用煤矸石酸浸液微波加热制备聚硅酸硫酸铝铁

研究了用煤矸石酸浸液在微波加热条件下制备聚硅酸硫酸铝铁(PSAFS),并用PSAFS处理模拟废水。考察了聚硅酸活化pH、陈化时间、体系pH、铁铝及铁硅的物质的量比、微波功率、微波加热时间对制备PSAFS性能的影响。结果表明,在聚硅酸活化pH=1.9、陈化时间20 min、pH=1.2、n(Fe~(3+))/n(Al~(3+))=1/1、n(Fe~(3+))/n(SiO_2)=9/1、微波功率380 W、微波加热时间3 min条件下,可获得PSAFS;XRD及FT-IR分析结果表明,制备的聚合产物主要为无定形PSAFS。     

Enhanced photoluminescence property of sulfate ions modified YAG:Ce~(3+) phosphor by co-precipitation method

The sulfate ions modified YAG:Ce~(3+) phosphors were prepared by co-precipitation method and characterized by X-ray diffraction,transmission electron microscopy,and photoluminescence.Effects of sulfate ions on the photoluminescence(PL) property of the as-prepared YAG:Ce~(3+) phosphors were studied,with sodium dodecyl sulfate(SDS) being added to R~(3+)(Ce~(3+),Y~(3+),Al~(3+)) ions.Results indicated that pure YAG:Ce~(3+) phosphors with different ratios of sulfate ions could be easily obtained by calcining the as-synthesized precursor at 950 ℃ for 2 h,the YAG:Ce~(3+) phosphors with an optimal mass ratio of 3.5 wt.%SDS had the highest emission intensity and the best dispersion behavior,and the fluorescence decay of the as-obtained YAG:Ce~(3+) phosphors was related to the lattice defect,reabsorption and cross correlation.Furthermore,thermal quenching properties of the YAG:Ce~(3+) phosphors and the YAG:Ce~(3+) phosphors with 3.5 wt.%SDS were also discussed,indicating that the YAG:Ce~(3+) with SDS phosphors could have potential applications in the daylight LEDs or warm white LEDs.     

Photoluminescence properties of YAG:Ce~(3+),Pr~(3+) nano-sized phosphors synthesized by a modified co-precipitation method

Monophasic Ce~(3+) and Pr~(3+) co-doped yttrium aluminum garnet(YAG:Ce~(3+),Pr~(3+)) nanoparticles with good dispersity and uniform grain sizes in the range of 50–80 nm were prepared by a two-step route, which consisted of a modified co-precipitation preparation of mixed metal hydroxide hydrate intermediates at low temperature of about 40 oC and a subsequent calcination conversion of the synthesized intermediates to crystalline nanoparticle products at about 1000 oC. The influences of both the lanthanide ion(Ce~(3+) and Pr~(3+)) doping concentration and different doping(Ce~(3+)/Pr~(3+)) ratio on the photoluminescence intensity were systematically investigated. The synthesized (Ce_(0.6)Pr_(0.4))_(0.04)Y_(2.96)Al_5O_(12) nanoparticles were near spherical nanoclusters with good dispersity and uniform sizes in the range of 50–80 nm for about 85% of the particles. The strongest photoluminescence intensity was observed for the (Ce_(0.6)Pr_(0.4))_(0.04)Y_(2.96)Al_5O_(12) nanoparticle products.     

碱中毒对烧结烟气SCR催化剂脱硝脱二噁英的影响

采用湿式浸渍法对商用V_2O_5-WO_3/TiO_2催化剂进行了碱金属硫酸盐(Na/K/Rb)中毒实验。在模拟铁矿烧结烟气条件下,对比了新鲜和中毒催化剂同时脱除NO_x和二噁英的活性(以氯苯作为二噁英的模拟物),并通过N_2吸脱附、XRD、NH_3-TPD、H_2-TPR和XPS等检测手段对催化剂进行了表征。结果表明:中毒催化剂的脱除NO_x和催化降解氯苯活性明显降低,失活率顺序为K_2SO_4Rb_2SO_4Na_2SO_4。催化剂中毒后,碱金属离子可以占据催化剂表面化学吸附氧空位,导致表面化学吸附氧数量减少,物质的量之比n(V~(5+))/n(V~(4+))降低,V物种可还原性减弱。     

