Hydrolysis of Golenkinia sp. by Using a Rotating Packed Bed Reactor and Regeneration of Solid Acid Catalyst

Abstract

In the hydrolysis of microalgae with a solid catalyst, a novel rotating packed bed reactor (RPBR) was developed to improve the recyclability of the Amberlyst 36, a solid-acid catalyst. In a previous study, the hydrolysis of Golenkinia sp. using Amberlyst 36 with nitric acid in a conventional batch reactor was carried out, but the solid catalyst could only be recycled for four consecutive runs due to damage to the catalyst structure. As a solution to this catalyst degradation/destruction problem, Amberlyst 36 was charged in the packed bed column and was rotated instead of using impellers in an autoclave reactor. The packed bed column prevented the solid-acid catalyst from physical attrition caused by stirring with impellers, resultantly the recyclability of the solid catalyst increased dramatically. In addition to this, our approach of using the rotating packed bed column facilitated the particle-particle interactions between the catalyst and biomass, as a result of which high sugar yields of more than 70% (g/g) was achieved within four runs. Moreover, the reusability of Amberlyst 36 could be raised to 11 runs by simply employing a combination of two additional processes, sonication and reactivation processes with sulfuric acid solution. With our novel approach of using RPBR, a solid catalyst can be used perpetually for hydrolysis of algal biomass, which makes the process of hydrolysis efficient and economical compare to the conventional batch reactor.