A Porous 3D Supramolecular Architecture of Cd(Ⅱ) Complex with Water Clusters as Pillars

A supramolecular complex of Cd(Ⅱ) with 1D water tapes as pillars[Cd2(dpa)2(phen)2- (H2O)2]·6H2O 1 (H2dpa = diphenic acid, phen = phenanthroline), has been synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group Pī with a = 9.7029(4), b = 11.9601(5), c = 12.1788(4) A, a = 71.6990(10), β = 71.8740(10), γ = 74.4680(10)°, V = 1252.39(8) A3 C52H48Cd2N4O16, Mr = 1209.76, Z = 1, Dc = 1.604 g/cm3,μ = 0.925 mm-1, F(000) = 612, R = 0.0679 and wR = 0.2514 for 3870 observed reflections (Ⅰ > 2σ(Ⅰ)). Two intramolecular Cd(Ⅱ) centers of this complex are encircled by two dpa2- ligands forming an 18-membered ring, which is further assembled into a pillared three-dimensional (3D) supramolecular architecture through the synergetic effect of intermolecular face-to-face π…π stacking and weak O-H…O hydrogen-bonding interactions. Moreover, this complex exhibits photoluminescence with the main emission bands located at about 456 nm upon excitation at 355 nm in the solid state at room temperature.     

A simple method for determining water content in organic solvents based on cobalt(Ⅱ)complexes

A method to determine water content in organic solvents was developed based on the color change of cobalt(Ⅱ) nitrate in different solvents.The color-change mechanism and optimal conditions for determining the water content were investigated.The results showed that there was a good linear relationships between the absorbance of cobalt(Ⅱ) complexes in organic solvents and water contents withγin 0.9989～0.9994.This method has the advantages of low cost,good reproducibility,good sensitivity,simple in operation,fast in detection,friendly to the environment and no limitation on linear range for determining water content.It was used to determine water in samples with a satisfactory recovery in 97.81%～101.24%.     

Preparation and application of a novel orotic acid chelating resin for removal of Cu(Ⅱ) in aqueous solutions

A novel chelating resin OABA,capable of removing Cu(Ⅱ) from aqueous solution,was synthesized via the reaction of macroporous chloromethylated PS-DVB copolymer beads with orotic acid.The elemental analysis(EA),Fourier transform infrared spectroscopy(FT-IR),and scanning electron microscopy microscope-energy dispersive X-ray spectroscopy(SEM-EDS) were used in the characterization of the synthesized chelating resin.Multiple,static batch adsorption experiments were conducted at different initial concentrations and temperatures.OABA showed good adsorption capacity for Cu(Ⅱ) and the equilibrium data could be well matched with the Freundlich isotherm model.Coexisting sodium chloride and calcium chloride in solutions favored the Cu(Ⅱ) adsorption.Moreover,the desorption process of Cu(Ⅱ) was tested and over 90%regeneration efficiency for the spent OABA was achieved at ammonia concentrations ranging from 1.0%to 2.0%.The results suggested that OABA would be a potential alternative adsorbent for Cu(Ⅱ),even with other heavy metal ion treatments of wastewater.     

基于双吡啶脲类Cd(Ⅱ)、Zn(Ⅱ)、Hg(Ⅱ)配合物的合成及晶体结构

间苯二胺和3-吡啶异氰酸酯在甲苯中加热回流得到双吡啶脲类配体L,然后将配体分别与CdSO₄·8H₂O,ZnI₂,HgI₂,HgCl₂进行配位反应,得到4个配合物{[Cd（L）（SO₄）（H₂O）₃]·H₂O}_n（1）,{[Zn（L）I₂]·2C₂H₅OH}_n（2）,{[Hg（L）I₂]·C₂H₅OH}_n（3）,[Hg（L）Cl₂]·H₂O（4）,并用元素分析、FT-IR、X射线单晶衍射、粉末衍射对其进行了表征。配合物1形成一维螺旋链结构,配合物2和3形成一维“之”字链结构,配合物4形成32元环状结构。     

