【摘要】：隨著世界的發(fā)展,化石燃料儲備進一步枯竭,能源危機的出現(xiàn)及全球變暖、環(huán)境污染等問題迫使人類尋找可再生能源。人類的生存離不開大自然,由于資源的過度開采,導(dǎo)致環(huán)境問題日趨嚴(yán)重,保護環(huán)境迫在眉睫。生物柴油技術(shù)來源于大自然——可再生的植物、動物油等提取的油脂,經(jīng)過化學(xué)反應(yīng)制備的一種可以替代化石燃料的可再生能源。生物柴油是一種可再生能源,燃燒產(chǎn)物清潔無害,目前其生產(chǎn)方式為堿性條件下的酯交換反應(yīng),堿性催化劑在較為溫和的條件下就可表現(xiàn)出較高的活性,但存在催化劑與產(chǎn)物分離困難,不利于其長期發(fā)展。(1)以FeCl3·6H_2O和FeCl2·4H_2O為原料(Fe3+、Fe2+摩爾比為2:1),制備磁性Fe_3O_4粒子,再以共沉淀法制備Fe_3O_4/MgAl-LDHs。在500℃下進行高溫焙燒得到Fe_3O_4/Mg(Al)O磁性固體堿。通過熱重(TG-DTG)、X射線衍射(XRD)、掃描電鏡(SEM)、能譜(EDS)、透射電鏡(TEM)、振動樣品磁強計(VSM)對其晶體熱穩(wěn)定性、組成、結(jié)構(gòu)、比表面積及磁學(xué)性能進行表征,并研究催化劑的酯交換活性。研究表明:MgAl-LDHs與Fe_3O_4形成一種復(fù)合物,具有類水滑石典型的層狀結(jié)構(gòu),也有一定的磁響應(yīng)能力,經(jīng)500℃焙燒后生成了Fe_3O_4/MgAl-LDO,其比表面積顯著增加,具有較高的酯交換活性。通過性能評價,在反應(yīng)溫度65℃,反應(yīng)時間4h,n(甲醇):n(微藻油)=13:1,m(Fe_3O_4/MgAl-LDHs):m(微藻油)=4%的最優(yōu)反應(yīng)條件下,生物柴油產(chǎn)率達90%,具有重復(fù)利用性。(2)以共沉淀法制備Zn改性的Fe_3O_4/ZnMgAl-LDHs新型固體堿催化劑,通過熱重(TG-DTG)、X射線衍射(XRD)、掃描電鏡(SEM)、能譜(EDS)、透射電鏡(TEM)、振動樣品磁強計(VSM)對其進行表征。研究結(jié)果表明,當(dāng)Zn2+的摻雜量為15%,n(甲醇):n(微藻油)=12:1,m(Fe_3O_4/ZnMg(Al)O):m(微藻油)=3%,65℃反應(yīng)3h時,Fe_3O_4/ZnMgAl-LDHs催化活性最高,微藻新型生物柴油的收率高達94%,在重復(fù)使用7次后,生物柴油收率仍高于82%。
[Abstract]:With the development of the world, fossil fuel reserves have been depleted further, the emergence of energy crisis and global warming, environmental pollution and other problems forced people to look for renewable energy. The survival of human beings can not be separated from nature. Because of the over-exploitation of resources, environmental problems are becoming more and more serious, so it is urgent to protect the environment. Biodiesel technology comes from nature, renewable plant, animal oil, etc. It is a kind of renewable energy which can replace fossil fuel by chemical reaction. Biodiesel is a kind of renewable energy, and the combustion product is clean and harmless. At present, its production mode is transesterification under alkaline conditions, and the alkaline catalyst can exhibit higher activity under mild conditions. However, it is difficult to separate the catalyst from the product, which is not conducive to its long-term development. (1) Magnetic Fe_3O_4 particles were prepared by using FeCl3 6H_2O and FeCl2 4H_2O as raw materials (Fe3, Fe2 molar ratio was 2:1). Preparation of Fe_3O_4/MgAl-LDHs. by coprecipitation Fe_3O_4/Mg (Al) O magnetic solid base was obtained by calcination at 500 鈩，

本文編號：2338678