银离子印迹CTS/TEA膜的制备及表征

介绍了一种银离子壳聚糖(CTS)/三乙醇胺(TEA)印迹膜[Ag(I)-IICTM]的制备方法:CTS溶液中加入交联剂与银盐,形成均一溶液,流延成膜之后浸泡入有机碱TEA凝固浴中,凝固成CTS/TEA/Ag(I),进行处理,洗脱Ag(I)之后形成Ag(I)-IICTM。制备印迹膜的优化条件为:CTS 2.0%、AgNO30.6%、交联剂3.0%、TEA 10.0%。FT-IR显示Ag(I)-IICTM吸附Ag+具有配位作用;SEM结果显示Ag(I)-IICTM与CTS/TEA/Ag(I)膜相比,表面明显粗糙,且出现均匀的纹理,再吸附银离子后有覆层;XRD结果表明制备Ag(I)-IICTM,TEA作为凝固浴比NaOH更适合。     

表面氨基化细菌纤维素对水中重金属离子吸附的热力学与动力学(英文)

以细菌纤维素(BC)为原料,通过化学改性法制备新型、高效且价廉的吸附材料——表面氨基化细菌纤维素,并对其进行表征及分析;同时以Cu~(2+)、Pb~(2+)和Cd~(2+)为研究对象,对其吸附热力学和动力学特性进行研究,并探讨吸附机理,建立数学模型。结果表明:氨基化细菌纤维素对Cu~(2+)、Pb~(2+)和Cd~(2+)的吸附过程更好地符合Langmuir等温方程和准二级反应动力学模型,说明吸附过程为单分子层吸附,以化学吸附作用为主。Elovich方程、粒子内扩散模型也能很好地反映吸附模式,说明是其吸附液膜扩散和粒子内扩散共同作用的结果。吸附过程是吸热反应,适当升高反应温度将有利于吸附发生。     

竹炭/壳聚糖复合吸附剂对银(I)的吸附性能与回收研究

研究了竹炭/壳聚糖复合吸附剂吸附银(I)的动力学和热力学,并进行了银的回收实验。动力学实验表明,复合吸附剂对银(I)的吸附符合准一级动力学方程,测定不同温度下复合吸附剂对银(I)吸附的表观速率常数,得到表观活化能Ea=29.2 k J/mol;热力学研究表明,复合吸附剂对银(I)的吸附符合Langmuir等温吸附方程,测得吸附热?H为40.8 k J/mol,说明复合吸附剂对银(I)的吸附过程为吸热过程,吸附过程主要为化学吸附,吉布斯自由能?G0,表明吸附质从溶液到吸附剂表面的吸附过程是自发过程。吸附回收实验表明:竹炭/壳聚糖复合吸附剂能应用于银的回收。     

斜生栅藻和汉氏菱形藻对Ag(Ⅰ)离子吸附的比较研究

近来的报道表明,利用藻类生物吸附处理含重金属离子的污水,具有效率高、费用低、污染小等优点,作者进行了斜生栅藻(Scenedesmus obliquus(Turp.) K黷z.)及汉氏菱形藻(Nitzschia hantzschiana Rabh.)对Ag(I)离子吸附的比较研究,发现在2种藻上所吸附的Ag都主要以+1价的形式存在;在相同条件下,汉氏菱形藻对Ag(I)离子的吸附能力明显比斜生栅藻高,在Ag+离子初始质量浓度为0.33 mg/ml、温度25?℃下,当吸附达到平衡后,斜生栅藻对Ag(I)离子的平均吸附量为15mg/g,而汉氏菱形藻为27mg/g。     

