Parameters | Inorganic flocculants | Organic flocculants |
---|---|---|
Nature of flocculants | Multivalent salts | Polyelectrolytes/polymers |
Key characteristics of an effective flocculant | Increasing molecular weight can increase the binding capabilities | Flocculants that have a high charge density are therefore more effective |
Sensitivity to pH | Coagulation using inorganic coagulants is highly sensitive to pH level | Coagulation using organic coagulants is less sensitive to pH |
Sensitivity to biomass concentration | Highly sensitive to concentration | Highly sensitive to concentration |
Dosage of flocculants required | A large concentration of inorganic flocculant is needed in order to maintain flocculation efficiency, and may contaminate the end product (e.g., addition of aluminum and iron salts) | Lower dosages of organic flocculants are required, and less or no contamination occurs |
Applicability | Although some coagulants may work for some microalgal species, they do not work for others | Wide range of applications for larger number of microalgal species |