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1.
研究了Keggin结构钼磷杂多化合物Na5[PM(H2O)Mo11O39]·nH2O(M=Mn2+,Co2+,Ni2+,Cu2+,Zn2+在溶液中的氧化还原性质,发现环境的改变可对杂多阴离子的极谱半波电位产生影响,其影响程度的大小决定于过渡金属离子本身的性质。取代后的钼磷杂多阴离子的半波电位顺序为Ni2+>Co2+>Zn2+>Cu2+>Mn2+,pH值的变化影响氧化还原性质,并阐述了变价金属Cu2+对杂多阴离子氧化还原性质的影响.  相似文献   

2.
沉淀基离子选择电极对干扰离子的动力学响应研究   总被引:4,自引:2,他引:2  
用活度阶梯法研究了AgI,AgBr,CuS,PbS和CdS电极对干扰离子的动力学响应.溶液中含一定浓度主要离子时上述电极对某些干扰离子响应非单一突跃型瞬时信号;溶液中不含主要离子时,除了AgBr电极响应Cl-外,其它都响应单一瞬时信号.离子交换产物的溶解度越小,离子的水合焓差越小,瞬时信号峰高度越大.离子水合焓差对瞬时信号峰高度的影响说明,试液高速喷向电极表面时由于扩散层厚度很薄,电极对干扰离子响应瞬时信号的峰电位不决定于离子扩散速度,而决定于离子交换速度.除CuS电极外,根据其它电极非单一突跃型瞬时信号所测定的平衡电位选择性系数Kxye与相应化合物溶度积比值是一致的.  相似文献   

3.
首次以meso-四(4-氨基苯基)卟啉为衍生化试剂,使其负载于碳硅凝胶填充材料上,在优化的实验条件下,于pH9.24的NH3·H20/NH4Cl缓冲介质中实现金属离子Cu2+、Mn2+、Pb2+、Fe2+、Cd2+、Ni2+的在线富集分离和ICP-AES测定.考察了影响在线预富集的各种因素,富集倍数可达6~57.8倍.检出限为ng/mL级,分析速率为6次/h.此法用于生物试样分析,结果满意.  相似文献   

4.
Kumar M  Rathore DP  Singh AK 《Talanta》2000,51(6):1187-1196
A stable chelating resin matrix was synthesized by covalently linking o-aminophenol (o-AP) with the benzene ring of the polystyrene–divinylbenzene resin, Amberlite XAD-2, through a –N=N– group. Elemental analyses, thermogravimetric analysis (TGA) and infrared spectra have characterized the resulting chelating resin. It has been used to preconcentrate Cu2+, Cd2+, Co2+, Ni2+, Zn2+ and Pb2+, prior to their determination by flame atomic absorption spectrometry. The optimum pH values for quantitative sorption of Cu, Cd, Co, Ni, Zn and Pb are 6.2–7.4, 5.6–7.2, 5.6–9.0, 6.0–9.0, 5.7–7.0 and 5.0–6.0, respectively. These metals are desorbed (recovery 91–98%) with 4 mol dm−3 HNO3. The sorption capacity of the resin is 3.37, 3.42, 3.29, 3.24, 2.94 and 3.32 mg of metal g−1 of resin, respectively, for Cu, Cd, Co, Ni, Zn and Pb. The effect of NaF, NaCl, NaNO3, Na2SO4, and Na3PO4 on the sorption of these metal ions has been investigated. These electrolytes are tolerable up to 0.01 mol dm−3 in case of all the metal ions, except Cl which is tolerable even up to 0.1 mol dm−3 for Zn and 1.0 mol dm−3 for Pb. The preconcentration factor for Cu, Cd, Co, Ni, Zn and Pb are 50, 50, 100, 65, 40 and 40 (concentration level 10–25 μg dm−3) respectively. Simultaneous enrichment of the six metals is possible. The method has been applied to determine Cu, Cd, Co, Ni, Zn and Pb content in well water samples (RSD≤8%).  相似文献   

5.
Aminopolycar☐ylate ligands were added to the 4-(2-pyridylazo)-resorcinol (PAR) postcolumn reagent to alter the reagent selectivity towards transition metals. Addition of ethylenediaminetetraacetic acid (EDTA) completely suppressed the reaction between PAR and the metal ions. Addition of 0.1 mM nitrilotriacetic acid (NTA) to 1 mM PAR lowered the response to specific transition metal ions, but completely suppressed the PAR response to the lanthanides. Increasing the NTA concentration to 8 mM resulted in complete suppression of the PAR response to all metal ions except Cu2+ and Co2+ for which the detection limits were 3 and 1 ng, respectively. The observed selectivity results from the slow rate of conversion of metal ions from the M(NTA)24− form to M(PAR)2.  相似文献   

6.
AStudyontheInfluenceofCu ̄2 ̄+,Cd ̄2 ̄+andPb ̄2 ̄+onTripleHelixPoly(A:2I) ̄*HUAEr-binga ̄b ̄,YANGPin ̄b ̄* ̄*,LIQing-shan ̄a,YANGBing-shen...  相似文献   

