Biosorption of Basic Orange using dried A. filiculoides

In order to understand the biosorption of Basic Organic (BO) textile dye on dried Azolla filiculoides (A. filiculoides), batch experiments were conducted under various conditions. The results show that biosorption of BO on dried A. filiculoides was dependent on the initial solution pH, biosorbent dosage, contact time and the initial BO concentration. Using the Langmuir equation, the biosorption capacity (qm) for BO was 833 mg/g at 303 K. The kinetic study suggested that the mechanism of biosorption was due to ion-exchange physisorption via the intra-particle diffusion and chemisorption on the external surface of dried A. filiculoides. Different techniques were used to characterize dried A. filiculoides and indicated that the biomass had a high cation exchange capacity (93.6 mmol/100 g), a large specific surface area (80.35–422.89 m2/g) and contained various functional groups which may play an important role in the physisorption and chemisorption of BO on the surface of A. filiculoides. The results showed that the removal ratio of BO reached 79.3% from wastewater containing 100 mg/L BO, indicating that the biomass could be used as a potential biosorbent for the removal of BO from industrial wastewater.