不同Mn/Fe比例天然含铁锰矿的As(Ⅲ)吸附性能与机制

水体中的砷主要以亚砷酸(As(Ⅲ))形态存在.金属氧化物常用于水体砷的去除,但其对As(Ⅲ)的亲和力较弱,导致水体砷很难去除,因此,寻求高效、廉价、绿色的除As(Ⅲ)材料具有显著的环境意义.天然含铁锰矿是一种高效的砷吸附剂,由于自然形成条件复杂,其不同含铁锰矿对As(Ⅲ)的去除性能存在较大差异.本研究以两种不同Mn/Fe比例的天然含铁锰矿(NFM-L、NFM-H)为研究对象,评估其对As(Ⅲ)的吸附性能,并结合XPS、XRD等光谱学表征手段探究其砷的去除机制.实验结果表明,NFM-L的Fe含量是NFM-H的5.61倍,其As(Ⅲ)的最大吸附量(24.82 mg·g^(−1))与吸附速率亦显著高于NFM-H(18.94 mg·g^(−1)),NFM-L和NFM-H对As(Ⅲ)的等温吸附曲线更符合Freundlich模型.影响因子实验表明,溶液pH值对NFM-L的影响更大,共存离子H_(2)PO_(4)^(−)能够显著抑制两种材料对As(Ⅲ)的吸附,但是材料粒径对As(Ⅲ)去除的影响较小.光谱学表征发现,两种矿物吸附砷后结构并未发生明显变化,但锰氧化物能将As(Ⅲ)氧化为As(V),从而显著提高了铁锰矿对砷的吸附能力.

Photochemical degradation of environmentally persistent perfluorooctanoic acid (PFOA) in the presence of Fe(Ⅲ)

Environmentally persistent and bioaccumulative perfluorooctanic acid （PFOA） was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe（Ⅲ）, 80% of PFOA with initial concentration of 48μmol/L （20 mg/L） was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe（Ⅲ） initiated degradation of PFOA irradiated with 254 nm UV light.

Simple, Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel(Ⅱ), Copper (Ⅱ), Cobalt (Ⅱ), and Iron (Ⅲ) with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.

综合化学实验设计:氧桥三核铁(Ⅲ)配合物的便捷制备与表征

目前本科化学实验教学内容在配合物制备实验方面主要涵盖了单核配合物,而对配合物家族中占有重要地位的多核配合物却很少涉及。基于此,我们依据科研成果设计了一个关于三核铁(Ⅲ)配合物的综合化学实验,以期通过该实验加深学生对配合物有关知识的理解和运用。本设计以廉价易得的九水合硝酸铁与三水合乙酸钠为原料,通过水浴加热反应、冷却结晶等步骤制备了一种氧桥三核铁(Ⅲ)配合物[Fe_(3)O(CH_(3)COO)_(6)(H_(2)O)_(3)]NO_(3)·4H_(2)O,通过配位滴定法测定了其铁元素含量,并对其进行了红外、热重、粉末X射线衍射和电子顺磁共振等表征测试。该实验制备方法简单快捷,易于操作,环保无污染。实验内容蕴含思政元素,目标配合物结构新颖,富有对称美,实验教学时亦可培养学生的审美意识,使其领略化学之美。本设计科教融合,有助于培养学生分析解决问题的能力,为本科生的综合化学实验教学提供了一个可行案例。

Repressing iron overload ameliorates central poststroke pain via the Hdac2-Kv1.2 axis in a rat model of hemorrhagic stroke

Thalamic hemorrhage can lead to the development of central post-stroke pain.Changes in histone acetylation levels,which are regulated by histone deacetylases,affect the excitability of neurons surrounding the hemorrhagic area.However,the regulato ry mechanism of histone deacetylases in central post-stroke pain remains unclea r.Here,we show that iron overload leads to an increase in histone deacetylase 2expression in damaged ventral posterolateral nucleus neurons.Inhibiting this increase restored histone H3 acetylation in the Kcna2 promoter region of the voltage-dependent potassium(Kv)channel subunit gene in a rat model of central post-stroke pain,thereby increasing Kcna2expression and relieving central pain.However,in the absence of nerve injury,increasing histone deacetylase 2 expression decreased Kcna2expression,decreased Kv current,increased the excitability of neurons in the ventral posterolateral nucleus area,and led to neuropathic pain symptoms.Moreover,treatment with the iron chelator deferiprone effectively reduced iron overload in the ventral posterolateral nucleus after intracerebral hemorrhage,reversed histone deacetylase 2 upregulation and Kv1.2 downregulation,and alleviated mechanical hypersensitivity in central post-stroke pain rats.These results suggest that histone deacetylase 2 upregulation and Kv1.2 downregulation,mediated by iron overload,are important factors in central post-stroke pain pathogenesis and co uld se rve as new to rgets for central poststroke pain treatment.