7.
采用离子交换法合成了FLN/OS-LDH复合体(FLN: 荧光素, OS: 1-辛烷磺酸钠, LDH: 镁铝型层状双金属氢氧化物), 并研究了其光致发光和对Fe3+的识别性能. 固态时, FLN不发光, 而FLN/OS-LDH复合体呈黄绿色荧光(发射波长为565 nm), 是荧光素(FLN)的特征发射光. 在甲酰胺(FM)中可将该复合体方便剥离为胶状悬浮液, 其发射波长发生蓝移, 为绿光发射(531 nm). 研究了复合体剥离液对金属离子的荧光识别特性, 发现其对Fe3+的选择性识别能力很强, 远优于其它离子(Mg2+, Ni2+, Co2+, Cu2+, Zn2+, Pb2+, Cd2+和Hg2+). 该复合体与Fe3+结合发生荧光猝灭现象, 可将其用作检测Fe3+的荧光传感器. Fe3+检测限为1.27×10-7 mol/L, 猝灭常数(Ksv)为3.44×102 L/mol.  相似文献   

8.
Safavi A  Shams E 《Talanta》1999,48(5):221-1172
Transport of Ag+ as Ag(CN)2 ions through a bulk liquid membrane is reported. The bulk liquid membrane used is a solution of Victoria blue (VB) in chloroform. The effects of pH of the source phase, cyanide concentration in the source phase, sodium hydroxide in the receiving phase, and VB concentration in the organic phase on the efficiency of the transport system were studied. The above system has a high selectivity for Ag+ and can selectively and efficiently transport Ag(CN)2 ion from aqueous solutions containing other cations such as alkali and alkaline earths, Zn2+, Pd2+, Cu2+, Cd2+,Hg2+, Co2+, Fe2+, Pb2+, Ni2+, and Al3+.  相似文献   

9.
为揭示外加电解质离子强度对重金属离子吸附的影响规律与内在机制, 制备了膨润土/木质素磺酸钠接枝丙烯酰胺-马来酸酐复合吸附树脂(BLPAMA), 研究了外加电解质离子强度对BLPAMA吸附单一和二元Pb2+/Cu2+的影响规律, 以及有、无外加0.2 mol/L NaNO3时BLPAMA对二元Pb2+/Cu2+的吸附等温线、吸附热力学及吸附动力学。 结果表明, 在单一Pb2+或Cu2+溶液中, 随离子强度增加, Pb2+和Cu2+吸附量降低;在二元Pb2+/Cu2+溶液中, 随离子强度增加, Pb2+吸附量降低而Cu2+吸附量提高。  相似文献   

10.
The ΔG, ΔH and ΔS values for the dissociation of 2-mercaptoethanol (MEL) and 3-mercapto-1,2-propanediol and for the formation of complexes between these ligands and the metal ions Ni2+, Zn2+, Cd2+ and Pb2+ have been determined calorimetrically in 0.5 M KNO3 and at 25°C.  相似文献   

11.
黄水波  张朝晖  周必武  赵承峰 《应用化学》2015,32(11):1299-1306
以苯胺修饰的磁性碳纳米管为基质,Cd2+为模板,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,在碳纳米管表面制备出一种新型磁性Cd2+印迹聚合物(MWNTs/MIIPs)。 采用扫描电子显微镜和红外光谱等技术手段对其形态和化学结构等进行详细表征。 吸附试验结果表明,该磁性印迹材料对Cd2+离子具有良好的吸附能力,最大吸附量为16.96 mg/g;选择吸附试验结果表明,该磁性印迹材料对Cd2+/Cu2+、Cd2+/Ni2+、Cd2+/Pb2+和Cd2+/Cr3+的相对选择因子分别是2.03、2.35、2.16和2.13。 结合原子吸收光谱分析技术,该材料MWNTs/MIIPs可用于大米中的Cd2+快速分离富集检测。  相似文献   

12.
铌的高灵敏度、高选择性的光度法似尚少见。最近有人[1]合成过4,5-二溴苯基萤光酮(下称Br-PF),但至今未见该试剂用于铌的胶束增溶光度法的测定。为此本文较系统地研究了在CTAB及乳化剂OP存在下Nb(V)与Br-PF的显色条件,结果表明本法具有很高的灵敏度(ε=2.1×105)和较高的选择性(存在掩蔽剂),可不经任何分离直接在水相中测定合金钢中的微量铌。  相似文献   

13.
The solid-liquid phase equilibria in the process of producing lithium hydroxide from lithium sulfate at 283.15, 298.15 and 323.15 K were studied via the isothermal solubility equilibrium method, and the solid species, phase diagrams, solution densities and pH were determined. The results show that four solid species of Na2SO4·10H2O, Na2SO4·2.5H2O, Na2SO4 and LiOH·H2O occurred in the system, among them, Na2SO4·2.5H2O was a new solid species not reported in the open literature, which was determined via chemical analysis, Karl Fischer water titration, X-ray diffraction(XRD), thermogravimetic analysis(TG) and differential scanning calorimetry(DSC) testing. Based on the SLE data, one systemic process to produce LiOH·H2O from Li2SO4·H2O was proposed including two crystallization steps at lower and higher temperatures.  相似文献   

