An Improved Purification Method for Preparation of Basic Nickel Carbonate of High Purity via Chemical Precipitation

The adsorption mechanism of Na^＋, Cl^- and other impurities on the surface of basic nickel carbonate was clarified by electric double layer model. Based on the mechanism, a new purification method was studied. The method can be described as washing-drying-rewashing-drying. The experimental results indicate that the process is very efficient to remove impurities adsorbed by the precipitate when using NiCl2 and Na2CO3 as the raw materials. The finished product＇s contents of sodium and chlorine are both less than 0.01 wt%.

Preparation and growth mechanism of plate-like basic magnesium carbonate by template-mediated/homogeneous precipitation method

In order to expand the application of the basic magnesium carbonate in the field of flame retardant,the plate-like basic magnesium carbonate(Mg5(CO3)4(OH)2.4H2O)was prepared successfully by template-mediated/homogeneous precipitation method,using magnesium chloride hexahydrate(MgCl2.6H2O)and urea(CO(NH2)2)as reaction materials.Phase and morphology of the product were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM)and atomic force microscope(AFM),respectively.The results showed that well-crystallized plate-like Mg5(CO3)4(OH)2.4H2O can be prepared at the water bath temperature of 100°C,water bath time of 24 h,the aging time of 5 h after adding organic template agent.The investigation on organic template mediated mechanism shows that the template affects the crystal morphology by changing surface energy of different crystal plane.Through a preliminary study on the growth mechanism of the product,it is found that the generation of the plate-like Mg5(CO3)4(OH)2.4H2O could be explained by two-dimensional nucleation/step growth mechanism.

Preparation of basic magnesium carbonate and its thermal decomposition kinetics in air

The thermal decomposition process of basic magnesium carbonate was investigated. Firstly, Basic magnesium carbonate was prepared from magnesite, and the characteristics of the product were detected by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. Subsequently, the thermal decomposition process of basic magnesium carbonate in air was studied by thermogravimetry-differential thermogravimetry （TG-DTG）. The results of XRD confirm that the chemical composition of basic magnesium carbonate is 4MgCO3·Mg（OH）2·4H2O. And the SEM images show that the sample is in sheet structure, with a diameter of 0.1-1 μm. The TG-DTG results demonstrate that there are two steps in the thermal decomposition process of basic magnesium carbonate. The apparent activation energies （E） were calculated by Flyrm-Wall-Ozawa method. It is obtained from Coats-Redfem＇s equation and Malek method that the mechanism functions of the two decomposition stages are D3 and A1.5, respectively. And then, the kinetic equations of the two steps were deduced as well.

Thermal decomposition kinetics of basic carbonate cobalt nanosheets obtained from spent Li-ion batteries:Deconvolution of overlapping complex reactions

A new non-isothermal method of kinetic analysis was employed to investigate the thermal decomposition kinetic modeling of the basic carbonate cobalt nanosheets（n-BCoC） synthesized from spent lithium-ion batteries（LIBs）. Fraser–Suzuki function was applied to deconvoluting overlapping complex processes from the overall differential thermal curves obtained under the linear heating rate conditions, followed by the kinetic analysis of the discrete processes using a new kinetic analysis method. Results showed that the decomposition of n-BCo C in air occurred through two consecutive reactions in the 136-270 ℃ temperature intervals. Decomposition started by hydroxide component（Co（OH）2） decomposition until to 65% and simultaneously carbonate phase decarbonation began. The process was continued by CO2 evolution and finally carbonate cobalt nanosheets have been produced. The reaction mechanism of the whole process can be kinetically characterized by two successive reactions： a phase boundary contracting reaction followed by an Avrami-Erofeev equation. Mechanistic information obtained by the kinetic study was in good agreement with FT-IR（Fourier transform infrared spectroscopy） and SEM（scanning electron microscopy） results.

One-Pot Synthesis of Dimethyl Carbonate over Basic Zeolite Catalysts

One-pot synthesis of dimethyl carbonate (DMC) from methanol, propylene oxide (PO) and carbon dioxide has been investigated using the basic zeolites as catalysts. Among the zeolites studied, Beta showed the best catalytic performance for DMC production. That the desilication of zeolite structure resulted in a hierarchical porosity of Beta, leading to more amount of KOH can be loaded on the surface of zeolite and therefore enhancing the base strength of the catalyst was proposed to be the reason for improved catalytic performance.

