固定床动力学模型在离子交换过程中的应用

为了掌握所选的Thomas模型,Yoon-Nelson模型和Adams-Bohart模型在固定床米格列醇离子交换过程中的应用情况,实验借助对不同质量浓度的米格列醇溶液在定量树脂和固定流速下研究其在固定床中离子交换过程,并通过对透过曲线实验数据分析来验证相关固定床动力学模型在此过程中的有效性。结果表明:固定床上样液质量浓度增大,达到平衡饱和点的时间将缩短,传质区长度增大,吸附率变小,上样液质量浓度在8 mg/mL时吸附量达到最大;用动力学模型拟合透过曲线的过程参数,结果表明Thomas模型和Yoon-Nelson模型具有较好的相关系数,Thomas模型的速率常数和最大吸附量值随着上样液质量浓度的降低而增大,Yoon-Nelson模型的速率常数随着上样液质量浓度的降低而减小,且在Yoon-Nelson模型中计算得到的透过曲线中出口质量浓度与上样质量浓度比值为1/2时所对应的计算值和实验值相差很小,Thomas模型和Yoon-Nelson模型可用于该过程的离子交换性研究。     

采用离子交换吸附对蛹虫草中虫草素的提取研究

采用超声波法对蛹虫草中虫草素进行粗提,筛选得到了最佳吸附介质阳离子树脂001×16,该介质对虫草素的吸附特性,包括吸附等温线、吸附动力学条件等进行了探讨。结果表明,001×16对虫草素的吸附等温线符合Langmuir方程,最佳吸附条件为pH值为4.0,温度15℃,吸附时间3 h。在此优化条件下,虫草素最大吸附量可达到1.3 mg/g。     

米格列醇在大孔D001树脂上的离子交换性研究

为掌握米格列醇在离子交换树脂上的吸附行为,采用改变恒温振荡器的温度、震荡速率和溶液pH值来研究固定浓度的米格列醇溶液在定量树脂上的离子交换吸附行为,并结合热力学和动边界模型对交换过程进行分析.结果表明:吸附温度增大,分配系数KD变小,吉布斯函数值△G变大,不利于离子交换吸附,离子交换过程为放热过程;米格列醇溶液在中性条...     

甘氨酸在离子交换树脂中扩散过程的控制步骤

研究了甘氨酸在001 ×7,001 ×4和D061 3种阳离子树脂上离子交换动力学过程,对甘氨酸在3种离子交换树脂上的扩散过程控制步骤进行分析.使用间歇式搅拌槽法分别测定了不同温度下甘氨酸在001 ×7,001 ×4和D061树脂上的吸附曲线,估算了颗粒扩散系数和相间传质系数,并比较了3种阳离子交换树脂吸附甘氨酸的特性...     

Optimization of molecular hydrogen production by Rhodobacter sphaeroides O.U.001 in the annular photobioreactor using response surface methodology

Photofermentative H₂ production at higher rate is desired to make H₂ viable as cheap energy carrier. The process is influenced by C/N composition, pH levels, temperature, light intensity etc. In this study, Rhodobacter sphaeroides strain O.U 001 was used in the annular photobioreactor with working volume 1 L, initial pH of 6.7 ± 0.2, inoculum age 36 h, inoculum volume 10% (v/v), 250 rpm stirring and light intensity of 15 ± 1.1 W m⁻². The effect of parameters, i.e. variation in concentration of DL malic acid, L glutamic acid and temperature on the H₂ production was noted using three factor three level full factorial designs. Surface and contour plots of the regression models revealed optimum H₂ production rate of 7.97 mL H₂ L⁻¹ h⁻¹ at 32 °C with 2.012 g L⁻¹ DL malic acid and 0.297 g L⁻¹ L glutamic acid, which showed an excellent correlation (99.36%) with experimental H₂ production rate of 7.92 mL H₂ L⁻¹ h⁻¹.     

AgBr/TiO2（001）纳米片可见光光催化剂的制备

以暴露高能面（001）面的TiO2纳米片为载体,NaBr和CTAB分别为溴源,通过浸渍-沉积法合成AgBr/TiO2（001）纳米片复合可见光催化剂。采用X射线衍射（XRD）、透射电镜（TEM）、X射线光电子能谱（XPS）、紫外-可见光谱（UV-Vis）等手段对其进行了表征。在可见光（λ〉420nm）的辐照下,通过降解甲基橙来评价合成样品的可见光催化性能,探讨AgNO3的用量、不同溴源和F-在TiO2纳米片表面残留对催化性能的影响。结果表明,以NaBr为溴源制备Ag/AgBr@TiO2复合催化材料,当AgNO3添加量为0.313 5g时,其综合效果最优;而以CTAB为溴源制备的样品其催化活性明显高于以NaBr为溴源制备的样品;TiO2纳米片表面残留F-离子对活性略有影响。     

Novel dual heterojunction between MoS2 and anatase TiO2 with coexposed {101} and {001} facets

This work prepared an anatase TiO₂ by controlling coexposed {101} and {001} facets. The anatase TiO₂ was composited with MoS₂, and the photocatalytic behavior was studied. The relationship between the exposed ratio of {001} facets and the enhancement proportion by the composite was compared. An appropriate exposed ratio of {001} facets, instead of a high ratio, can cause the highest enhancement proportion for photocatalytic activity. This finding confirmed that exposed {001} facets are not the main factors for improving photocatalytic activity. Dual heterojunction was observed to form between MoS₂ and anatase TiO₂ with coexposed {101} and {001} facets, which is a crystal‐face heterojunction between {101} and {001} facets and a semiconductor heterojunction between MoS₂ and {001} facets of TiO₂. In this dual heterojunction, photo‐induced electrons in TiO₂ will flow into {101} facets of TiO₂, instead of MoS₂, whereas the photo‐induced holes in TiO₂ will flow into MoS₂ to reach a high separation efficiency. This finding further revealed the elevating mechanism of constructing heterojunction based on coexposed crystal faces.     

Improved photocatalytic hydrogen evolution by facet engineering of core-shell structural CdS@ZnO

The synthesis of photocatalysts with controlled facets has become an important approach to enhance the H₂ evolution activity. However, the relationship between different exposed facets of heterojunctions and photocatalytic performance still needs to be further investigated. In this study, three types of CdS@ZnO core-shell architectures with tunable heteroinnerfaces were fabricated. Hexagonal wurtzite ZnO samples with different percentages of exposed (001) facet showed up as rod-like, short rod-like and disk-like morphologies, respectively, subsequently, self-assembled flower-like CdS coated on the whole facet of ZnO, constructing a core-shell nanostructure with the corresponding tunable heterointerfaces. Under visible-light irradiation, it was discovered that the performance of hydrogen evolution is proportional to the ratio of (001) facet of ZnO in CdS@ZnO core-shell structures. Further photoelectric tests indicated that the (001) facet of ZnO by CdS modification can form a more perfect combination than that of (100) facet of ZnO, which exhibits higher electron conduction and separation performance.     

Evolution of {001}<110> orientation and related lattice rotation of Al alloy 6111 during rolling

The texture evolution and lattice rotation in Al alloy 6111 with an initial {001} <110> component during symmetrical and asymmetrical rolling were investigated by means of orientation distribution function(ODF). The results show that the as-rolled initial {001}<110 > entation evolves into not only the copper orientation but also all the other orientations along the β fiber, including the brass orientation, by lattice rotation around special directions. Compared with the symmetrical rolling, the {001}<110 > component in the surface layer on the slower roller side evolves more quickly into the orientations along the β fiber during asymmetrical rolling, while that in the surface layer on the faster roller side evolves more slowly.