Preparation and characterization of nanosized Gd_xBi_(0.95-x)VO_4:0.05Eu^(3+) solid solution as red phosphor

A complete solid solutions with monophasic zircon-type structure of vanadates of formula GdxBio.95-xVO4：0.05Eu3＋ （x = 04）.95） are synthesized by combined method of co-precipitation and hydrothermal synthesis. Their microstructures and morphologies are characterized by X-ray powder diffraction and transmission electronic microscope, and the results show that each of all the samples has a monophasic zircon-type structure. The absorption spectrum of the prepared phosphor shows a blue-shift of the fundamental absorption band edge with increasing the gadolinium content. Under UV-light and visible-light excitation, all the prepared phosphors show the typical luminescence properties of Eu3＋ in the zircon-type structure. The emission intensity of GdxBi0.95-xVO4：0.05Eu3＋ （x = 0.55） is strongest in all samples under UV-light and visible-light excitations. Finally, the mechanisms of luminescence of Eu3＋ in the GdxBi0.95-xVO4：0.05Eu3＋ （x = 0-0.95） solid solutions are analyzed and discussed.

Energy transfer relation of a novel Ce^(3+)/Pr^(3+)/Eu^(3+) co-doped Sr_(2.975-x)La_xAlO_(4+x)F_(1-x) solid solution phosphor

The photoluminescence properties and energy transfer of a new Ce3＋/pr3＋/Eu3＋ co-doped solid-solution composi- tion of Sr2.975-xLaxAlO4＋xF1-x （LSAF） phosphor are investigated. Upon doping Pr3＋ into lattices of LSAF：Ce host, a shoulder emission peak is observed at about 620 nm, owing to the transition of 1D2 →3H4. Addition of Eu3＋ to LSAF：Ce3＋, Pr3＋ phosphor results in a sharp emission peaked at 675 nm for the 5D0 →TF3 transition and an increase of the intensity of red emission for Pr3＋ with increasing Eu3＋ concentration. The pathways of energy transfer among Ce3＋, Pr3＋, and Eu3＋ are proposed to be responsible for color addition of a red component to the primary yellow emission, enabling a potential adjustable color for blue excitable warm white.

Exploration of New Phosphors Using a Mineral-Inspired Approach in Combination with Solution Parallel Synthesis

The concept, as well as the methodology of using a mineral-inspired approach in combination with solution parallel synthesis (SPS) for exploration of new phosphors among Na/Sr(Ba)/Al-silicate and Zr(Ti)-silicate minerals, is reported. By employing the proposed approach, we have discovered new phosphors of NaAlSiO4:Eu2+ and BaZrSi3O9:Eu2+, that emit green-yellow (553 nm) and blue-green (480 nm) light, respectively, when excited by radiation of 290 to 420 nm.

Design of the Metal Precursors Molecular Structures in Impregnating Solutions for Preparation of Efficient Ni Mo/Al_2O_3 Hydrodesulfurization Catalysts

The molecular structures of metal precursors in the impregnating solution were designed so as to prepare efficient Ni Mo/Al_2O_3 hydrodesulfurization(HDS) catalysts. At first, five typical impregnating solutions were designed; the existing metal precursors, such as [Mo4(citrate)2O11]^(4-)-like, [P2Mo18O62]^(6-)-like and [P2Mo5O23]^(6-)-like species in the solutions were confirmed by laser Raman spectroscopy(LRS). The UV-Vis spectra results indicated that the solutions containing both phosphoric acid and citric acid could change the existing form of nickel species. Five corresponding Ni Mo/Al_2O_3 catalysts were prepared by the incipient wetness impregnation method. The LRS analysis results of dried catalysts showed that the above metal precursors could be partly retained on alumina support after impregnation and drying, although the interface reaction between different metal precursors and alumina support unavoidably took place. Then the catalysts were sulfided and characterized by N2 physisorption, TEM and XPS analyses. The results showed that different metal precursors in impregnating solution could mainly result in the difference in both the morphology of(Ni)Mo S2 slabs and the promoting effect of Ni species. The catalyst prepared mainly with [P2Mo5O23]^(6-)-like species used as precursors exhibited worse dispersion of(Ni)Mo S2 slabs and lower ratio of Ni–Mo–S active phases than the one with [Mo4(citrate)2O11]^(4-)-like species. Promisingly, the catalyst prepared with co-existing [Mo4(citrate)2O11]^(4-)-like, [P2Mo18O62]^(6-)-like and [P2Mo5O23]^(6-)-like species showed better hydrodesulfurization activity for 4,6-DMDBT thanks to its more well-dispersed Ni–Mo–S active phases.

