原煤和黑液水煤浆燃烧特性的热分析对比研究

在热天平上进行黑液水煤浆和原煤的燃烧、热解实验,得到不同升温速率下的燃烧、热解特性曲线和碳转化率特征曲线。试验结果表明,黑液水煤浆中的钠及其化合物在燃烧过程中催化作用明显,并且黑液中有机物成分对燃烧起到一定促进作用。在20 ℃/min升温速率下黑液水煤浆和原煤的燃烧活化能分别为12.98 kJ/mol和106.59 kJ/mol,反映出黑液水煤浆比原煤有更好的着火特性。     

福建无烟粉煤纸浆黑液富氧流化床催化气化研究

在实验室小型流化床反应器中研究了福建龙岩无烟粉煤纸浆黑液富氧催化气化的特性，考察了纸浆黑液催化剂添加量不同时氧体积分数变化对碳转化率、产气率、煤气组成与热值的影响。结果表明，纸浆黑液催化和富氧气体燃烧的双重作用明显地提高了煤的碳转化率和煤气有效组成；纸浆黑液中钠碱对煤焦气化的催化与对煤灰分中SiO2和Al2O3等氧化物的熔制反应同时发生并存在着竞争；纸浆黑液中钠碱对高温碳与气化剂之间多种反应表现出不同程度的促进。龙岩无烟粉煤在纸浆黑液富氧催化气化时适宜操作条件是氧的体积分数40％和蒸汽/富氧比为1.4kg/m3～2.0kg/m3。碳转化率94％、煤产气率为3.62m3/kg、煤气热值为7.33mJ/m3。     

黑液与石油焦共热解及其产物特性研究

运用热重-红外联用(TGA-FTIR)和扫描电镜(SEM)对黑液与石油焦的共热解过程进行了实验研究,考察了两者在共热解过程中的热失重、挥发性组分释放及固体产物表面形貌特性;同时运用热重(TGA)探究了热解固体产物黑液半焦和石油焦的CO2共气化反应特性。结果表明,在黑液与石油焦共热解过程中,温度低于600℃时,两者的热解相互独立;温度达到600℃之后,相对于黑液和石油焦单独热解的加权平均值,挥发性气体产物CO2和CO的释放峰值温度向低温区移动,失重特性也随之发生变化;800℃下的共热解固体产物表面产生新的形态特征,黑液的烧结得到抑制;850℃下的黑液半焦与石油焦CO2共气化实验表明,两者在共气化过程中存在协同效应,各自的碳转化率和气化速率明显提高,整体碳转化率提高了51.27%,气化反应速率最大值增大了两倍。     

芦苇浆黑液在流化床上的热解实验研究

为了掌握芦苇浆黑液的热解行为,利用流化床在530、580、630、680、730和780 ℃ 六个床温下对芦苇浆黑液在氮气氛围下的热解过程进行了实验研究,分析了床温对气相产物、碳的转化率、NO_x和SO₂的排放浓度、焦油成分和热解焦微观形貌的影响。结果表明,热解气中的主要成分为CO、CH₄、CO₂和H₂,床温的升高有利于H₂和CO的生成,而不利于CH₄和CO₂的生成;可燃气体积分数随着床温的升高而升高,其值从59.2%(530 ℃)升高到66.1%(780 ℃);床温较高时,热解产生的焦油量较少,其中,多环芳烃化合物的相对含量较多,该值在780 ℃时最高为46.88%。     

造纸黑液制取胡敏酸铵

胡敏酸铵是具有类似植物生长刺激素作用的一种肥料,可以提早种籽发芽,促进根系发育,加强植物体内有机物的合成和积累,促进土壤有机质的分解与转化,有利于作物对可溶性养分的吸收,达到农作物增产的目的。在制浆造纸工业中,纤维原料经碱液蒸煮产生大量的黑液,如果直接排入江河,将会污染水源,危害农业和渔业的生产,造成严重的社会公害。在无产阶级文化大革命中,造纸行业广大职工大搞综合利用,利用硫酸盐制浆的黑液制成了农肥胡敏     