基于双吡啶脲类Cd(Ⅱ)、Zn(Ⅱ)、Hg(Ⅱ)配合物的合成及晶体结构

间苯二胺和3-吡啶异氰酸酯在甲苯中加热回流得到双吡啶脲类配体L,然后将配体分别与CdSO_4·8H_2O,ZnI_2,HgI_2,HgCl_2进行配位反应,得到4个配合物{[Cd(L)(SO_4)(H_2O)_3]·H_2O}n(1),{[Zn(L)I_2]·2C_2H_5OH}n(2),{[Hg(L)I_2]·C_2H_5OH}n(3),[Hg(L)Cl_2]·H_2O(4),并用元素分析、FT-IR、X射线单晶衍射、粉末衍射对其进行了表征。配合物1形成一维螺旋链结构,配合物2和3形成一维"之"字链结构,配合物4形成32元环状结构。     

A novel method for Co(Ⅱ) and Cu(Ⅱ) analysis by capillary electrophoresis with chemiluminescence detection

Based on the fact that some metal ions can catalyze the chemiluminescence(CL)reaction of luminol with K_3Fe(CN)_6,a novel capillary electrophoresis CL method was developed for the determination of Co(Ⅱ)and Cu(Ⅱ).The separation was carried out with a 10 mmol/L sodium acetate solution containing 0.8 mmol/L luminol and 2.0 mmol/Lα-HIBA(adjusted to pH 4.8 by HAc solution).The post-capillary reagent was 2.0 mmol/L K_3Fe(CN)_6 which was adjusted to pH 13.0 by NaOH solution.Under the optimum conditions,the detection limits(S/N=3)for Co(Ⅱ)and Cu(Ⅱ)were 7.5×10~(-11)mol/L and 7.5×10~(-9)mol/L,with the linear range of 7.5×10~(-9)mol/L to 1.0×10~(-6)mol/L and 7.5×10~(-8)mol/L to 5.0×10~(-5)mol/L, respectively.     

硫酸体系中P507浸渍树脂吸附Cd(Ⅱ)的研究

选用2-乙基已基膦酸单(2-乙基已基)酯(P507)为萃取剂,HZ818大孔树脂为载体,以干法浸渍技术制备了P507浸渍树脂.研究了吸附平衡时间、溶液pH和树脂用量对硫酸体系中该浸渍树脂吸附Cd(Ⅱ)的影响.静态吸附实验表明,吸附过程符合准二级动力学模型.采用0.5mol/L的盐酸溶液可将吸附在树脂上的Cd(Ⅱ)洗脱下来.     

Zn(Ⅱ)-EDTA和Cd(Ⅱ)-EDTA在草酸根掺杂溴化银颗粒乳剂中的增感效应

使用反馈式微机控制双注乳化仪,在晶体生长过程特定时间内,加入一定量的草酸盐,制得了草酸根离子处于晶体次表面的立方体溴化银微晶乳剂,并对其进行传统的硫加金化学增感、Zn(Ⅱ)-EDTA或Cd(Ⅱ)-EDTA增感以及光谱增感.对实验过程的考察和感光性能的测试结果表明,Zn(Ⅱ)-EDTA或Cd(Ⅱ)-EDTA对细微粒溴化银颗粒乳剂均有显著的增感效应;Zn(Ⅱ)-EDTA或Cd(Ⅱ)-EDTA增感可在传统硫加金增感基础上与光谱增感协同作用,三者具有兼容和可加和性;Zn(Ⅱ)-EDTA或Cd(Ⅱ)-EDTA增感可在传统硫加金增感与光谱增感协同作用的基础上,与草酸根内部掺杂增感兼容,实现四者的协同作用,而不引起乳剂灰雾增加.     