Solvent extraction of zinc from zinc sulfate solution

The extraction of zinc from zinc sulfate solution was investigated, using 20% saponified D2EHPA as an extractam and 260^# sulfonate kerosene as a diluent. The solution was stirred for 8 min at phase ratio （Vσ/Va） of 1.0：1.0, initial pH of 2.0 and stirring speed of 200 r/min. The results show that 75% zinc can be extracted from the zinc sulfate solution when the concentration of zinc is 18.7 g/L after being settled for 10 min. 88.60% zinc can be stripped by 196 g/L sulfuric acid, and zinc ion can be separated from ferric ion.

Dancing bubble sonoluminescence in phosphoric acid solution

Sonoluminescence is more distinctly observed in phosphoric and sulfuric acid,which exhibit high viscosity and lower vapor pressures relative to water.Within an 85-wt%phosphoric acid solution saturated with argon(Ar),variations in the light-emitting regimes of bubbles were noted to correspond with increments in the driving acoustic intensity.Specifically,the bubbles were observed to perform a dance-like motion 2 cm below the multi-bubble sonoluminescence(MBSL)cluster,traversing a 25-mm^(2) grid during the camera exposure period.Spectral analysis conducted at the beginning of the experiment showed a gradual attenuation of CN(B^(2)S–X^(2)S)emission concurrent with a strengthening of Ar(4p–4s)atom emission lines.The application of a theoretical temperature model to the spectral data revealed that the internal temperature of the bubbles escalates swiftly upon their implosion.This study is instrumental in advancing the comprehension of the underlying mechanisms of sonoluminescence and in the formulation of a dynamic model for the behavior of the bubbles.

溶剂萃取法自铝材抛光废液中分离去除硫酸及其机理的研究

研究了利用溶剂萃取体系自铝材抛光废液中分离去除硫酸并纯化提取磷酸的工艺。系统考察三烷基胺(N235)浓度、萃取温度、相比、振荡时间等因素对萃取率的影响,并用McCabe-Thiele图解法预测理论阶段数,结果表明在相比为O/A=2的三个理论阶段后,98%以上的H_(2)SO_(4)将被去除。设计了一系列串级实验进行三级逆流萃取模拟,得到H_(2)SO_(4)的萃取率为95.40%,H_(3)PO_(4)的萃取率仅为3.33%。结果表明该体系对硫酸具有较高选择性,可实现H_(3)PO_(4)与H_(2)SO_(4)的高效分离。通过机理研究可知,萃取配合物以H_(2)SO_(4)·2[N235]形式存在,H_(2)SO_(4)通过与N235形成离子对络合物被萃取进入有机相中。

溶液燃烧法制备长余辉发光材料——介绍一个大学化学综合性实验

介绍了一个长余辉发光材料的制备、表征,及性能测试的大学化学综合性实验。内容包括:尖晶石型碱土铝酸盐发光材料的制备,物相纯度的表征,以及发光性能的测试。本实验安全、简单、迅速,富有观赏性。学生通过本实验可以掌握溶液燃烧的物理化学原理,提高基本实验技能,更重要的是呈现化学之美,激发学生科学研究的兴趣。

