption equations.

Use of ferricyanide for gold and silver cyanidation

Low gold and silver leaching kinetics has been commonly observed in traditional gold-silver cyanidation process, especially in heap leaching and in situ leaching operations. The different mineralogy of gold and silver in the ores is suspected to be the main reason, e.g., the occurrence of low solubility acanthite (Ag2S) typically results in low overall silver extraction. Due to the low solubility of oxygen in cyanide solution, the reactivity and availability of oxidant is believed to be the critical limitation for gold and silver dissolution. The use of ferricyanide as the auxiliary oxidant for gold and silver cyanidation has been examined. The rotating disc test results prove the assistant effect of ferricyanide on increasing the dissolution rate of gold and silver. The potential use of ferricyanide in gold/silver cyanidation process is proposed based on the leaching results of actual ores.

Metal Free Polymer/Graphite Electrode-Ferricyanides Catholyte System for MFC with High Performance

A Microbial fuel cell(MFC)with metal free polymer/graphite electrodes(150 mm×150 mm)was constructed.The electrodes with flowing channels,which were different in roughness,were designed.No additional catalyst was coated on the electrode,therefore the MFC was cheaper and possessed good durability with high performance.The effect of roughness,K3Fe(CN)6 concentration and sprayed air on the performance of the constructed MFC was investigated.Results showed that the roughness of electrode can significantly affect the performance of MFC.The power density of MFC increased by 1.56 times owing to the arithmetic mean roughness which has increased by 1.41 times.With an increasing K3Fe(CN)6 concentration,the performance of MFC also improves.The MFC with K3Fe(CN)6 only(30 mM)showed the highest power density of 1260 mW/m2,which is by 21.4 times and 1.3 times higher than those of MFCs with spraying air only(59 mW/m2)and with K3Fe(CN)6+air(1005 mW/m2),respectively.This showed that the appropriate concentration of K3Fe(CN)6 can significantly improve the power density,while the air has a negative effect when it is sprayed onto K3Fe(CN)6 catholyte.A coulombic efficiency of 34.2%and an energy efficiency of 13.3%with a COD degradation rate of 73.5%were achieved with MFC using K3Fe(CN)6 only.The overpotentials of MFC were also calculated.It can be seen that both theηohmic andηconcentration were very low as compared to theηactivation,and theηconcentration can be ignored because its effect was less than 3 mV.The theoretical calculation suggested that with an increasing conversion rate of K3Fe(CN)6,the cathode potential decreased and reached 0.31 V at a conversion rate of 0.99.While the anode behaves differently for constant pH and changeable pH as the reaction progresses,which reveals that the buffer solution and removal of protons play an important role in maintaining the anode potential.

Electrocatalytic Determination of Dopamine in the Presence of Ascorbic Acid by Poly-L-proline and Ferricyanide Compound Film Modified Electrode

A novel biosensor was fabricated by the electrochemical polymerization of poly-L-proline（P-LP） and ferricyanide（FC） to form a compound film on a glassy carbon electrode（GCE）. The compound film modified electrode（P-LP/FC/GCE） shows electrocatalytic activity toward dopamine（DA） in a phosphate buffer solution（PBS, pH = 4.0） with a diminution of the overpotential and an increase in peak current. P-LP/FC/GCE was used to study the electrocatalytic oxidation of DA and ascorbic acid（AA） by means of cyclic voltammetry（CV）, differential pulse voltammetry（DPV） and amperometric i-t curve techniques. The overlapping anodic peaks of DA and AA were resolved into two well-defined voltammetric peaks in CV and DPV with the potential differences of about 200 and 225 mV, respectively. The peak current of DA is linearly change with the concentration of DA in a range of 1 × 10^-7 to 1.14 × 10^-4 mol/L with the correlation coefficient of 0.9997. The detection limit is 4.4~10-8 mol/L（S/N=3）. P-LP/FC/GCE exhibited an excellent selectivity, sensibility and stability for the determination of DA, and can be applied to the determination of dopamine injections with satisfied results.