Ozonated graphene oxides as high efficient sorbents for Sr(Ⅱ) and U(Ⅵ) removal from aqueous solutions

Ozone was used to oxidize graphene oxides(GO) to generate ozonated graphene oxides(OGO) with higher oxygen-containing functional groups. The as-prepared OGO was characterized by Fourier transformed infrared spectroscopy(FTIR), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). Based on the results of potentiometric acid-base titrations, the total carboxylic acid concentration on OGO surface was calculated to be 3.92 mmol/g, which was much higher than that on GO surface. The results of adsorption experiments indicated that the adsorption capacities of OGO for Sr(II) and U(VI) removal were improved significantly after ozonization.     

酸处理对海泡石的表面及其吸附Pb(Ⅱ)、Cd(Ⅱ)的影响

离子吸附;脱镁率;比表面;酸处理对海泡石的表面及其吸附Pb(Ⅱ)、Cd(Ⅱ)的影响     

Chemical modification of rose leaf with polypyrrole for the removal of Pb (II) and Cd (II) from aqueous solution

The rose leaf was successfully modified through coating with polypyrrole (PPy) in chemical oxidative route in order to remove Pb(II) and Cd(II) from aqueous media. The rose leaf/polypyrrole (RL/PPy) composites were characterized in terms of morphology, chemical structure, and conductivity properties. The spectrum were obtained from FTIR results which support the formation of RL/PPy composites. FTIR and SEM results indicate that the polypyrrole is completely covered on rose leaf. The conductivity of composite (1.8215 S/cm) was higher than polypyrrole (2.06 × 10^?3 S/cm). The metal removal studies were monitored by Ultraviolet Visible Absorption Spectrometer (UV-Vis). The optimum conditions were detected for adsorption by changing some experimental conditions (such as adsorbent dosage, contact time and stirring speed, initial concentration of the metal solutions and pH). Following the determination of the optimum conditions, the results of the metal removal from wastewater studies were performed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Under the optimum conditions, the ICP-OES results obtained for waste water showed the useability of composite for the removal of Pb(II) and Cd(II). The Langmuir and Freundlich models are subjected to adsorption datas. The datas fitted better when by using Freundlich model.     

Preparation and characterization of magnetic bioadsorbent for adsorption of Cd(II) ions

A facile magnetic chitosan composite used for heavy metal ions removal was prepared. The adsorbents with large specific area and rich carboxyl groups exhibited good removal of Cd(II) ions and could be easily separated with magnetic separation. The adsorption capacity of Cd(II) was 48 ​mg ​g⁻¹ and the removal efficiency reached 86.7% after five cycles. Thus, the prepared magnetic chitosan composite could act as a potential adsorbent for Cd(II) ions removal.     

Cd(II) determination in the presence of aqueous micellar solutions

The equilibrium constants and molar absorptivities for the fast formation of a 1:3 complex between cadmium(II) (Cd(II)) and dithizonate anion, in the presence of cationic and non-ionic surfactants, allowed a simple and fast spectrophotometric determination of total cadmium. Indeed, the molar absorptivities of the Cd(II)-dithizone (Dz) complex formed in the presence of the neutral Triton X-100 and cationic cetyltrimethylammonium bromide (CTAB) surfactants are almost twice the value observed in the standard method and the maxima of absorption are shifted by about 40 nm when compared with the standard method. Clearly, the use of neutral and cationic surfactants promotes a higher value of the molar absorptivities of the complex, resulting in an increase in the sensitivity of the method. Application of the method to the desorption of Cd(II) ions from clays is illustrated.     

Cationic covalent organic framework via cycloaddition reactions as sulfur-loaded matrix for lithium-sulfur batteries

The postsynthetic modification provided effective approaches for the functionalization of imine covalent organic frameworks (COFs). To address the rapid decline of sulfur cathodes caused by the shuttle effect of soluble lithium polysulfide, cationic COFs (COF-PA-AI) used as sulfur-loaded matrix materials for lithium-sulfur (Li-S) batteries was designed and prepared by cycloaddition. Benefiting from the ordered channels and the strong interaction between quaternary ammonium cations and polysulfide anions, COF-PA-AI/S displayed faster electrochemical kinetics, greater tolerance to high current shocks, and better rate performance as the cathode. Besides, the discharge capacity of COF-PA-AI/S also remained at 665.3 mA h/g after 200 cycles at 0.5 °C, which was higher than that of COF-Ph/S. This work not only demonstrated the possibility of a postfunctionalization method based on the intermediate COF-PA but also expanded the scope of application of the COFs and provided a new idea for the application of COF materials to the cathodes of Li-S batteries.     

