Synthesis of Branched Polyethylene via Bulky α-Diimine Nickel(II)-Catalyzed Ethylene Chain-Walking Polymerization

The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, which contains both dibenzhydryl and phenyl groups, was determined by X-ray crystallography. The compound has a pseudo-tetrahedral geometry at the Ni center, showing pseudo-C2-symmetry. Upon activation with modified methylaluminoxane (MMAO), Ni1 exhibits high catalytic activity up to 1.02 × 107 g PE (mol Ni h)−1 toward ethylene polymerization, enabling the synthesis of high molecular weight branched polyethylene. The molecular weights and branching densities could be tuned over a very wide range. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature. The branching densities were decreased with increasing the polymerization temperature.

基于NIELVISII+平台的超声波传感器温度分布测量技术研究

通过对超声波传感器温度分布测量技术的研究了解,我们发现其作为一种非接触式测温方式,在高温、高腐蚀等恶劣环境中具有广泛的应用。超声波传播速度和衰减量可用于计算被测物体内部的温度分布,实现温度测量。相比传统的接触式测温法,超声测温法无需与被测对象直接接触,避免了传感器受到高温环境影响的问题,因此提高了测量的精度,并扩大了测温范围和深度。基于此,本文进行了NI ELVIS II+平台的超声波传感器温度分布测量技术研究,超声波传感器温度分布测量原理分析。本文得到了气体介质的温度和声波速度之间的函数关系,并据此建立了声学测温模型,从而实现温度的准确测量和检测。超声波温度检测系统的总体设计。根据相关的技术指标,对相关测温原理进行详细分析,对相位差法和飞行时间法两种测温方案进行了深入阐述,并且比较两种方案的优缺点及适用范围,在此基础上提出了基于相位差法的设计方案,依据此,最终给出系统总体设计方案。

Highly Efficient and Selective Removal of Pb（II） ions by Sulfur-Containing Calcium Phosphate Nanoparticles

A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The resulting SCP exhibited a noticeable enhanced performance for Pb（II） removal in comparison with hydroxyapatite （HAP）, being capable of easily reducing 20 ppm of Pb（II） to below the acceptable standard for drinking water within less than 10 min. Remarkably, the saturated removal capacities of Pb（II） on SCP were as high as 1720.57 mg/g calculated by the Langmuir isotherm model, exceeding largely that of the previously reported absorbents. Significantly, SCP displayed highly selective removal ability toward Pb（II） ions in the presence of the competing metal ions （Ni（II）, Co（II）, Zn（II）, and Cd（II））. Further investigations indicated that such ultra-high removal efficiency and preferable affinity of Pb（II） ions on SCP may be reasonably ascribed to the formation of rodlike hydroxypyromorphite crystals on the surface of SCP via dissolution-precipitation and ion exchange reactions, accompanied by the presence of lead sulfide precipitates. High removal efficiency, fast removal kinetics and excellent selectivity toward Pb（II） made the obtained SCP material an ideal candidate for Pb（II） ions decontamination in practical application.

Poly(styrene-co-divinylbenzene)-PAMAM-IDA chelating resin: Synthesis, characterization and application for Ni(II) removal in aqueous

PS-PAMAM-IDA chelating resins were prepared by low-generations of polyamidoamine(PAMAM) and then chloroacetic acid functionalizing commercially available ammoniated polystyrene matrix, to preconcentrate Ni2+ from synthetic aqueous samples. Different generations of PAMAM were used to obtain different chelating resins, PS-IDA, PS-1.0G PAMAM-IDA and PS-2.0G PAMAM-IDA. The synthesized resins were characterized by FTIR and elemental analysis. The effect of solution pH, kinetic studies, resin loading capacity, matrix effects etc., on metal ion adsorption to adsorbent phase, were studied by batch method. The PS-1.0G PAMAM-IDA resin was the most excellent adsorbents, with a maximum adsorption capacity of(24.09±1.79) mg/g for Ni2+ ion at pH=7. The interpretation of the equilibrium data was given by Langmuir isotherms model, and the correlation coefficient values for PS-IDA, PS-1.0G PAMAM-IDA and PS-2.0G PAMAM-IDA resins were 0.992, 0.994 and 0.987, respectively.