A fluorescent probe based on a spiropyran for sensitive detection of Ce~(3+) ion

A spiropyran-based probe was developed.It serves as a fluorescence turn-on probe for selective detection of Ce~(3+) in both ethanol and aqueous(water/ethanol,1:9 or 9:1,v/v) media.Ce~(3+) can induce photochromism of the probe though the probe exhibits negligible photochromic property by itself.The probe is sensitive to Ce~(3+) and the detection limit reaches 1.7 μmol/L.It exhibits a high selectivity for Ce~(3+)ion over other common metal cations including Li~+,Na~+,Ag~+,Sr~(2+),Ni~(2+),Co~(2+),Hg~(2+),Zn~(2+),Cr~(3+),Al~(3+),Fe~(3+) and Bi~(3+) and lanthanide ions Nd~(3+),Yb~(3+) and La~(3+).The probe may be used for quantitative determination of the concentration of Ce~(3+) ion in a range of 1-10 μmol/L and for application to environmental water samples.Sensing mechanism of the probe towards Ce~(3+) ion is proposed.     

Color-tunable Ca10Na(PO4)7:Ce3+/Tb3+/Mn2+ phosphor via energy transfer

A series of Ca_(10)Na(PO_4)_7:Ce~(3+)/Tb~(3+)/Mn~(2+)(CNPO:Ce~(3+)/Tb~(3+)/Mn~(2+)) phosphors with high brightness were synthesized by high-temperature solid-state method. X-ray diffraction(XRD), scanning electron microscopy(SEM), diffuse reflectance spectra(DRS), photo luminescence(PL) spectra, luminescence decay curves and thermally stability were performed to characterize the as-prepared samples. For Ce~(3+)-doped samples, an intense and broad band emission is present under 265 nm excitation. When Ce~(3+) and Tb~(3+)are codoped, energy transfer(ET) process from Ce3+ to Tb3+ is demonstrated with electric dipole-dipole interaction. The internal and external quantum efficiencies(QEs) of CNPO:0.15 Ce~(3+), 0.04 Tb~(3+), 0.005 Mn~(2+)are measured to 76.79% and 54.11% under 265 nm excitation and temperature-dependent PL intensity can remain 51.78% at 150 ℃ of its initial intensity at 25 ℃. It is indicated that single-phased white lightemitting CNPO:Ce~(3+)/Tb~(3+)/Mn~(2+) phosphor can serve as a promising phosphor for illumination devices.     

pH值对浸渍法制备的铈钨钛脱硝催化剂的影响

通过调变分步浸渍法制备过程中的溶液pH值,制备了一系列的铈钨钛复合金属氧化物催化剂,以研究它们在NH_3-SCR(NH_3-Selective catalytic reduction)反应中的脱硝表现。重点考察了催化剂制备过程中溶液的pH值的变化对脱硝催化剂的影响。XRD表征结果显示,提高pH值有利于氧化钨在催化剂表面的高分散。XPS分析、NH_3-TPD分析及NH_3-SCR活性测试的结果显示,随着制备过程中pH值的增大,催化剂的表面W原子浓度、Ce~(3+)/Ce~(4+)比、O_α/O_β比、表面酸量或NO_x转化率都呈现先上升然后趋缓(或略降低)的变化趋势。高分散的WO_3物种与CeO_2物种之间的相互作用及表面W原子浓度一定程度的升高被认为是催化剂脱硝活性上升的主要原因。在pH=9的条件下制得的铈钨钛复合金属氧化物催化剂展现了最优的SCR脱硝活性,并在300℃～450℃范围内NO_x转化率保持在90%以上。     

铈组轻稀土离子La~(3+)、Ce~(3+)、Pr~(3+)在卤化银感光乳剂中的掺杂效应

铈组轻稀土离子La~(3+)、Ce~(3+)、Pr~(3+)在碘溴化银照相乳剂中掺杂,将影响该乳剂的感光性能。La~(3+)的表面掺杂导致乳剂减感,其重要原因之一在于La~(3+)的加入使乳剂相对吸收光能量减低,对卤化银光解产生不利影响;Ce~(3+)的体相掺杂使乳剂增感,可归因于Ce~(3+)在碘溴化银中起到了深化电子陷阱的作用,从而有利于潜影形成与集中;Pr~(3+)则无论是体相掺杂或表面掺杂都具有提高乳剂感光度和反差的作用,但体相掺杂较表面掺杂还有降低灰雾的效果。     

