IMMOBILIZING MICROALGAE IN HYBRID MATRICES AS A GREEN TECHNOLOGY FOR NATURAL GAS SWEETENING USING NOVEL STATIC SYSTEM

Photosynthetic microorganisms have been widely studied as an alternative technology for CO₂ capture. Aiming to overcome some operational challenges in the application of these microorganisms for gas treatment on a large scale, the immobilization of microalgae in solid matrices emerges as an alternative to facilitate effective management of microalgae culture during harvesting process. In this work, different matrices for microalgae immobilization composed of silica/alginate were obtained varying silica precursors. The synthesized materials were characterized in terms of their specific surface area, cell viability, transparency and physical-chemical properties. Additionally, a new methodology was developed to evaluate the CO₂ capture by microalgae using a pressurized system with natural gas mixture. Tests were carried out exploring the influence of some variables, such as headspace volume, cell concentration, stirring and pressure. Once the optimized parameters were established, the amount of CO₂ captured by immobilized microalgae was investigated for 7 days by determining the CO₂ relative concentrations using gas chromatography. The results of immobilized microalgae showed levels of CO₂ removal of 41.4%. This work proved the potential application of the studied biomaterial for natural gas processing, making even more feasible the adoption of this technology for selective capture of CO₂ on an industrial scale.

Keywords:
microalgae; carbon capture; silica hydrogel; immobilized microorganisms