Neural Network Modeling for Ni(II) Removal from Aqueous System Using Shelled Moringa Oleifera Seed Powder as an Agricultural Waste

A single-layer Artificial Neural Network (ANN) model was developed to predict the removal efficiency of Ni(II) ions from aqueous solution using shelled Moringa Oleifera seed (SMOS) powder. Batch experiments resulted into standardization of optimum conditions: biomass dosage (4.0 g), Ni(II) concentration (25 mg/L) volume (200 mL) at pH 6.5. A time of forty minutes was found sufficient to achieve the equilibrium. The ANN model was designed to predict sorption efficiency of SMOS for target metal ion by combining back propagation (BP) with principle component analysis. A sigmoid axon was used as transfer function for input and output layers. The Levenberg–Marquardt Algorithm (LMA) was applied, giving a minimum mean squared error (MSE) for training and cross validation at the ninth place of decimal.

Removal of Pb(II) from Aqueous Solutions by Zeolites, Porcelanite and Sands: Correlation of Morphology and Chemical Composition to Batch Removal Efficiency

Chemical compositions of natural zeolites, porcelanite (opal-CT) and local sands were determined by X-ray fluorescence (XRF) and correlated with their Pb(II) removal efficiencies. Zeolites and porcelanite were from the Mikawer, Aritain and Hannon areas in Jordan. Sands (white, red and yellow) were from the United Arab Emirates (UAE). The effect of Pb(II) concentration and zeolite dosage on removal efficiency was investigated at 25.0°C using the batch equilibrium method. Commercial kaolinite, silica and alumina were also studied for comparison. Removal efficiencies, in mg Pb(II)/g adsorbent, were: 76.9, 52.7 and 42.1 for Hannon, Mikawer and Aritain zeolites, respectively;58.2 for porcelanite;29.7, 11.0 and 8.5 for yellow, red and white sand, respectively;7.2, 3.3 and 1.3 for kaolinite, silica and alumina, respectively. XRF data indicate that adsorbents with intermediate molar ratios of Si/Al, in the range 2.70 - 2.93, are most efficient in Pb(II) removal. Scanning electron microscope (SEM) images of adsorbents suggest that morphology, in addition to chemical composition, plays a key role. In particular, a combination of factors, including shapes and sizes of crystals, channels in zeolites and pores in porcelanite, appear to favor removal of Pb(II).

Elimination, Kinetics and Thermodynamics of Fe(II) Ions by Adsorption in Static and Dynamic Conditions on Activated Carbons in Aqueous Media

This work investigated the removal, kinetics and thermodynamics of iron(II) ions (Fe(II)) by adsorption in static and dynamic conditions in aqueous media on activated carbons (AC-i30min, AC-i1h, and AC-i24h), prepared from palm nut shells collected in the city of Franceville to Gabon, using potassium hydroxide (KOH) as the activating agent. Results on the elimination of Fe(II) in static and dynamic adsorption on prepared activated carbons (ACs) showed that the AC-i24h adsorbent has the best Fe(II) adsorption capacities at saturation (Qsat). The Qsat obtained on AC-i24h in static and dynamic conditions (17.87 and 10.38 mg/g, respectively) were higher than those of AC-i30min (13.89 and 5.54 mg/g respectively) and AC-i1h (14.92 and 8.64 mg/g respectively). Moreover, the static adsorption was more effective in the removal of Fe(II) ions in aqueous media in our experimental conditions. The percentage removal (%E) of Fe(II) obtained on prepared activated carbons in static conditions was better than those obtained in dynamic conditions, especially on AC-i24h, where the %E was 89.27% in static and 61.56% in dynamic. In kinetics, results showed that the pseudo-second-order kinetic model best described the adsorption mechanisms of Fe(II) on prepared activated carbons in static adsorption, with mainly of chemisorption on the solid surfaces. However, in dynamic conditions, the pseudo-first-order kinetic model was more suitable. In addition to the weak interactions between Fe(II) and the activated carbon surfaces, strong interactions (chemisorption) were also observed. Also, thermodynamic data obtained on AC-i24h in static adsorption indicated that the adsorption of Fe(II) was spontaneous and increased with temperature (ΔG˚ H˚ = 503.54 KJ/mol).

