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Long-chain poly-arginine functionalized porous Fe3O4 microspheres as magnetic flocculant for efficient harvesting of oleaginous microalgae
- Liu, Pei-Rui, Wang, Ting, Yang, Zi-Yu, Hong, Yu, Hou, Yang-Long
- Algal research 2017 v.27 pp. 99-108
- Chlorella, active sites, adsorption, arginine, flocculation, harvesting, hydrogen bonding, iron oxides, microalgae, molecular weight, porosity
- Considering the porous characteristics of magnetic porous Fe3O4 microspheres, this study aims to utilize long-chain poly-arginine (PA) to obtain PA-modified porous Fe3O4 microspheres (p-Fe3O4@PA). The microspheres possessed a loose porous structure on the surface, and the average pore size was 224.2Å. The harvesting efficiency for Chlorella sp. HQ improved markedly compared with that of p-Fe3O4 after modification with three PAs with different molecular weights. p-Fe3O4@PA-2 (PA molecular weight: 15,000–70,000) had the best performance with a decreasing dosage from 300mgL−1 to 10mgL−1. The results indicated that PA modification at a higher molecular weight could promote microalgae adsorption, whereas PA modification of an excessively high molecular weight (>70,000) was not conducive to microalgae harvesting. The modification percentage of p-Fe3O4@PA (57.9%) provided abundant adsorption media and active sites for Chlorella sp. HQ adsorption. Bridging flocculation and hydrogen bonding between Chlorella sp. HQ and p-Fe3O4@PA greatly enhanced harvesting efficiency. In addition, the p-Fe3O4@PA could maintain good cycling stability because of the relatively large size of the microspheres.