PREPARATION AND CHARACTERIZATION OF NOVEL CHITOSAN DERIVATIVES:ADSORPTION EQUILIBRIUM OF IRON(Ⅲ) ION

The adsorption of Fe(Ⅲ)ions from aqueous solution by chitosan alpha-ketoglutaric acid(KCTS)and hydroxamated chitosan alpha-ketoglutaric acid(HKCTS)was studied in a batch adsorption system.Experiments were carried out as function of pH,temperature,agitation rate and concentration of Fe(Ⅲ)ions.The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and isotherm constants were determined.The Langmuir model agrees very well with experimental data.The pseudo-first-order a...

Structure and Magnetic Property of an Oxygenand Carboxamide-bridged One-dimensional Iron(Ⅲ) Complex [Fe_2(μ-O)(bpb)_2]_n

The structure of the title complex [Fe2（μ-O）（bpb）2]n （bpb 2=1,2-bis（pyridine-2carboxamido） benzenate） has been characterized by single-crystal X-ray diffraction analysis.The complex （C36 H24 Fe2N8O5,Mr=760.33） crystallizes in the monoclinic space group P2 1/c with a=8.4615（17）,b=33.704（7）,c=11.173（2）,β=91.12（3）o,V=3185.7（11）3,Z=4,D c=1.585 g/cm 3,μ（MoK）=0.970 mm-1,F（000）=1552,R int=0.0381,the final R=0.0454 and wR=0.1114.The magnetic susceptibilities of the complex have been examined in the temperature range of 2-300 K.The magnetic data were fitted to give the parameters of J d=-77.7（9） and J c=-11.5（6） cm-1.

离子色谱法测定复方聚乙二醇电解质散(Ⅲ)中氯离子、硫酸根和碳酸氢根的含量

目的建立同时测定复方聚乙二醇电解质散(Ⅲ)中氯离子、硫酸根和碳酸氢根含量的离子色谱法。方法色谱柱为Dionex Ionpac^(TM) AS11-HC阴离子分析柱,保护柱为Dionex IonPac^(TM) AG11-HC,以10 mmol/L氢氧化钾为淋洗液进行等度洗脱,流速为1.2 mL/min,检测器为电导检测器,抑制器为Dionex AERS,抑制电流为30 mA,柱温为30℃,进样体积为10μL;按外标法计算氯离子和硫酸根的含量,按双对数拟合的标准曲线法计算碳酸氢根的含量。结果该色谱条件下,氯离子、硫酸根、碳酸氢根能有效分离,其线性范围分别为0.055~0.219 mg/mL(r为0.9999)、0.155~0.618 mg/mL(r为1.0000)、0.065~0.121 mg/mL(r为0.9999);回收率分别为98.06%~101.34%、97.37%~101.25%、97.16%~99.81%,RSD分别为1.1%、1.3%、1.0%(n=9);精密度、准确度、稳定性、耐用性考察的RSD均小于2%。结论建立的离子色谱法简单快速,准确度、精密度和耐用性良好,可同时测定复方聚乙二醇电解质散(Ⅲ)中氯离子、硫酸根、碳酸氢根的含量,适用于该药品的质量控制。

Azo-dye adsorption activity of iron(Ⅲ) loaded novolac-based network sorbents

Iron(Ⅲ) loaded novolac-based network adsorbents 1 and 2 were studied for efficient removal of azo-dye pollutants from aqueous solutions. The adsorption behavior was evaluated by using methyl orange and orange-G as model azo dyes. The effect of parameters such as contact time and initial dye concentration on the adsorption of azo dyes was studied. The results showed that loading of Fe(Ⅲ) onto the sorbent networks has noticeable effect on azo-dye sorption capacity. The adsorption equilibrium data were fitted to Freundlich isotherm model. Besides, the reusability of the dye loaded sorbents was investigated on adjusting pH of solutions.

