Using modified-clay as green-natural flocculant for efficient microalgae harvesting

Microalgae harvesting is one of the major bottleneck of microalgae industries, constituting up to ۳۰% of total biomass production costs. In this research, natural bentonite was modified with cationic surfactant to be implemented for microalgae harvesting. Characterizations of the clay and modified-clay were performed using SEM, FTIR and XRD. The effect of key parameters such as pHsolution and flocculants dosage on harvesting microalgae efficiency was investigated. The characterization results proved that the bentonite was successfully modified by cationic surfactant. The effect of pH indicated that increased pH leads to decreased harvesting efficiency. Maximum biomass harvesting of ۹۵% was achieved using modified-clay under their optimum dosage of ۰.۸ g/L and after ۲۰۰ min sedimentation time. Our finding suggested modified-clay as a promising flocculants that could be applied as low-cost and eco-friendly for the harvesting of microalgae.