黑液水煤浆主要矿物元素在炉内的迁移和沉积行为研究

为了研究黑液水煤浆的灰沉积机理，采用沿烟气行程从实验炉不同部位抽取空间灰粒和提取相应位置炉壁灰渣样相结合的方法，并与常规水煤浆相对比，研究了各主要矿物元素（Na、K、Si、Al、Fe、Ca）在烟气流中的迁移趋势和沉积特性。并且通过X射线衍射（XRD）和扫描电镜（SEM）等分析从微观角度进行了验证。结果表明，与常规水煤浆不同的是，Na、Si、Al的迁移和沉积是引起黑液水煤浆沾污结渣的主要矿物元素，灰沉积物中主要包括无水芒硝、霞石等低熔融温度富Na物相，而Fe的沉积是次要因素。     

混合气气氛下纸浆黑液和钙混合催化剂的催化气化特性

采用热重法在单一和混合催化剂(即3%钙和5%钠-黑液单-催化剂及一种3%钙和5%钠-黑液混合催化剂),温度750℃～950℃及常压条件下对三种高变质无烟煤(福建龙岩、丰海和尤溪煤)研究了混合气气化过程中对碳转化率、气化反应速率及有害污染含硫气体相对量的催化效应.纸浆黑液和钙混合催化剂具有两者的的协同作用,在混合气气化过程中,3%钙和5%钠-黑液混合催化剂可极大地增加碳转化率和气化反应速率系由于该混合催化剂碱性表面化合物[-COM]、[-CO2M]及可交换的钙酚盐和羧酸钙[(-COO)2Ca]的存在加速了反应C 2CO2=2CO和C H2O→CO H2的结果,且这一催化作用比水蒸气气化过程更强烈.通过添加碳酸钙于纸浆黑液催化剂的气化方法,除去促进催化剂功效和增加碳转化率以外,也可达到有效的脱硫作用,但是这一较好的操作温度需低于900℃.     

氧化黑液木素-Mn2+(Cu2+、Zn2+)螯合物稳定性的研究

随着造纸工业的发展 ,造纸黑液的污染愈来愈受到人们的重视。目前 ,人们已采用多种方法来试图消除或降低黑液的污染。其中一重要方法是 :通过酸析法等从造纸黑液中分离出木素 (亦称木质素 ) [1] 。据估计 ,我国造纸厂每年可提取数百万吨的干木素。因此 ,有效地开拓造纸黑液木素的应用途径 ,不仅可以解决造纸厂的后顾之忧 ,更重要的是可为社会提供大量的物质财富 ,成为当今重要的研究课题。最近 ,我们通过氧化黑液木素与无机盐作用制得木素螯合微肥。试验结果表明 :与无机盐相比 ,木素螯合微肥表现出较强的肥效作用 ,这种作用可能与氧化木素…     

麦草造纸黑液中木质素的提取及结构分析

采用有机溶剂萃取的方法从麦草造纸黑液中提取木质素,并采用红外光谱（FT—IR）、^1H NMR、紫外光谱等方法对其结构进行了表征．试验表明,所提取的木质素具有明显的紫丁香基和愈疮木基苯环结构．同时测定了木质素的元素组成和甲氧基含量,并计算得到经典的C9结构模型,其结构形式为C9H8.89O1.17（OCH3）1.39.     

阳离子木素胺的制备及其电泳研究

木质素(木素)存在于植物纤维中,具有复杂空间网状结构,也是造纸黑液的主要污染成分。木素分子中含有-COOH、-OH等活性基团,通过Mannich反应,可把荷正电的有机胺基团接到木素分子结构中,使其电性改变;     

Nano-architecture platinum catalyst layer prepared by electrophoresis deposition for PEM fuel cells

A Pt-loaded carbon black electrode was prepared by pulsed electrophoresis deposition in a Pt colloid solution as a plating bath to overcome the growth problem of a Pt catalyst during deposition in an electrochemical process. This method is a promising technique for preparing Pt catalyst layers at the polymer electrolyte/electrode interface. The particle size of the Pt catalyst loaded by electrophoresis deposition was the same as that of Pt nanoparticles (3–4 nm) in a colloid and the particle size was maintained even during deposition. The loading of the Pt catalyst was controlled by the pH of the Pt colloid and deposition time. The Pt nanoparticles were deposited on a carbon black electrode to a depth of 2.5 μm.     

