The role of surface Zn²⁺ ions in the transesterification of vegetable oils over ZnO supported on Al₂O₃ and Fe₂O₃

Abstract

ZnO–Al2O3 and ZnO–Fe2O3 with different loadings of ZnO (5–20 wt%) along with ZnAl2O4 and ZnFe2O4 were prepared and tested in the transesterification of sunflower, waste cooking oil and Jatropha oil.

RETRACTED ARTICLE: Investigating the Heteronjunction between ZnO/Fe2O3 and g-C3N4 for an Enhanced Photocatalytic H2 production under visible-light irradiation

“…In addition, the peaks of Zn 2p at 1019.9 and 1022.3 eV were identified as Zn 2+ -O-Fe 3+ and Zn-N in Fig. 3(c), respectively 29–31 . The binding energies of Fe 2p 1/2 and Fe 2p 3/2 were identified at 724.0 and 710.7 eV, respectively, which are in good accord with the standard spectra of Fe 2p1/2 and Fe 2p3/2 in Fe 2 O 3 .The peaks of Fe 2p at 713.6, 715.4 and 718.8 eV were attributed to Fe 3+ -O-Zn 2+ , Fe(OH) 3 , and N-Fe-OH in Fig.…”

Widely used catalysts in biodiesel production: a review

“…In the meantime, the ZnAl 2 O 4 /ZnFe 2 O 4 catalyst was also examined for the transformation of oil, such as sunower oil, WCO and JCO. 331 During the reaction, the Zn 3d electrons of the ZnAl 2 O 4 and ZnFe 2 O 4 spinels were likely to take part in the electronic excitation; thereby, the Zn 3d electrons are probably going to undertake a vital job to enhance the catalyst reactivity. In 2012, Xie et al 332 synthesized the SnO 2 -SiO 2 catalyst by loading 8 wt% Sn onto SiO 2 , followed by calcination (550 C) and exploited it in the transformation of soybean to FAME, yielding 81.7% under the optimal reaction conditions.…”

Pure and Al-doped ZnO obtained by the modified Pechini method applied in ethanolic transesterification of cottonseed oil

“…For the ZnO-Al 2 O 3 system, different papers report the catalytic activity of the ZnAl 2 O 4 spinel [10,11]. For instance, Thirunavukkarasu et al [10] ), which reached more than 80%.…”

“…For instance, Thirunavukkarasu et al [10] ), which reached more than 80%. Another interesting paper [13] reports the use of Zn-doped Al 2 O 3 (20 mol% ZnO) as a catalyst in the ethanolic and methanolic transesterification of soybean oil.…”

“…Zinc oxide is an amphoterous oxide and has been used as a catalyst for transesterification reactions in its pure form, mixed with other oxides or salts, or as a support or matrix for other substances [8][9][10][11][12][13]. Nascimento et al [8] compared the efficiency of ZnO with CaO, CaTiO 3 and TiO 2 , which were all obtained by the polymeric precursor method.…”