配合物[Ni(Me_(3)en)(acac)]BPh_(4)合成、分析实验实施结果与讨论——第10届全国大学生化学实验邀请赛无机及分析化学实验试题部分内容实施结果与讨论

介绍南京大学为第10届全国大学生化学实验邀请赛设计的无机及分析化学实验试题,即“配合物[Ni(Me_(3)en)(acac)]BPh_(4)的合成及其溶剂/热致变色行为研究”实验中有关合成及组成测定部分实验实施过程、结果及其拓展问题的探讨内容。以所展示的详细直观的合成实验流程为载体,围绕着合成两大目标“质”和“量”,即如何才能得到又“好”又“多”的[Ni(Me_(3)en)(acac)]BPh_(4)配合物的问题为导向,以设问、探讨的方式引导学生认识合成过程中实验条件的控制、实验现象的分析以及中间产物及杂质的分离、分析鉴定等对指导合成的意义,培养学生分析、判断、归纳、总结的能力以及批判性思维能力。

配合物[Ni(Me3en)(acac)]BPh4合成过程优化的基本思路与初步实施结果——第10届全国大学生化学实验邀请赛无机及分析化学实验试题合成过程优化的基本思路与初步实施结果

主要介绍有关配合物[Ni(Me3en)(acac)]BPh_(4)的合成过程优化的基本思路及初步实施的结果。在引导学生认识配合物[Ni(Me_(3)en)(acac)]BPh_(4)的合成原理、条件和过程的基础上,以原实验合成过程要吸干合成原料Ni(NO_(3))_(2)·6H_(2)O固体表面的游离水为切入点,在探讨水对合成体系影响的实验过程中,结合实验原理以及合成过程和条件,提出了几条不完全相同的合成途径,并通过实验进行初步探究和验证,以培养学生的问题意识与解决问题的能力。并为这个实验面向不同层次、不同教学需求的学生的广泛开展奠定了基础。

“配合物[Ni(Me_(3)en)(acac)]BPh_(4)的溶剂/热致变色行为研究”实验实施结果与讨论——第10届全国大学生化学实验邀请赛无机及分析化学实验试题部分内容实施结果与讨论

介绍南京大学为“第10届全国大学生化学实验邀请赛”设计的“无机及分析化学实验试题”,即“配合物[Ni(Me_(3)en)(acac)]BPh_(4)的合成及其溶剂/热致变色行为研究”实验中有关溶剂/热致变色行为研究部分实验实施过程、结果及其有关问题探讨内容等。以所展示的详细直观的溶剂/热致变色实验现象启发学生探讨和解释其溶剂/热致变色的原理,总结其溶剂/热致变色规律,让学生直观认识配合物的结构决定其性质的涵义,培养学生分析、判断、归纳、总结的能力以及批判性思维能力。

光子晶体传感器的制备及对Ni(II)的检测

以丙烯酸(AA)和羧甲基纤维素钠(CMC)作为功能单体,通过嵌入到三维甲基丙烯酸甲酯(PMMA)光子晶体阵列中进行聚合,构建了纤维素基的光子晶体水凝胶膜传感器。功能基团与目标金属离子Ni(II)之间产生配位作用,使得水凝胶膜结构色所对应的反射峰光谱发生的蓝移,通过蓝移量所对应的颜色变化定位目标物的浓度。传感器通过裸眼和光纤光谱仪实现对Ni(II)的直接、敏感和快速的半定量检测,检测限为3.5×10^(−7)M,检测浓度范围为10^(−6)~10^(−1)M。

Removal of Cd（II） by Nanometer AIO（OH） Loaded on Fiberglass with Activated Carbon Fiber Felt as Carrier

A new nanometer material, nanometer AlO（OH） loaded on the fiberglass with activated carbon fibers felt（ACF） as the carrier, was prepared by hydrolytic reaction for the removal of Cd（II） from aqueous solution using column adsorption experiment. As was confirmed by XRD determination, the hydrolysis production loaded on fiberglass was similar to the orthorhombic phase AlO（OH）. SEM images showed that AlO（OH） particles were in the form of small aggregated clusters. The Thomas model was applied for estimating the kinetic parameters and the saturated adsorption ability of Cd（II） adsorption on the new adsorbent. The results showed that the maximum adsorption capacity of Cd（II） was 128.50 mg·g^-1 and 117.86 mg·g^-1 for the adsorbent mass of 0.3289 g and the adsorbent mass of 0.2867 g, respectively. The elution experiment result indicated that the adsorbed Cd ions was easily desorbed from the material with 0.1 mol·L^-1 HCl solution. Adsorption-desorption cycles showed the feasibility of repealed uses of the composited material. The adsorption capacities were influenced by pH and the initial Cd（II） concentration. The amount adsorbed was greatest at pH 6.5 and the initial Cd（II） concentration of 0.07 mg·L^-1, respectively. Nanometer AlO（OH） played a major role in the adsorption process, whereas the fiberglass and ACF were assistants in the process of removing Cd（II）. In addition, the adsorption capacities for Cd（II） were obviously reduced from 128.50 mg·L^-1 to 64.28 mg·L^-1 when Pb ions were present because Pb ions took up more adsorption sites.

