类芬顿铁基功能材料除砷的应用与机制（英文）

亚砷酸盐(As(Ⅲ))和砷酸盐(As(V))是天然水中砷的主要存在形态,其中As(Ⅲ)由于其高毒性和高迁移率,对人类和环境的危害远大于As(V)。因此,将As(Ⅲ)预氧化为As(V)被认为是降低砷毒性、提高砷去除率的有效手段。由于铁基功能材料具有较高的催化活性和砷亲和力,在非均相类芬顿体系中可以快速将As(Ⅲ)氧化为As(V),然后通过吸附和表面共沉淀将As(V)从水中去除。本文综述零价铁和铁(羟基)氧化物等不同铁基功能材料对砷去除的影响,以进一步阐明非均相芬顿法中As(Ⅲ)的催化氧化及去除机理。最后,本文还展望了应用于As(Ⅲ)氧化的铁基功能材料目前面临的主要挑战和机遇。     

铜电解液净化中铜砷的分离与回收(英文)

经二氧化硫还原、蒸发结晶,使铜电解液中铜、砷、锑和铋得到有效去除。结晶产物经过溶解、氧化、中和、沉淀、过滤和蒸发结晶,得到三氧化二砷和硫酸铜。当采用SO2将铜电解液中As(Ⅴ)充分还原为As(Ⅲ),并加热蒸发浓缩铜电解液中硫酸浓度至645g/L时,铜电解液中铜、砷、锑和铋的去除率分别为87.1 %,83.9 %,21.0 %和84.7%。在温度30℃,将65g结晶产物溶于200mL自来水时,砷的去除率为92.81%。将所得滤液在如下条件下净化:n(Fe):n(As)为1.2,双氧水为理论用量的19倍,氧化温度为45℃,氧化时间为40min,终点pH为3.7,净化后蒸发浓缩结晶,所得硫酸铜溶液中硫酸铜含量达到98.8%。     

多巯基磁性生物竹炭纳米复合材料的化学共沉积制备及其高效去除水溶液中的As(Ⅲ)（英文）

通过简单的化学共沉淀方法制备多基团磁性生物竹炭纳米复合材料(BBC@n Fe-SH)并用于废水中As(Ⅲ)的去除。研究表明,BBC@nFe-SH的磁场强度达到83376 A/m,具有极好的磁回收性。在pH 5.0、40℃的条件下BBC@n Fe-SH对As(Ⅲ)的最大吸附容量为98.63 mg/g,且在120 min内达到反应平衡。SEM、FTIR、VSM和XPS等分析表明,As(Ⅲ)的去除机制为BBC@nFe-SH表面的含氧基团与As(Ⅲ)的络合作用。在水处理过程中BBC@n Fe-SH表现出较好的稳定性和可回收性,可以通过1mol/LNa OH淋洗实现材料的再生活化。因此,BBC@n Fe-SH在含砷废水处理方面具有极大的应用潜力。     

氨基功能化CoFe2O4-SiO2 磁性复合材料的制备及其在去除水中重金属离子的吸附性能

钴-铁氧体纳米粒子(CoFe₂O₄ NPs)通过改良的共沉淀法制备,CoFe₂O₄-SiO₂磁性复合材料通过st?ber法合成,为了吸附重金属离子CoFe₂O₄-SiO₂进行了氨基功能化。这种吸附剂的晶体结构、形貌、颗粒尺寸、化学组成和分子结构采用X射线衍射图谱(XRD)、扫描电子显微镜(SEM)以及傅里叶变换红外光谱(FTIR)进行表征。此复合材料具有优良的磁性能,由于其高的饱和磁化强度,磁铁可以将其在30秒内快速分离。同时,CoFe₂O₄ NPs的磁性能可以通过烧结温度进行调节,随烧结温度提高,磁性能增强。溶液的pH及反应时间对重金属离子吸附的影响进行了研究,此外此吸附剂对Cu (II)、Cd (II)、Mn (II) 和Zn (II)具有较高的吸附容量和去除率,这一结果使此复合材料可以潜在应用于废水中重金属离子的吸附上。     

离子强度、阴阳离子和腐殖酸对纳米零价铁去除溶液中U(Ⅵ)的影响

采用液相还原法制备纳米零价铁(nZⅥ)去除溶液中的U(Ⅵ),讨论溶液pH与离子强度、共存阴阳离子和腐殖酸对去除效果的影响,并对nZⅥ进行表征研究,分析纳米零价铁去除U(Ⅵ)的机理。结果表明:纳米零价铁对溶液中的U(Ⅵ)有很好的去除效果,pH值对去除效果有显著影响,而离子强度对纳米零价铁去除U(Ⅵ)几乎没有影响。阳离子对铀的去除有一定的影响,其中Ca~(2+)和Mg~(2+)的影响较大,而Na~+和K~+几乎没有影响。阴离子对纳米零价铁去除U(Ⅵ)也有一定的影响,其影响顺序由大到小依次为NO_3~-、SO_4~(2-)、ClO_4~-、CO_3~(2-)、HPO_4~(2-)。腐殖酸对纳米零价铁去除溶液中U(Ⅵ)在pH≤4.5时有明显的促进作用;当pH4.5以后,腐殖酸对纳米零价铁去除U(Ⅵ)具有明显的抑制作用。     