Separation of fission produced 106Ru and 137Cs from aged uranium targets by sequential distillation and precipitation in nitrate media

Summary Ruthenium-106 and ¹³⁷Cs have been separated from thermal-neutron irradiated UO₃ targets aged for ~2.5 years by distillation and surface interactions in nitrate media of controlled chemical composition. After digestion of the aged targets with their aluminum wrapper in 2M NaOH solution, nitric acid was added to complete dissolution of the formed residue. The prepared fission product solution was separated from ¹²⁹I and 91.8% ¹⁰⁶Ru by sequential distillation from 20% and 40% HNO₃ solutions containing H₂O₂ and KMnO₄, as oxidants, and by boiling for 4 and 2.5 hours, respectively. The recovery yield of ¹⁰⁶Ru collected in 0.1M NaOH solution was ~68.2% with a radionuclidic purity of 399.99%. Thereafter, the fission product solution was brought to pH 9.5 by addition of NaOH solution to precipitate Al(OH)₃, MnO₂, and Na₂U₂O₇ which selectively retained the remaining fission products leaving, mainly, ¹³⁷Cs in the supernatant solution. The recovery yield of ¹³⁷Cs was ≥97.3% with ~99.75% radionuclidic purity. The gamma-ray emitter contaminants which could be detected and identified in the recovered ¹³⁷Cs solution, were ~0.25% ¹³⁴Cs and ~1.4 ^. 10^-3% ^152,155Eu.     

A novel synthesis of chitosan nanoparticles in reverse emulsion

Physical hydrogels of chitosan in the colloidal domain were obtained in the absence of both cross-linker and toxic organic solvent. The approach was based on a reverse emulsion of a chitosan solution in a Miglyol/Span 80 mixture, generally regarded as safe. Temperature and surfactant concentration were optimized, and the impact of the degree of acetylation (DA) and the molar mass of chitosan was investigated. When chitosan had a DA above 30%, only macroscopic gels were obtained, because of the predominance of attractive Van der Waals forces. The lower the molar mass of chitosan, the better the control over particle size and size distribution, probably as a result of either a reduction in the viscosity of the internal aqueous phase or an increase in the disentanglement of the polymer chain during the process. After extraction and redispersion of the colloid in an ammonium acetate buffer, the composition of the particles was around 80% of pure chitosan corresponding to a recovery of 60% of the original input. These new and safe colloids offer wide perspectives of development in further applications.     

Zeta Potential,Size, and Semiconductor Properties of Zinc Sulfide Nanoparticles in a Stable Aqueous Colloid Solution

A stable aqueous colloid solution of zinc sulfide (ZnS) nanoparticles was obtained by chemical condensation using ethylenediaminetetraacetic acid disodium salt. The mechanism of prolonged aggregative stability of solution at pH 7–8 with ~7-nm nanoparticles was determined as a result of the zeta potential measurements by dynamic light scattering. The blue and red shifts of the fundamental absorption edge of zinc sulfide semiconductor nanoparticles associated with the small size of nanoparticles and the defective state of their surface were found by optical spectrophotometry.     

Determination of cadmium in grains by isotope dilution ICP–MS and coprecipitation using sample constituents as carrier precipitants

A coprecipitation method using sample constituents as carrier precipitants was developed that can remove molybdenum, which interferes with the determination of cadmium in grain samples via isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). Samples were digested with HNO₃, HF, and HClO₄, and then purified 6 M sodium hydroxide solution was added to generate colloidal hydrolysis compounds, mainly magnesium hydroxide. Cadmium can be effectively separated from molybdenum because the cadmium forms hydroxides and adsorbs onto and/or is occluded in the colloid, while the molybdenum does not form hydroxides or adsorb onto the hydrolysis colloid. The colloid was separated by centrifugation and then dissolved with 0.2 M HNO₃ solution to recover the cadmium. The recovery of Cd achieved using the coprecipitation was >97%, and the removal efficiency of Mo was approximately 99.9%. An extremely low procedural blank (below the detection limit of ICPMS) was achieved by purifying the 6 M sodium hydroxide solution via Mg coprecipitation using Mg(NO₃)₂ solution. The proposed method was applied to two certified reference materials (NIST SRM 1567a wheat flour and SRM 1568a rice flour) and CCQM-P64 soybean powder. Good analytical results with small uncertainties were obtained for all samples. This method is simple and reliable for the determination of Cd in grain samples by ID-ICPMS. Figure Overview of a coprecipitation method using sample constituents     

