Efficient production of biodiesel from high free fatty acid-containing waste oils using various carbohydrate-derived solid acid catalysts

• Published in: Bioresource technology 2008-12, Vol.99 (18), p.8752-8758
• Main Authors: Lou, Wen-Yong, Zong, Min-Hua, Duan, Zhang-Qun
• Format: Article
• Language: English
• Subjects: Acids; Applied sciences; biodiesel; Biodiesel production; Bioelectric Energy Sources; Biofuel production; Biological and medical sciences; Biotechnology; Carbohydrate-derived catalysts; Carbohydrates - chemistry; Catalysis; catalysts; cellulose; cooking fats and oils; Energy; Esterification; Exact sciences and technology; Fatty Acids, Nonesterified - metabolism; food wastes; free fatty acids; Fundamental and applied biological sciences. Psychology; glucose; High FFAs; Industrial applications and implications. Economical aspects; methyl esters; Plant Oils - metabolism; Pollution; Refuse Disposal; Spectrum Analysis; starch; Starch-derived solid acid catalyst; sucrose; texture; Time Factors; transesterification; Waste oils; waste utilization; Wastes; yields
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2008.04.038

In the present study, such carbohydrate-derived catalysts have been prepared from various carbohydrates such as d-glucose, sucrose, cellulose and starch. The catalytic and textural properties of the prepared catalysts have been investigated in detail and it was found that the starch-derived catalyst had the best catalytic performance. The carbohydrate-derived catalysts exhibited substantially higher catalytic activities for both esterification and transesterification compared to the two typical solid acid catalysts (sulphated zirconia and Niobic acid), and gave markedly enhanced yield of methyl esters in converting waste cooking oils containing 27.8 wt% high free fatty acids (FFAs) to biodiesel. In addition, under the optimized reaction conditions, the starch-derived catalyst retained a remarkably high proportion (about 93%) of its original catalytic activity even after 50 cycles of successive re-use and thus displayed very excellent operational stability. Our results clearly indicate that the carbohydrate-derived catalysts, especially the starch-derived catalyst, are highly effective, recyclable, eco-friendly and promising solid acid catalysts that are highly suited to the production of biodiesel from waste oils containing high FFAs.