(2016) Esterification of fatty acids from waste cooking oil to biodiesel over a sulfonated resin/PVA composite. Catalysis Science and Technology, 2016 (6). pp. 5590-5598. ISSN 2044-4761 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/33644/1/ZhangHL%20Catalysis%20Science %20%26%20Technology%202016%20online.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Sulfonated cation exchange resins (s-CER) have been widely studied as a replacement of liquid acids for the catalysis of esterification of free fatty acids (FFAs) to produce biodiesel with water as the only by-product. However, the water produced has strong affinity to sulfonate groups in s-CER, which blocks the reactive sites for esterification and thus reduces the activity of the catalyst. To overcome this technical barrier, we have designed an s-CER/PVA composite by incorporating s-CER fines within a poly (vinyl alcohol) (PVA) matrix. PVA has much stronger absorption preference of water than s-CER and has very low selectivity for the reactants (FFAs and methanol), which enables the continuous removal of the produced water and liberation of reactive sulfonate sites in s-CER for catalysis. With s-CER/PVA, the FFAs conversion was increased from 80.1 % to 97.5 % after 8-hour reaction and the turnover frequency (TOF) was increased more than 3.3 times. The TOF of s-CER/PVA was also 2.6 times of that of sulfuric acid, suggesting that the water less, heterogeneous sulfonate sites are more reactive than water-blocked homogeneous ones. The reusability of the s-CER/PVA was also enhanced due to that the produced water that could cause deactivation of the s-CER was largely removed by PVA.

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