A preliminary study of sustainable coagulant produces from chicken eggshells to accelerate microalgae harvesting

Abstract Microalgae have emerged as a promising feedstock for biofuels and biochemicals, but the energy-intensive and costly harvesting processes hinder their large-scale commercialization. This study investigates the synthesis and application of coagulants derived from chicken eggshells for the efficient harvesting of microalgae, specifically Chlorella sp. Conventional harvesting methods are often energy-consuming and rely on synthetic chemicals. Thus, using a waste material such as eggshell encouraging the need for sustainable alternatives. Utilizing waste materials like eggshells, composed primarily of calcium carbonate, presents a cost-effective and organic solution. The study evaluates the impact of flocculation parameters, including pH and coagulant dosage, on the agglomeration efficiency of microalgae and media. Results indicate that optimal agglomeration efficiency of 97.81% occurs at a pH of 6, while the optimal agglomeration efficiency of 96.98% is achieved with a coagulant dosage of 6.0 g/L. This research highlights the potential of eggshell-derived coagulants to enhance microalgae harvesting, contributing to a more sustainable bioeconomy by promoting the circular use of agricultural waste.