Modified mussel shell powder for microalgae immobilization to remove N and P from eutrophic wastewater.

Graphical abstract Highlights • A porous K-CMSP was prepared with mussel shell powder and activated by K 2 CO 3. • K-CMSP modified with L-ARG had rendered a positively charged surface. • Immobilized microalgae could survive for more than 60 days. • Immobilized microalgae could revive to normal growth level within 10 days. • The removal rate of N and P by immobilized microalgae were 95.0% and 88.63%. Abstract In this work, calcined mussel shell powder (CMSP) was activated by K 2 CO 3 (K-CMSP), and this porous K-CMSP surface was modified by L-arginine (L-ARG) to render porous biomass a positively charged surface, which was innovatively utilized as a carrier to immobilize microalgae by adsorption via electrostatic interactions. The pore and the surface structures of CMSP and K-CMSP were characterized by XRD, FTIR, BET and SEM. The surface morphology of immobilized microalgae was visualized via using inverted optical microscope and SEM. It was found that microalgae could survive for 60 days, and the loss rate of chlorophyll-a preserved at −24 °C was the lowest, 44.73%. The microalgae could revive to normal growth level within 10 days and the cell content of microalgae was the highest at 25 °C, 2.8022 × 106 cell/mL. At 25 °C, the highest removal rate of N and P was obtained about 95.0% and 88.63%, respectively. [ABSTRACT FROM AUTHOR]