A Green and Facile Solid-state Synthesis Method for the Preparation of Diazenecarboxamide Azo Compounds with Potassium Ferricyanide and Sodium Hydroxide System

Eleven new-typed azo compounds were synthesized in good yields by dehydrogenating the corresponding aryl substituted semicarbazides using potassium ferricyanide and sodium hydroxide system under solid-state conditions.

Potassium Ferricyanide Oxidative Cyclizationof Arylaldehyde with o-Phenylenediamine and o-Aminophenol to 2-Arylbenzimidazoles and 2-Arylbenzoxazoles

Some new benzimidazoles and benzoxazoles have been prepared under mild condition by oxidative cyclization of arylaldehyde witho-phenylenediamine ando-aminophenol using potassium ferricyanide as oxidant

Preparation of Iron Ferrocyanide-Supported Nanofiber Membrane for Purification of Cesium-Contaminated Water

The earthquake in northeastern Japan that occurred on March 11, 2011 brought about the nuclear accident, resulting in the detection of radioactive cesium in soil and water over a wide region around Fukusihma. In this study, with the aim of the establishment of an effective method for removing cesium from water contaminated with cesium, the functionalized membrane with large cesium adsorption capacity per unit mass was prepared by combining nanofibers having a large specific surface area with iron ferrocyanide having a high selectivity for cesium adsorption. The nanofiber membrane made of polyacrylonitrile (PAN) was used as a base material of the functionalized membrane. Nanofiber membranes were immersed in the dispersions of iron ferrocyanide with various concentrations and pH values. After taking it out, it was dried at various temperatures and then non-immobilized iron ferrocyanide was completely removed through cleaning. As a result of the evaluation of completed affinity membranes, the amount of iron ferrocyanide immobilized by the nanofiber membrane increased significantly with the increase in the iron ferrocyanide concentration but subsequently showed a tendency to decrease rapidly, resulting in a distinct maximum at the iron ferrocyanide concentration of 3 wt%. And, the supported amount of iron ferrocyanide to the nanofiber membrane increased as pH became lower. Moreover, it was found that as high temperature as possible without exceeding the glass transition temperature of PAN was optimal as a drying temperature of prepared affinity membrane.

Selective Adsorption Properties and Stable Solidification of Cs by Insoluble Ferrocyanide Loaded Zeolites

In Fukushima NPP-1, large amounts of HALW （high-activity-level water） accumulated in the reactor, turbine building and the trench in the facility is treated by circulating injection cooling system. The development of highly functional adsorbents and stable solidification method contributes to the advancement of the decontamination system and environmental remediation. The present study deals with： （1） preparation of insoluble ferrocyanide loaded zeolites; （2） selective uptake of Cs~ in seawater; and （3） estimation of Cs immobilization ratio and stable solidification. Various kinds of Cs-selective composites loaded with insoluble ferrocyanides （CoFC, NiFC） into the zeolites （zeolite A （A51, A-51J）, zeolite X （LSX）, chabazite （modified chabazite） and natural mordenite （SA-5）） matrices have been prepared to use successive impregnation/precipitation methods by Tohoku University. As for Cs~ adsorption, these composites had relatively large uptake （%） over 95%, distribution coefficients （Kd） above 103 cm3/g and excellent adsorption kinetics even in seawater. The immobilization ratio （%） of Cs for the CoFC saturated with Cs＋was estimated at different calcination temperatures up to 1,200 ℃ in advance. The immobilization ratio was less than 0.1% above 1,000℃, indicating that the adsorbed Cs~ ions are completely volatilized and insoluble ferrocyanides had no immobilization ability for Cs. In contrast, the insoluble ferrocyanide-loaded zeolites had excellent Cs immobilization ability; in the case of insoluble ferrocyanide-loaded natural zeolites （NiFC-SA-5, CoFC-modified chabazite）, the immobilization ratio was above 99% and 96% even after calcination at 1,000 ℃ and 1,100 ℃, respectively, indicating that nearly all Cs ions are immobilized in the sintered solid form. On the other hand, the immobilization ratio for the insoluble ferrocyanide-loaded A and X zeolites （NiFC-A （A51, A51J）, NiFC-X） tended to decrease with calcining temperature; for example, the immobilization ratio for NiFC-X at 1,000 ℃and 1,100 ℃ was estimated to be 74.9% and 55.4%, respectively, and many spots concentrating Cs were observed on the surface. The difference in immobilization behavior between natural zeolites and synthetic ones is probably due to the phase transformation and surface morphology at higher temperature above 1,000 ℃. The stable solidification of insoluble ferrocyanides was thus accomplished by using the excellent Cs immobilization abilities of zeolite matrices （Cs trapping and self-sintering abilities）.

