热水系统成矿的物理化学特征

本文对成矿热水系统研究中的成矿热液基础成分，物理化学状态作了总结，分析了沉积岩中含金属热液的系统的物理化学效应，综合了卤水系统硫化物沉积的各种他热水沉积后的化学变化等，对近代热液矿床理论提出一些新认识。

Self-assembly of hierarchical ZnSnO_3-SnO_2 nanoflakes and their gas sensing properties

A new type of hierarchical ZnSnO3-SnO2 flower-shaped nanostructure composed of thin nanoflakes as secondary units is successfully prepared through a simple hydrothermal process. The polyhedral ZnSnO3 core acts as a sacrificed template for the growth of hierarchical SnO2 nanoflakes, and the average thickness of SnO2 nanoflakes is around 25 nm. The time-dependent morphology evolution of ZnSnO3-SnO2 samples was investigated, and a possible formation mechanism of these hierarchical structures is discussed. The gas sensor based on these novel ZnSnO3-SnO2 nanostructures exhibits high response and quick response- recovery traits to ethanol （C2H5OH）. It is found that ZnSnO3-SnO2 nanoflakes have a response of 27.8 to 50×10-6 C2H5OH at the optimal operating temperature of 270 °C, and the response and recovery time are within 1.0 and 1.8 s, respectively.

Hydrothermal synthesis of nanosized ZSM-22 and their use in the catalytic conversion of methanol

ZSM‐22 zeolite with different crystal lengths was prepared using a modified hydrothermal method. Rotation speed, Si/Al molar ratio and co‐solvent have important effects on the crystal size of ZSM‐22. The nanosized zeolite samples were characterized by X‐ray diffraction, X‐ray fluorescence, nitrogen adsorption, scanning electron microscopy, temperature‐programmed desorption of am‐monia and solid state nuclear magnetic resonance. The catalytic performance of nanosized ZSM‐22 was tested using the conversion of methanol. Compared to conventional ZSM‐22, the nanosized ZSM‐22 zeolite exhibited superior selectivity to ethylene and aromatics and lower selectivity to propylene. Stability against deactivation was clearly shown by the nanosized ZSM‐22 zeolite. A higher external surface area and smaller particle size make this nanosized ZSM‐22 zeolite attractive for catalytic applications.

Hydrothermal synthesis of monodisperse Zn_(x)Cd_(1-x)S spheres and their photocatalytic properties

Monodisperse ZnxCd1-xS spheres were successfully fabricated with a high yield by a facile hydrothermal route.The as-prepared samples were characterized by X-ray diffractometry,scanning electron microscopy and UV-vis diffusion reflectance spectroscopy.The results indicate that all the prepared samples have the same hexagonal wurtzite phase and exhibit good size uniformity and regularity.Degradation of rhodamine-B（RhB） was used to evaluate the photocatalytic activities of ZnxCd1-xS samples.Zn0.4Cd0.6S possessed the best photocatalytic activity and exhibited high stability during the reaction.

Two-step hydrothermal synthesis of Sn_2Nb2O_7 nanocrystals with enhanced visible-light-driven H_2 evolution activity

We use a two‐step hydrothermal method to successfully synthesize Sn2Nb2O7nanocrystals with an average size of approximately20nm.The as‐obtained samples are characterized by powder X‐ray diffraction,ultraviolet‐visible diffuse reflectance spectroscopy,Brunauer‐Emmett‐Teller analysis,scanning electron microscopy,and transmission electron microscopy.The photocatalytic activity of the Sn2Nb2O7nanocrystals is evaluated by photocatalytic water splitting under visible light irradiation.The Sn2Nb2O7nanocrystals with a large surface area of52.2m2/g show an enhanced visible‐light‐driven photocatalytic H2production activity,approximately5.5times higher than that of bulk Sn2Nb2O7powder.The higher photocatalytic activity of Sn2Nb2O7nanocrystals is mainly attributed to its relatively high dispersity of nanosized particles and larger specific surface area when compared with the bulk powder.