Bioadsorption of Cd (II) from Contaminated Water on Treated Sawdust: Adsorption Mechanism and Optimization

Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catalyst to form MMU-SD. The reaction of MMU-SD was carried out under different conditions including MMU/SD molar ratio, catalyst concentration, and reaction time and temperature. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent and adsorbate concentrations on the adsorption capacity of Cd (II) ions onto MMU-SD. Langmuir, Freundlich and Redlich-Peterson isotherm models were applied in the adsorption studies. The experimental data were analyzed using various sorption kinetic models. The removal processes of Cd (II) onto MMU-SD particles could be well described by the pseudo-second order model. The maximum adsorption capacity of Cd(II) onto MMU-SD was 909 mg/g. Similarly, the Freundlich constant 1/n value was 0.45.

Synthesis, Crystal Structure and Catalytic Properties of a New 2D Nickel(II) Coordination Polymer Based on Flexible Bis(benzimidazole)

A new Ni(II) coordination polymer [Ni(L)2(SCN)2]n(L = 1,4-bis(benzimidazol-1-yl)butane) was synthesized hydrothermally and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system, space group C2/c with a = 9.4760(3), b = 24.0408(8), c = 16.5871(5) A, β = 99.832(3)°, V = 3723.2(2) A3, Z = 4, Dc = 1.348 g/cm3, F(000) = 1576, the final R = 0.0486 and w R = 0.0936 for 2938 observed reflections with I 】 2σ(I) for the complex. Structural analysis shows that the coordination polymer possesses a 2D(4,4) layer structure which is composed of Ni(II) centers bridged by L ligand with two kinds of conformations and further assembled into a 3D supramolecular network via π-π stacking interactions. In addition, the fluorescence and catalytic properties, for the degradation of Congo red, of the complex were investigated.

Synthesis and Structure of L-Aspartato- nickel(II) Complex with Benzimidazole

The title complex Ni(C4H5NO4)(C7H6N2)31.75(H2O) (C25H26.5N7NiO5.75, Mr = 575.74) has been prepared and its crystal structure was determined by X-ray diffraction method. The crystal of this chiral complex belongs to monoclinic, space group P21 with a = 13.208(1), b = 10.741(1), c = 19.398(1) ? b = 104.39(1)o, V = 2665.8(4) 3, Z = 4, Dc = 1.435 g/cm3, m(MoKa) = 0.780 mm-1 and F(000) = 1198. The final R = 0.0504 and wR = 0.1267 for 9159 observed reflections (I > 2s(I)), and R = 0.065 and wR = 0.1299 for 11006 independent reflections. The complex assumes a distorted octa- hedral coordinate geometry formed by one aspartate dianion and three benzimidazole ligands. The aspartate chelates to the Ni atom as a tridentate ligand. The lattice water molecules are hydrogen- bonded to the Ni complex molecule.

Study on the Effect of A Magnetic Field on Pb(II) Removal Using Modified Chitosan

This work examined the removal of Pb(II) using a chitosan derivative (SB, synthesized from benzaldehyde) assisted by a magnetic field. The adsorption capacity for Pb(II) was investigated. It was found that 1) the pH and concentration of the ion solution, as well as exposure time and strength of magnetic field, affected the degree of adsorption;and 2) studies of the adsorption isotherms and kinetics of ions onto SB revealed that SB showed enhanced adsorption capacity towards Pb(II) ions in a magnetic field compared with magnetically untreated samples. The Langmuir and Freundlich isotherm were applied to describe the experimental adsorption, and the maximum adsorption capacity of SB for Pb(II) was 2.5040 mg/g, when assisted by a magnetic field of 480 kA/m.