纳米α-Fe_(2)O_(3)/壳聚糖修饰玻碳电极的电化学行为研究

通过不同温度煅烧获得不同比表面积的α-Fe_(2)O_(3)纳米颗粒,将纳米α-Fe_(2)O_(3)与壳聚糖制成复合材料。利用滴涂法,将纳米α-Fe_(2)O_(3)/壳聚糖复合材料修饰在玻碳电极上,并通过循环伏安法研究纳米α-Fe_(2)O_(3)/壳聚糖/玻碳电极对铁氰化钾电化学性能的影响。结果表明:随着烧结温度从280℃提高到700℃时,α-Fe_(2)O_(3)纳米颗粒的比表面积由136.5m^(2)/g变为2.1m^(2)/g。纳米α-Fe_(2)O_(3)/壳聚糖/玻碳电极能显著提高铁氰化钾的电化学性能,与裸电极相比,氧化和还原电流均显著提高,其电化学催化性能与其纳米α-Fe_(2)O_(3)比表面积密切相关,比表面积越大峰电流就越强。在最佳实验条件下,浓度在510^(-4)~510^(-3)mol/L范围内,铁氰化钾的还原电流与浓度呈良好的线性关系,检出限为1.25×10^(-5)mol/L,该修饰电极重复性和稳定性较好。

Ferricyanide-Promoted Oxidative Activation and Ligation of Protein Thioacids in Neutral Aqueous Media

Ferricyanide-promoted oxidative activation of Nacylatedα-aminothioacids for amide bond formation withα-aminonitriles was recently shown to be a plausible pathway for prebiotic peptide synthesis.Herein we describe the finding that by adding sodium azide and thiols,ferricyanide oxidation can elicit highly efficient and clean conversion of fully unprotected peptide or protein thioacids in neutral aqueous media to the corresponding thioesters.This transformation enables the development of ferricyanide-promoted thioacid-based native chemical ligation(NCL)as a new redox-based method for chemical protein synthesis,which does not need to change pH and is therefore operationally easy for ligation at small scales.The effectiveness of the ferricyanide-promoted thioacid-based NCL was illustrated by synthesis of an ISG15-modified MDA5 segment under nondenaturing conditions and synthesis of an acetylated ubiquitin(Ub)-modified histone H2A through an N-to-C sequential ligation.This work broadens the concept of on-demand oxidative activation strategy for protein ligation and provides a new useful supplement to the repertoire of methods for chemical protein synthesis,particularly for studies on proteins carrying Ub family modifications.

含铯废水中亚铁氰化物的粒径分布及组成分析

亚铁氰化物是处理含Cs^(+)离子放射性废水的一种重要方法。为了研究亚铁氰化物处理Cs^(+)离子时的置换机理以及基础性质,本文按照M^(2+)/Fe(CN)64-=1.33的比例投加共沉淀剂(其中M^(2+)代表了Ni^(2+)、Cu^(2+)、Co^(2+)、Cd^(2+)),在不同的模拟水样中制备了亚铁氰化物。利用激光粒度分布仪器考察了M(NO_(3))_(2)与亚铁氰化钾形成共沉淀物的粒径分布。利用高氯酸和加热装置对制备的亚铁氰化物进行溶解以分析其组成。结果表明:共沉淀物的粒径几乎全部处于0.1~10μm;Cs^(+)和Mg^(2+)离子主要取代K^(+)和部分取代M^(2+)离子,Na^(+)离子只取代K^(+)离子;对1.00 mg/L Cs^(+)离子的去除率高于99%;对其吸附容量高达310mg/g以上。总之,亚铁氰化物粒径较小,Na^(+)和Mg^(2+)存在不会影响亚铁氰化物对Cs^(+)离子的去除。