Organotemplate-free Hydrothermal Synthesis of SUZ-4 Zeolite: Influence of Synthesis Conditions

Various conditions were investigated in detail for the novel organic template-free static hydrothermal synthesis of SUZ-4 zeolite in the presence of seeds. The obtained samples were characterized by XRD （X-ray diffraction）, SEM （scanning electron microscope）, TG （thermal gravimetric analysis）, ICP （inductively coupling plasma） elemental analysis, nitrogen sorption isotherm and surface area. The results show that pure SUZ-4 zeolites with high crystallinity are obtained in a broad window of synthesis conditions： seed mass concentration 0.2%-2%, SIO2/A1203 molar ratio 21 25, KOH/SiO2 molar ratio 0.33 0.43, H20/SiO2 molar ratio 7.14-38.1, aging time 24 h, crystallization temperature 160℃, and crystallization time 6-10 d. Also, crystallinity and size of the rod-like SUZ-4 zeolite crystals are found to alter with the conditions.

Design Energy Efficient Water Utilization Systems Allowing Operation Split

This article deals with the design of energy efficient water utilization systems allowing operation split. Practical features such as operating flexibility and capital cost have made the number of sub operations an important parameter of the problem. By treating the direct and indirect heat transfers separately, target freshwater and energy consumption as well as the operation split conditions are first obtained. Subsequently, a mixed integer non-linear programming （MINLP） model is established for the design of water network and the heat exchanger network （HEN）. The proposed systematic approach is limited to a single contaminant. Example from literature is used to illustrate the applicability of the approach.

Preparation of MnO_2 and calcium silicate hydrate from electrolytic manganese residue and evaluation of adsorption properties

Electrolytic manganese residue(EMR), a high volume byproduct resulting from the electrolytic manganese industry, was used as a cheap and abundant chemical source for preparing MnO2 and EMR-made calcium silicate hydrate(EMR-CSH). The MnO2 is successfully synthesized from the metal cations extracted from EMR, which can effectively recycle the manganese in the EMR. By the combination of XRD, SEM and EDX analysis, the as-prepared MnO2 is found to exhibit a single-phase with the purity of 90.3%. Furthermore, EMR-CSH is synthesized from EMR via hydrothermal method. Based on the detailed analyses using XRD, FT-IR, FE-SEM, EDX and BET surface area measurement, the product synthesized under the optimum conditions(p H 12.0 and 100 °C) is identified to be a calcium silicate hydrate with a specific surface area of 205 m2/g incorporating the slag-derived metals(Al and Mg) in its structure. The as-synthesized material shows good adsorption properties for removal of Mn2+ and phosphate ions diluted in water, making it a promising candidate for efficient bulk wastewater treatment. This conversion process, which enables us to fabricate two different kinds of valuable materials from EMR at low cost and through convenient preparation steps, is surely beneficial from the viewpoint of the chemical and economical use of EMR.

Calorimetric Determination of Enthalpy of Formation of Natural Gas Hydrates

This paper reports the measurements of enthalpies of natural gas hydrates in typical natural gas mixture containing methane, ethane, propane and iso-butane at pressure in the vicinity of 2000 kPa (300 psi) and 6900 kPa(1000psi). The measurements were made in a multi-cell differential scanning calorimeter using modified high pressure cells. The enthalpy of water and the enthalpy of dissociation of the gas hydrate were determined from the calorimeter response during slow temperature scanning at constant pressure. The amount of gas released from the dissociation of hydrate was determined from the pumped volume of the high pressure pump. The occupation ratio (mole ratio) of the water to gas and the enthalpy of hydrate formation are subject to uncertainty of 1.5%.The results show that the enthalpy of hydrate formation and the occupation ratio are essentially independent of pressure.

Synthesis of ZnO whiskers via hydrothermal decomposition route

ZnO whiskers with a length of 30-40μm and a diameter of about 1μm were synthesized by co-precipitation of ZnSO 4 and Na2CO3 solution at room temperature followed by hydrothermal treatment of the as-prepared Zn5(CO3)2(OH)6 precursor at 160 ℃for 6 h.The increase of the initial solution pH promotes the hydrothermal conversion of the particulate Zn5(CO3)2(OH)6 to ZnO whiskers.The presence of minor amount of EDTA in the hydrothermal solution promotes the one dimensional growth of ZnO whiskers,leading to the formation of ZnO whiskers with a length of 50-60μm and a diameter of 1-2μm.