Monitoring of Zn(II) and Cd(II) adsorption on activated carbon from aqueous multicomponent solutions by differential pulse polarography (DPP)

The adsorption process of Zn(II) and Cd(II) from aqueous solution has been investigated from both kinetic and equilibrium standpoints, using differential pulse polarography (DPP) on a mercury dropping electrode as the analytical technique. With such an aim, adsorption experiments were performed using not only a single metal ion–Zn(II) or Cd(II) solution but also a multi-component ion metal–Zn(II), Cd(II) and Hg(II) solution. The influence of the pH change in the multi-component ion metal solution on the adsorption of Zn(II) and Cd(II) was also studied. The adsorption processes is relatively fast for Zn(II) and Cd(II). The presence of two foreign ions in the solution slightly speeds up the adsorption process for Zn(II) and significantly slows it down for Cd(II). The adsorption isotherms are similarly shaped for Zn(II) and Cd(II). The addition of the foreign ions has a more unfavourable effect on the adsorption for Cd(II) than for Zn(II). At pH 2, neither Zn(II) nor Cd(II) is adsorbed practically on the carbon. The voltammetric approach has proved to be a fast and efficient method that, at the same time, enables one to monitor the adsorption of Zn(II) and Cd(II) with potential on-line application, which could be useful in waste-water treatment.     

A covalent organic framework (COF)-MnO2 based dual signal sensing platform for sensitive alkaline phosphatase activity detection via dynamic regulating the mimicking oxidase content

It is of great significance to accurately monitor the alkaline phosphatase (ALP) level as it plays an important role in living body activities. Herein, we develop a COF- MnO₂ system for ALP activity detection via the dynamic regulating the MnO₂ nanosheets content. MnO₂ nanosheets with oxidase-mimicking property can oxide the colorless 3,3′,5,5′-Tetramethylbenzidine (TMB) into blue oxidized TMB (oxTMB). The hexagonal structure and ordered mesoporous channels of DMTP-TAPB COF provide excellent space to accommodate the product oxTMB. The confinement of the dye molecules into COF structure leads to enhance color change and obvious fluorescence quench of the sensing system. The fluorescence quenching and color change dependent on the ALP level as it can dynamic regulate the MnO₂ content via the enzymatic hydrolysis of ascorbate-2-phosphate. Therefore, a COF-MnO₂ based dual signal sensing platform is successfully constructed to detect ALP activity, giving detection limit of 0.11 U L^-1 and 0.23 U L^-1 for fluorescence and colorimetric procedures, respectively. The practical application of the designed sensing platform is verified through the detection of ALP activity in serum samples, and satisfactory results are obtained.     

Entrapment of Lentinus sajor-caju into Ca-alginate gel beads for removal of Cd(II) ions from aqueous solution: preparation and biosorption kinetics analysis

A white rot fungus species Lentinus sajor-caju biomass was entrapped into alginate gel via a liquid curing method in the presence of Ca(II) ions. The biosorption of cadmium(II) by the entrapped live and dead fungal biomass has been studied in a batch system. The heat-treatment process enhanced the biosorption capacity of the immobilized fungal biomass. The effect of initial cadmium concentration, pH and temperature on cadmium removal has been investigated. The maximum experimental biosorption capacities for entrapped live and dead fungal mycelia of L. sajur-caju were found to be 104.8±2.7 mg Cd(II) g⁻¹ and 123.5±4.3 mg Cd(II) g⁻¹, respectively. The kinetics of cadmium biosorption was fast, approximately 85% of biosorption taking place within 30 min. The biosorption equilibrium was well described by Langmuir and Freundlich adsorption isotherms. The change in the biosorption capacity with time is found to fit pseudo-second-order equations. Cadmium binding properties of entrapped fungal preparations have been determined applying the Ruzic equations. Since the biosorption capacities are relatively high for both entrapped live and dead forms, they could be considered as suitable biosorbents for the removal of cadmium in wastewater treatment systems. The biosorbents were reused in three consecutive adsorption/desorption cycles without significant loss in the biosorption capacity.     