14.
FTIR-ATR technology is used to study the efflorescence kinetic of Na_2SO_4 and mixed Na_2SO_4/CTAB aerosols.As the RH decreased linearly,the v_3-SO_4~2 band shifts from 1094 cm~1 to 1132 cm~1,suggesting the phase transition of Na_2SO_4 from solution to crystal phase(Ⅲ).For pure Na_2SO_4 aerosols,the ERH is 75.1%RH,whereas the efflorescence point of mixed Na_2SO_4/CTAB aerosols(74.2%) is lower.By further analysis of IR differential spectra,the ratio of Na_2SO_4 crystals in mixed aerosols is only 62.7%and the heterogeneous nucleation rate of Na_2SO_4 in Na_2SO_4/CTAB mixed aerosols is lower than that in pure Na_2SO_4 aerosols.They showed that CTAB assembled into reversed micelle and part Na_2SO_4 droplets are in the core to form core-shell structure,and CTAB shell prevents core Na_2SO_4 solutions from crystallizing.However,the counter ion Br for CTAB reversed micelle can interact with Na~+ ions,which decreases the crystallization rate of free Na_2SO_4 droplets and ERH is delayed.  相似文献   

15.
Simple structural compounds 1 to 3 were synthesized.The presence of Cu2+ resulted in the fluorescence and absorption spectra change of 1 and 2,which indicated that 1 and 2 showed a highly selective response to Cu2+ over other metal ions.However,3 showed no selectivity for metal ions,which means that the compound could bind with several metal ions,such as,Ni2+,Zn2+,Cd2+.Hg2+, Pb2+,Fe3+,Mg2+,Ca2+,and Co2+,except Cu2+ and Ag+.The different spectral responses were attributed to the difference in binding sites for 1 and 3.  相似文献   

16.
Na-A zeolite was successfully synthesized via the alkaline fusion method with oil shale ash as the raw material. The adsorption capacity of it was tested by removing Cu2+, Ni2+, Pb2+ and Cd2+ from aqueous solutions. The results reveal the maximum adsorption capacity of adsorbent for Pb2+, Cu2+, Cd2+ and Ni2+ were 224.72, 156.74, 118.34 and 53.02 mg/g, respectively. The effects of contact time and pH value of solutions on the adsorption efficiency of the zeolite were evaluated. Besides, The equilibrium adsorption data and the batch kinetic data were correlated with Langmuir and Freundlich models and the pseudo-first-order and pseudo-second-order models separately. The results show that the Langmuir isotherm and the pseudo-second-order equation were more suitable for the adsorption of Na-A zeolite for the metal ions. In addition, Thermodynamic parameters of the adsorption(the Gibbs free energy, entropy, and enthalpy) were also evaluated and discussed. The results demonstrate that the adsorption process was spontaneous and endothermic under natural conditions and the synthesized zeolite was an effective adsorbent for the removal of metal ions from aqueous solution.  相似文献   

17.
An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode (nano-PPCPE) has been successfully developed, and used to detect Cd2+ and Pb2+. The results showed that the electrodes can quantitatively detect trace Cd2+ and Pb2+, and with satisfied limit of detection, which has great significance in electrochemical analysis and detection.  相似文献   

18.
In this work, P2-Na0.6[Mg(II)0.3Mn(IV)0.7] O2 with inoxidizable elements (Na+, Mg2+ and Mn4+) except O2- was synthesized and investigated, which exhibited high reversible capacity (~210 mAh/g) with highly reversible ARR characteristic.  相似文献   

19.
藻胆蛋白是一组同源捕光色素蛋白,由多肽链及相连的开链四吡咯环色团构成。多肽链对色团的调控形成不同藻胆蛋白的特征吸收及荧光光谱。这些色团是藻蓝胆素(吸收带590~670 nm)、藻红胆素(吸收带530~570 nm)和藻尿胆素(吸收带490~500nm)。藻尿胆素由于在共轭体系中含有较少的双键,所以与前二者比,在较短波长有吸收。它们总是与藻红胆素伴生,在藻胆蛋白中作为敏化基团存在。  相似文献   

20.
类水滑石及杂多阴离子柱撑水滑石具有可调变的二维孔道结构,活性组分可在较宽的范围内进行调变,从而使其成为有应用前景的氧化催化剂'·'.迄今,以完整结构形态的水滑石为催化剂的催化氧化研究尚未见报道.我们发现['-'j,含可变价元素的类水滑石和过渡金属取代型杂多阴离子柱撑水滑石具有在较低温度下活化分子氧,从而实现活泼烃类a-H氧化的能力·本文报道了M。AIXW;;ZO。。(M=Mg'",Zn'";X=p,St;Z=Mn2+,Fe2+,C。2+,Ni'",Cll'")层柱材料上环己烯的催化氧化行为.1实验部分M。AI-XW;;ZO。。系列杂多…  相似文献   

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