Moreover, they found that the surface character of MO was responsible for the enhancement of harvesting efficiency as it can shift from hydrophilic to hydrophobic. Mohamed et al. (2017) examined MO and alum performance for microalgae harvesting were compared. Regarding Scenedesmus sp. harvesting, the recovery efficiency using alum was 94.87% at 50 mg/L doses, but the recovery efficiency using MO was high (96.5%) at a low dosage (10 mg/L). This result revealed the superiority of MO in terms of microalgae harvesting. Interestingly, Yang et al. (2021) examined the performance of four natural coagulants (chitosan, cationic starch, tanfloc, and MO) for microalgae harvesting. The results showed that investigated natural coagulants enhanced microalgae harvesting by two mechanisms: bridging and electrostatic binding. In addition, the authors reported that pH did not affect the performance of MO, while it affected other natural coagulants.
Chitosan applications for microalgae harvesting
| Type of cultivation . | Chitosan dosage . | Experimental conditions . | Microalgae removal (%) . | References . |
|---|---|---|---|---|
| Jar test microalgae reactor | 15 mg/L | Chlorophyll-a concentrations 80–800 mg m3, pH 7 | 90 | Divakaran & Pillai (2002) |
| PBR microalgal–bacterial culture broth for fish wastewater treatment | 214 mg/L | Flocculation speed 131 rpm | 92 | Riaño et al. (2012) |
| Lab-scale microalgae reactor | 10 mg/g of algae | pH 7 | 99 | Xu et al. (2013) |
| Anaerobic domestic sewage treatment reactor | 20 mg/L | pH 9.9 | 90 | Şirin et al. (2012) |
| Marin microalga (Nannochloropsis oculata) | 75 mg/L | pH (8–9) | 90 | Acosta-Ferreira et al. (2020) |
| Fresh water microalgae (Nannochloropsis sp.) | 22 mg/L | Initial pH 6, final pH 10 | 97–99 | Chua et al. (2020) |
| Microalgae cultivated in domestic wastewater using PBR | 17–26 mg/L | pH 7 COD 150 mg/L NH4-N 31 mg/L NO3-N 50 mg/L | 95 | Mohd Yunos et al. (2017) |
| Type of cultivation . | Chitosan dosage . | Experimental conditions . | Microalgae removal (%) . | References . |
|---|---|---|---|---|
| Jar test microalgae reactor | 15 mg/L | Chlorophyll-a concentrations 80–800 mg m3, pH 7 | 90 | Divakaran & Pillai (2002) |
| PBR microalgal–bacterial culture broth for fish wastewater treatment | 214 mg/L | Flocculation speed 131 rpm | 92 | Riaño et al. (2012) |
| Lab-scale microalgae reactor | 10 mg/g of algae | pH 7 | 99 | Xu et al. (2013) |
| Anaerobic domestic sewage treatment reactor | 20 mg/L | pH 9.9 | 90 | Şirin et al. (2012) |
| Marin microalga (Nannochloropsis oculata) | 75 mg/L | pH (8–9) | 90 | Acosta-Ferreira et al. (2020) |
| Fresh water microalgae (Nannochloropsis sp.) | 22 mg/L | Initial pH 6, final pH 10 | 97–99 | Chua et al. (2020) |
| Microalgae cultivated in domestic wastewater using PBR | 17–26 mg/L | pH 7 COD 150 mg/L NH4-N 31 mg/L NO3-N 50 mg/L | 95 | Mohd Yunos et al. (2017) |