Mn^(4+)掺杂氟化物红色发光粒子的表面钝化和白色发光二极管应用

Mn^(4+)掺杂的氟化物红色荧光粉的耐湿性差,严重影响了白色发光二极管(WLEDs)的光色稳定性。本工作基于绿矾溶液的还原性,将K_(2)SiF_(6)∶Mn^(4+)颗粒表面的Mn^(4+)还原成可溶的低价态Mn^(2+),实现了氟化物粒子的表面钝化及高耐湿性。在水浸360 h后,表面钝化的K_(2)SiF_(6)∶Mn^(4+)粒子的发光强度仍保持初始强度的95%,而未处理的K_(2)SiF_(6):Mn^(4+)颗粒发光强度迅速降为初始值的46%。此外,采用绿矾溶液对表面已水解的氟化物荧光粉进行简单的浸泡,可使其完全恢复原来的发光强度。电感耦合等离子体-原子发射光谱、X射线光电子谱、元素能谱等表征结果显示,经绿矾溶液处理的K_(2)SiF_(6):Mn^(4+)粒子表面的Mn^(4+)浓度显著减小,证实了惰性壳层K_(2)SiF_(6)的形成,揭示了氟化物粒子耐湿性显著提升的原因。此外,经高温(85℃)高湿(85%)的条件老化1 000 h后,WLEDs器件中表面钝化的K_(2)SiF_(6)∶Mn^(4+)粒子仍保持着100%的红色发光强度,明显高于未钝化的氟化物的59%,进一步证实了绿矾溶液钝化的K_(2)SiF_(6)∶Mn^(4+)红色荧光粉具有非常优异的环境稳定性。

废磷酸脱铝技术的研究进展

磷酸是一种重要的化工原料,常用于铝的化学抛光处理以及铝合金等金属的表面处理。铝离子在溶液中不断积累,进而改变化学抛光液的组成和性质,并形成含铝废磷酸。磷酸也用于蚀刻铝制零部件的铝箔层和显示面板的铝层以溶解氧化铝,因此也会产生含铝废磷酸。随着磷资源的不断消耗,未来获取磷酸资源面临严峻挑战。基于环境保护的迫切要求,必须脱除废磷酸中的铝离子,以便更好地回收和利用磷酸资源。本文介绍了去除废磷酸中铝离子的方法,分析了这些方法的利弊,并对未来废磷酸脱除铝离子的研究方向进行了展望。

Corrosion resistance of electrodeposited RE-Ni-W-P-SiC-PTFE composite coating in phosphoric and ferric chloride

Corrosion rate and anode polarization curves of electrodeposited RE-Ni-W-P-SiC-PTFE composite coating in various concentrations of phosphoric and ferric chloride were researched. The results show that corrosion rate of the composite coatings increases with the increasing concentrations of phosphoric and ferric chloride, and reaches the maximum value when phosphoric concentration is 40% and ferric chloride concentration is 20% (mass fraction, the same below if not mentioned). Anode polarization curves of the composite coatings show that anode polarization current density of the composite coatings heat-treated at 200 ℃ or 500 ℃ is lower than that of other coatings heat-treated at 300 ℃ or 400 ℃, which displays that the composite coatings heat-treated at 200 ℃ or 500 ℃ have better corrosion resistance. Besides, corrosion resistance of the composite coating heat-treated at 500 ℃ is better than that as deposited and RE-Ni-W-P-SiC composite coating heat-treated at 400 ℃, and is also better than that of 316L stainless steel.