硅藻土-钨渣基陶粒对废水溶液中铜离子的吸附（英文）

为了在中国南方有色矿冶区同时实现工业钨渣的资源化利用和重金属废水的处理,以钨渣和硅藻土为主要原料制备一种新型陶粒,对其与溶液中重金属Cu~(2+)的吸附规律进行研究。结果表明:新制备的近球形陶粒表面粗糙多孔,内部有许多贯穿性孔道与外部相连通;陶粒的主要物相组成含有MnFe_2O_4。在303 K、铜离子初始浓度100 mg/L、陶粒投加量0.5 g和300 min条件下,陶粒对Cu~(2+)的吸附量为9.421 mg/g,吸附去除率达94.21%。随着陶粒投加量的增大,其对溶液中Cu~(2+)的总吸附量增大,单位吸附量降低;陶粒对Cu~(2+)的吸附量随试验pH值的增大而增大。陶粒对Cu~(2+)的等温吸附更符合Freundlich模型,吸附主要发生在非均质表面,为优惠吸附;陶粒对铜离子的吸附动力学符合准二级动力学方程,吸附过程主要受液膜扩散、表面吸附以及颗粒内扩散因素控制。对于实际重金属废水的处理,陶粒对重金属离子的吸附初始阶段受扩散控制,此时,可通过加强搅拌的方式提高Cu~(2+)的去除率。     

壳聚糖选择性吸附分离镍、钴新过程

本文以成型壳聚糖为吸附剂进行溶液中Ni-Co的分离,通过Ni~(2+)和Co~(2+)与壳聚糖上氨基的络合能力差异达到Ni~(2+)、Co~(2+)分离的目的。结果表明:利用NaOH与壳聚糖醋酸溶液可制备出粒度约为60μm的层状成型壳聚糖;成型壳聚糖对Ni~(2+)、Co~(2+)的吸附符合拟二级动力学方程和Freundlich方程;经吸附焓变计算发现成型壳聚糖对Ni~(2+)的吸附为吸热反应,而对Co~(2+)的吸附为放热反应;吸附机理表明,壳聚糖上的氨基和羟基与Ni~(2+)、Co~(2+)发生结合反应。以萃取分离后得到的高Co~(2+)低Ni~(2+)溶液为原料,成型壳聚糖吸附后溶液中Ni~(2+)含量由73×10~(-6)降低至30×10~(-6),实现杂质的深度脱除。     

高锰酸钾改性黄芪废渣活性炭对Cd~(2+)的吸附（英文）

以黄芪废渣为原料,用KOH为活化剂制备黄芪废渣活性炭,并用KMnO_4改性,改性前后的黄芪废渣活性炭用于对水溶液中Cd~(2+)的吸附。采用扫描电子显微术、比表面积测定、X射线衍射、红外光谱和贝母滴定等方法对改性前后的黄芪废渣活性炭进行表征;通过静态吸附实验考察改性前后黄芪废渣活性炭对水溶液中Cd~(2+)的吸附性能。结果表明,KMnO_4改性后活性炭表面含氧官能团增加,MnO_2沉积到活性炭表面。改性前后的黄芪废渣活性炭对Cd~(2+)的吸附符合准二级动力学方程,等温吸附更符合Langmuir模型,改性前后的黄芪废渣活性炭对Cd~(2+)的饱和吸附量分别是116.96和217.00mg/g。KMnO_4显著改变了黄芪废渣活性炭的物理化学性质和表面结构,改性后的黄芪废渣活性炭对Cd~(2+)的吸附能力明显提高。     

羊栖菜对水环境中Cd~(2+)的吸附特性

以非活性羊栖菜粉为吸附剂,研究羊栖菜对水溶液中Cd~(2+)的吸附特性。结果发现:在最佳吸附pH为5,温度为313.15K,吸附剂浓度为1g/L,Cd~(2+)初始浓度为40mg/L左右时,羊栖菜对镉离子的去除率的最大值为92.54%,且吸附10 min时,即达到最大去除率93.95%;在60 min时,基本达到吸附平衡,羊栖菜对Cd~(2+)的去除具有快速、去除率高的特点。动力学实验数据符合准二级动力学模型,Langmuir对热力学实验平衡数据的拟合较高,最大理论吸附容量为68.49 mg/g。通过方程拟合和SEM分析发现吸附过程发生了离子交换。FTIR分析显示,羟基、羧基等官能团在吸附过程中发挥了作用,通过解吸可以实现羊栖菜粉的再生和循环利用。     