二段脱铜液还原结晶法脱砷新工艺

对铜电解液脱砷方法进行研究,提出以二段脱铜液为原料,采用SO2还原结晶法脱砷新工艺。在二段脱铜液中通入SO2,将其中的As(Ⅴ)还原成As(Ⅲ),还原后的溶液通过蒸发结晶析出As2O3,达到二段脱铜液脱砷的目的。结果表明:当As(Ⅴ)浓度为12.41 g/L、H2SO4浓度为253.00 g/L、反应温度为60℃时,向二段脱铜液中通入SO290 min后静置90 min,二段脱铜液中As(Ⅴ)的还原率达到94.54%。还原后的溶液进行蒸发结晶,当蒸发前与结晶后的体积比(V0:V1)为3.5时,砷的脱除率达到91.33%,结晶产物为As2O3。与传统脱砷工艺相比,新工艺具有操作简单、成本低廉及砷的脱除效果明显等优势。     

采用负载Ni_(0.5)Zn_(0.5)Fe_2O_4磁性纳米粒子芦荟壳灰从水溶液中快速高效去除Ag(Ⅰ)（英文）

采用负载Ni_(0.5)Zn_(0.5)Fe_2O_4磁性纳米粒子芦荟壳灰从水溶液中去除Ag(Ⅰ)。采用XRD、SEM、BET等温线、振荡试样磁力计(VSM)和傅里叶变换红外光谱(FT-ⅠR)表征该吸附剂。采用该吸附剂在不同p H值(2~7)、吸附剂量(0.01~0.5 g)、Ag~+浓度(50,100,200,300,500,700和1000 mg/L)下测定Ag(Ⅰ)的吸光度。在最佳条件(30 min,p H=5)下,得到最高的Ag~+去除率。在50 m L 100 mg/L Ag~+溶液中,最佳吸附剂量是0.20 g,去除率为98.3%。基于Langmuir等温线,得到最大单层饱和吸附量为243.90 mg/g。表征结果表明,吸附剂的比表面积和孔体积分别为814.23 m2/g和0.726 cm3/g。实验数据与Langmuir和Freundlich等温线模型吻合。合成的吸附剂对水溶液中Ag(Ⅰ)吸附具有理想的表面积和吸附容量。     

ZnO@NiO纳米晶粒吸附去除氰化物的动力学和热力学（英文）

合成了ZnO、NiO和ZnO@NiO纳米晶粒,采用红外光谱(FTIR)、X射线衍射(XRD)和扫描电镜(SEM)技术对其进行表征。ZnO、NiO和ZnO@NiO的平均颗粒尺寸为32、50和48 nm。对这些纳米晶粒去除氰化物的能力进行了测定。实验结果表明,与ZnO和NiO相比较,ZnO@NiO纳米晶粒去除氰化物的能力更强。ZnO@NiO纳米晶粒对氰化铁的去除能力比对氰化钠的更高。研究了反应时间、溶液pH值(2~12)、纳米晶粒用量(0.02~0.4 g)和氰化物浓度(5~50 mg/L)等参数对氰化物去除效果的影响。在最优条件下:pH5,纳米晶粒用量0.2 g,反应时间30 min,ZnO@NiO纳米晶粒对20 mg/L氰化物的去除率可达到90%以上。ZnO@NiO纳米晶粒对氰化物的吸附去除动力学影响规律符合Langmuir准二级吸附动力学模型(k2=4.66×10-2,R=0.999)。热力学研究表明,25°C下,反应的标准焓变化为7.87 kJ/mol,自由能变化为-18.62 kJ/mol。纳米晶粒对氰化物的吸附是一个吸热的自发过程。ZnO@NiO纳米晶粒是一种能有效的去除水或废水中氰化物的吸附剂。     

As(Ⅴ)-Fe(Ⅱ)体系常压臭葱石合成过程过饱和度对形貌和稳定性的影响

针对低溶液过饱和度是常压臭葱石合成过程的关键要素这一问题,本文在As(Ⅴ)-Fe(Ⅱ)体系下,通过Fe²⁺缓慢氧化来控制溶液过饱和度,研究了pH对Fe²⁺氧化速率的影响、Fe²⁺氧化速率与过饱和度的关系和过饱和度对砷铁沉淀率、臭葱石组分含量、颗粒粒径、形貌及其稳定性的影响。结果表明,Fe²⁺的氧化速率随初始pH值的降低而降低,而溶液过饱和度随Fe²⁺氧化速率的降低而降低。较低的初始过饱和度不利于砷铁的沉淀,对渣中砷铁含量影响不显著,但对渣中硫含量影响较大。初始过饱和度从7.86升至78.86时,砷、铁沉淀率分别从77.05%、53.9%升至88.66%、61.79%,渣中砷、铁和硫含量分别为30.74%、24.14%和0.58%～0.17%。臭葱石颗粒粒径随初始过饱和度的增加而先增加后减小,初始过饱和度值为11.7时,颗粒尺寸达到最大87.5μm。初始过饱和度为7.86～24时,形成类球型臭葱石颗粒;初始过饱和度值为24～78.86时,形成无规则型臭葱石颗粒。通过控制初始过饱和...     

Leptospirillum ferriphilum耐砷能力的驯化及驯化机制

为了获得耐砷能力较高的中度嗜热嗜酸浸矿菌Leptospirillum ferriphilum,采用连续转接驯化法进行耐砷驯化,并对菌株的驯化机制进行研究。结果表明:驯化后Leptospririllumferriphilum菌的As(Ⅲ)和As(Ⅴ)耐受浓度分别提高到7.0g/L和11.0g/L;As(Ⅴ)驯化菌株对砷黄铁矿的浸出作用明显比As(Ⅲ)驯化菌株强;砷驯化菌细胞官能团发生明显变化,多糖和蛋白质含量明显增多,细胞表面负电荷明显降低,以适应高砷的环境。同步辐射原位C-K边XANES谱图表明,驯化菌糖类和蛋白质的分布位置发生了变化;DFT理论计算表明,驯化菌更容易吸附到矿物表面上。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。