Synthesis and Photoluminescence of BaMgAl_(10)O_(17)∶Eu^(2+) Phosphor by Oxalate Co-precipitation Process

Single phase of Ba1-x MgAl10O17 ： x Eu^2＋ （0.02≤ x ≤ 0. 14） phosphors was first successfully prepared by coprecipitation in aqueous medium with a “reverse strike” method, using oxalic acid and ammonia together as precipitants. Completely crystallized phosphors were obtained at 1300 ℃, which is 300 ℃ lower than the temperature of solid-state reaction. Their photoluminescence was investigated under UV and VUV region, respectively. The emission spectra of Ba1-x MgAl10O17：xEu^2＋ samples excited by 254 or 147 nm showed a characteristic wide band with the peak centred at about 450 454 nm. Optimum emission intensity reached at x = 0.1 and then concentration quenching occurred. The synthesized phosphor shows 10% higher emission intensity than that prepared by solid-state reaction.

Effects of synthesis conditions on the structural and electrochemical properties of layered LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 cathode material via oxalate co-precipitation method

The uniform layered LiNi1/3Co1/3Mn1/3O2 cathode material for lithium ion batteries was prepared by using （Ni1/3Co1/3Mn1/3）C2O4 as precursor synthesized via oxalate co-precipitation method in air. The effects of calcination temperature and time on the structure and electrochemical properties of the LiNi1/3Co1/3Mn1/3O2 were systemically studied. XRD results revealed that the optimal calcination conditions to prepare the layered LiNi1/3Co1/3Mn1/302 were 950℃ for 15 h. Electrochemical measurement showed that the sample prepared under the such conditions has the highest initial discharge capacity of 160.8 mAh/g and the smallest irreversible capacity loss of 13.5% as well as stable cycling performance at a constant current density of 30 mA/g between 2.5 and 4.3 V versus Li at room temperature.

Effect of Ferric Chloride on the Properties of Biological Sludge in Co-precipitation Phosphorus Removal Process

This paper studied the effect of ferric chloride on waste sludge digestion,dewatering and sedimentation under the optimized doses in co-precipitation phosphorus removal process.The experimental results showed that the concentration of mixed liquid suspended solid(MLSS) was 2436 mg.L-1 and 2385 mg.L-1 in co-precipitation phosphorus removal process(CPR) and biological phosphorous removal process(BPR),respectively.The sludge reduction ratio for each process was 22.6% and 24.6% in aerobic digestion,and 27.6% and 29.9% in anaerobic digestion,respectively.Due to the addition of chemical to the end of aeration tank,the sludge content of CPR was slightly higher than that of BPR,but the sludge reduction rate for both processes had no distinct difference.The sludge volume index(SVI) and sludge specific resistance of BPR were 126 ml.g-1 and 11.7×1012 m.kg-1,respectively,while those of CPR were only 98 ml.g-1 and 7.1×1012 m.kg-1,indicating that CPR chemical could improve sludge settling and dewatering.

Reaction kinetics and mechanism of calcium oxide in dilute sodium aluminate solution with oxalate based on lime causticization

The formation kinetics and mechanism of tricalcium aluminate hydrate and calcium oxalate in dilute sodium aluminate solution and sodium oxalate solution were studied respectively based on the lime causticization, and the optimal conditions for removing the oxalate in dilute sodium aluminate solution as well as the mechanism were finally obtained.The formation processes of tricalcium aluminate hydrate and calcium oxalate are mainly controlled by the chemical reaction and the inner diffusion respectively,and the corresponding reaction rate equations as well as the apparent activation energy were calculated. The hydrocalumite with a spatially interleaved structure will form in dilute sodium aluminate solution with sodium oxalate, greatly removing the oxalate impurity by absorption. Calcium oxalate can be converted to tricalcium aluminate hydrate with the increasing reaction time. The oxalate causticization efficiency and the alumina loss rate can be over 90% and below 31% respectively when reacted at 50℃ with a stirring rate of 200 r/min.