Octa-membered Water Ring Chain Based on Sulfonic Group in Ni(II) Complex with 2-[(E)-(2-Oxidophenyl)methyleneamino] Ethanesulfonato and 2,2′-Bipyridinyl

The title compound, [Ni（tssb）（2,2-bipy）2].5（H2O） 1 （tssbH2 =2-[（E）-（2-oxido- phenyl）methyleneamino]ethanesulfonato, 2,2-bipy = 2,2＇-bipyridinyl）, belongs to orthorhombic, space group Pbcn with a = 20.3983（18）, b = 17.6929（15）, c = 17.0897（15） nm, V= 6167.8（9） nm^3, Mr= 688.38, Z = 8, De = 1.481 g.cm^-3, F（000） = 2880,μ = 0.758 mm-1 and S =1.099. Each NiIr atom is six-coordinated by one N and one O atoms from one tssb^2- anion and four N atoms from two 2,2-bipy ligands to give a distorted octahedral geometry. Noticeably, there exists a rare octa-mem- bered water ring which presents a 1D chain by sulfonic group.

Removal of CO from reformed fuels by selective methanation over Ni-B-Zr-O_δ catalysts

The Ni-B-Oδ and Ni-B-Zr-Oδ catalysts were prepared by the method of chemical reduction, and the deep removal of CO by selective methanation from the reformed fuels was performed over the as-prepared catalysts. The results showed that zirconium strongly influenced the activity and selectivity of the Ni-B-Zr-Oδ catalysts. Over the Ni-B-Oδ catalyst, the highest CO conversion obtained was only 24.32% under the experi-mental conditions studied. However, over the Ni-B-Zr-Oδ catalysts, the CO methanation conversion was higher than 90% when the temperature was increased to 220℃. Additionally, it was found that the Ni/B mole ratio also affected the performance of the Ni-B-Zr-Oδ catalysts. With the increase of the Ni/B mole ratio from 1.8 to 2.2, the CO methanation activity of the catalyst was improved. But when the Ni/B mole ratio was higher than 2.2, the performance of the catalyst for CO selective methanation decreased instead. Among all the catalysts, the Ni29B13Zr58Oδ catalyst investigated here exhibited the highest catalytic performance for the CO selective methanation, which was capable of reducing the CO outlet concentration to less than 40 ppm from the feed gases stream in the temperature range of 230-250℃, while the CO2 conversion was kept below 8% all along. Characterization of the Ni-B-Oδ and Ni-B-Zr-Oδ catalysts was provided by XRD, SEM, DSC, and XPS.

Synthesis and Structure of (Oxydiacetato)-nickel(II) Complex with Diaminobithiazole

The title complex [Ni(C4H4O5)(C6H6N4S2)(H2O)]2.5H2O has been prepared and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic, space group P21/n with a = 16.499(2), b = 10.132(1), c = 11.177(2) , b = 109.76(1)o, V = 1758.4(4) 3, Mr = 452.11, Z = 4, Dc = 1.708 g/cm3, m = 1.391 mm-1, F(000) = 932, R = 0.0424 and wR = 0.1088 for 2341 observed reflec- tions (I>2s(I)). The complex assumes a distorted octahedral coordination geometry formed by one oxydiacetate dianion, one diaminobithiazole and one coordinated water molecule. The parallel thiazole rings of adjacent complex molecules overlap to each other, and the separation of 3.458(7) ?suggests the existence of - stacking.

Preparation, Characterization, and Application of Manganese Oxide Coated Zeolite as Adsorbent for Removal of Copper(II) Ions from Seawater

The present study is aimed to examine the adsorption characteristics of Cu(II) by using the novel cellulose acetate composite and to apply it for the removal of Cu(II) from real wastewater samples. In order to achieve this objective, ethylenediamine, diethylenetriamine, triethylenetetramine and te-traethylenepentanene were used for immobilization of grafted cellulose acetate-nanoscale manganese dioxide. Cellulose was extracted from mangrove species Avicennia marina and converted to cellulose acetate then it was formed composite with nano-manganese dioxide via precipitation of nano-manganese dioxide on it. The composite was grafted with acrylamide monomer before immobilization. The synthesized compounds were used for adsorption of Cu(II) and characterized by FT-IR, TGA and SEM. The adsorption characteristics of synthesized sorbents were optimized. Langmuir and Freundlich models were used to establish sorption equilibria. The analytical applications of these modified materials were applied successfully for the removal of Cu(II).