铝钙粉浸出渣制备沸石及其对锌冶炼废水的吸附性能

以聚合氯化铝(PAC)生产过程中铝钙粉浸出渣为原料,通过酸浸-焙烧-水热晶化工艺制备沸石,并研究其对锌冶炼废水中重金属的去除效果。结果表明:铝钙粉浸出渣通过酸浸-焙烧-水热晶化过程,当原料n(SiO_2)/n(Al_2O_3)=2时,产物物相为结构完整的A型沸石;当原料n(SiO_2)/n(Al_2O_3)=6时,产物物相为结构完整的P型沸石。拟二级动力学方程计算得到A型沸石对Zn~(2+)、Cd~(2+)的平衡吸附量分别为97.09、12.39 mg/g,P型沸石对Zn~(2+)、Cd~(2+)的平衡吸附量分别为57.84、10.82mg/g。Freundlich吸附等温线拟合结果表明,A型沸石和P型沸石吸附Zn~(2+)、Cd~(2+)机理均为非均相表面的复杂吸附。当废水pH为8、吸附温度为25℃、吸附时间为150 min时,采用A型沸石处理锌冶炼废水,产渣量为1.1 g/L,废水中Cu~(2+)、Pb~(2+)、Zn~(2+)、Cd~(2+)、总砷(AsT)浓度分别由1.68、13.12、147.00、15.14、4.06 mg/L降至0.06、0.05、0.52、0.03、0.01 mg/L,达到《铅、锌污染物排放标准》(GB25466—2010)。     

铝钙粉浸出渣的活化及其在锌冶炼废水处理中的应用

以PAC生产过程中铝钙粉浸出渣为原料,采用盐酸和氢氧化钠进行活化,并对其在锌冶炼废水中吸附重金属的性能进行研究。考察铝钙粉浸出渣及其活化产物结构、比表面积、孔结构的变化,分析了pH值、吸附时间和重金属浓度对其吸附性能的影响,并以氢氧化钠活化产物为吸附剂进行了工业实验。结果表明:铝钙粉浸出渣经盐酸和氢氧化钠活化后,其结构均由岛状变为层状。铝钙粉浸出渣、盐酸活化产物和氢氧化钠活化产物的比表面积分别为21.8、63.1、28.1 m~2/g,BJH孔径分别为36.06、43.54和236.35 nm,孔容分别为0.03、0.09和0.14cm~3/g。pH=8,吸附温度为25℃,吸附时间为150min时,由Langmuir方程得到铝钙粉浸出渣对Cd~(2+)、Zn~(2+)和As(V)的饱和吸附量分别为2.81、497.57和2.45mg/g,盐酸活化产物对Cd~(2+)、Zn~(2+)和As(V)的饱和吸附量分别为3.44、516.32和2.04 mg/g,氢氧化钠活化产物对Cd~(2+)、Zn~(2+)和As(V)的饱和吸附量分别为7.64、526.32和4.72 mg/g。工业实验结果表明:吸附过程具有化学吸附特征,废水中Cu~(2+)、Pb~(2+)、Zn~(2+)、Cd~(2+)和As(V)的浓度由1.68、13.12、147.00、15.14和1.56 mg/L降至0.01、0.05、0.52、0.03和0.02 mg/L,达到《铅、锌污染物排放标准》(GB25466—2010)。     

泡沫塑料分离富集微量银的研究

研究了用聚氨酯泡沫塑料分离富集微量银的方法,对银与邻二氮菲的配合物的吸附选择性和富集效果较佳,在EDTA存在下,其它金属离子不被吸附,银可用1m0l/L HNO_3定量洗脱。     

铜基银枝晶的制备和氧还原电催化性能

通过迦尔瓦尼置换反应在不同的Ag+溶液中制备出了铜基银枝晶,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和电化学工作站分别对样品的结构、微观形貌以及电化学性能进行了表征。结果表明,随着溶液中Ag+浓度和反应时间的增加,银的形貌从团簇状向树枝状转变,氧还原电催化性能也增强;在相同浓度Ag+溶液中,SO42-比NO3-更能促进枝晶的生长,但当阴离子是NO3-时比阴离子是SO42-时所制备的银枝晶的氧还原电催化性能更好;在10 mmol/L AgNO3溶液中,反应时间为1800 s时制备的银枝晶电极使H2O2的还原峰电流最大,在0.1 mol/L Na2SO4+5mmol/L H2O2溶液中,恒电位为-0.32 V时,其稳态电流密度可达2.83 mA/cm2。初步提出了银枝晶的生长机制和H2O2的氧还原催化机制。     