The Structure Development of Cellulose Dissolved in the Phosphoric Acid/Polyphosphoric Acid Solvent

Cellulose,being as the most abundant nature polymer material and the most promising oil substitute,attracts more and more interests.A new cellulose dissolution system,phosphoric acid(PA)/polyphosphoric acid(PPA) solvent,was investigated in this study.It had been found that a larger cellulose solid content could be dissolved quickly in a hypothermic situation.By evaluating the stability of regenerated cellulose film and the formation of anisotropic solution,the dissolution behavior of cellulose was investigated.Wide-angle X-ray diffraction(WAXD) and Fourier transform infrared spectroscopy(FT-IR) were employed to characterize the crystalline structure and morphology of regenerated cellulose.The measurement results revealed a transition from cellulose-Ⅰ of raw cellulose to cellulose-Ⅱ of regenerated cellulose and a decrease of crystallinity of cellulose after dissolved.This was attributed to the interaction between cellulose and acid solvent,which leaded to the breakage of cellulose intra-and inter-molecule hydrogen bonds and the conformation change of cellulose C6-OH.Moreover,the formation process of cellulose liquid crystal solution was illustrated by polarized light microscope(PLM).That may be induced by the rearranging movement of the cellulose macromolecular chains.

复杂组成缓冲溶液pH值的讨论

缓冲溶液是酸碱解离平衡的重点内容,为解决复杂组成缓冲溶液pH值计算的问题,以磷酸盐体系为例,讨论了三种组成的缓冲溶液pH值的计算方法,考察了近似计算和精确计算的区别,旨在培养学生的逻辑思维和推导能力,加深学生对基本概念和理论的理解,也是对现行教材有益的补充.

赤泥磷酸浸出液中稀土的萃取行为研究

赤泥是铝土矿生产氧化铝过程中产生的固体残渣,含有铁、硅、铝、钛及稀土等多种有价组分。在已预先分离赤泥中大部分铁、硅、铝、钛的前提下,采取溶剂萃取的方式对赤泥磷酸浸出液中的稀土作进一步分离与纯化,研究了在中性磷型萃取剂TBP、酸性磷型萃取剂P204和P507分别作用下,稀土La、Ce、Sc、Y以及主要杂质组分Al、Fe、Ti、Ca的萃取行为,结果表明:TBP对稀土的萃取效果较差,P507对稀土Sc、Y及杂质Fe、Ti的萃取能力较强,P204萃取稀土的能力优于P507;采用质量分数2%P204作为萃取剂,在溶液pH为1.5、相比为1∶3的条件下,磷酸浸出液中Sc、Y的萃取率分别为90%、99%,La、Ce及杂质Fe、Al、Ti、Ca萃取率均低于5%;将P204质量分数升至20%,La、Ce萃取率可分别达到85%、95%。因此可通过采用P204分步萃取的方式有效分离磷酸浸出液中的稀土。

废磷酸系刻蚀液制备电池级磷酸铁

以废磷酸系刻蚀液为原料、铁粉为铁源、H_(2)O_(2)为氧化剂,采用氧化沉淀法一步合成结晶态FePO4。考察了铁磷摩尔比、反应温度、H_(2)O_(2)投加量、pH、煅烧温度对FePO4制备的影响,利用XRD、SEM等手段表征了FePO4的形貌和晶体结构。实验结果表明,在铁磷摩尔比1.000、反应温度90℃、n(H_(2)O_(2))∶n(H3PO4)1.05、pH 2.2~2.4、煅烧温度600℃的最佳工艺条件下,废刻蚀液中PO43-、NO3-、醋酸的去除率分别为87.70%、87.42%和90.25%,FePO4的产品转化率为77.99%,所制备的FePO4晶体结构规则,结晶度高,粒径为2.0~6.0μm,铁、磷质量分数和杂质元素含量等指标均能满足《电池用磷酸铁》(HG/T 4701—2021)的要求。

Solution combustion synthesis and luminescence properties of (Y,Gd)Al_3(BO_3)_4:Eu^(3+) phosphors

Ultrafine Y0.95–xGdxEu0.05Al3(BO3)4 phosphors with different Gd3+ concentrations were prepared by a solution combustion method, and characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM). Results showed that the pure phase of YAl3(BO3)4 was obtained at 1000 oC and the prepared particle size varied with calcining temperatures. Photoluminescence spectra indicated that the dominant emission peak was observed at 612 nm due to the 5D0→7F2 transition of Eu3+. The luminescence intensity of ...