Direct Preparation of the Nanocrystalline MnZn Ferrites by Using Oxalate as Precipitant

Oxalate was generally used as a precipitant for synthesis of MnZn ferrites during the co-precipitation process. However, the MnZn ferrite couldn’t be directly obtained and a calcination process was needed. In this research, we reported a direct preparation of the MnZn ferrite nanoparticles by using co-precipitation method, together with refluxing process. XRD measurements proved that crystallite size of the obtained samples increased with an increase in pH value of the co-precipitation solution, and that the crystallite size of about 25 nm was obtained for the sample at a pH of 13. This sample showed the maximum Ms of 58.6 emu/g, which was about one times larger than that of 12 (pH value). Calcination to the obtained samples result in an enlargement in their crystal size and an improvement in their magnetic properties with an increase in temperatures. The samples calcinated in CO2 + H2 atmosphere presented good stability, and the maximum Ms value of 188.2 emu/g was obtained for the 1100。C-heated sample. Unfortunately, precipitation of some Fe2O3 at 800。C suggested poor stability of the nanocrystalline MnZn ferrite in N2 atmosphere.

Influence of pretreatment process on structure, morphology and electrochemical properties of Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 cathode material

The layered Li[Ni1/3Mn1/3Co1/3]O2 was separately synthesized by pretreatment process of ball mill method and solution phase route, using [Ni1/3Co1/3Mn1/3]3O4 and lithium hydroxide as raw materials. The physical and electrochemical behaviors of Li[Ni1/3Mn1/3Co1/3]O2 were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field emission scanning electron microscopy （FESEM） and electrochemical charge/discharge cycling tests. The results show that the difference in pretreatment process results in the difference in compound Li[Ni1/3Co1/3Mn1/3]O2 structure, morphology and the electrochemical characteristics. The Li[Ni1/3Mn1/3Co1/3]O2 prepared by solution phase route maintains the uniform spherical morphology of the [Ni1/3Co1/3Mn1/3]3O4, and it exhibits a higher capacity retention and better rate capability than that prepared by ball mill method. The initial discharge capacity of this sample reaches 178 mA-h/g and the capacity retention after 50 cycles is 98.7% at a current density of 20 mA/g. Moreover, it delivers high discharge capacity of 135 mA-h/g at a current density of 1 000 mA/g.

乙醇酸甲酯合成工艺的研究及应用进展

乙醇酸甲酯是一种重要的化工原料,研究乙醇酸甲酯合成工艺具有重要意义。介绍了乙醇酸甲酯的合成工艺,分别为氯乙酸水解法、甲酸甲酯与甲醛偶联法、甲醛羰化酯化法、草酸二甲酯加氢还原法、乙二醇与甲醇合成法、生物质转化法、甲缩醛与甲酸自由基偶联法、甲醛与氢氰酸加成法及乙二醛与甲醇一步合成法,对比了各工艺的优缺点,指出了乙醇酸甲酯在可降解塑料、食品、药品、农药及化工领域的用途,分析了乙醇酸甲酯生产工艺研究进展,最后对乙醇酸甲酯合成工艺进行了总结及展望。传统的乙醇酸甲酯生产工艺存在较多问题,且难以大规模生产。采用草酸二甲酯加氢还原法合成乙醇酸甲酯,然后制备乙交酯及聚乙醇酸的路线在中国具有广阔的发展前景,在解决全流程中存在的问题后,有望实现大规模工业化生产。生物质转化法以可再生的纤维素等资源为原料合成乙醇酸甲酯,具有绿色低碳的优点,有助于实现双碳目标。