Amperometric detection of gold by differential pulse voltammetry using a DNA biosensor

A DNA biosensor with [Ru(DA-bpy)3]Cl2(DA-bpy:4,4'-diamino-2,2'-bipyridine) (RuL) as the electrochemical probe was prepared on pyrolytic graphite electrode (PGE) through the supramolecular interaction between RuL complex and DNA template. Cyclic voltammetry of RuL-DNA film showed a pair of stable and reversible peaks corresponding to the Ru(III)/Ru(II) redox potential of -0.165 V versus Ag|AgCl in pH 7.4 0.1 mol·L-1 Tris-HCl. The electron transfer was expected across the double-strand DNA by an "electron tunneling" mechanism. When the DNA biosensor was immerged in gold (III) buffer solution, the current peak signal (I) of the RuL-DNA supramolecular depressed and △I was linear in the concentration range of Au ion from 1 × 10-7 to 2 × 10-5 mol·L-1 with a regression coefficient of 0.9879. The detection limit was 5 × 10-8 mol·L-1. The developed procedures were applied to the analysis of synthetic samples of real materials with good sensitivity and selectivity.     

Novel nanoporous binary Ag-Ni electrocatalysts for hydrazine oxidation

From an aqueous mixture of Ag(Ⅰ)-EDTA complex and Ni(Ⅱ) nitrate, silver and nickel particles were co-deposited on the surface of titanium substrates by the hydrothermal method using hydrazine hydrate as a reduction agent. The prepared titanium-supported nano-scale Ag and Ag-Ni particles (nano Ag/Ti, nano Ag_(86)Ni_(14)/Ti, nano Ag_(77)Ni_(23)/Ti, and nano Ag_(74)Ni_(26)/Ti) exhibit nanoporous 3D network textures. Their electrocatalytic activity towards hydrazine oxidation in alkaline solutions was evaluated by cyclic voltammetry and chronoamperometry. The results show that the four samples present a low onset potential of ca. -0.60 V vs. SCE and considerably high and stable anodic current den-sities for hydrazine oxidation. Among them, the nano Ag_(86)Ni_(14)/Ti electrode exhibits the highest anodic current density towards hydrazine oxidation, showing an increment of electro-active sites on the nano Ag_(86)Ni_(14)/Ti due to the addition of Ni to Ag particles.     

Electrochemical codeposition of typical α+β phases Mg-Li alloys from the molten LiCl-KCl-MgCl_2 system

Electrochemical codeposition of Mg-Li alloys on molybdenum electrodes was investigated in LiCl-KCl(50 wt.%:50 wt.%) melts containing different concentrations of MgCl2 at 973 K.Cyclic voltammograms show that the underpotential deposition of lithium on pre-deposited magnesium leads to the formation of liquid Mg-Li alloys.The deposition potentials of Mg(II) and Li(I) ions gradually near each other with MgCl2 concentration decreasing.Mg-Li alloys with typical α + β phases could be obtained by potentiostatic electrolysis from LiCl-KCl melts containing 5 wt.% MgCl2 at -2.25 V vs.Ag/AgCl(cathodic current density 1.70 A·cm-2) for 2.5 h.α phase, α + β phases, and β phase Mg-Li alloys with different lithium contents were obtained by potentiostatic electrolysis from LiCl-KCl melts with the different concentrations of MgCl2.The samples were characterized by X-ray diffraction and scanning electron microscopy.     

