Influence of algal organic matter in the in-situ flotation removal of Microcystis using positively charged bubbles

Cheng, Shaozhe; Zhang, Haiyang; Wang, Hailing; Mubashar, Muhammad; Li, Lili; Zhang, Xuezhi

doi:10.1016/j.biortech.2024.130468

Cited by 6 publications

(1 citation statement)

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“…Such differences can be due to the fact that cells adapt to the habitat they live in, so depending on where the strains were isolated, their cell wall present different properties, which can have important impacts on the physicochemical properties of the cell surface (notably hydrophilic/hydrophobic properties). Moreover, various strains of the same species may exhibit variations in the composition of the algal organic matter (AOM) they generate, which can significantly impact both flocculation and flotation processes . Thus, in this work, we investigated the potential of PO-chitosan to interact with the cell wall of a different C.…”

Section: Introductionmentioning

confidence: 99%

The Biophysical Properties of Microalgal Cell Surfaces Govern Their Interactions with an Amphiphilic Chitosan Derivative Used for Flocculation and Flotation

Demir-Yilmaz,

Pappa,

Lama

et al. 2024

ACS Appl. Bio Mater.

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Microalgae show great promise for producing valuable molecules like biofuels, but their large-scale production faces challenges, with harvesting being particularly expensive due to their low concentration in water, necessitating extensive treatment. While methods such as centrifugation and filtration have been proposed, their efficiency and cost-effectiveness are limited. Flotation, involving air-bubbles lifting microalgae to the surface, offers a viable alternative, yet the repulsive interaction between bubbles and cells can hinder its effectiveness. Previous research from our group proposed using an amphiphilic chitosan derivative, polyoctyl chitosan (PO-chitosan), to functionalize bubbles used in dissolved air flotation (DAF). Molecular-scale studies performed using atomic force microscopy (AFM) revealed that PO-chitosan's efficiency correlates with cell surface properties, particularly hydrophobic ones, raising the question of whether this molecule can in fact be used more generally to harvest different microalgae. Evaluating this, we used a different strain of Chlorella vulgaris and first characterized its surface properties using AFM. Results showed that cells were hydrophilic but could still interact with PO-chitosan on bubble surfaces through a different mechanism based on specific interactions. Although force levels were low, flotation resulted in 84% separation, which could be explained by the presence of AOM (algal organic matter) that also interacts with functionalized bubbles, enhancing the overall separation. Finally, flocculation was also shown to be efficient and pH-independent, demonstrating the potential of PO-chitosan for harvesting microalgae with different cell surface properties and thus for further sustainable large-scale applications.

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Section: Introductionmentioning

confidence: 99%