柠檬酸辅助下三水碳酸镁晶须的水合制备研究

以菱镁矿煅烧所得活性氧化镁为原料,柠檬酸为助剂,采用水合法制备了三水碳酸镁晶须,主要研究柠檬酸用量、热解温度和热解时间对晶体制备过程的影响。利用X射线衍射(XRD)和扫描电镜(SEM)分析了产物的物相组成及微观形貌。结果表明:热解温度90℃,柠檬酸用量0.3%~3%,热解时间30~120min时,均获得结晶和分散性良好,平均直径为3.5μm的三水碳酸镁晶须;柠檬酸辅助下,热解温度75~95℃,得到平均长径比为15的棒状MgCO_3·3H_2O晶须。柠檬酸对MgCO_3·3H_2O向4MgCO_3·Mg(OH)_2·4H_2O相转变进程具有抑制作用。

水合硫酸铜制备实验的改进

概述了CuSO4·5H2O制备的几种不同方法。对教材中CuSO4·5H2O制备中存在的问题进行了分析,并对该实验进行了改进。实验以过氧化氢、硫酸、铜粉为原料,改用95%乙醇洗涤硫酸铜晶体。改进后实验操作简单,产品产率达95%以上,且反应过程无NO2等有毒气体释放,显著提高教学效果。

醋酸铬(Ⅱ)水合物制备实验的新设计

在实验教学中培养学生的创新意识,探究尝试将《无机化学实验》中的醋酸铬水合物制备这一学生较难独立完成、有一定操作难度的实验设计为：一次性加酸获得近常压的氢气还原气氛,用手动倾倒法使Cr2＋溶液进入醋酸钠溶液。结果发现：新的设计使实验操作简易、省时安全、产率高、经济环保,是一种非常简易实用的实验方法。

实验室水合物物理模型的电磁特性初步研究

天然气水合物模拟实验是水合物研究的重要组成部分。这里介绍了实验室THF水合物的特性及其制备过程,并使用高频探地雷达对水合物模型测试。通过对不同的模型进行测量,分析其界面波形曲线规律特征,推断THF水合物的界面反射信号,估算其介电常数。研究发现,THF水合物对雷达波具有良好的电磁反射响应,顶、底界面反射信号清晰,与正演模型能够较好对应。使用物探方法技术对实验室水合物模型进行电磁特性研究,为探索建立陆域天然气水合物物探方法技术体系方面发挥了积极地作用。

定容过程气体水合物相平衡计算研究

在Chen-Guo模型的基础上,考虑到水合物浆制备的两种基本过程,即定容反应过程和定压反应过程,同时在深入理解两相闪蒸平衡计算过程的基础上,开发出适用于定容条件下水合物浆相平衡计算的计算过程。该方法对水合物浆制备结果的预测及水合物浆性质的计算具有重要意义。

水合物储运天然气技术中双级串联制备系统

分析了3种水合物合成反应器(搅拌式反应器、鼓泡式反应器和喷淋式反应器)的原理及特点。提出了一种水合物快速、高效制备的新型工艺———喷淋-鼓泡装置和喷淋-搅拌装置双级串联系统,介绍了工艺流程,建立了水合物制备仿真监控系统。介绍了水合物的分解。

Preparation of AgSnO_2 composite powders by hydrothermal process

Silver-tin oxide powders were synthesized by the hydrothermal method with Ag(NH_3)_2^+ solution and Na_2SnO_3 solution as raw materials and Na_2SO_3 as reductant. The precipitation conditions of Na2SnO3 solution and the reduction conditions of Ag(NH_3)_2^+ were also investigated. The powders prepared were characterized by differential thermal analysis (DTA), X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and energy spectrum analysis. The results show that pH value of the solution is a key parameter in the formation of Sn(OH)_4 precipitate and the reduction reaction of Ag(NH_3)_2^+ can release H+ ions, which results in synchronous precipitation of Sn(OH)_6~2- as Sn(OH)_4. The reduction of Ag(NH_3)_2^+ and precipitation of Na_2SnO_3 occur simultaneously and the coprecipitation of silver and tin oxide is reached by the hydrothermal method. The silver-tin oxide composite powders have mainly flake shape of about 0.3 μm in thickness and there exists homogeneous distribution of tin oxide and silver in the powder synthesized.