Magnetically separable CoFe2O4/CoxFey/activated carbon composites for Cd(II) removal from wastewater

CoFe₂O₄ and Co_x Fe_y were anchored into activated carbon (AC) to synthesize CoFe₂O₄/Co_x Fe_y /AC composites using the sol–gel method for Cd(II) adsorption from wastewater. The results indicated that CoFe₂O₄ and Co_x Fe_y nanoparticles existed in the pores of AC. The magnetic properties of CoFe₂O₄/Co_x Fe_y /AC indicated it could be separated and retrieved easily using an external magnet after Cd(II) adsorption. The effects of solution pH, temperature and initial Cd(II) concentration on the Cd(II) adsorption of AC and CoFe₂O₄/Co_x Fe_y /AC were investigated. The standard free energy, enthalpy change and entropy change were evaluated. The kinetic parameters of Langmuir and Freundlich isothermal equation were analyzed, and the Freundlich kinetic model was feasible for describing the Cd(II) adsorption process of CoFe₂O₄/Co_x Fe_y /AC composites.     

Conducting polymer engineered covalent organic framework as a novel electrochemical amplifier for ultrasensitive detection of acetaminophen

Two-dimensional covalent organic framework(COF) has distinctive properties that offer potential opportunities for developing advanced electrode materials.In this work,a core-shell material composed of TAPB-DMTP-COF(TAPB,1,3,5-tris(4-aminophenyl)benzene;DMTP,2,5-dimethoxyterephaldehyde)core and conducting polymer shell,TAPB-DMTP-COF@PANI,was synthesized solvothermally using a polymerization method.The structural cha racteristics of the prepared composite were revealed by X-ray diffraction patterns(XRD),fourier transform infrared spectra(FTIR),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM).The electrochemical analyses were verified by subsequent monitoring of trace levels of acetaminophen.This resultant composite not only facilitated acetaminophen to interact with absorption sites by π-π stacking effect and hydrogen bonding but also overcame the poor conductivity of COF.Under the optimal conditions,a low limit of detection of0.032 μmol/L and wide linear range of 0.10-500 μmol/L were obtained.The electrochemical platform was almost unaffected by other interfering substances,and successfully applied for the practical detection of acetaminophen in commercial tablet,human blood serum and urine.The enhanced performance makes this COF based core-shell composite a promising material in electrochemical senso r.     

Syntheses,structure and characterization of a fourfold interpenetrated 3D Cd(II) organic framework constructed with a zwitterionic ligand

A 3-D cadmium(II) organic framework with a fourfold interpenetrated diamond topological structure, {[CdLBDC]·(H₂O)₂}_n (1), was synthesized through zwitterionic ligand H₃LBr₃ (1,1′,1″-(2,4,6-trimethylbenzene-1,3,5-triyl)-tris(methylene)tris(4-carboxypyridinium)tribromide), secondary ligand H₂BDC (1,4-benzenedicarboxylic acid) and Cd(NO₃)₂·4H₂O by solvothermal method. Compound 1 was characterized by elemental analyses, FT-IR spectroscopy, powder, and single-crystal X-ray diffraction and thermogravimetric analysis. The photophysical properties of 1 were investigated by solid-state diffuse reflectance spectrum. In 1, each L is linked by two separate Cd(II)-centered distorted tetrahedra, which are also linked by two L, thereby forming a head-to-tail connected 2-D layer structure and further building the 3-D framework through BDC^2?-chelating-bridging between layers.