Preparation of basic nickel carbonate particles in solution system of Ni(Ⅱ)-NH_3-CO_3^(2-)-H_2O

Based on the principles of simultaneous equilibrium and mass balance, a series of thermodynamic equilibrium equations of Ni（Ⅱ）-NH3-CO2-3-H2O system at ambient temperature were deduced theoretically and the thermodynamic diagrams of lg[Ni]T versus pH at different solution compositions were drawn, which was quite effective to explain the formation mechanism of precipitation particles with different microscopic shapes. When pH of the solution is below （7.0,） free nickel ions are dominant and when the precipitant is added, the fast coagulation will take place leading to the loose flocculation particles. While pH is above 7.0, because of the coordination of nickel ion with ammonia, the precipitation proceeds slowly accompanying with the release of Ni2+ from the multi-coordinated Ni（NH3）2+n（n=1, 2, …, 6）, which easily leads to the formation of the dense spherical particles.

Prepartion of Flake-Like Basic Magnesium Carbonate from the Ammonium Sulfte Leaching Liquid of Asbestos Tailing

The flake-like basic magnesium carbonate was prepared from the ammonium sulfate leaching liquid of asbestos tailings. The method of X-ray diffraction, Fourier transform infrared spectra, TA-DTG and SEM analysis had been used to research the influence of the reaction temperature on the phase, structure and morphology of the product during the preparation of the basic magnesium carbonate. The results indicates that the product was needle-like magnesium carbonate hydrate at the lower reaction temperature (from 35 ℃ to 65℃), with the increase of the reaction temperature (75 ℃ to 95 ℃ ), the needle-like magnesium carbonate hydrate (MgCO3·xH2O) transformed to flake-like basic magnesium carbonate [Mg5(CO3)4(OH)2·4H2O], the reaction temperature plays an important role in the preparation of flake-like basic magnesium carbonate, the preparation of flake-like basic magnesium carbonate was a nucleation-dissolution-recrystallization growth mechanism process.

The Aggregation Kinetics of Colloidal Particles of Basic Yttrium Carbonate

The aggregation kinetics of basic yttrium carbonate pericles in aqueous solution havebeen studied using dynamic light-scattering techniques. In 1.00mol/l NaCl solution fast diffusionlimited aggregation behavior was observed with an increase in aggregate size over time describedby a power law. The aggregates are characterized by a fractal dimension D=1.82. Smoluchowskiand fractal theories were used to characterize the aggregation mechanism and to obtain theaggregation rate constant.

Microwave absorbing characteristics and temperature increasing behavior of basic cobalt carbonate in microwave field

The microwave absorbing characteristics of basic cobalt carbonate,cobalt oxide(Co3O4),and the mixture of basic cobalt carbonate and cobalt oxide were investigated by means of microwave cavity perturbation,their temperature increasing curves were measured,and their ability to absorb microwave energy was also assessed based on the temperature increasing behavior of the material exposed to microwave field.Analyses of spectrum attenuation and relative frequency shift show that basic cobalt carbonate has weak capability to absorb microwave energy,while cobalt oxide has very strong capability to absorb microwave energy.It is feasible to thermally decompose basic cobalt carbonate though addition of small amount of cobalt oxide in microwave fields.The capability to absorb microwave energy of sample increases with an increase in mixing ratio of Co3O4.

A green route for the preparation of layered double hydroxides from basic magnesium carbonate

Layered double hydroxides(LDHs)have received extensive attention in many fields such as catalysis,environmental management and medical applications.Typically,expensive soluble metal salts are commonly used as the starting materials for the synthesis of LDHs.Here,we report a novel synthesis route for Mg/Al-LDH by using inexpensive basic magnesium carbonate as the starting material.X-ray diffraction(XRD)and solid-state nuclear magnetic resonance(ssNMR)data show that LDHs with rich defects are formed rapidly at room temperature and good crystallinity can be obtained after further hydrothermal treatment.These results provide a simple,rapid and green preparation method for LDHs.

Influence of Absolute Basicity and Capillary Porosity on Carbonation of Concrete

The single influence of capillary porosity and coupling effects of absolute basicity and capillary porosity on concrete carbonation were investigated. The experimental results showed that carbonation rate of concrete at a given absolute basicity （AB） increased moderately with the increase of the porosity ranging from 6.2% to 9.25%, and increased rapidly with porosity from 9.25% to 12.8%.The coupling effect mainly embodied in disappeared mutation point of capillary porosity, and the distributing regions of carbonation depth were clearly partitioned in the coupling influence of absolute basicity and capillary porosity. A design method on carbonation related durability of concrete based on the coupling effects was proposed.