基于慢特征分析与最小二乘支持向量回归集成的草酸钴合成过程粒度预报

草酸钴合成过程是钴湿法冶炼的关键单元操作,其粒度分布是重要的质量指标,然而难以在线实时测量。同时,草酸钴合成过程通常存在非线性、多约束和慢时变特征。因此,提出一种集成慢特征分析(slow feature analysis,SFA)与最小二乘支持向量回归(least square support vector regression,LSSVR)的草酸钴粒度预报模型对草酸钴合成过程质量指标实现在线测量。在该方法中,首先,SFA方法可以有效地捕获过程的慢特征向量,解决慢时变问题;然后,利用LSSVR方法建立慢特征与粒度之间的非线性关系模型,进而实现质量指标在线预报。最后,应用非线性的数值案例以及草酸钴合成过程数据,验证该方法的有效性。实验结果显示:相较于单一的径向基函数神经网络(radial basis function neural network,RBFNN)、LSSVR预测模型以及SFA与NN相结合的预报模型,所提方法在数值案例中的预测精度分别提升了13.31%、2.26%、1.72%;在草酸钴合成过程中的预测精度分别提升了13.27%、9.96%、8.92%。

不同炮制方法对黄精草酸钙针晶形态及含量的影响研究

目的研究黄精不同炮制品的草酸钙针晶形态差异以及测定不同炮制品的草酸钙含量。方法于2021年7月至2022年8月,利用显微镜观察净制、清蒸、酒蒸、酒炖、黑豆制等5个生黄精的炮制品中草酸钙针晶形态,采用高效液相色谱法测定草酸钙的含量。结果不同黄精炮制品的草酸钙针晶呈束状,离散、碎裂程度不同;炮制后,清蒸黄精的草酸钙针晶所受破坏程度最小,酒蒸黄精的最大。草酸钙含量:酒蒸黄精1.95%>酒炖黄精1.70%>黑豆制黄精1.56%>清蒸黄精0.99%>生黄精0.83%。结论与生品相比,不同炮制方法均对黄精草酸钙针晶有一定破坏,但破坏程度不同;酒蒸黄精的草酸钙含量在四种黄精炮制品中最高,清蒸黄精最低。

草酸盐控制析出技术在进口矿生产氧化铝中的应用

在低温拜耳法高浓度一段分解生产氧化铝过程中,流程内草酸盐持续积累至饱和析出对种分过程控制和产品质量影响较大。本文研究了在低温拜耳法高浓度晶种分解过程中晶种的草酸盐含量变化对成核的影响,创新性使用草酸盐控制剂(OCA)来促进草酸盐在种分系统内独立成球析出,以此消除草酸盐含量高对生产过程和产品质量的影响。研究了草酸盐控制剂在晶种分解不同周期内的作用和效果,获得了成熟的种分过程中草酸盐独立成球技术。

Growth of High Magnetic a-Fe2O3 and Fe3O4 Nanowires via an Oxide Assisted Vapor-Solid Process

We describes a controllable synthesis procedure for growing a-Ee2O3 and Ee3O4 nanowires. High magnetic hematite a-Fe2O3 nanowires are successfully grown on Fe0.5Ni0.5 alloy substrates via an oxide assisted vapor-solid process. Experimental results also indicate that previous immersion of the substrates in a solution of oxalic acid causes the grown nanowires to convert gradually into magnetite （Fe3O4） nanowires. Additionally, the saturated state of Fe3O4 nanowires is achieved as the oxalic acid concentration reaches 0.75 mol/L. The average diameter and length of nanowires expands with an increasing operation temperature and the growth density of nanowires accumulates with an increasing gas flux in the vapor-solid process. The growth mechanism of a-Fe2O3 and Fe3O4 nanowires is also discussed. The results demonstrate that the entire synthesis of nanowires can be completed within 2 h.

