水热法合成NaP1型粉煤灰沸石的性能表征

通过碱性介质中的水热反应,由粉煤灰合成了单一沸石矿物种的NaP1沸石,并对合成产品进行了表征.经粉晶X射线衍射鉴定,合成产物中主要矿物成分为NaP1沸石,另有少量尚未反应的石英和莫来石.在电子显微镜下,粉煤灰颗粒呈球形且表面光滑,而合成产物颗粒表面粗糙.粉煤灰合成沸石含有大量的交换性Ca2 ,且与粉煤灰原料相比,SiO2含量明显减少,Al2O3稍有增加,SiO2/Al2O3比值由3.3降至1.8.红外光谱分析和差热分析证实了合成的粉煤灰沸石中沸石水的存在.NaP1型粉煤灰沸石的阳离子交换容量(CEC)达213 cmol/kg,比表面积达29 m2/g,分别比粉煤灰高约100倍和26倍.     

合成条件对粉煤灰合成沸石过程中沸石生成和品质的影响

系统研究了由粉煤灰合成沸石过程中温度、反应时间、液固比和NaOH浓度等合成条件对沸石生成及其阳离子交换容量(CEC,CationExchangeCapacity)的影响.结果表明,温度主要影响沸石矿物的结晶度;液固比主要影响沸石种类;NaOH浓度和反应时间对两者均产生明显影响.合成产物的CEC随温度、液固比、反应时间呈快速增加,并在分别达到110℃、2.5和16h时趋于一最大值.NaOH浓度越高,合成产物CEC也越高,至2mol·L^-1时达到最大,之后显著下降.考虑到合成成本,最佳合成条件初步归纳为:温度110-120℃,反应时间8-16h,液固比2.5,NaOH浓度2mol·L^-1.     

添加La2O3对粉煤灰合成Al2O3-SiC复合粉体的影响

以粉煤灰和活性炭为原料,通过碳热还原反应在Ar气氛下合成Al_2O_3-SiC粉体,探究了一条低成本合成Al_2O_3-SiC粉体的可行途径。研究了添加La_2O_3对合成过程的影响。采用XRD和SEM表征了材料的物相组成和显微形貌。结果表明:当粉煤灰与活性炭质量比为100∶44,在1 550℃下保温5h,添加6%(质量分数)的La_2O_3时,可合成性能良好的Al_2O_3-SiC粉体,颗粒分布均匀,平均粒径为0.5~1μm,较不添加La_2O_3合成温度降低约50℃。     

粉煤灰基地聚物水泥的改性及其对Pb(Ⅱ)吸附的研究

为了解决过多向自然界排放含有重金属的废物,造成生态环境破坏问题,根据地聚物水泥具有很好的吸附性能及在处理含有铅废物方面特殊作用,本实验中添加天然沸石对粉煤灰基地聚物水泥改性,通过XRD证明有结晶的沸石相P型沸石结晶和方沸石出现,并用静态吸附试验证明改性后吸附能力增强,探讨了地聚物水泥水化产物粉体对铅的吸附性能及其主要影响因素。     

Comprehensive Characterization of Pond Ash and Pond Ash Slurries for Hydraulic Stowing in Underground Coal Mines

In this study, the physicochemical and self-heating characteristics of pond ashes from Talcher Thermal Power Station (TTPS), located in the Angul district of the Indian state of Odisha are studied. The study revealed that the TTPS pond ashes belong to Class F fly ash category consisting mainly of SiO₂, Al₂O₃, and Fe₂O₃, with a small amount of CaO. The presence of mineral phases, namely, quartz, mullite, magnetite, and hematite in the pond ash are confirmed by x-ray diffraction. Based on the pond ash properties, various properties of the slurries of one representative pond ash, namely, density, volume concentration, and viscosity are determined by varying the ash concentration from 45% to 65% with an increment of 5%. As well, the critical deposition velocities of slurries as a function of slurry concentration and pipe diameter are determined. The results showed that the slurry viscosity increases exponentially with increase in solid content and the critical velocity increases linearly with increase in slurry concentration and pipe diameter. The relationships generated through regression analysis can be used to quickly predict the critical velocity of similar types of ash slurries for any known slurry concentrations and pipe sizes.     

