Chitosan coagulation–membrane filtration of Chlorella vulgaris

Filtration separation of Chlorella vulgaris, a species with excellent potential for CO2 capture and lipid production, was studied using a surface-modified hydrophilic polytetrafluoroethylene (PTFE) membrane. Coagulation using chitosan effectively removed turbidity at >100 mg l−1 chitosan. The membrane filtration flux at 1 bar was increased with chitosan dose. The filtered cake at the end of filtration tests peaked in solid content at 100 mg l−1 chitosan, reaching 30.5% w/w, about 50% higher than that of the original suspension. Coagulation using 100 mg l−1 chitosan followed by PTFE membrane filtration at 1 bar is a feasible process to harvest C. vulgaris from the algal froth.

► Filtration separation of Chlorella vulgaris was studied with surface-modified PTFE membrane. ► Chitosan coagulation effectively removed turbidity at >100 mg l−1 chitosan. ► The filtered cake has solid content at 100 mg l−1 chitosan of 30.5% w/w. ► The cake with minimum water–solid binding strength produces the driest filter cake.