Preparation of Thermosensitive Chitosan Formulations Containing 5-Fluorouracil/Poly-3-hydroxybutyrate Microparticles Used as Injectable Drug Delivery System

The auto-gelling and drug release properties of the thermosensitive chitosan-β-glycerophosphate formulation were investigated. According to rheological study, gelation lag time of chitosan/β-glycerophosphate （GP） solutions varied from 2 to 60min with different deacetylation degree of chitosan, pH, gelation temperature, and the particles in the sol. The gelation properties were also found to influence the release profilles of a hydrophilic drug, 5-fluorouracil （5-FU）. Morphological examination by scanning electron microphotography demonstrated that large ＂pores＂ occurred during the gel-forming process, which created hydrophilic environment and led to the rapid initial release of the drug （85% in f＇LrSt 8h）. Poly-3-hydroxybutyrate （PHB）, a biodegradable material, was applied here as scaffold to capture 5-FU into microparticles with high encapsulation efficiency by solvent-nonsolvent method. Combination of these microparticles into the chitosan-β-GP formulation could drop the rapid initial release from 85% down to 29% in the optimized PHB content （75%, by mass）. The release could sustain for about 10 months. Tiffs study provided an understanding of the potential of injectable implant using thermosensitive chitosan-β-GP formulation containing PHB based particles for the water soluble drugs that need the property of long-term delivery.

Hydrophobic aggregation of ultrafine kaolinite

The hydrophobic aggregation of ultrafine kaolinite in cationic surfactant suspension was investigated by sedimentation test,zeta potential measurement and SEM observation. SEM images reveal that kaolinite particles show the self-aggregation of edge-face in acidic media,the aggregation of edge-face and edge-edge in neutral media,and the dispersion in alkaline media due to electrostatic repulsion. In the presence of the dodecylammonium acetate cationic surfactant and in neutral and alkaline suspension,the hydrophobic aggregation of face-face is demonstrated. The zeta potential of kaolinite increases with increasing the concentration of cationic surfactant. The small and loose aggregation at a low concentration but big and tight aggregation at a high concentration is presented. At pH=7 alkyl quarterly amine salt CTAB has the best hydrophobic aggregation among three cationic surfactants,namely,dodecylammonium acetate,alkyl quarterly amine salts 1227 and CTAB.

Research on Preparation Method of Static Head Space for Volatile Organic Compounds in Drinking Water

[Objective] This research aimed to study the pre-treatment conditions of head space so as to establish a HS-GC determination method, which is suitable for China's conditions, for trace volatile organic compounds in drinking water. [Method]The preparation method of head space was adopted for the volatile organic compounds in drinking water. [Result] The 20 kinds of volatile organic compounds in drinking water all could be detected simultaneously by using HS-GC-FID method,and they all could be separated well. The HS-GC-FID method could analyze the detected substances qualitatively and quantitatively. In addition, this detection method was characterized by larger linear range of concentration, higher precision, higher detection limit and higher recovery rate. [Conclusion] Under certain conditions, HSGC can reduce the loss of volatile organic compound in drinking water and improve the sensitivity of detection. Moreover, the detection results meet the requirements by quality control.

Fabrication of graphene oxide composite membranes and their application for pervaporation dehydration of butanol

As a new kind of2D nanomaterials, graphene oxide （GO） with 2-4 layers was fabricated rio a modified Hummers method and used for the preparation ofpervaporation （PV） membranes. Such GO membranes were prepared via a facile vacuum-assisted method on anodic aluminium oxide disks and applied for the dehydration of butanol. To obtain GO membranes with high performance, effects of pre-treatments, including high-speed centrifugal treat- ment of GO dispersion and thermal treatment of GO membranes, were investigated. In addition, effects of operation conditions on the performance of GO membranes in the PV process and the stability of GO membranes were also studied. It is of benefit to improve the selectivity of GO membrane by pre-treatment that centrifuges the GO dispersion with 10000 r· min^- 1 for 40 min, which could purify the GO dispersion by removing the large size GO sheets. As prepared GO membrane showed high separation performance for the butanol/water system. The separation factor was 230, and the permeability was as high as 3.1 kg·m^- 2·h^-1 when the PV temperature was 50 ℃ and the water content in feed was 10% （by mass）. Meanwhile, the membrane still showed good stability for the dehydration of butanol after running for 1800 min in the PV process. GO membranes are suitable candidates for butanol dehydration via PV process.