Hierarchical porous MgBO_2(OH) microspheres: Hydrothermal synthesis,thermal decomposition, and application as adsorbents for Congo red removal

A facile eco-friendly hydrothermal route （180 ℃, 12.0 h） has been developed for the first time to the uniform hierarchical porous MgBO2（OH） microspheres without the aid of any organic additive, surfactant or template, by using the abundant MgCl2·6H2O, H3BO3 and NaOH as the raw materials. The as-obtained porous microspheres exhibit a specific surface area of 94.752 mg·g-1, pore volume of 0.814 cm3.g-1, and ca. 84.0% of which have a diameter of 2.25-3.40 μm. The thermal decomposition of the porous MgBO2（OH） microspheres （650 ℃, 2.5 ℃. min-l） leads to the porous Mg2B2O5 rnicrospheres with well-retained morphology. When utilized as the adsorbents for the removal of CR from mimic waste water, the present porous MgBO2（OH） microspheres exhibit satisfactory adsorption capacity, with the maximum adsorption capacity qm of 309.1 mg-g-1, much higher than that derived from most of the referenced adsorbents. This opens a new window for the facile green hydrothermal synthesis of the hierarchical porous MgBO2（OH） microspheres, and extends the potential application of the 3D hierarchical porous metal borates as high-efficiency adsorbents for organic dyes removal.

Synthesis of ZSM-5 with the silica source from industrial hexafluorosilicic acid as transalkylation catalyst

A new effective process to improve the utilization of industrial fluorosilicic acid of phosphate fertilizer by-product has been investigated to comprehensive application of the silicon and fluorine source. Two-step ammoniation was applied to recover high-quality silica. The recovered silica can be used to hydrothermal synthesize ZSM-5 zeolite without impurity phase contamination, which was confirmed by XRD, TG, SEM, BET and EDS characteristic techniques. It was found that with the increase of SiO_2/Al_2O_3 ratio and the extension of reaction time, the crystal type transform from the orthorhombic to the monoclinic phase. The impurity fluorine content of the recovered SiO_2 from H_2SiF_6 has great influence on the hydrothermal process for ZSM-5 crystal structure formation.Moreover, the increase of fluorine ions content in the hydrothermal process can control the crystal morphology and size of synthesized ZSM-5. Catalytic properties of synthesized HZSM-5 with different SiO_2/Al_2O_3 ratio in transalkylation of toluene and 1,2,4-trimethylbenzene show good and stable catalytic performance. The ZSM-5 synthesized with recovered silica source exhibits similar catalyst life as the performance of small particle size HZSM-5, because the ZSM-5 synthesized with the silica source from industrial hexafluorosilicic acid prefers a thin disk crystal along the b axis direction, which shortens the diffusion distance of generated products.

Hydrothermal Synthesis and Properties of Y-zeolite-containing Composite Material with Micro/mesoporous Structure

A Y-zeolite-containing composite material with micro/mesoporous structure had been synthesized from kaolin by means of the in-situ crystallization method. The obtained samples were investigated by XRD and BET methods. Evaluation of catalytic activity of both the commercial Y-zeolite and the novel Y-zeolite-containing composite material was carried out in the pulse micro-chromatography platform with two probe molecules of different molecular sizes： VGO feedstock and 1,3,5 tri-isopropyl benzene. It was found that the Y-zeolite-containing composite material was richer in external surface and meso-/macro-pores; the Y-zeolite-containing composite material demonstrated a smaller rate of deactivation compared to the commercial Y-zeolite.

Mass Spectrometric Investigation of the Chemical Composition of Caramel Formed upon Heating of Disaccharides

Disaccharides are a very important group of carbohydrates, being main components of many daily food products. The heating of these biomolecule causes the formation of caramel, an extremely complex material. The dominant fraction of non-volatile compounds, responsible for both color and flavor of food products, has been studied on a few occasions. Herein, the composition of caramels obtained by heating of sucrose, lactose and maltose were studied using combined mass spectrometry techniques. High resolution electrospray mass spectrometry was applied followed by targeted multi-stage LC-tandem mass spectrometry （ESI-MSn） and MALDI-MS. Novel graphical interpretation strategies such as van Krevelen and Kendrick mass analysis have been applied to study the composition of caramels. Products of caramel include oligomerization, depolymerization, hydration and dehydration products. Oligomers with up to eight carbohydrate units and dehydrated oligomers losing up to eight water molecules have been identified.