Luminescence of emission-tunable Na_(15.6)Ca_(3.84)Si_(12)O_(36):Ce~(3+),Tb~(3+),Na~+ phosphors for near-ultraviolet light-emitting diodes

A series of Na_(15.6)Ca_(3.84)Si_(12)O_(36):Ce~(3+),Tb~(3+),Na~+(NCS:Ce~(3+),Tb~(3+),Na~+) phosphors were prepared by conventional solid-state reaction method, and their photoluminescence properties under near-ultraviolet(NUV) excitation were studied. The excitation spectrum of Ce~(3+)-single-doped NCS showed a broad excitation band from 250 to 400 nm, which could well match with the emission wavelength of the NUV LED chip. Upon 365 nm excitation, the NCS:Ce~(3+),Na~+ phosphor demonstrated a blue emission in the range of 400–600 nm with the predominated peak at 443 nm. By co-doping Tb~(3+) into NCS:0.04Ce~(3+),0.04Na~+, tunable-emission was realized due to the energy transfer from Ce~(3+) to Tb~(3+), and nearly white light was also obtained. The investigation also revealed that warm white light could be further generated by combining the NCS:0.04Ce~(3+),y Tb~(3+),(0.04+y)Na~+ with other red-emitting phosphors. Thus, the NCS:Ce~(3+),Tb~(3+),Na~+ phosphors could be promising candidate for white LEDs.     

Synthesis and luminescence properties of novel Ce3+-doped Yb3Al5–xGaxO12 garnets with very fast decay time

A novel series of Ce~(3+)-doped Yb_3 Al_(5-x)Ga_xO_(12)(x = 0, 1,2, 3,4, 5) powders of ytterbium aluminum gallium garnets were synthesized by high temperature solid-state reaction in a carbon reducing atmosphere. The ytterbium aluminum garnets were characterized by X-ray powder diffraction, UV-Vis diffuse reflectance spectra, photoluminescence spectra and decay curves. Moreover, the substitution effect for the Al~(3+) sites with Ga~(3+) in 0.5 at%Ce:Yb_3 Al_(5-x)Ga_xO_(12)(x = 0,1, 2, 3, 4, 5) garnets were discussed. With the increase of Ga~(3+) ion concentration, the visible absorption peaks within 400-450 nm have blue shift phenomenon,while the absorption peaks in the range of 330-350 nm and the absorption band edge red shifts.Furthermore, the short decay times are very short with less than 10 ns due to the Yb~(3+) + Ce~(3+)→ Yb~(2+) + Ce~(4+) electron transfer reaction.     

特殊离子对嗜酸性铁氧化混合菌活性的影响研究

为了探明铀矿浸出过程中不同氧化剂处理所得的吸附尾液对浸矿液制备体系中嗜酸性铁氧化混合菌的影响机制,本研究利用实际浸矿尾液作为培养基,以Acidithibacillus ferrooxidans,Leptospirillum ferrooxidans及Acidithibacillus thiooxidans等为主的3种混合菌种作为受试材料,通过批示实验研究含不同浓度Cl~-, Al~(3+)和Mn~(2+)的浸铀尾液体系对混合菌生长和铁氧化活性的影响。结果表明:混合菌在各离子类型尾液中的生长呈现为二段式生长,且抑制效应主要表现于延滞期阶段,其中Mn~(2+)和Al~(3+)所导致的抑制属于多代次培养后可适应的影响因素,延滞期依次:0～300 h (Cl~-), 10～30 h (Al~(3+))和10～30 h (Mn~(2+));各离子对混合菌铁氧化活性的影响差异较大,其抑制率由大到小的顺序为Cl~-Al~(3+)Mn~(2+);高含量的离子抑制混合菌的生物铁氧化能力, 741 mmol·L~(-1)的Al~(3+)或1092 mmol·L~(-1)的Mn~(2+)或192 mmol·L~(-1)的Cl~-能完全抑制混合菌的生长。研究结果将为推动铁氧化细菌在浸矿尾液再生体系内的稳定应用进程提供理论指导和实验支持。     

Synthesis and application of biocompatible nontoxic nanoparticles for reclamation of Ce3+ from synthetic wastewater: Toxicity assessment,kinetic, isotherm and thermodynamic study