Preparation, characterization and salt-resistance of a coal based super absorbent composite

Potassium humate was extracted from brown coal. A novel super absorbent composite, poly （acrylic acid-co-acryla- mide）/potassium humate （PAA-AM/KHA）, was prepared by graft polymerization of acrylic acid, acrylamide and coal based potassium humate using N, N＇-methylenebisacrylamide as a crosslinker and potassium peroxydisulfate as an initiator. The effects of reaction temperature, degree of neutralization of the poly （acrylic acid） and the amounts of crosslinker, initiator and potassium humate were investigated. Salt resistance tests were also carded out. The composite prepared under optimal conditions had a potassium bumate content of 10% and exhibited a water absorption of 770 g/g in distilled water, and 349, 286 and 41 gig in 0.5 mol/L KC1, MgC12 and A1CI3 solutions respectively. The results indicate that the salt resistance of PAA-AM/KHA was superior to that of poly （acrylic acid-co-acrylamide） because of the collaborative effect of functional groups of the coal based potassium humate. The PAA-AM/KHA micro powder was characterized by IR spectroscopy and the micrographic surface was characterized by scanning electron microscopy. Introduction of potassium humate into the poly （acrylic acid-co-acrylamide） structure creates a composite more suitable for use as a water-managing material in the renewal of arid and desert environments. The salt resisting property of the composite is improved, production costs are reduced and the growth stimulant effect is still present.

Enhancing the separation performance by introducing bioadhesive bonding layer in composite pervaporation membranes for ethanol dehydration

A high performance composite membrane was prepared under the inspiration of bioadhesion principles for pervaporative dehydration of ethanol.Chitosan(CS)and polyacrylonitrile(PAN)ultrafiltration membranes were used as the active layer and the support layer,respectively.Guar gum(GG),a natural bioadhesive,was introduced as the intermediate bonding layer to improve the separation performance and stability of the fabricated CS/GG/PAN composite membranes.The contact angle of the GG layer was just between those of the CS layer and the PAN layer,minimizing the difference of hydrophilicity between the active layer and the support layer.The peeling strength of the composite membrane was significantly enhanced after the introduction of the GG layer.The effects of preparation conditions and operation conditions including GG concentration,operating temperature and ethanol concentration in feed on the pervaporation performance were investigated.The as-fabricated CS/GG/PAN composite membrane showed the optimum performance with a permeation flux of up to804 g·m-2·h-1and a separation factor higher than 1900.Besides,the composite membranes exhibited a desirable long-term operational stability.

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.

Solubilities of 2-Naphthalenesulfonic Acid Monohydrate and Sodium 2-Naphthalenesulfonate in Sulfuric Acid Solution and Their Application for Preparing Sodium 2-Naphthalenesulfonate

The solubilities of 2-naphthalenesulfonic acid monohydrate and sodium 2-naphthalenesulfonate in sulfuric acid solutions were measured at temperatures ranging from 278,15 to 338.15 K by using a dynamic method. The concentration of sulfuric acid solution ranged from 0 to 80wt%. The solubilities of 2-naphthalenesulfonic acid monohydrate and sodium 2-naphthalenesulfonate increased with temperature, and both of them were the lowest at 70wt% of sulfuric acid solution （ w3 0 = 0.70） while the highest in pure water. The solubility data were correlated by the modified Apelblat equation. Based on the solubility difference between 2-naphthalenesulfonic acid monohydrate and sodium 2-naphthalenesulfonate, a new technique in which sodium sulfate was used to replace sodium sulfite in the neutralization reaction was developed. The suitable mole ratio of H20 to Na2SO4 in the neutralization reaction was 80 ： 1, and that of 2-naphthalenesulfonic acid monohydrate to Na2SO4 was 3.2 ： 1. The material balance under the suitable mole ratios was given and discussed.

Study on Preparation of Porous ZnO Microspheres and Photocatalytic Performance

This paper introduces the method of porous ZnO microspheres by sodium citrate assisted hydrothermal synthesis with a mild, economy： first, basic synthesis globose precursor of Zinc Carbonate Hydroxide, then followed by thermal decompose the precursor to obtain porous Zinc Oxide microspheres. The morphology and structure of the precursor and synthesized porous microspheres were characterize by a series of methods, and did a series of experiments by changing dosage and reaction time of the sodium citrate and urea, finally the paper discussed the formation mechanism of porous ZnO microspheres.