An Efficient and Novel Synthesis of Carbamate Esters from the Coupling of Amines, Halides and Carbon Dioxide in the Presence of Basic Resin

A convenient, efficient, one-pot, novel process has been developed for the synthesis of carbamates from corresponding alkyl halides and amines using basic resin/CO2 system.

THE FABRICATION OF CARBON AEROGELS BY GELATION IN ISOPROPANOL WITH BASIC CATALYST

A new method for the fabrication of carbon aerogels is reported in this paper. Resorcinol and furfural were gelated in isopropanol with basic catalysts and then dried directly under isopropanol supercritical condition, followed by carbonization under nitrogen atmosphere. The bulk densities of carbon aerogels obtained are in the range of 0.21g/cm3~0.27g/cm3 and the sizes of the interconnected carbon nano-particles are in the range of 20nm^30nm. All of the aerogel samples exhibit high BET surface areas in the range of 730m2/g^900m2/g. The bulk density, micro-pore volume, meso-pore volume and meso-pore diameter can be controlled by gelation conditions such as R/I ratio and R/C ratio.

Study on the supramolecular systems of two basic violets with cyclodextrins by MWNTs/Nafion modified glassy carbon electrode

Abstract The electrochemical properties of two basic violets （methyl violet and ethyl violet） at the MWNTs/Nafion modified glassy carbon electrode were investigated. The redox of the basic violets is two-electron and two-proton process, and methyl violet presents stronger electron transfer capacity than ethyl violet. Meanwhile, the inclusion constants of the two basic violets with five CDs were determined by differential pulse voltammetry （DPV）. The two basic violets and CDs can form 1：1 complexes, The inclusion capacities of the two basic violets follow the same order： CM-β-CD 〉 HP-β-CD 〉 TM-β-CD 〉 DM-β- CD 〉 β-CD. ？2009 Yu Jing Guo. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Carbon Budget for Basic Needs:Implications of International Equity and Sustainability

The fundamental way of satisfying the basic needs of human development is to secure the basic needs,limit luxurious and wasteful emissions,and ensure the fulfillment of climate targets,so as to achieve intra-and intergenerational equity.In this paper,the author discusses and analyzes a series of challenges that the development has to face,such as poverty elimination,urbanization,and industrialization,and the problems of increased consumption that is brought about by the improvement of living standards;the author distinguishes the stock emission,which does not need annual updating,and the flow emission of regular consumption;the author also defines the standards of energy consumption and carbon emissions that can meet the basic needs.On this basis,the author proposes the concept and method of carbon budget,compares this method with other means,and in particular,studies and analyzes the implications of international equity and sustainability of carbon budget as part of the international climate regime design.

Study on the growth of honeycomb-like film of basic zinc carbonate induced by bovine serum albumin LB film template

Honeycomb-like films of basic zinc carbonate were successfully prepared on FTO(SnO_(2):F)conductive glass using bovine serum albumin(BSA)as a template at room temperature.After low-temperature annealing,a high-specific-surface-area porous ZnO film with excellent electron mobility was obtained.The surface morphology,crystallization performance,and photoluminescence characteristics of basic zinc carbonate thin films and annealed ZnO thin film were analyzed by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),photoluminescence spectroscopy(PL)and UV-Visible spectroscopy(UV-vis).By comparing with those samples prepared without any protein,it was determined that the complexation between BSA molecules and Zn^(2+)ions was the primary factor in the synthesis of porous films of basic zinc carbonate.The experimental results showed that the ZnO thin film samples prepared with this method had high specific surface area and broadband luminescence characteristics in the near ultraviolet range.