(Ⅰ+Ⅱ)MIXED MODE HYDROGEN INDUCED CRACKING

Hydrogen induced cracking(HIC)of 0.3% C,1% Cr,1% Mn,1% Si high strength steel hasbeen studied under simple mode Ⅰ,mode Ⅱ and(Ⅰ+Ⅱ)mixed mode loading conditions.Af-ter being hydrogen-charged in IN H_2SO_4 solution,the material behaved hydrogenembrittlement in all the cases studied.The threshold K_(ⅡH)/K_(ⅡX) of HIC under mode Ⅱ load-ing was 0.27,which was nearly the same as that K(ⅠH)/K_(ⅠX)=0.29 under mode Ⅰ loading.While the thresholds of-HIC under(Ⅰ+Ⅱ)mixed mode loading were 0.36,0.41 and 0.37 cor-responding to the K_Ⅱ/K_Ⅰ ratio of 0.27,0.4 and O.81.The results show that simple mode Ⅰor mode Ⅱ loading is more susceptible to hydrogen embrittlement than(Ⅰ+Ⅱ)mixed mode.For explaining the experimental results,the effects of triaxial stress as well as plasticdeformation ahead of crack tip has been discussed.     

S300树脂对汽车失效催化剂浸出液中Pd(Ⅱ)的吸附行为

基于实验室合成的S300树脂对汽车失效催化剂浸出液中Pd2+吸附过程进行研究,考察温度、溶液体系中HCl浓度、吸附时间等因素对Pd2+在S300树脂上吸附行为的影响,并对Pd2+在S300树脂中的动力学特性、交换等温线、复杂体系中的选择性以及解吸过程进行研究,根据表征结果分析在盐酸体系下S300树脂的吸附机理.结果表明...     

硅胶表面AuCl_4~-印迹聚乙烯亚胺的制备及识别特性研究

将功能高分子聚乙烯亚胺(polyethyleneimine,PEI)化学接枝在硅胶微粒表面,形成功能接枝材料PEI-g-SiO2;再以AuCl4-为模板离子,乙二醇二缩水甘油醚(EGDE)为交联剂,将接枝在硅胶表面的PEI大分子链进行交联,同时实施AuCl4-的印迹,制备了AuCl4-印迹材料IIP-PEI-g-SiO2。采用静态法考察了IIP-PEI-g-SiO2对AuCl4-的吸附特性。实验结果表明,IIP-PEI-g-SiO2对AuCl4-具有优良的吸附性能与较强的记忆识别能力。吸附容量可以达到23.59mg/g,相对于Cu2+,印迹材料对AuCl4-的选择性系数为32.45。此外,IIP-PEI-g-SiO2还具有优良的重复使用性能。     

Adsorption of Ag（Ⅰ） on H2TiO3 from aqueous solutions

Adsorption of silver ions from aqueous solution onto H2TiO3 was studied. Equilibrium experimental studies were performed to determine the adsorption capacity of H2TiO3 for silver ion at various pH values. Batch experiments were conducted in the range of pH value 3-7 and silver ions concentration 10-200 mg/L. The results show that the adsorption is strongly dependent on pH value. The equilibrium absorption capacity of H2TiO3 increases significantly with the increase of pH value from 3 to 7. The adsorption of silver ion obeys the Langmuir isothermal equation well in the concentration range studied, the adsorption constant is 0.054 7, 0.052 4, 0.0881 at pH 5, 6 and 7, respectively, and the maximum adsorption capacities are 23.64, 29.76 and 40.82 mg/g.     

Preparation of silver tin oxide powders by hydrothermal reduction and crystallization

Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw materials. H2C2O4 was used as the co-precipitator of silver ions and tin ions. The co-precipitation conditions were investigated. The results show that the co-precipitate of Ag2C2O4 and Sn（OH）4 is available when the pH value of the solution is 4.27-8.36. Using the obtained precipitate as precursor,the reduction of Ag＋ and the crystallization of tin oxide were carried out simultaneously by the hydrothermal method and silver tin oxide composite powders were obtained. The composite powders were characterized by X-ray diffraction （XRD） analysis,scanning electron microscope （SEM）,and energy spectrum analysis. The results show that the silver tin oxide composite powders are small with a diameter of about 2 μm and with homogeneous distribution of tin.