The aim of present study is to synthesize forsterite nanoparticles(FRST) for the reclamation of cerium ions(Ce~(3+)) from synthetic wastewater.The aim to synthesize FRST nanoparticles is due to its biocompatible and nontoxic nature.The formation of nanoparticles with average diameter of 58 nm was confirmed by TEM analysis.SEM images of bare FRST nanoparticles show a heterogeneous surface with porous nature.BET surface area of FRST nanoparticles is calculated to be 33.69 m~2/g.The significant uptake of Ce~(3+) ions can be obtained for all the selected concentrations(25-150 mg/L) within 2 h of adsorbent—adsorbate interaction.The pH study shows that by increasing pH from acidic to alkaline range,higher removal can be achieved.Temperature study demonstrates the endothermic nature of Ce~(3+)adsorption.The value of sticking probability suggests very high sticking probability of Ce~(3+) ion for FRST nanoparticles.Ce~(3+) uptake is favored by higher temperature and with the increase in temperature from298 to 328 K,Langmuir adsorption capacity increases from 36.45 to 42.99 m~2/g.Applicability of FRST nanoparticles was also investigated for other light and heavy rare earth elements in single solute and multisolute systems,FRST nanoparticles show the significant removal of divalent metallic pollutants as well.The assessment of chemical toxicity of treated wastewater was carried out with the bioluminescent photobacterium(Vibrio fischeri) and decreased toxicity was observed in treated water samples.The outcome of present study suggests that the FRST nanoparticles can be efficiently utilized for the removal of Ce~(3+) ions and a wide range of other pollutant species as well.     

化学溶液法在LaAlO3单晶基体上制备YBa2Cu3O7-x薄膜的研究

采用三氟乙酸盐-金属有机沉积(TFA-MOD)法在LaAlO3单晶基体上成功地制备了YBa2Cu3O7-x超导薄膜(简称YBCO薄膜),并比较系统地研究了烧结温度对YBCO薄膜的影响。在烧结温度为820℃时,所制备的YBCO薄膜完全呈c-轴取向,无a-轴取向的晶粒和杂质相存在,YBCO薄膜的表面无裂纹存在,表面平整,超导转变温度Tc≈90K,转变宽度ΔTc=1K,临界电流密度(Jc)可达1.2MA.cm-2(77K,0T)。     

ScF_3的水热法制备及掺Ce~(3+)光谱性质研究

首次用低温水热法制备了ScF_3晶体及其掺杂Ce~(3+)的粉体.通过X射线粉末衍射(XRD),扫描电镜(SEM),荧光光谱(FS)对样品进行了表征.结果表明,所用氟化物的种类和反应温度对ScF_3的制备至关重要.以NaF作为原料更容易得到纯的ScF_3.当水热温度为120℃时,产物为ScF_3晶体,而温度升高至180℃时则为NaScF4复合氟化物.所制备的ScF_3呈针尖棒状放射形.考察了ScF_3:Ce~(3+)粉体荧光光谱性质,讨论了其与同类型的稀土氟化物的荧光光谱的比较.     

共沉淀法制备多孔纳米氟氧钇粉体及其性能研究

利用共沉淀法制备了具有稀土离子掺杂的氟氧钇(YOF∶Yb~(3+),Ho~(3+))多孔材料,并对其显微组织形貌、相结构、荧光性质、吸附能力以及表面润湿性进行了分析。结果表明,该纳米粉体颗粒具有尺寸小、均一性高的特点;其荧光发射能力随Ho~(3+)的增加逐渐降低,且荧光寿命较高;煅烧后多孔颗粒的表面积可达413.67m~2/g,其吸附性能及表面润湿性良好。     

射频磁控溅射制备Ba0.7Sr0.3TiO3薄膜的表面结构调控

研究了Pt/Ti/SiO2/Si基片上制备Ba0.7Sr0.3TiO3(BST7/3)薄膜时,基片加热温度和溅射功率对薄膜显微形貌和成相的影响。实验结果表明:常温下低功率溅射的BST7/3薄膜,表面形貌非常平整,但为非晶态物质的堆积;400℃高功率150 W溅射4 h的BST薄膜,其最大表面起伏约为40 nm;400℃低功率、长时间8 h溅射的BST薄膜,其表面起伏约为12 nm;说明在保证BST充分成相的前提下,可以通过控制溅射功率和时间调控BST薄膜的表面形貌,降低表面粗糙度,使之适于后续器件制备工艺。介电性能测量表明,400℃,75 W,8 h溅射获得的BST7/3薄膜体现出典型的位移型铁电体特征;1 kHz薄膜的损耗约为0.04。     

