磷镍复合改性HZSM-5催化乙醇脱水制乙烯

在离子交换法制备的Ni改性HZSM-5的基础上,采用等体积浸渍法引入不同含量的H3PO4改性,制备了磷镍复合改性的HZSM-5并用于乙醇脱水制乙烯。采用XRD、N2吸附脱附、PyTPD、27Al MAS NMR等表征手段考察了改性对分子筛的影响。结果显示:P添加后促进了骨架铝的脱离,导致强酸量进一步减少,提高了催化剂的使用寿命。活性评价结果表明,以8%磷酸改性的催化剂催化效果最好。然后考察了反应条件对其催化乙醇脱水制乙烯的影响,得到最适宜反应条件为温度260℃、质量空速1.5 h-1、进料乙醇体积分数为50%。在此条件下进行了稳定性测试,50 h内乙醇转化率大于97%,乙烯选择性高于98%,和仅用镍改性相比稳定性显著提高。     

Washing effect on properties of LiNi0.8Co0.15Al0.05O2 cathode material by ethanol solvent

Different LiNi_0.8Co_0.15Al_0.05O₂ cathode materials were washed by ethanol solvent. Inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier transformed infrared (FTIR) spectrum, X-ray diffraction (XRD), scanning electron microscopy (SEM), charge–discharge test and electrochemical impedance spectroscopy (EIS) were used to evaluate the elemental contents, structures, morphologies and electrochemical properties of samples. The results show that ethanol washing can remove effectively the synthetic residues LiOH/Li₂O on the freshly-prepared LiNi_0.8Co_0.15Al_0.05O₂ and make the sample much more resistant to H₂O and CO₂, without destroying its bulk structure, surface morphology and electrochemical performances. Moreover, the discharge specific capacity and cycle performance of LiNi_0.8Co_0.15Al_0.05O₂ after storage in air with a relative humidity of 80% for three months are improved by immediate ethanol washing.     

制约纤维素乙醇的技术难点及其研究进展

从原料预处理技术、纤维素酶技术、水解发酵工艺以及原料的综合利用技术等几个方面,对制约木质纤维素乙醇的技术难点进行了分析与讨论。     

关于醋酸加氢制乙醇技术的分析

本文针对醋酸一步法和两步法加氢制乙醇技术进行了简要介绍,并对两种方法进行了分析比较,得出了一步法相对两步法在技术合理性及生产成本方面具有一定的优势的结论。     

绿色合成法制备乙酸乙酯

以硫酸氢钠为催化剂,以乙酸和乙醇为原料合成了乙酸乙酯,讨论了相关影响因素。确定了最适宜的反应条件:酸醇物质的量比为1.5:1;催化剂取1.0g/0.2mol乙醇;反应时间是1.5h。在此最佳反应条件下,产品收率达到80.6%。此外,催化剂硫酸氢钠能够重复使用若干次。与传统的制备方法相比,本方法遵循发展循环经济的指导方针,既达到了节能减排与清洁生产的目的,同时又提高了产品收率。     

中国生物燃料乙醇产业发展现状、存在问题及政策建议

燃料乙醇等生物质能源由于其技术的可实现性、资源的可持续性以及环境的友好性已经成为各国替代能源的重要发展方向。本文阐述了燃料乙醇产业发展的历程和现状,指出燃料乙醇产业发展中存在的问题,并提出了解决问题的对策。     

分离条件对乙醇法麦草浆黑液总糖及粗木素含量的影响

乙醇法制浆黑液里含有丰富的多糖成分,对其进行资源回收和利用是对生物质资源的高值化利用。本文从乙醇法麦草浆黑液酸析木素工艺入手,探讨了pH值、温度等因素对黑液中总糖及粗木素含量的影响。在酸析黑液pH值2.5～3.5,温度60～70℃条件下,乙醇法麦草浆黑液中的多糖含量可达9.5～9.8g·L-1。     

Mechanism study of the ethanol oxidation reaction on palladium in alkaline media

In this work, the mechanism of the ethanol oxidation reaction (EOR) on a palladium electrode was studied using the cyclic voltammetry method. The dissociative adsorption of ethanol was found to proceed rather quickly and the rate-determining step was the removal of the adsorbed ethoxi by the adsorbed hydroxyl on the Pd electrode. The Tafel slope was found to be 130 mV dec⁻¹ at lower potentials, which suggests that the adsorption of OH⁻ ions follows the Temkin-type isotherm on the Pd electrode. In comparison, the Tafel slope increased gradually to 250 mV dec⁻¹ at higher potentials. The change in the Tafel slope indicated that, at higher potentials, the kinetics is not only affected by the adsorption of the OH⁻ ions, but also by the formation of the inactive oxide layer on the Pd electrode.     

乙醇提取海南番木瓜中木瓜蛋白酶的工艺研究

主要是采用乙醇作为提取剂对番木瓜中木瓜蛋白酶进行提取,并通过紫外法测定其酶的活性。实验中,我们对各种影响因素进行了研究分析。并确定出几组最佳工艺参数,结果表明:在提取工艺中,L-cys和EDTA添加量分别为0.04mol/L和0.004mol/L时对木瓜蛋白酶活性起到最佳保护作用,乙醇添加量为45%,pH为7.0时能获得最佳提取效果。在测定工艺中,最适酶反应时间为10min,最适酶反应温度为80℃,同时,在实验中我们也考察了金属离子对酶活性的影响,实验结果得,Cu2+、K+对木瓜蛋白酶活性有一定的抑制作,而Ca2+离子则对其活性有一定的激活作用,且在浓度为0.05mol/L时效果最为明显。