Aerobic Enantioselective Epoxidation of Styrene Analogues Induced by (β-Diketone)-iron( Ⅲ ) Complex

Tris（d,d-dicampholylmethanato） iron （Ⅲ） complex, Fe（dcm）3, was found to be an excellent catalyst for asymmetric oxygenation of styrene analogues into the corresponding epoxides. Good chemical yields and higher enantioselectivity were obtained with combined use of molecular oxygen and an aldehyde at 30℃, Some factors influencing enantioselectivity were discussed.

Effect of cerium ion(Ⅲ) on corrosion resistance of organic-inorganic hybrid coating on surface of aluminum-tube used in refrigeration equipment

Organic?inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol?gel method, and the structure of the coating was confirmed by FT-IR. The results of the characterization show that the corrosion resistance of the coating with 1.5 mmol/L cerium ion (III) gains significant improvement, in which the colour retention time of CuSO4 extends to 500 s, the anti-acid and alkali corrosion rates reduce by 67% and 70% compared with the blank one, respectively, and the salt spray tests also show good corrosion resistance. The electrochemical tests demonstrate that the self-corrosion current density and potential of the sample with hybrid coating are about 2.877×10?7 A/cm2 and?0.550 V, respectively. The metallographic and SEM images show that the hybrid coating is uniform and dense, and the EDS analysis confirms that the coating is mainly composed of Al, Si and Ce elements.

Adsorption behavior and mechanism of Bi(Ⅲ) ions on rutile-water interface in the presence of nonyl hydroxamic acid

The adsorption behavior and mechanism of Bi（Ⅲ） ions on the rutile-water interface were investigated through micro-flotation, Zeta potential measurement, adsorption amount measurement and X-ray photoelectron spectroscopy（XPS）. According to the results of micro-flotation, Bi（Ⅲ） ions could largely improve the rutile flotation recovery（from 62% to 91%）, and they could increase the activating sites and reduce the competitive adsorption between nonyl hydroxamic acid negative ions and OH-ions, which determined that Bi（Ⅲ） ions were capable of activating rutile flotation. The adsorption of Bi（Ⅲ） ions onto the rutile surface led to the shift of Zeta potential into the positive direction, which was good for the adsorption of nonyl hydroxamic acid anions. In addition, the results of XPS indicated that the chemical environment around Ti atom had not changed before and after the adsorption of Bi（Ⅲ） ions. Based on the adsorption mechanism of Bi（Ⅲ） ions, it was deduced that firstly Bi（Ⅲ） ions occupied the vacancies of the original Ca^2＋, Mg^2＋ and Fe^2＋ ions on the rutile surface; secondly Bi（Ⅲ） ions covered on the rutile surface in the form of hydroxides.

基于Fe(Ⅲ)和邻苯二胺显色反应快速检测硫化物

比较了不同金属离子(Fe^(2+)、Fe^(3+)、Cu^(2+)、Zn^(2+)、Al^(3+)、Na^(+)、Ca^(2+)、Mg^(2+)、K^(+)、Ag^(+)、Cr^(3+))对邻苯二胺(OPD)的氧化能力,基于Fe^(3+)能直接氧化OPD产生黄色发荧光的产物而构建了Fe^(3+)-OPD显色体系。结合硫化物的还原性以及对金属离子较强的亲和性,开发了一种通过比色法选择性检测硫化物的方法。结果表明,在pH 4.0NaAc-HAc缓冲液中,Fe^(3+)-OPD显色体系的吸光度和荧光强度与NaHS的浓度分别在10~200μmol/L和5~150μmol/L范围内呈线性关系,荧光法的检出限可达0.1μmol/L,体系内其他还原性物质及硫醇对NaHS的检测无干扰。将Fe^(3+)-OPD显色体系结合纸芯片构建的纸基比色体系蓝色分析色道值(B值)与NaHS的浓度在20~150μmol/L范围内呈线性关系,检出限为2μmol/L,并可用于定量检测加标自来水和胎牛血清中的硫化物。

