Chen W, Wu Z, Peng R, Wu W, Li X, Cao D, Zhang Z, Niu K. Low-cost diatomite supported binary transition metal sulfates: an efficient reusable solid catalyst for biodiesel synthesis.
RSC Adv 2023;
13:6002-6009. [PMID:
36816082 PMCID:
PMC9936845 DOI:
10.1039/d2ra07947j]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/05/2023] [Indexed: 02/19/2023] Open
Abstract
Using a simple method of impregnation and then calcination, diatomite supported binary transition metal sulfates (Fe and Zr, designated as Fe2(SO4)3&Zr(SO4)2@diatomite) were prepared and used as a catalyst in the preparation of renewable biofuels. The synthesised Fe2(SO4)3&Zr(SO4)2@diatomite catalyst (Fe2(SO4)3 : Zr(SO4)2 : diatomite = 1 : 2 : 6, mass ratio) was thoroughly characterised using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, microbeam X-ray fluorescence (μ-XRF) spectroscopy and thermogravimetric analysis (TG). The results demonstrated that the sulfate was successfully loaded onto the diatomite with a uniform distribution. The N2 adsorption/desorption analysis indicated that the catalyst's specific surface area was 1.54 m2 g-1. The catalyst exhibited outstanding performance in the preparation of renewable biofuel (biodiesel) from waste fatty acids and the optimal parameters were methanol-to-oil 1.25 : 1, reaction temperature 70 °C, catalyst concentration 10 wt%, reaction time 4 h. The conversion was found to reach 98.90% under optimal parameters, which is better than that of Fe2(SO4)3·xH2O, Zr(SO4)2·4H2O, Fe2(SO4)3@diatomite and Zr(SO4)2@diatomite. Moreover, the catalyst can be recycled by simple filtration and reused for three cycles after regeneration without noticeable reduction in catalytic activity.
Collapse