Coagulant-specific intracellular release and capture dynamics in algae removal: Insights into Process behavior and...

To comprehensively understand coagulant-specific behaviors in algal-laden water, this work focused on the release and cooperative removal mechanism of intracellular substances in algal cells during the traditional coagulation process. Compared with polyferric chloride (PFC), polyaluminium chloride (PAC) and polytitanium chloride (PTC) were more efficient for the removal of DOC, with a similar removal efficiency reaching 44 %, but their coagulation behavior was far different. PAC resulted in the residue of a large amount of small molecular organic matter due to its high affinity with pectic acid in the cell wall. However, despite the fact that PTC damaged algal cells and induced the release of intracellular substances, the effluent did not contain low molecular weight substances. The adsorption and capture effects of Ti hydrolysis products and flocs on organic matter were strong, far exceeding the release rate of intracellular substances. During the coagulation process, mechanical agitation could primarily induce the release of intracellular substances through cellular stress responses rather than cell damage. Extracellular macromolecular substances could interact with intracellular substances to form macromolecular complexes, playing a certain role in assisting coagulation. This work provides new insights into the mechanism of traditional coagulation in treating algae-laden water.