Catalytic degradation of methylene blue by Fenton like system: model to the environmental reaction

To develop more efficient chemical methods for the demineralization of organic pollutants from water bodies, which one was also mimic to the nature, a degradation of methylene blue by Fe(Ⅲ) and H 2O 2 in the absence of light instead of Fe(Ⅱ) and H 2O 2 was studied. Results showed that use of Fe (Ⅲ) is more promising than Fe(Ⅱ). The present study reflects that Fenton reaction is more efficient, in the presence of a small amount of salicylic acid is added which is a one of the priority pollutant.

Effect of Fe(Ⅲ) on the bromate reduction by humic substances in aqueous solution

Humic substances are ubiquitous redox-active organic compounds of environment. In this study, experiments were conducted to determine the reduction capacity of humic acid in the man-ix of bromate and Fe（Ⅲ） solutions and the role of Fe（Ⅲ） in this redox process. The results showed that the humic acid regenerated Fe（Ⅱ） and reduced bromate abiotically. The addition of Fe（Ⅲ） could accelerate the bromate reduction rate by forming humic acid-Fe（Ⅲ） complexes. Iron species acts as electron mediator and catalyst for the bromate reduction by humic acid, in which humic acid transfers electrons to the complexed Fe（Ⅲ） to form Fe（Ⅱ）, and the regenerated Fe（Ⅱ） donate the electrons to bromate. The kinetics study on bromate reduction further indicated that bromate reduction by humic acid-Fe（Ⅲ） complexes is pH dependent. The rate decreased by 2-fold with the increase in solution pH by one unit. The reduction capacity of Aldrich humic acid was observed to be lower than that of humic acid or natural organic matter of Suwanne River, indicating that such redox process is expected to occur in the environment.

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.

Adsorption behavior of Sb(Ⅲ) in single and binary Sb(Ⅲ)-Fe(Ⅱ) systems on cationic ion exchange resin: Adsorption equilibrium, kinetic and thermodynamic aspects

The present study dealt with the mechanism of competitive adsorption of Sb(Ⅲ)and Fe(Ⅱ)ions from a copper-containing aqueous solution on Purolite S957,a commercially available cationic ion-exchange adsorbent.Experiments were conducted using aqueous copper sulfate solutions containing either single or conjoint ions,using both sedentary and batch adsorption techniques to ascertain the sensitivity of the adsorption process to variation in p H,mass of resin,contact time,and temperature as well as establishing the optimal range of variables for maximum ion removal.The data from single ion adsorption tests were fitted by non-linear regression techniques to Henry,Langmuir,Freundlich,Temkin,and Dubinin–Radushkevich isotherm models.Freundlich isotherm for Sb(Ⅲ)and Freundlich and Henry models for Fe(Ⅱ)solutions best express the adsorption equilibrium data;while for binary ion electrolytes,the extended Freundlich model fitted the data satisfactorily.The kinetic model adequately describing adsorption was shown to be the pseudo-first-order,underscoring the dominant role of physical adsorption playing in the process.Thermodynamic parameters for the adsorption process reveal differences in the Sb(Ⅲ)adsorption mechanism from single ion and Sb(Ⅲ)-Fe(Ⅱ)containing electrolytes.The adsorption of Sb(Ⅲ)alone is endothermic,whereas the process becomes exothermic in the Sb(Ⅲ)-Fe(Ⅱ)system.

Reduction of Sulphur-containing Aromatic Nitro Compounds with Hydrazine Hydrate over Iron(III) Oxide-MgO Catalyst

Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron（Ⅲ） oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.

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.

铁离子(Ⅱ/Ⅲ)/Nafion膜体系的阻抗分析

对Fe(Ⅱ/Ⅲ)离子在Nafion膜中的电荷传输以及在溶液扩散层中的传质过程进行了理论上的分析,利用小幅度阶跃电位作为激励信号的阻抗测量法测定了该体系的阻抗并求出了Fe(Ⅱ/Ⅲ)离子在膜中的扩散系数和标准速度常数。同时讨论了电极电位和支持电解质浓度对体系阻抗的影响。实验的结果与理论推导的结果相一致。