跨越九百年的青山绿水:从化学视角解密《千里江山图》

《千里江山图》作为中国的十大传世名画之一,不仅代表了青绿山水画艺术的发展历程,更是中国古老文明的缩影。该画作流传久远,历时九百余年依旧绚烂多彩,与其材质、颜料、胶结材料密切相关。本文从化学视角出发,分析《千里江山图》使用的颜料与胶结材料,并以拟人化的方式逐个介绍它们的性格与特点,如“石墨大哥”“赭石阿姨”“青绿兄弟”“砗磲姑娘”和“明胶叔叔”。探讨他们的化学成分与理化性能,揭示这些惊艳的颜料共同打造《千里江山图》辉煌的秘诀。通过激发古典艺术与现代科技的思考,促进艺术鉴赏与科技创新的融合。

防爆柴油机排气颗粒物的微观结构研究

为研究废气水洗箱和含氧燃料对防爆柴油机排气颗粒物微观结构随工况变化的影响,利用扫描电子显微镜(Scananing Elecron Microscope,SEM)对0#柴油(D100)和丁醇/柴油混合燃料(BD20)的排气颗粒物的微观形貌、分形特征和粒径分布进行研究。其中,丁醇的质量分数为20%。结果显示:经过废气水洗箱后,颗粒物内吸附质含量增多,密集程度升高,在多数工况下,颗粒物支链减少,且BD20有利于减少颗粒物碳烟粒子含量;颗粒物的计盒维数分布在1.70~1.85,且经过废气水洗箱的颗粒物结构更紧密,计盒维数更大,D100的计盒维数大于BD20的计盒维数;颗粒物基础碳粒子粒径分布在10~90 nm,废气水洗箱对颗粒物有沉降作用,使颗粒物平均粒径减小,BD20的平均粒径小于D100平均粒径。

The photo-decomposition and self-restructuring dynamic equilibrium mechanism of Cu_(2)(OH)_(2)CO_(3)for stable photocatalytic CO_(2)reduction

Developing suitable photocatalysts and understanding their intrinsic catalytic mechanism remain key challenges in the pursuit of highly active,good selective,and long-term stable photocatalytic CO_(2)reduction(PCO_(2)R)systems.Herein,monoclinic Cu_(2)(OH)_(2)CO_(3)is firstly proven to be a new class of photocatalyst,which has excellent catalytic stability and selectivity for PCO_(2)R in the absence of any sacrificial agent and cocatalysts.Based on a Cu_(2)(OH)_(2)^(13)CO_(3)photocatalyst and 13CO_(2)two-sided^(13)C isotopic tracer strategy,and combined with in situ diffused reflectance infrared Fourier transform spectroscopy(DRIFTS)analysis and density functional theory(DFT)calculations,two main CO_(2)transformation routes,and the photo-decomposition and self-restructuring dynamic equilibrium mechanism of Cu_(2)(OH)_(2)CO_(3)are definitely revealed.The PCO_(2)R activity of Cu_(2)(OH)_(2)CO_(3)is comparable to some of state-of-the-art novel photocatalysts.Significantly,the PCO_(2)R properties can be further greatly enhanced by simply combining Cu_(2)(OH)_(2)CO_(3)with typical TiO_(2)to construct composites photocatalyst.The highest CO_(2)and CH_(4)production rates by 7.5 wt%Cu_(2)(OH)_(2)CO_(3)-TiO_(2)reach 16.4μmol g^(-1)h^(-1)and 116.0μmol g^(-1)h^(-1),respectively,which are even higher than that of some of PCO_(2)R systems containing sacrificial agents or precious metals modified photocatalysts.This work provides a better understanding for the PCO_(2)R mechanism at the atomic levels,and also indicates that basic carbonate photocatalysts have broad application potential in the future.

高碳铬铁冶炼过程影响因素的研究进展

本文通过总结国内外相关文献,认为影响高碳铬铁冶炼的主要因素为炉料的物理性能、化学性能和化学成分,且炉料的物理性能和化学性能受炉料的化学成分影响。同时,阐述了MgO、Al_(2)O_(3)、SiO_(2)、CaO和碳质还原剂等化学成分对高碳铬铁冶炼的影响,其中碳质还原剂对炉料的电阻率起决定作用;MgO、Al_(2)O_(3)和SiO_(2)等则更多影响冶炼时的熔化性、熔点和黏度等参数。本文还分析了各化学成分对铬铁矿还原的影响,其中Fe、FeO、Fe_(3)O_(4)、SiO_(2)、CaO、NaOH以及硼酸盐等在一定程度上能促进铬铁矿的还原,而MgO则会抑制铬铁矿的还原。此外,归纳总结了镁铝比和炉渣碱度对高碳铬铁冶炼的影响,将镁铝比控制在1.3~1.9,炉渣碱度不超过1.4,可以达到降低冶炼电耗、焦耗和提高铬回收率的效果。