Luminescent silole nanoparticles as chemoselective sensors for Cr(VI)

Colloidal suspensions of 3-aminopropylmethyl(tetraphenyl)silole nanoparticles can be used as selective chemosensors for carcinogenic chromium(VI) analyte. Methylhydrosilole is functionalized by hydrosilation of allylamine, and the colloid is prepared by the rapid addition of water to a THF solution of the silole. The method of detection is through electron-transfer quenching of the fluorescence of the silole colloid (lambda(em) = 485 nm at 360 nm excitation) by the analytes, with hundred parts per billion detection limits. Stern-Volmer plots are linear up to 10 ppm in the case of chromium, but exhibit saturation behavior near 5-10 ppm for arsenic. Dynamic light scattering experiments and AFM measurements show the particle sizes to be around 100 nm in diameter and dependent on solvent composition, with a particle size dispersity of +/-25%. The fluorescence lifetimes of the silole in solution and colloid are approximately 31 ps and approximately 4.3 ns, respectively, while the silole has a lifetime of 6 ns in the bulk solid. A minimum volume fraction of 80% water is necessary to precipitate the colloid from THF, and the luminescence continues to rise with higher water fractions. Colloids in a pH 7 phosphate-buffered suspension show both higher sensitivity and greater selectivity (100-fold) for CrO4(2-) detection than for other oxoanion interferents, NO3-, NO2-, SO4(2-), and ClO4-.     

负电性纳米银的制备及性质研究

制备了一种表面带负电的胶态纳米银,用透射电镜、吸收光谱、 SERS谱对该纳米银进行了研究.发现纳米银的粒径分布均匀,平均粒径为11 nm,吸收峰为422 nm,常温下放置7个月仍具有较强的SERS活性.当阴离子型分子吲哚丁酸、阳离子型分子碱性品红、亚甲兰及中性分子邻菲罗邻分别吸附在其上时,观察到阳离子型分子碱性品红和亚甲兰及中性分子邻菲罗邻的SERS谱,而阴离子型分子吲哚丁酸则无SERS谱出现.     

茜素红可见分光光度法测氯霉素的含量

研究了氯霉素与茜素红之间的络合反应,确定了最佳反应条件,建立了一种快速、简便测定氯霉素含量的可见分光光度法。研究表明,在pH=11.41的B-R介质中,氯霉素与茜素红在室温条件下即可形成1∶1型络合物,该络合物的λmax=474 nm,表观摩尔吸光系数ε为1.19×104L/(mol.cm)。氯霉素的浓度在2.0×10-7～3.0×10-5mol/L范围内服从比耳定律,相关系数r为0.9985。测定结果的相对标准偏差为0.86%(n=10),回收率为99.4%～101.2%。     

Electrochemical behavior and composition of bismuth sulfide coatings

Cyclic potentiodynamic voltammetry and X-ray photoelectron spectroscopy were used to study the electrochemical behavior and composition of bismuth sulfide coatings deposited by successive ionic layer adsorption and reaction on glassy carbon in a colloid solution of bismuth(III) compounds, with Na₂S as a sulfidizing agent.     

聚丙烯酰胺母液过滤袋更换周期的影响因素

在聚丙烯酰胺(HPAM)过滤袋内发现大量缠结在一起的高分子线团、黄色胶状物、黑色黏稠物等杂质;这些物质导致滤袋堵塞、过滤效率降低、滤袋内压差增大,最终使得滤袋胀破.目前的解决方法为短期更换滤袋,难以从根本上解决问题.为此,分析了HPAM母液过滤袋更换周期的影响因素,探讨了延长滤袋更换周期的可行性.结果表明,针对聚丙烯酰...