煤制乙二醇主要工艺单元技术新进展

在碳达峰、碳中和目标下,实现煤化工行业高质量发展是当务之急。从我国建成世界上第一套煤制乙二醇工业化示范装置开始,煤制乙二醇迎来了井喷式的大发展。本文对草酸酯催化加氢制乙二醇技术主要单元的技术和工艺进行了总结和梳理,着重分析了催化剂和工艺操作注意事项,以期为业内提供一些参考,共同促进煤制乙二醇行业的技术进步和发展。

钴/锌双金属多孔氧化物的制备及其活化过一硫酸盐降解亚甲基蓝的性能

采用草酸盐-热解法制备钴/锌双金属多孔氧化物复合材料,并用于催化过一硫酸盐(PMS)处理亚甲基蓝(MB)溶液。以Co(NO_(3))_(2)·6H_(2)O和Zn(NO_(3))_(2)·6H_(2)O为金属离子源,草酸为沉淀剂,Co^(2+)和Zn^(2+)同步沉淀获得钴锌草酸盐前驱体,将草酸盐热解后获得具有不同Co/Zn摩尔比的多孔Co_(3)O_(4)/ZnO复合氧化物催化剂。结果表明:Co/Zn原料比为1∶5的复合材料(Co_(1)Zn_(5))催化活性最佳,在催化剂用量和PMS浓度分别为0.02 g·L^(-1)和0.6 mmol·L^(-1)时,其对MB溶液的降解率可达98.49%。电子顺磁共振(EPR)测试结果表明,Co_(1)Zn_(5)/PMS催化氧化体系对MB的降解遵循自由基和非自由基双重机理。Co_(1)Zn_(5)较之Co_(3)O_(4)催化活性提升的原因:PMS形成的弱酸性环境引起复合材料中ZnO的部分溶解,使得活性组分Co_(3)O_(4)更多地暴露,从而增加催化剂与PMS接触反应的机会。

一氧化碳羰化偶联合成草酸二甲酯生产工艺特点及过程控制

文章介绍了一氧化碳羰化偶联合成草酸二甲酯工艺的相关生产装置,结合装置生产运行,从反应原理、系统氮元素平衡两个方面归纳总结了该生产工艺的特点,并从工艺生产控制和安全生产控制入手,分析了一氧化碳羰化偶联合成草酸二甲酯工艺在生产过程中控制方向的要点,为开展一氧化碳羰化偶联合成草酸二甲酯工艺的学习提供了基础理论。

外源草酸对采后番荔枝后熟及耐藏性的影响

研究外源草酸对采后番荔枝后熟软化及保鲜效果的影响,为番荔枝贮藏保鲜提供新方法。以AP番荔枝为试材,采用5mmol/L草酸溶液浸泡果实20min并在15℃条件下贮藏,研究草酸处理对果实的后熟软化、开裂及相关生理指标的影响。结果表明:草酸处理有效延缓了番荔枝果实硬度的下降和可溶性固形物含量的上升,抑制了果实的开裂及果胶酯酶(PE)、多聚半乳糖醛酸酶(PG)酶活性;草酸处理还能提高果实贮藏后期超氧化物歧化酶、过氧物酶的活性,抑制果实可溶性蛋白质和VC含量的下降;同时,草酸处理也抑制了果实中多酚氧化酶活性的升高和MDA含量的积累。相关性分析表明PE活性、PG活性与果实软化和开裂密切相关。外源草酸能有效地抑制采后番荔枝的后熟衰老进程,有较好的保鲜效果。

半夏炮制解毒机制的研究I

目的:阐明半夏炮制时采用8%明矾水或pH>12碱水炮制的解毒机制。方法:以药典规定的明矾浓度和碱液浓度浸泡生半夏,并采用电子显微镜扫描观察、氧化还原滴定法测定草酸钙含量、家兔眼刺激性实验等。结果:生半夏经过药典规定的8%明矾水浸泡或以10%的Na2CO3浸泡后,刺激性成分草酸钙针晶被锈蚀溶解,不溶性草酸钙含量从1%以上急剧下降到0.5%以下,半夏的刺激性也随之下降;半夏炮制后草酸钙含量降低到0.5%以下几乎不引起刺激性。结论:8%明矾水或pH>12以上的碱水炮制可以使生半夏药材中具有强刺激性成分草酸钙针晶的针形晶体破坏,含量降低,刺激性毒性降低;茜草、山药等无刺激性药材中草酸钙针晶的晶形、质地和含量与半夏具有非常大的差异。

