Chicken Bone as a Bioresource for the Bioceramic (Hydroxyapatite)

Natural hydroxyapatite (HAP) is isolated from waste chicken bone by thermal calcinations at different temperatures in the range of 200 °C to 1000 °C. The isolated HAP has been characterized using thermo gravimetric analysis (TG) and differential thermal analysis (DTA), Fourier Transformed Infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission electron microscope (FE-SEM), and energy dispersive X-ray (EDX). The XRD results showed that the enhanced crystallinity of HAP phase by thermal calcination above 600 °C and the crystal size has been found to increase with increasing temperature of thermal calcinations due to agglomeration. Value addition for the waste chicken bone is given by the isolation of useful bioceramics (HAP) and the optimum temperature for the thermal calcination is found to be 600 °C. The isolated HAP has been characterized as carbonated HAP of B type with the hexagonal structure. These results will not only make the chicken bone as an important bioresource for the HAP but will also reduce the environmental pollution caused by dumping of the waste chicken bone.     

Pd/MnOx+Pd/γ-Al2O3整体式催化剂降解地表臭氧

用高锰酸钾与硝酸锰氧化还原反应制备了高活性的氧化锰(MnO x)催化组分,用胶溶法制备了高比表面积的γ-Al2O3载体,分别用等体积浸渍法制备了Pd/MnO x和Pd/γ-Al2O3催化剂,然后将两者机械混合涂覆于堇青石上制得Pd/MnO x+Pd/γ-Al2O3整体式催化剂。采用X射线衍射(XRD)、X射线光电子能谱(XPS)、程序升温还原(H2-TPR)和低温N2吸附-脱附对催化剂进行了表征。考察了在300至700℃焙烧MnO x对催化剂降解地表O3活性的影响。结果表明,Pd和MnO x之间存在协同作用;MnO x焙烧温度对催化剂活性有一定的影响,其中以600℃焙烧时催化剂的活性最高,O3的起始(12℃)转化率达到88%,完全转化温度为18℃。MnOx的物相和催化剂表面的吸附氧物种对催化活性影响较大,适当比例的MnO2和Mn2O3共存有利于O3分解,表面吸附氧为O3分解的活性氧物种。     

SO2对钙基CO2吸收剂循环煅烧/碳酸化反应的影响

在循环煅烧/碳酸化反应系统中,研究了SO₂对钙基吸收剂CaCO₃捕集CO₂的影响,获得了SO₂对钙基吸收剂碳酸化特性、煅烧特性以及循环稳定性的影响规律,并结合SEM分析结果,从循环煅烧/碳酸化反应角度,分析了可能存在的原因。结果表明,钙基吸收剂吸收CO₂的能力随着循环反应次数的增加逐渐发生衰减,在SO₂影响下,这种衰减会进一步加剧,且衰减程度随着SO₂浓度的增加而增大,经过十次循环后,碳酸化转化率分别为25.5%(0%SO₂)、16.9%(0.1%SO₂)和5.2%(0.2%SO₂)。造成这种衰减加剧的主要原因是反应产生较厚的硫酸化产物层,硫酸化产物层使颗粒表面孔隙发生堵塞,阻碍了CO₂在吸收剂内部的扩散,降低了碳酸化转化率。     

罗丹明B敏化TiO2可见光分解水产氢研究

通过低温煅烧处理罗丹明B和P25(TiO₂)的混合物一步合成了罗丹明B敏化的TiO₂复合光催化剂。X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)表征结果显示,低温煅烧处理未改变P25的晶相结构和形貌。紫外-可见光吸收光谱和红外光谱表征表明,罗丹明B和P25之间发生了强的相互作用,荧光光谱表征结果证实低温煅烧处理导致的强相互作用有利于电子从罗丹明B向P25传输。可见光光催化分解水实验结果表明,250℃下煅烧处理得到的复合光催化剂具有最佳的产氢速率,可达到65.1 μmol/(g·h),是相同光催化反应条件下罗丹明B和P25物理混合光催化剂的1.8倍。     

焙烧温度对K-Cu/Zn/La/ZrO2催化剂上异丁醇合成的影响

采用共沉淀法制备了Cu/Zn/La/ZrO₂催化剂,并浸渍K对其进行改性.以合成气合成异丁醇为探针反应,考察了焙烧温度对K-Cu/Zn/La/ZrO₂催化剂合成反应的影响.采用XRD、TG、BET、NH₃-TPD、H₂-TPR、Raman及XPS等手段表征了催化剂的结构和表面性质.结果表明,催化剂体相结构、比表面积与其催化活性没有直接关系;催化剂表面强酸中心的存在不利于异丁醇的生成;Cu-Zn-Zr活性组分间协同作用对催化剂活性影响很大,450 ℃焙烧温度下,Cu-Zn-Zr活性组分间协同作用最强,CuO最容易还原,催化活性最高,此时CO的转化率(物质的量)达到69.47%,醇中异丁醇的选择性(质量分数)为19.09%,甲醇+异丁醇的选择性(质量分数)为95.02%.     