阳离子对嗜酸氧化亚铁硫杆菌氧化活性的影响

以嗜酸氧化亚铁硫杆菌(Acidthiobacillus ferrooxidans,At.f,FN811931)为研究对象,研究了脉石矿物溶出阳离子(K~+,Mg~(2+),Ca~(2+)和Al~(3+))对At.f菌氧化活性的影响。研究结果表明:不同阳离子对At.f菌氧化活性的影响效应不同,其影响由大到小的顺序依次为Mg~(2+),Al~(3+),K+,Ca~(2+),当Mg~(2+),Al~(3+),K~+浓度分别超过1,5,10 g·L~(-1)时显著降低了At.f菌的氧化活性,而Ca~(2+)在所研究0~2 g·L~(-1)浓度范围内对At.f菌氧化活性影响不大。培养25 h时,低浓度条件下(0.5 g·L~(-1)),K+,Ca~(2+),Al~(3+),Mg~(2+)作用下的Fe~(2+)的氧化率分别为67.78%,68.76%,65.27%,61.28%,均高于不添加任何离子作用下的Fe~(2+)的氧化率(60.74%);高浓度条件下(15 g·L~(-1)),K+,Al~(3+),Mg~(2+)作用下的Fe~(2+)的氧化率分别为35.82%,25.25%,21.47%,均低于不添加任何离子作用下的Fe~(2+)的氧化率。阳离子Mg~(2+),Al~(3+),K~+随离子浓度的增加,Fe~(2+)的氧化率均呈现逐渐降低的趋势。     

CaS:Ce,Cl薄膜的电致发光

本文研究了CaS:Ce,Cl材料及其薄膜交流电致发光器件的发光特性。发现随Ce~(3+)掺杂浓度增加,发射谱峰向长波方向移动,同时Ce~(3+)的~2D(5d)→~2F_(6/2)(4f)的辐射跃迁相对变弱,而~2D(5d)→~2F_7/2(4f)的辐射跃迁则相对变强,在电致发光中,除出现正常的5d→4f电子态辐射跃迁外,还发现了其它一系列的发射谱峰。这些谱峰可能是由于Ce~(3+)处于周围不同数目硫空位的Ca位所造成的,器件的起亮电压为70伏,发光亮度约为8cd/m~2。     

Ce~(4+)掺杂对CaO-SiO_2-MgO-Al_2O_3系透辉石微晶玻璃析晶行为的影响

在采用熔融法制备含Ce~(4+)的CaO-SiO_2-MgO-Al_2O_3系透辉石微晶玻璃过程中,采用差示扫描量热法(DSC)、扫描电子显微镜(SEM)和X射线衍射(XRD)相结合的分析检测方法,研究了Ce~(4+)掺杂对基础玻璃结构的稳定性、热处理后晶体层的晶体形态及晶相组成的影响规律。研究结果表明,Ce~(4+)掺杂能显著提高基础玻璃的玻璃化转变温度,提高基础玻璃结构稳定性并抑制透辉石晶体长大,CeO_2不能作为CaO-SiO_2-MgO-Al_2O_3系微晶玻璃的有效晶核剂。Ce~(4+)掺杂对CaO-SiO_2-MgO-Al_2O_3系微晶玻璃的析晶矿物种类和数量均无明显影响。     

稀土矿浮选中柠檬酸对铈离子活化方解石的影响研究

通过单矿物浮选试验、Zeta电位测试和红外光谱分析等方法,研究稀土矿浮选中柠檬酸CA对Ce~(3+)离子活化方解石的去活作用机理。试验研究结果表明,矿浆中Ce3+离子的浓度低于1×10~(-4)mol/L时对方解石浮选有活化作用,采用柠檬酸CA可达到去活目的。机理分析结果表明,柠檬酸CA能与方解石表面的Ce3+离子生成一种稳定的络合物,可降低方解石表面的Zeta电位,去除Ce~(3+)离子对方解石的活化作用。