Biomass Group, Nanjing Agricultural University, PO Box 68, 40 Dianjiangtai Road, Nanjing 210031

Biodiesel production by transesterification with homogeneous catalysts (e.g, sodium methoxide, sodium or potassium hydroxide) is one of the most common methods, but it is difficult to recycle due to they are dissolved in methanol and glycerol mixture. So, researchers have focused on finding suitable heterogeneous solid catalysts, such as K2CO3 supported activated carbon, CaO, Sr/MgO, MnO and TiO, to replace homogeneous liquid catalysts. However, solid base catalysts are easy to deactivate when low qualified oils with high acid value (AV) are used as raw materials due to soap formation.
Mr. Zhang Fan, a PhD student, under the guidance of Professor Zhen Fang in Xishuangbanna Tropical Botanical Garden (CAS), prepared cheap and active magnetic heterogeneous catalyst (Na2SiO3@Fe3O4/C) for the production of biodiesel from oils with high acid value (AV) under ultrasonic (US) irradiation and magnetic stirring (MS). With the catalyst and assisted by US, soybean biodiesel yield reached > 90% in only 20 min (or at 318 K) and 97.9% under the optimal conditions. It was easily magnetically separated for 5 cycles with 94.9% recovery rate and biodiesel yield > 80% with both US and MS. The catalyst transesterified Jatropha oil with biodiesel yields of 94.7%, 93.2% and 83.5% at AV of 1.3, 4.8 and 7.3 (mg KOH/g) with US. High biodiesel yield (90.7%) was still achieved from high AV oil (4.8) at low US energy density (0.1 W/mL) and MS. The catalyst combined with US and MS can find practical application for direct production of biodiesel from oils with high AV, and recovered easily for recycles.
The results are published in fuel:
F Zhang, Zhen Fang*, YT Wang, Biodiesel Production Directly from Oils with High Acid Value by Magnetic Na2SiO3@Fe3O4/C Catalyst and Ultrasound, Fuel, 150, 370-377 (2015).

Na2SiO3@Fe3O4/磁性催化剂的制备及其用于超声波直接从高酸值油脂生产生物柴油

由于石化资源有限并且燃烧后二氧化碳浓度急剧升高，所以开发利用可再生的生物质燃料具有重要的价值和意义。生物柴油是一种清洁、可再生、碳中性并可替代石化柴油的液体燃料。利用均相催化剂（如：甲醇钠、氢氧化钾或氢氧化钠）通过酯交换反应制备生物柴油是最常用的方法，但是由于此类催化剂会溶解到甲醇和甘油中使得其难以循环再利用。所以研究人员一直努力寻找合适的非均相固体催化剂，例如碳载K2CO3、CaO、Sr/MgO、 MnO和TiO取代均相液体催化剂。但是碱性非均相固体催化剂由于皂化反应，不适宜用高酸值油（如废弃煎炸油、动物油脂和小桐子油）制备生物柴油。同时，与超声波辐射相比，在机械搅拌方式下，需要更长时间（如3 h）的酯交换反应制备生物柴油。
中国科学院西双版纳热带植物园生物能源组博士生张帆在方真研究员的指导下，成功合成了磁性非均相固体催化剂（Na2SiO3@Fe3O4/C），并利用该固体催化剂在超声波和机械搅拌条件下用于高酸值油脂制备生物柴油。实验结果表明：在20分钟45摄氏度的超声波辅助条件下大豆油得率高于90%（最优条件下可以达到97.9%），在机械搅拌和超声波辐射协同作用时，该催化剂循环五次后生物柴油得率仍然高于80%且催化剂回收率为94.9%。利用该催化剂催化转化不同酸值（1.3、4.8 和 7.3 mg KOH/g）小桐子油，其生物柴油得率分别为94.7%、93.2% 和 83.5%，并且在较低的超声波能量密度下（0.1 W/mL），高酸值小桐子油（4.8 mg KOH/g）的生物柴油得率仍然可以达到90.7%。结合机械搅拌和超声波辅助条件，Na2SiO3@Fe3O4/C可以实现高酸值原料油直接转化制备生物柴油。相关研究成果发表在国际著名能源期刊Fuel上：
F Zhang, Zhen Fang*, YT Wang, Biodiesel Production Directly from Oils with High Acid Value by Magnetic Na2SiO3@Fe3O4/C Catalyst and Ultrasound, Fuel, 150, 370-377 (2015).

图为可磁性分离的催化剂Na2SiO3@Fe3O4/C用于小桐子生物柴油制备

Recently, Elsevier-Scopus listed Prof. Zhen Fang in “2014 Most Cited Chinese Researchers” in energy.
方真研究员进入“2014年中国高被引学者”能源领域榜单（Elsevier-Scopus).
Dr. Zhen Fang, a researcher in bioenergy, returned to China in 2007 from McGill, Canada formed biomass group in CAS as leader and professor. He is specializing in thermal/biochemical conversion of biomass, nanocatalyst synthesis and its applications, pretreatment of biomass for biorefineries. He obtained his PhDs from China Agricultural University (Biological & Agricultural Engineering, Beijing) and McGill University (Materials Engineering, Montreal).
He is the inventor of “fast hydrolysis” process， Editor-in-Chief, Springer Book Series – Biofuels and Biorefineries; Editor-in-Chief, Journal of Technology Innovations in Renewable Energy; Associate Editor, Biotechnology for Biofuels (IF 6.2, Highest IF in Biofuels); and Editorial Advisory Board Member of Biofpr (Biofuels, Bioproducts and Biorefining, IF 4.3) as well as Energy, Sustainability and Society (a Springer open Journal).
He has 174 scientific papers, reports, books and patents, including 86 papers (31 as first author, 55 as corresponding author) published in top journals (most of them in Q1)  in the areas of energy & fuel, and chemical engineering (Scopus paper: 87; cites: >2000; H index: 23- Scopus Author ID: 7402681505; He wrote 3 books (2 in English), 10 book chapters, 29 papers in refereed conference proceedings and 7 reports, edited 10 English books in renowned international publishers (e.g., Springer), gave 32 keynote & invited lectures and 27 oral presentations & posters, and filed 27 Chinese, 3 US and 3 international PCT invention patents (17 Chinese and 1 US patents were authorized).