H_(2)O_(2)催化氧化缓释螯合铁离子处理碱性含氰废水的研究

黄金氰化过程中产生的废水多为碱性且含有大量亚铁氰络离子、铜氰络离子和游离氰根,为消除废水中氰化物对环境的污染并实现处置后废水回用,本文采用在弱碱性环境下引入EDDHA-Fe有机螯合铁离子并加入H_(2)O_(2)催化氧化方法分解氰根,同时氧化螯合剂释放铁离子形成普鲁士蓝沉降,实现对碱性废水中络合氰根进行了有效脱除。结果表明,在最佳实验条件下,滤液中氰化物沉淀去除效果显著,去除率达99.77%,滤液中总氰化物浓度由221.59mg/L下降至0.51mg/L,在不影响水体碱度的前提下有效实现了废水脱氰,处置后的废水可直接回用。

不同尺寸的AuNPs对废水中污染物的催化降解性能

废水中难降解、强毒性污染物的处理仍是目前亟待解决的问题。金纳米颗粒(AuNPs)具有较大的比表面积、良好的催化活性和生物相容性,在废水处理领域获得广泛的关注。然而,AuNPs的催化活性受颗粒尺寸的影响较大。本文采用化学还原法制备出不同尺寸的AuNPs,并分别对废水中污染物铁氰化钾K_(3)Fe(CN)6和对硝基苯酚(4-NP)进行催化降解以探究AuNPs的催化活性。透射电镜(TEM)和紫外-可见吸收光谱(UVvis)表征结果显示,所制备的AuNPs具有与尺寸相关的催化活性,随尺寸的降低催化活性逐渐增强,4 nm的AuNPs能实现200 s内K_(3)Fe(CN)6和4-NP的快速还原,38 nm以上的AuNPs催化性能较低,且在小尺寸区间,催化活性变化更快。此外,AuNPs循环使用6次后仍保持50%以上的催化活性。

食品中亚硝酸盐检测关键影响因素探究

目的:运用《食品安全国家标准食品中亚硝酸盐与硝酸盐的测定》(GB 5009.33—2016)第二法分光光度法对食品中亚硝酸盐进行检测,分析影响检测结果的关键因素。方法:将标准溶液和待测溶液在同等条件下进行测定,扩展标准曲线线性范围,将检测过程分为4个步骤,分别进行加标回收试验,结合氧化还原反应标准电极电势分析影响检测结果的关键因素。结果:亚铁氰化钾溶液久置后可能分解产生Fe^(3+),Fe^(3+)可氧化亚硝酸根导致检测结果偏低,其他溶液相对稳定。结论:GB 5009.33—2016中分光光度法稳定可靠,亚铁氰化钾溶液的稳定性是影响检测结果的关键因素。

以三氯化铁为掩蔽剂原子荧光法测定水中硒的含量

本文通过条件试验发现,采用原子荧光法测定水中硒时,一定浓度以上的Cu^(2+)会对硒的结果产生干扰,即:当水中Cu^(2+)含量小于500μg/L时,对测定结果影响较小;大于500μg/L时,测定结果会严重偏低。因此,可加入铁氰化钾或三氯化铁溶液掩蔽。同时,由于铁氰化钾溶液见光或受热时可能会发生分解反应,产生有毒物质,因此,建议采用三氯化铁作为掩蔽剂。

铁氰化铜/石墨烯复合物材料用于过氧化氢的灵敏检测

首先采用化学法制备了铁氰化铜纳米微粒,将石墨烯与其超声分散后得到铁氰化铜/石墨烯复合材料.利用扫描电子显微镜(SEM)和傅里叶转换红外光谱技术对石墨烯及石墨烯复合材料进行了形貌和成分性能表征.采用电化学测试技术研究了铁氰化铜/石墨烯复合材料对过氧化氢分子的电催化性能,研究结果表明该复合材料对过氧化氢表现出优异的电催化活性,在较宽的浓度范围内,具有较好的线性关系.该电极材料有望用于灵敏检测过氧化氢的传感平台.