Synthesis of Na-X zeolite from low aluminum coal fly ash: Characterization and high efficient As(V) removal

Na-X zeolite was successfully prepared from low aluminum coal fly ash (LACFA) via fusion-hydrothermal treatment. The influence of various synthesis parameters was investigated, including aluminum additives (AlCl₃·6H₂O, Al(NO₃)₃·9H₂O, AlF₃·3H₂O and NaAlO₂), dosages of NaAlO₂, weight ratio of LACFA/NaOH, crystallization temperature and time. The results indicated that the addition of Al species played a key role in the synthesis process of purity Na-X zeolite, and the corresponding relative crystallinity of the obtained samples was in the order of Na-X zeolite_(Al)???Na-X zeolite_(Cl)?>?Na-X zeolite_(N)?>?Na-X zeolite_(F) (Here, “Al”, “Cl”, “N” and “F” represent NaAlO₂, AlCl₃·6H₂O, Al(NO₃)₃·9H₂O and AlF₃·3H₂O, respectively). And the optimal operating conditions were: the weight ratio of LACFA/NaOH?=?0.83, short crystallization time 360?min, low crystallization temperature 90?°C and 0.038?mol NaAlO₂. Additionally, X-ray fluorescence (XRF), X-ray powder diffraction (XRD), Fourier Transforms Infrared (FT-IR) and Scanning Electron Microscopy (SEM) were employed to determine the resultant samples. Based on the results of As(V) adsorption experiment, the experimental data was suitable fitted by Freundlich adsorption isotherm model, and the theoretical maximum adsorption capacity was 27.79?mg/g at pH?=?2.14. The kinetics studies suggested that “surface reaction” was the rate-determining step of adsorption process, and the thermodynamics studies indicated that the adsorption process was spontaneous and endothermic. These results deemed that the LACFA was suitable for preparing Na-X zeolite_(Al), and the obtained Na-X zeolite_(Al) was served as a promising adsorbent to remove As(V) from acid wastewater.     

油页岩渣水热法合成沸石及其性能表征

以油页岩渣为原料,采用NaOH熔融水热合成法和NaOH溶液水热合成法合成了沸石.利用X射线图谱、FT-IR图谱和Cr6+吸附实验探讨了样品的结构及吸附性能.结果表明,NaOH熔融水热合成法合成的为Na-A型和SOD型沸石混合物,NaOH溶液水热合成法合成的为Na-P型和SOD型沸石混合物;2种合成方法对Cr6+的吸附率相差不大,考虑到合成的成本,选用NaOH溶液水热合成法;随着NaOH溶液浓度的增加,产品对Cr6+的吸附率增大,当NaOH溶液浓度为8mol/L时,吸附率可达到89.1%.     

高岭土合成4A分子筛及其表征

采用ＴＧ－ＤＴＡ、ＸＲＤ、ＳＥＭ等现代测试技术以及测定钙离子交换量的方法研究了焙烧高岭土与碱液作用制备４Ａ分子筛的反应过程,给出了采用高岭土制备４Ａ分子筛扔最佳条件,并提出了以焙烧高岭土合成的４Ａ分子筛其形成机理应以异相成核为主,焙烧高岭土的碱液溶解为融洽上合成过程的控制步骤的新观点。     

掺粉煤灰和不同外加剂对水泥水化放热过程的影响

通过水化热测量研究了掺加缓凝型减水剂、引气剂和粉煤灰对硅酸盐水泥的水化放热过程的影响。结果表明,掺入缓凝型减水剂能不同程度地延缓水泥的水化放热过程,降低水泥的水化热,掺入引气剂对水泥水化放热几乎没有影响,而掺粉煤灰可显著降低水泥水化热。     

微生物絮凝剂与粉煤灰联合处理水中pb2+的响应面优化

目前,用微生物絮凝剂(MBF)与粉煤灰联合处理重金属的方法鲜有报道.从内蒙古地区盐碱地中筛选出一株具有较高絮凝活性的菌株HG6,16S rDNA鉴定为Oceanobacillus polygoni,以其制备出MBF.采用BBD(box-behnken design)法研究了MBF与粉煤灰联合去除废水中pb2+的最佳条件组合,设定响应值为pb2+的去除率,方差分析显示,模型F值为17.30,P=0.000 5,相关系数R2 =0.901 7,拟合模型极显著.在最优条件:粉煤灰投加量1.46 g/L,MBF投加量0.888 g/L,CaCl2投加量15.6 mL/L(1％,w/V)时,测得pb2+的去除率达到99.75％.通过傅里叶变换红外光谱、Zeta电位分析发现,MBF-HG6与粉煤灰对pb2+的捕集过程中存在电中和及吸附架桥作用机理.     

粉煤灰制备SiO_2气凝胶及其复合材料的研究进展

气凝胶材料因其具有独特的性能而成为当今国际新材料领域的研究热点。简要分析了我国目前的粉煤灰利用状况,详细综述了国内外利用粉煤灰为硅源,采用溶胶-凝胶法和常压干燥法制备SiO2气凝胶材料的研究进展,列举了SiO2气凝胶在各个领域的应用现状,指出了当前研究中存在的问题以及未来的研究方向,并展望了利用粉煤灰制备SiO2气凝胶材料的研究与应用前景。     

垃圾焚烧炉渣-粉煤灰复合水泥的性能研究

研究了垃圾焚烧炉渣及粉煤灰单掺和复掺时硬化水泥浆体的力学性能和水化机理,比较了两者的活性,探讨了两者作为辅助性胶凝材料利用的可行性.研究表明:掺有垃圾焚烧炉渣及粉煤友的复合水泥,其强度均有不同程度的下降,它们的掺入在一定程度上延缓了水泥的水化过程,且垃圾焚烧炉渣的水化反应活性稍高于粉煤灰;掺垃圾焚烧炉渣及粉煤灰的复合水泥中重金属离子浸出量小,在等掺20%的条件下,浸出量远低于国家标准,说明在一定的情况下,焚烧炉渣及粉煤灰作为辅助性胶凝材料使用是安全的.     

