Development of surface-engineered super-hydrophobic antifouling membrane based microalgal photobioreactor for enhancing CO ₂ sequestration and biomass productivity

Escalating the efficacy of microalgal cultivation process is proposed in photobioreactor by using an innovative membrane-based bubble sparger for efficient dissolution of gas phase CO₂ using <i>Scenedesmus</i> sp. Surface functionalization was done on tubular ceramic substrates using Hexadecyltrimethylsiloxane (HDTMS) for enhancing mass transfer and antifouling property. The optimum membrane was found to be super-hydrophobic, contact angle >153°. The membrane sparger (HMS) based system resulted in higher biomass concentration (2.26 g/l) and higher CO₂ bio-fixation efficiency (0.57 g CO₂/l/day) after seven days compared to 0.69 g/l and 0.15 g CO₂/l/day for the conventional bubble sparger (CBS) system. Moreover, for HMS system biomass concentration and CO₂ bio-fixation efficiency increases up to 3.12 g/l and 0.80 g CO₂/l/day respectively using dairy wastewater (50%). The overall study demonstrates the applicability of proposed process for enhancing <i>Scenedesmus</i> sp. biomass productivity and CO₂ sequestration in membrane photobioreactor (C-MPBR) process using industrial waste resources along with minimizing microalgae induced biofouling of the spargers.