Aminoclay-conjugated TiO2 synthesis for simultaneous harvesting and wet-disruption of oleaginous Chlorella sp.

Abstract

In microalgae-based biorefinement, the integration of harvesting and lipid extraction steps could reduce the costs of downstream processes. One potential of integrated methods, microalgae harvesting by aminoclay-conjugated TiO2 has been considered. Therein, aminoclay plays an efficient role in microalgae flocculation and direct cell disruption by TiO2 photocatalytic performance under UV-light irradiation. In the present study, two TiO2 photocatalysts, a commercial anatase/rutile bicrystalline (of similar to 5 nm diameter) and anatase/brookite bicrystalline (of similar to 3.5 nm diameter) by sol-gel reaction at room temperature, were distributed uniformly onto an aminoclay matrix by ultrasound-irradiated TiO2 particles, resulting in aminoclay-conjugated TiO2 composites. Within 10 mm, the injection of aminoclay-conjugated TiO2 into the prepared 1.5 g/L-concentration microalgal feedstocks produced an similar to 85% harvesting efficiency for oleaginous Chlorella sp. KR-1. Subsequently, the harvested wet-microalgae biomass was UV-irradiated at 365 nm for 3 h, thereby effecting the disruption of similar to 95% of cells.