Effect of calcination conditions on the properties of a catalyst for ethylbenzene dehydrogenation

Summary The effects of calcination conditions on the properties of the catalyst for dehydrogenation of ethylbenzene were studied by using TG, DTA, and XRD. The formation temperature of polyferrite was higher than 600°C. The strength of the catalyst changed during calcination. Higher temperature enhanced the strength and improved the activity of catalyst. The calcination model has great influences on the catalyst performance. Multi-stage calcination improved the catalyst activity.     

富钙生物油煅烧过程中孔结构变化特性的研究

在热重分析仪上进行富钙生物油煅烧实验。结果表明,富钙生物油的煅烧过程分为三个阶段,分别是生物油部分组分的脱CO₂和H₂O阶段、有机酸钙盐分解阶段、碳酸钙分解阶段。其中,有机酸钙盐分解对煅烧产物的孔结构有重要影响。在450℃~600℃,气体析出的气蚀作用与生物油中高分子化合物的碳化沉积现象同时存在,两者共同作用,但后者占主导,高分子化合物的碳化沉积主要发生在500℃~600℃。600℃以后,碳酸钙开始分解,释放出CO₂,气蚀作用使煅烧产物内部形成新的微孔,产物具有发达的孔结构。相同煅烧温度下,富钙生物油煅烧产物的孔隙特性明显优于CaCO₃。     

Ho~(3+)/Yb~(3+)∶8YSZ纳米粉体制备及发光性能研究

通过化学共沉淀法制备Ho~(3+)/Yb~(3+)共掺杂的氧化钇稳定的氧化锆(8YSZ)纳米粉体。研究了煅烧温度对Ho~(3+)/Yb~(3+)共掺杂8YSZ纳米粉体荧光光谱和上转换发光性能的影响。结果表明:在448 nm波长激发光激发下,Ho~(3+)/Yb~(3+)∶8YSZ纳米粉体有一个549 nm的绿光发射峰,随着煅烧温度的升高,Ho~(3+)/Yb~(3+)∶8YSZ纳米粉体的荧光强度先升高后降低。980 nm波长激光激发下,Ho~(3+)/Yb~(3+)∶8YSZ纳米粉体在450~750 nm范围内有一个中心波长在539 nm的绿光发射峰和一个中心波长在650 nm的红光发射峰,随着煅烧温度的升高,纳米粉体的颗粒尺寸增大的同时,其上转换发光强度也逐渐增大。     

Effect of heat treatment on the properties and structure of TiO2 nanotubes: phase composition and chemical composition

Titanium oxide (TiO₂) nanotubes prepared by electrolytic anodisation of a titanium electrode have been systematically heat treated to control the conversion of the as‐prepared amorphous structure to nanocrystalline anatase and rutile. Raman spectroscopy revealed that the temperature of calcination is critical in determining the structure and crystallinity of the titania. X‐ray Photoelectron Spectroscopy analysis shows the as‐prepared film to consist mainly of oxide, although a small amount of fluoride contamination remains from the electrolyte. Organic components from post‐anodising cleaning treatments were also present. Fluorine ions are gradually ejected from the anodic layer during annealing and the fluorine concentration is negligible in samples that are heat treated above 400 °C. Choosing the appropriate annealing temperature allows the structure to be made up of defined proportions of anatase and rutile with a reduced contamination of species from the electrolyte or organic solvents. Copyright © 2010 John Wiley & Sons, Ltd.     

共沉淀法制备YAG粉体影响因素研究

采用共沉淀法制备出性能良好的YAG(Y3A12(A1O4)3)纳米粉,对前驱体及不同温度下煅烧后的粉体进行差热、红外光谱、X射线衍射、比表面积和透射电镜等分析。结果表明:YAG粉体大小均匀,近似球形,且随着煅烧温度的升高,其颗粒逐渐变大,当温度达到1000℃时粉体全部为纯YAG立方相。随着母盐溶液(Y(NO3)3+Al(NO3)3)浓度的降低颗粒逐渐减少,并且粉体中YAM(Y4A12O9),Y2O3等相转化为纯YAG立方相。