Two Anderson-based supramolecular compounds modified by 4,4'-dipyridy synthesized in one-pot

Using symmetrical rigid organic ligand 4,4'-dipyridy(4,4'-bipy),two new Anderson-based supramolecular compounds,namely,[H_(2)(4,4'-bipy)]_(3)·(TeMo_(6)O_(24))·(H_(2)Mo_(6)O_(19))(1)and{Cu_(2)[H(4,4'-bipy)]_(2)(H_(2)O)_(6)(TeMo_(6)O_(24))}·4H_(2)O(2),were synthesized in one-pot under hydrothermal conditions.The compounds 1 and 2 have been tested by IR spectra,elemental analyses and single-crystal X-ray diffraction.Compound 1 contains one discrete Anderson anion,one Lindqvist anion and three 4,4'-bipy organic ligands.The anions and 4,4'-bipy alternate with each other by hydrogen bonding,building a supramolecular 1D chain.Adjacent 1D chains are interlinked through hydrogen bonding interactions to further connect a supramolecular 2D layer.Compounds containing both Anderson and Lindqvist polyanions are not common in the crystal structure of POMs.Compound 2 contains one Anderson anion and two metal-organic subunits{Cu_(2)[H(4,4'-bipy)]_(2)(H_(2)O)_(6)}^(6+)as modifiers.The Anderson anions and{Cu_(2)[H(4,4'-bipy)]_(2)(H_(2)O)_(6)}^(6+)subunits are organized into alternating through hydrogen bonding interactions to construct a supramolecular 1D chain.Additionally,the electrochemical properties of compounds 1 and 2 as well as photocatalytic properties are investigated.Results show that compounds 1 and 2 have photocatalytic activity,which can photocatalyze the degradation of organic dyes MB and AF.Also,compounds 1 and 2 have good electrochemical properties for amperometric detection of NO2-and Cr(Ⅵ).Furthermore,Compound 2 can be used as materials of supercapacitor.

Double layered,one-pot hydrothermal synthesis of M-TiO_2(M=Fe^(3+),Ni^(2+),Cu^(2+)and Co^(2+)) and their application in photocatalysis

A double layered, one-pot hydrothermal method was adopted in this work to prepare transition metal ions （Fe3＋, Ni2＋, Cu2＋ and Co2＋） doped TiO〉 The morphology and chemical properties of TiO2 and the status of metal ions were characterized with XRD, TEM, BET, UV-Vis and XPS analysis. TEM images show that the obtained TiO2 was very uniform with an average particle size of 10.4 nm. XPS, TEM and XRD results show that transitional metals were doped onto TiO2 in the form of ions. Photocatalytic decomposition of oxalic acid under UV illumination and methylene blue degradation under visible light on these materials were conducted, respectively. The results reveal that Cu2＋-TiO2 and C02＋-TiO2 showed a highest activity under UV and visible light illumination, respectively, and they were both more active than commercial P25 TiO2. With this special design of double layers, the hydrolysis of titanium precursor in the system with water can be easily controlled and metal ions are simply doped. This strategy can be further applied to synthesize metal ion doped TiO2 using various metal precursors with controllable amounts, and thus lead to better optimization of highly active photocatalyst.

Hydrothermal synthesis and characterization of rare-earth ruthenate pyrochlore compounds R_2Ru_2O_7(R=Pr_(3+),Sm(3+)-Ho(3+))

A series of pyrochlore oxides, R2Ru2O7 (R=Pr3+, Sm3+–Ho3+) were synthesized under mild hydrothermal conditions. All the samples crystallize in uniform octahedron characteristically. The products were characterized by powder X-ray diffraction, scanning electron microscopy, energy-disperse X-ray spectroscopy, and dc susceptibility, and the factors that affected the crystallization were discussed. It was found that the purity of products depends strongly on the raw materials and the amount of alkalinity in the initial reaction mixtures. The ZFC and FC susceptibilities of all of the compounds R2Ru2O7 at low temperature were also measured and discussed.