School of Chemical and Process Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, LS2 9JT, UK.
Centre of Excellence in Environmental Studies (CEES), King Abdulaziz University, Jeddah, Saudi Arabia.
J Environ Manage. 2019 Nov 1;249:109316. doi: 10.1016/j.jenvman.2019.109316. Epub 2019 Aug 29.
This paper aims to examine the influence of various catalysts on biodiesel production, especially from non-food feedstocks with an ambition to optimize the catalytic biodiesel production. Homogenous acid catalysts are mainly used in biodiesel production, but they cannot be recovered and demand costly fuel purification as being corrosive. Similarly, enzyme catalysts are expensive in industrial-scale production of biodiesel. However, heterogeneous catalysts simplify the easy separation of product and by-products from the catalyst along with catalyst reusability and reduction of waste. Solid acid and base catalysts offer more advantages due to their non-toxicity, high surface area, reusability, higher stability, and the simplicity of purification. Solid base catalysts yield better activity than solid acid catalysts, however, they cannot esterify large amounts of free fatty acids (FFAs) in non-food feedstocks. The solid acid catalysts have the added advantages of being more tolerant to high amounts of FFAs and being able to simultaneously esterify FFAs and transesterify triglycerides in cheap feedstocks like waste cooking oil. Recently, an array of inorganic, organic and polymeric solid acid and nanomaterial-based catalysts have been developed using cheap feedstocks. However, the issues of low reactivity, small pore sizes, low stabilities, long reaction times, and high reaction temperatures still need to be solved. The developments of producing efficient, cheap, durable, and stable solid acid and nanomaterial-based catalysts have been critically reviewed in this study. Furthermore, the challenges and future perspectives of production of biodiesel and its industry growth have also been discussed.
本文旨在研究各种催化剂对生物柴油生产的影响，特别是从非食用原料中生产生物柴油，以优化催化生物柴油的生产。均相酸催化剂主要用于生物柴油生产，但不能回收，且腐蚀性强，需要昂贵的燃料净化。同样，酶催化剂在生物柴油的工业规模生产中成本较高。然而，多相催化剂简化了产品和副产物与催化剂的容易分离以及催化剂的可重复使用和废物减少。固体酸和碱催化剂具有非毒性、高比表面积、可重复使用性、更高的稳定性和简单的净化等优点，提供了更多的优势。固体碱催化剂比固体酸催化剂具有更好的活性，但不能酯化非食用原料中大量的游离脂肪酸（FFAs）。固体酸催化剂具有更高的容忍度，可以同时酯化非食用原料中的大量 FFAs 和转酯化甘油三酯，具有成本效益。最近，已经使用廉价原料开发了一系列无机、有机和聚合物固体酸和基于纳米材料的催化剂。然而，低反应性、小孔径、低稳定性、长反应时间和高反应温度等问题仍需解决。本研究对高效、廉价、耐用和稳定的固体酸和基于纳米材料的催化剂的开发进行了批判性的回顾。此外，还讨论了生物柴油生产及其行业增长的挑战和未来前景。