Recent selected english books:

1. 1. Zhen Fang, R. L. Smith, Jr., X. Qi (Editors), Hydrogen Production from Renewable Resources, Springer Book Series – Biofuels and Biorefineries, 13 chapters, Contract-signed, Expected published in 2015.
2. 2. Zhen Fang, R. L. Smith, Jr., X. Qi (Editors), Production of Biofuels and Chemicals with Microwave, Springer Book Series – Springer Book Series – Biofuels and Biorefineries, Springer-Verlag, Heidelberg Berlin, ISBN 978-94-017-9611-8, hardcover, 300 pages, 2014.
3. 3. Zhen Fang, R. L. Smith, Jr., X. Qi (Editors), Production of Biofuels and Chemicals with Ultrasound, Springer Book Series – Springer Book Series – Biofuels and Biorefineries, Springer-Verlag, Heidelberg Berlin, ISBN 978-94-017-9623-1, hardcover, 415 pages, 2014.
4. 4. Zhen Fang, C. Xu (Editors), Near-critical and Supercritical Water and Their Applications for Biorefineries, Springer Book Series – Biofuels and Biorefineries, Springer-Verlag, Heidelberg Berlin, ISBN 978-94-017-8922-6, hardcover, 520 pages, 2014.
5. 5. Zhen Fang, R. L. Smith, Jr., X. Qi (Editors), Production of Biofuels and Chemicals with Ionic Liquids, Springer Book Series – Biofuels and Biorefineries, Springer-Verlag, Heidelberg Berlin, ISBN 978-94-007-7710-1, hardcover, 353 pages, 2013. (Highly downloaded: 6,313 chapter downloads for Jan-May 2014).
6. 6. Zhen Fang (Editor), Liquid, Gaseous and Solid Biofuels – Conversion Techniques, InTech – Open Access, ISBN 978-953-51-1050-7, hardcover, 541 pages, 2013. (31293 chapter downloads for March 2013-June 2014).
7. 7. Zhen Fang (Editor), Biofuels – Economy, Environment and Sustainability, InTech – Open Access, ISBN 978-953-51-0950-1, hardcover, 386 pages, 2013. (24127 chapter downloads for Jan 2013-June 2014).
8. 8. Zhen Fang (Editor), Pretreatment Techniques for Biofuels and Biorefineries, Springer-Verlag, Berlin Heidelberg,  ISBN 978-3-642-32734-6, hardcover, 476 pages, 2013. (Among the top 25% most downloaded eBooks in 2013).
9. 9. Zhen Fang (Editor), Biodiesel – Feedstocks, Production and Applications, InTech – Open Access, ISBN 978-953-51-0910-5, hardcover, 487 pages, 2013. (35026 chapter downloads for Dec 2012-June 2014).
10. 10. J. M. Marchetti, Zhen Fang (Editors), Biodiesel: Blends, Properties and Applications (Hardback). New York: Nova Science Publishers, Inc., ISBN 13: 9781613246603 ISBN 10: 1613246609, 379 pages, Sep. 2011.
11. 11. Zhen Fang (Author), Rapid Production of Micro- and Nano-particles Using Supercritical Water, Springer-Verlag, Berlin Heidelberg, ISBN: 978-3-642-12986-5, hardcover, 120 pages, 2010.
12. 12. Zhen Fang (Author), Complete Dissolution and Oxidation of Organic Wastes in Water, VDM Verlag Dr. Müller, Saarbrücken, Germany, ISBN: 9783639144246, paperback, 192 pages, April 2009.

Climate change and rising oil prices have urged the needs for researching alternative energy. Among possible alternative resources, lignocellulosic biomass is one of the promising raw materials, which has been intensively studied recently. （更多…）

Biodiesel is an environment-friendly renewable energy. The critical issues on biodiesel studies are the development of recyclable and reusable solid catalyst and the use of non-edible oil such as Jatropha oil as feedstock. Fang’s team from XTBG uses coprecipitation-calcination-reduction method to prepare solid CaFe₂O₄-Ca₂Fe₂O₅-Fe₃O₄-Fe catalyst with certain magnetism. This catalyst maintains a relative high activity on catalytic transesterification, and concurrently solves the separation of solid catalyst from products, as well as the disposal of waste acidic liquid and unwanted emulsification in homogeneous catalysis. The conversion of soybean and Jatropha oils to biodiesel over this catalyst reach 83.5% and 78.2%, respectively. The main active components of catalyst are calcium ferrites on the catalyst surface. The magnetic catalyst could be recycled and reused for three times, which shows a potential application for the green production of biodiesel.

Related paper titled “Biodiesel Production from Soybean and Jatropha Oils by Magnetic CaFe₂O₄-Ca₂Fe₂O₅-Based Catalyst” was published on the journal “Energy” (Energy, 2014, 68: 584-591, IF =3.65).

Loss of hemicellulose and inability to effectively decrystallize cellulose, result in low yield and high cost of sugars derived from biomass. Dilute sulfuric acid pretreatment could easily remove most of hemicellulose as sugars. （更多…）