Synthesis and Characterization of Novel Corncob-Based Solid Acid Catalyst for Biodiesel Production

Abstract

In the present study, highly efficient catalysts based on corncob were synthesized for the esterification process. The synthesized catalysts were characterized by BET, XRD, and FT-IR. The effect of catalyst impregnation, carbonation, and sulfonation was studied in detail. The highest conversion of oleic acid (∼94.4%) was observed using a catalyst synthesized at H 3 PO 4 impregnation ratio = 1 and time = 5 h; carbonization temperature = 723 K and time = 8 h; sulfonation temperature = 393 K and time = 15 h. Further, the performance of the catalyst was studied for the esterification of fatty acids (FAs) and free fatty acids (FFAs) present in Karanja oil. The catalyst showed ∼90% conversion of FAs/FFAs within 2 h at 338 K using a molar ratio of 1:10 (FA to methanol)/ 1:20 (Karanja oil to methanol) and a catalyst loading of 10 wt %. Furthermore, the reusability test of the catalyst revealed that it can be used for 20 times in a batch reactor to give ∼90% conversion of the oleic acid.

State‐of‐the‐Art of the Synthesis and Applications of Sulfonated Carbon‐Based Catalysts for Biodiesel Production: a Review

“…The reusability of the corncob‐based SCC in the oleic acid esterification was also conducted at 65 °C for 20 cycles by using methanol, ethanol, n ‐hexane as regeneration agents. [ 123 ] The outcome of the study evidenced the excellent stability of the catalyst regenerated by n ‐hexane, where ∼90% oleic acid conversion was achieved for each cycle with only insignificant decline in activity as shown in Figure 11 . It was observed that the catalyst performance of glucose‐based SCC maintained FFA conversion at 76% for five consecutive cycles during the PFAD esterification and declined to <70% after the sixth cycle [38c] .…”

“…SCC derived from sugarcane bagasse, [ 42,92 ] glucose, [38b-d] oil palm EFB, [36a] palm seed, [ 48 ] corncob, [ 122,123 ] palm kernel shell, [ 2 ] bamboo, [ 2 ] cow dung, [ 41 ] bituminous coal, [ 112,124,125 ] murumuru kernel shell, [ 93 ] and orange peel [ 45 ] have been used in the esterification of PFAD previously. Nonedible PFAD is produced as a by‐product in the oil palm processing factories in the fatty acid deodorization and stripping stages.…”

A review of sustainable biodiesel production using biomass derived heterogeneous catalysts

“…A number of reports published demonstrate increased solid acid heterogeneous catalysts doped with sulfated oxides. For example typical solid superacids such as SO 4 2– /ZrO 2 , SO 4 2– /TiO 2 , SO 4 2– /TaO 5 , SO 4 2– /Nb 2 O 5 [ 66 , 69 , 263 , 312 – 314 , 316 , 319 , 320 ]. Table 9 is a summary showing modified metal oxides doped with sulfated metal oxides for the production of biodiesel.…”

Corncob residue as heterogeneous acid catalyst for green synthesis of biodiesel: A short review

“…There are two common ways of sulfonation on corn cob as acid catalyst preparation, reflux system, and thermal treatment using an autoclave Teflon reactor. These two methods have a different effect on BET surface area and pore properties of catalyst [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71]. Ibrahim et al [53] found that the surface area of solid catalysts before and after sulfonation by using a reflux system was almost identical, i.e.…”

“…It was due to the insertion of -SO3H groups on the surface. Hussain and Kumar [59] reported the change of surface area before and after sulfonation of corncob-derived heterogeneous catalyst in which the surface area decreased after sulfonation from 1268 m 2 .g -1 to 641 m 2 .g -1 . They claimed that the decrease on surface area after sulfonation indicated that the -SO3H groups successfully grafted onto surface, which acted as the active sites.…”