Magnetic Flocculant for High Efficiency Harvesting of Microalgal Cells

Abstract

Magnetic flocculant was synthesized for the highly efficient recovery of microalgal cells. The highest flocculation was achieved using the magnetic flocculant synthesized with iron oxide and 0.1 mg/mL cationic polyacrylamide (CPAM). This resulted in a recovery efficiency of more than 95% within 10 min using a dosage of 25 mg/L for Botryococcus braunii and 120 mg/L for Chlorella ellipsoidea. For both species, the adsorption isotherm data fit the Freundlich model better than the Langmuir model, indicating that the adsorption process was a heterogeneous multilayer. The maximum adsorption capacity was 114.8 and 21.4 mg dry cells/mg-particles at pH 7 for B. braunii and C. ellipsoidea, respectively. The primary flocculation mechanism was bridging, which was assisted by the electrostatic interactions between the microalgal cells and the magnetic flocculant under acidic conditions. These results provide new opportunities and challenges for understanding and improving the harvesting of microalgae using magnetic separation.

Surface Observation and Magnetism of Oil-Extracted Botryococcus braunii Residues before and after Carbonization

“…Effective oil production and applications of the extracted oil need further study [15][16][17][18]. The number of reports of these improvements is increasing year by year in applications.…”

Harvesting of freshwater and marine microalgae by common flocculants and magnetic microparticles

“…Over the past years, several magnetic particles have been employed for the separation or entrapment of microalgae. These materials include uncoated iron oxides (Bitton et al 1975;Xu et al 2011;Prochazkova et al 2013), surface functionalized iron oxide nanoparticles with cationic polyacrylamides (Wang et al 2014), chitosan (Eroglu et al 2012;Lim et al 2012), polyvinylpyrrolidone (Eroglu et al 2013), and cationic polyelectrolytes (Toh et al 2014a). Among various separation methods for microalgal harvesting, magnetic separation exhibits high recovery efficiency at short operation time, and no residual magnetic nanoparticles remain in the liquid after separation (Xu et al 2011).…”

Novel Magnetic Cross‐Linked Lipase Aggregates for Improving the Resolution of (R, S)‐2‐octanol

“…18 Magnetic particles coated with PEI (Fe 3 O 4 -PEI, MP 1 ) and magnetic particles coated with CPAM (Fe 3 O 4 -CPAM, MP 2 ) were prepared according to our previous reports. 19,20 Fe 3 O 4 -PMMA with dendritic -NH 2 (MP 3 ) were prepared according to the method previously reported. 21 The other reagents were purchased from Beijing Chemical Reagents (Beijing, China).…”

“…1,7,13 Cross-linking is a reaction; therefore, the time required to obtain the maximum λ is very important. 32 The MCLLAs of YLL were prepared using varying cross-linking times (4,8,12,20, and 24 h). The results (presented in Fig.…”