Luminescence properties of a solid solution typed(Ba,Ca)_3MgSi_2O_8: Eu^(2+), Mn^(2+)phosphor with a 660 nmfeatured photosynthetic action spectrum

A solid-solution-phase Ba1.75Ca1.25MgSi2O8： Eu2＋, Mn2＋ phosphor in the photosynthetic action spectrum with dual band emissions at 438 nm and 660 nm is fabricated. X-ray diffraction （XRD） confirms the presence of the solid-solution phase. With the supporting information from the diffuse reflection spectrum, a feasible way to obtain higher energy-transfer （ET） efficiency is attained, and the ET efficiency of Eu2＋-Mn2＋ is enhanced to 76%. The mechanism of this enhancement is owing to variation of the solid solution composition of Ca3MgSi208 and Ba3MgSi2Os, which contributes to the extension of the critical distance. Temperature-dependent results show an en- hancement which is attributed to Ca. These enhancements show great promise for improving coo-lighting devices.

改性水玻璃加固细砂室内试验研究

为了探讨磷酸改性水玻璃对工程中细砂层加固的可行性和有效性,在合理确定改性水玻璃配合比的基础上,利用无侧限压力仪和直剪仪对加固砂样的应力应变关系及抗剪强度开展研究,分析改性水玻璃溶液对细砂层的加固效果和机理。试验结果表明:磷酸改性的水玻璃溶液对细砂具有明显加固作用,最优体积配合比为水∶磷酸∶水玻璃=13∶1∶3.3。每1 m^(3)改性水玻璃可固结素砂最大约4 m^(3)。固砂体的轴向抗压强度随时间增长呈现先增大后减小的趋势,无侧限抗压强度处于140 kPa~213 kPa范围,凝结时间为42 h时,抗压强度达到最大。较原状细砂,加固初期黏聚力可增加6 kPa~28 kPa,内摩擦角有所降低;随着凝结时间的增加,黏聚力逐渐减小而内摩擦角有所恢复。

改性水玻璃溶液加固地下松散砂层的试验研究

以工程建设项目为背景,探究在实际工程中采用磷酸溶液代替硫酸溶液对水玻璃进行化学改性后作为注浆材料对地下松散砂土层加固的可行性和有效性。通过对溶液物理性能研究的室内试验,确定适合采用的溶液配合比,然后进行无侧限抗压强度试验和直接剪切试验,以此分析改性水玻璃溶液对砂土层的加固效果和加固机理。最后,采用Midas有限元软件建立地铁盾构开挖的三维数值模型,对地铁隧道开挖的安全性进行影响评估,根据数值模拟结果可以直观分析加固方法的有效性。试验结果表明:磷酸改性的水玻璃溶液对松散砂土具有明显加固作用,适合在实际工程中使用的溶液最优体积配合比为水∶磷酸∶水玻璃=13∶1∶3.3;根据模拟渗透试验可知,1m^(3)的浆液可固结砂土约4.75m^(3)。试样的抗剪强度参数值随溶液凝结硬化时间的增长呈线性变化,当溶液对砂土粘聚力和内摩擦的作用达到平衡时抗剪强度最大。

废铝蚀刻液中硝酸、磷酸和醋酸浓度的电位滴定法连续测定研究

废铝刻蚀液是由硝酸、磷酸和醋酸组成的一种混酸,把握混酸中各酸的含量是该工业废液回收利用的重要前提。以乙醇/乙二醇共混物为溶剂,以氢氧化钠/乙醇溶液为滴定剂,采用一步法连续电位滴定对铝蚀刻液混酸中各单酸浓度进行分析,优化了滴定条件并进行了实验验证。结果表明,在最优滴定条件下,混酸中各酸的测定值与实际值的偏差均较小。可满足现实生产中废混酸回收利用的分析要求,有望获得实际应用。