外源草酸延缓采后芒果成熟及其生理基础的研究

【目的】研究外源草酸对采后芒果(Mangifera indica L.)的保鲜效应,为芒果贮藏保鲜提供新方法。【方法】芒果栽培种'圣心'采后经5mmol·L-1草酸溶液浸果10min后在常温(25℃)下贮藏,研究草酸处理对果实的成熟进程及其相关生理指标的影响。【结果】草酸处理后在贮藏期间果实的软化、可溶性固形物(SSC)增加、可滴定酸(TA)降低和果皮细胞的电解质渗漏量增加的速率都显著低于未处理的果实;处理果实果皮的超氧歧化酶(SOD)活性在采后6～15d提高,脂氧合酶(LOX)活性在6、9d时降低,同时,超氧阴离子(O2-·)在采后贮藏的前12d和过氧化氢(H2O2)在9、12d时含量分别降低;13d后处理果实的乙烯释放量显著降低;贮藏结束时(18d),草酸处理果实的表皮红色着色好于对照,腐烂率显著低于对照,果肉口感没有产生变异。【结论】外源草酸有效地延缓采后芒果的成熟进程;草酸提高果皮的SOD活性和降低LOX活性从而导致活性自由基(ROS)含量下降,以及降低果实的乙烯释放量等生理效应与延缓果实成熟密切相关,同时有助于果实的抗病性;草酸处理是采后芒果贮藏保鲜的一种可选新方法。

CO合成草酸二乙酯偶联与再生反应匹配的研究

在偶联反应和再生反应动力学和反应机理研究的基础上 ,计算机模拟了在负载型Pd催化剂上 ,CO与亚硝酸乙酯气相偶联制备草酸二乙酯 ,反应生成的NO与乙醇发生再生反应这一洁净工艺过程。根据模拟结果 ,模型放大试验实现了偶联反应和再生反应的有机匹配 ,基本上达到了污染物的零排放。

拜耳工艺中草酸钠问题的研究现状

综述了拜耳法生产氧化铝工艺中,杂质草酸钠的行为及其对生产过程的影响,着重介绍了各种控制和去除草酸钠的方法,并对今后的研究方向进行了展望。

基于CIELAB颜色空间分析法和HPLC测定法对僵蚕不同炮制品的外观性状和内在质量的控制研究

目的：对中药僵蚕不同炮制品的颜色特征建立数据化判断标准,同时测定各炮制品中草酸铵的含量。方法：采用CIELAB颜色分析法研究僵蚕不同炮制品的颜色,采用HPLC法测定其抗惊厥的有效成分草酸铵的含量。结果：在颜色测定分析中,糖麸炒僵蚕的L值区间数值较小,亮度最暗,姜麸炒、蜜麸炒、姜麸炒L值较为接近,外观亮度比较相似;清炒僵蚕L值区间数值较大,亮度较高。清炒僵蚕的a值区间数值较小,较为接近白色,姜炙僵蚕次之,麸炒、蜜麸炒、糖麸炒、姜麸炒的a值比较接近,介于16.0~18.0,颜色偏红。清炒僵蚕的b值区间数值最小,最为接近白色,而姜麸炒僵蚕b值区间数值较大,较为接近黄色。在草酸铵的含量测定中,糖麸炒僵蚕草酸铵含量降低最为明显,姜炙僵蚕、姜麸炒僵蚕其次,清炒僵蚕、蜜麸炒僵蚕有所下降,麸炒僵蚕降低程度最轻。结论：基于CIELAB颜色空间技术的特征颜色提取分类方法能够表示中药炮制品的实际视觉描述分类关系,具有一定的可行性;中药僵蚕的各种炮制工艺对其草酸铵含量的变化有不同的影响,其中以麸炒僵蚕的影响为最小。