粉煤灰激活中ATR/FTIR、FTIR和NMR的分析与比较

采用ATR/FTIR对南京热电厂Ⅰ级粉煤灰及经过NaOH激发后的样品进行了分析，并且同FTIR和NMR的分析结果进行比较。研究结果表明：以表征表面特征的ATR/FTIR方法可以清晰地表征粉煤灰表面出现的变化，且随着碱浓度的提高变化明显，而以表征宏观几率特征的FTIR和NMR则没有反映出粉煤灰表面出现的变化。ATR/FTIR在粉煤灰的表面研究中具有独到效果。     

Infrared optical properties of calcium lanthanum sulfide

The fundamental infrared optical properties of CaLa₂S₄ were determined by specular reflectance measurements from theoretically dense, optically transparent, polycrystalline ceramics. Kramers-Kronig transformation of the reflectance spectra permitted the extraction of refractive index, and transverse and longitudinal optic modes. Five transverse modes predicted by factor group analysis were observed with the intense high wavenumber mode occurring at 142 and 205 cm^− 1. The other three modes are weak and occur at 37, 59, and 86 cm^− 1. The two high wavenumber intense modes have identifiable longitudinal modes at l51 and 318 cm^− 1.     

Synthesis,Characterization and Photocatalytic Activity of TiO_2 Film/Bi_2O_3 Microgrid Heterojunction

TiO2 film modified by Bi2O3 microgrid array was successfully fabricated by using a microsphere lithography method.The structure and morphology of TiO2 film,Bi2O3 film and TiO2 film/Bi2O3 microgrid heterojunction were characterized through X-ray diffraction,atomic force microscopy and scanning electron microscopy.The optical transmittance spectra and the photocatalytic degradation capacity of these samples to rhodamine B were determined via ultraviolet-visible spectroscopy.The results indicated that the coupled system showed higher photocatalytic activity than pure TiO2 and Bi2O3 films under xenon lamp irradiation.The enhancement of the photocatalytic activity was ascribed to the special structure,which could improve the separation of photo-generated electrons and holes,enlarge the surface area and extend the response range of TiO2 film from ultraviolet to visible region.     

Glowing Combustion Synthesis,Characterization, and Toxicity Studies of Na2CaSiO4 Powders

Here, we are reporting the glowing combustion synthesis of Na₂CaSiO₄ powders for the first time at low temperature. L-alanine was used as reductant, and nitrates of sodium and calcium were used as oxidants. Phase evolution and formation was studied using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Thermo gravimetric analysis-Differential thermal analysis (TGA–DTA) techniques. Powder morphology and particle size distribution were characterized using scanning electron microscopy (SEM), dynamic light scattering (DLS) techniques. Results confirms the formation of single phasic, microcrystalline sodium calcium silicate (Na₂CaSiO₄ phase) in cubic crystal system. Evaluation of hemolysis and (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) (MTT) tests suggest that Na₂CaSiO₄ powders exhibit negative response in in vitro conditions.     

粉煤灰活性硅铝的微波制样快速测定方法

讨论了粉煤灰活性硅铝测定中加热回流制样方法的不足和采用微波技术制样的原理与关键参数.试验研究了影响粉煤灰活性硅铝测定的微波制样功率和时间,与加热回流制样的测定结果比较表明,采用210W微波处理15min制样所测定的活性硅铝结果与加热回流方法制样所测得的相当.确定粉煤灰活性硅铝测定中微波制样条件为210W微波处理15min,微波制样可用于快速测定粉煤灰活性硅铝.     

稻壳灰制备TiO2-SiO2复合载体脱硝催化材料

鉴于农业废弃物稻壳灰中非晶态硅含量高的特点,以稻壳灰为原料,采用共沉淀法制备了以TiO₂-SiO₂复合材料为载体,锰、铈为活性组分的脱硝催化材料。探究了SiO₂的添加对催化材料微观结构的影响,并对不同硅含量催化材料的脱硝机理进行了相关分析。实验结果表明,与纯TiO₂为载体的催化材料相比,TiO₂-SiO₂复合材料为载体的催化材料表面颗粒大小均匀,呈蓬松状态堆积,比表面积及孔容都有所增加,弱酸性位点的数量也大大增加,当SiO₂与TiO₂的物质的量比为4∶1时,催化材料的脱硝效率可达90%以上。