Production and Quality Evaluation of Pringles from Composite Flour of Cocoyam and Wheat Flour

Work assessed ＂Pringles＂ as an imitate snack produced from composite flour of cocoyam and wheat. This was carried out in order to exploit the nutritional and aesthetic value of cocoyam （Colocasia escullenta Vat.） to improve the overall quality of the Pringles as against its production from potato and wheat composite flour. Composite flour （100%：0%, 90%：10%, 80%：20%, 70%：30%, 60%：40% and 50%：50%） of cocoyam and wheat respectively as the major raw materials were adopted and used for the production of the Pringles. Physicochemical analysis （pH, water absorption capacity （WAC）, bulk density （BD） and swelling capacity （SC））; proximate analysis （protein, fats, ash, moisture and carbohydrate content） and sensory evaluation （colour, texture, taste and overall acceptability） were carried out on the samples produced using standard methods. Physicochemical analysis showed the pH of 5.48 to 6.61, WAC （12.00 to 17.50）, BD （1.43 to 1.56） and SW （1.03 to 1.38）. However, sample with 10% cocoyam and 90% wheat composite flour gave the best physicochemical properties of pH （5.98）, WAC （14.00）, BD （1.56） and SC （1.38）. The proximate analysis showed that carbohydrate content ranging between 53.36 to 61.12, and protein content （8.17 to 12.29）, fat content （16.67 to 23.97）, ash content （3.49 to 45.53）, fiber content （1.71 to 2.83） and moisture content （8.76 to 14.54）. Sample B equally gave the nutrient proximate combination of appreciable percentage on the average. The result of the sensory evaluation showed that there is no significant difference between the samples produced in terms of aroma. There is a significant different between samples A, B and the remaining samples in terms of colour and taste. On the overall acceptability, samples A, C and D showed no significant difference but the highest mean score was found with sample B. Conclusively, acceptable snack （Pringles） can be produced from cocoyam and wheat in ratio 90%： 10%, respectively.

Study on Preparation of Temperature-sensitive Injectable Hydrogel

To get a sort of new scaffold material for soft tissue reconstruction,we have prepared XLHA-PNIPAAm and XLHA-MC injectable hydrogels through blending crosslinked HA(XLHA) and two temperature-sensitive materials differed in degradation poly(N-isopropylacrylamide)(PNIPAAm) and methylcellulose(MC),respectively.We tested the injectablility,enzymatic biodegradability,temperature-sensitivity,structure cytotoxicity and hemolysis of the two injectable hydrogels.Our research has successfully obtained the preparation condition of XLHA-PNIPAAm injectable hydrogel,and verified that adding non-degradable material PNIPAAm can postpone the degradation of HA more effectively than degradable material MC.PNIPAAm prepared with 5 kGy dose radiation,MBAAm/NIPAAm(M/M)=0.015,monomer concentration=3% produced XLHA-PNIPAAm with slowest enzymatic biodegradability.DSC results showed that temperature-sensitivity of the XLHA-PNIPAAm was more stable than that of XLHA-MC.Two composite hydrogels were qualified in cytotoxicity and hemolysis tests and the biocompatibility of XLHA-PNIPAAm hydrogel showed better than XLHA-MC hydrogel.

Preparation, Characterization and Biological Activity Studies of New Azo Compounds

A new series of azo were derived from 2,5-di（p-amino phenyl）-3,6-diphenyl pyrazine in the presence of benzoic acid, salicylic acid, p-amino salicylic acid, p-methoxy phenol and pmethyl phenol. The structures of the synthesized compounds were determined on the basis of their FTIR, UV （ultraviolet）, elemental analysis and H-NMR （H-nuclear magnetic resonance） spectral date. The purity of synthesized compounds was checked by performing TLC （thin layer chromatography）. The antibacterial activity was evaluated in DMSO （dimethyl sulfoxide）.

离体小鼠股骨骨小梁与骨皮质CT样品制备探索

目的 探索不同的样品制备方法对离体小鼠股骨骨小梁密度(BMD)与骨皮质密度(TMD)CT定量测量的影响。方法 购入6~8周雌性BALA/C小鼠20只,取出40根小鼠股骨浸泡于戊二醛溶液1周,将小鼠股骨随机分为无水合制备组和水合制备组,每组20根。无水合制备组于扫描当天直接从戊二醛溶液中取出离体小鼠股骨,扫描过程中采用直接暴露在空气中。水合制备组于扫描前1天将固定于戊二醛溶液中的离体小鼠股骨放入EP管中,加入纯净水进行12 h水合,扫描过程中内部采用湿润纸巾包裹,外边再包保鲜膜,模拟小鼠股骨在活体的环境下进行显微CT(Mirco-CT)扫描。两组采用完全一致的CT扫描参数,进行重建与分析,对比两组BMD和TMD检测结果。结果 水合制备组BMD检测结果高于无水合制备组,差异有统计学意义(P<0.05);两组TMD检测结果比较,差异无统计学意义(P>0.05)。结论 无水合制备法直接影响了BMD的测量结果准确性,对TMD的测量结果产生的影响较小,使用水合制备法更能保证实验结果的准确性。