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[en] Studies on the molecular construction and structures of M(NO_3)_2 (M = Cu(II), Ni(II)) complexes with 1,2-bis(dimethyl- 3-pyridylsilyl)ethane (L) have been carried out. Formation of each molecular skeleton appears to be primarily associated with a suitable combination of bidentate N-donors of L and coordinating nature of octahedral metal(II) ions: [Cu(NO_3)_2(L)_2] yields a 2-dimensional sheet structure consisting of 44-membered Cu_4L_4 skeleton whereas [Ni(L)_2(H_2O)_2](NO_3)_2 produces an interpenetrated 3-dimensional structure consisting of 66-membered cyclohexanoid (M_6L_6) skeleton. The Cu(II) ion prefers nitrate whereas the Ni(II) ion prefers water molecules as the fifth and the sixth ligands
[en] An innovative system for isolating nanocellulose was established that uses Ni(NO3)2 transition metal salt without the assistance of mechanical disintegrations or mineral acid and was compared with the classic production by tedious acid hydrolysis. Optimization study on Ni(II)-catalyzed hydrolysis of cellulose isolated from oil palm (Elaeis guineensis) empty fruit bunch (OPEFB) towards nanocellulose yield was investigated. Response surface methodology-central composite design was used to design and optimize the experiments with three operating parameters: pH of Ni(NO3)2 (pH 2–4), reaction time (20‒100 min) and reaction temperature (25‒65 °C). The present study indicated that the nanocellulose yield as high as 81.37% was achieved under hydrolysis conditions of pH 3, 58 °C within 58 min. At the optimum conditions, the OPEFB derived nanocellulose rendered high crystallinity of 91.1% and excellent thermal stability of 341 °C. Evidence of the successful isolation of nanocellulose was proven by HRTEM observation revealing fibrils formed the long and interconnected network-like structure with the average width of 41.1 ± 1.6 nm and several micrometers in length, which resulted in high aspect ratio. Thus, the obtained nanocellulose via Ni(II)-catalyzed hydrolysis has numerous potential applications and represent a green alternative for the treatment of OPEFB. This study provided a facile high yield procedure for the production of nanocellulose with similar characteristics to traditional nanocellulose, which was significant to the commercialization of nanocellulose.
[en] The LIBS (laser induced breakdown spectroscopy) is one of the best methods to analyze the elemental composition of metal oxide samples without the pre-treatment process such as the dissolution of samples. In general, as the intensities of emission spectra caused by laser beams depends mainly on the structure and composition of target materials so called the matrix effect, the emission spectrum database on various metallic oxides should be prepared in order to apply the LIBS technique for the analysis of CRUD. In the present study, we prepared various metal mixed oxides to obtain LIBS spectrum database for the analysis of CRUD. The metal oxides were synthesized by a hydrolysis of nickel nitrate and iron nitrate mixed solutions and heat treated under a high temperature steam condition. Their composition, crystal structure and chemical bonding were identified by using ICP-AES (Inductive Coupled Plasma - Atomic Emission Spectroscopy) spectra, XRD (X-Ray Diffraction) patterns and FT-IR (Fourier Transform-Infrared Spectroscopy) spectra, respectively. After this, the emission spectrum database of the metals including Ni, Fe, Cr, B in the oxides were established in order to analyze the CRUD. In addition, we established a laser beam transport technique by using an optical fiber to improve the mobility of the analysis system
[en] The effectiveness of FZ-82-4, a new chelating agent, for therapeutic and removing nickel and to compare it with of copper reagent, the experiments are carried out in rats. Obtained results show that for therapeutic and removing nickel nitrate, FZ-82-4 was more effective than copper reagent, with a much lower nickel retention in kidney and liver, and that for removing nickel, it was related to administering time and dose
[en] Micro-nanostructured nickel has been prepared as anode materials for Li ion batteries, via a rheological phase reaction method. Ni2C2O4.xH2O (x = 2 or 2.5) as precursors are obtained from the solid-liquid rheological mixture of (NH4)2C2O4.H2O and Ni(NO3)2. The nickel powders are prepared by thermal decomposition of the precursors. The structural, morphological and electrochemical performance are investigated by means of thermogravimetry (TG), differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and typical electrochemical tests. The micro-nanostructured nickel displays an initial discharge capacity of 457 mAh g-1. It also has a remarkable cycling stability with an average capacity fade of 0.17% per cycle from 13th to 50th cycle in 0.01-3.00 V versus Li at a constant current density of 100 mA g-1.
[en] A procedure for determining germanium in soil samples using electrothermal atomic absorption spectrometry is discussed. The analyte is leached from the solid sample by the addition of 1 ml of concentrated hydrofluoric acid to 10-300 mg of sample, and the mixture is then submitted to a 10 min ultrasonic treatment. After adding 0.4 g boric acid and 3 ml concentrated hydrochloric acid, germanium is extracted into 1 ml chloroform and back-extracted into an aqueous phase containing (0.05%, w/v) nickel nitrate. Ten micro liter of aqueous phase are introduced into the atomizer and the analytical signal from germanium is obtained using a fast-heating cycle. The detection limit, calculated using three times the standard error of estimate (sy/x) of the calibration graph, is 0.015 μg g-1. The reliability of the procedure is verified by analyzing several certified reference materials
[en] The crystallization process in a quarternary aqueous system of magnesium, nickel and cerium nitrates was studied by the isothermal method. The crystallization fields of Mg(NO3)2x6H2O; Ce(NO3)3x6H2O, Ni(NO3)2x6H2O, 3Mg(NO3)2x2Ce(NO3)3x24H2O; 3Ni(NO3)2x2Ce(NO3)3x24H2O and those of hydrated solid solutions based on magnesium and nickel nitrates are delimited
[en] This work reports the electrochemical determination of bisphenol A (BPA), hydroquinone (HQ) and catechol (CC) using glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNT) and nickel oxide nanoparticles (NiO). MWCNT were functionalized with sulfonitric solution (3H2SO4:1HNO3) and dispersed in dimethylformamide for the MWCNT/GCE manufacturing. The MWCNT/GCE was modified with NiO using cyclic potential in pH 4 maintained by an acetate buffer solution containing 0.008 mol L−1 of nickel nitrate. The concentration of the nickel solution and the number of cycles in the electrodeposition were studied. Morphological characterization of NiO/MWCNT/GCE was carried out by scanning electron microscopy and the presence of NiO was observed. The electrochemical behavior was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy using BPA solution and the results were compared with those of GCE. The NiO/MWCNT/GCE presented the lowest charge transfer resistance. The electrochemical detection of BPA, HQ and CC was developed using differential pulse voltammetry. The analytical curves showed an excellent linear response and the detection limits for the simultaneous determination of BPA, HQ and CC were 2.8 × 10−8 mol L−1, 2.70 × 10−8 mol L−1 and 5.9 × 10−8 mol L−1, respectively.