ZrMo oxides supported catalyst with hierarchical porous structure for cleaner and sustainable production of biodiesel using acidic oils as feedstocks

Abstract

Ameliorating the reactant mass transfer and fabricating the multiple active sites on the catalyst surface are feasible strategies to synthesize efficient and recyclable catalysts for efficient biodiesel production by using acidic oils as feedstocks. Herein, hierarchical porous solid acids with Zr and Mo oxides as active sites were prepared by using polystyrene spheres (PS) and P123 as templates. It was shown that the active species of Zr and Mo oxides were uniformly dispersed on the hierarchical porous silica support, and the solid catalysts featured high surface area and interconnected mesoporous/macropores with high mass diffusive extent, showing improved catalytic performances for the biodiesel production as compared to the control catalyst without hierarchical pores, owing to the mass transfer enhancement and more easily accessible active sites. The transesterification reaction in 93.8% of oil conversion as well as complete conversion of free fatty acids (FFAs) were simultaneously performed by using this solid catalyst, hence achieving one-pot transformation of acidic oils to biodiesel and minimizing the complex and tedious separation process. Moreover, the higher water and FFA-resistance capacity was shown for this solid catalyst, posing its more suitable for the biodiesel production with acidic oils as feedstocks. This hierarchical porous solid catalyst could be facilely recycled using simple filtration, and still maintained high activities after reuse for five runs, which rendered it to have the potential of cost-effective production of biodiesel in particular from low-grade acidic oils.