Recovery and reuse of TiO2 photocatalyst from aqueous suspension using plant based coagulant - A green approach

Separation of TiO2 from aqueous suspension is a major constraint in heterogeneous photocatalytic water treatment. As an alternative for existing less effective immobilization techniques, the application of plant based coagulant for the recovery and reuse of TiO2 was investigated for the first time. Aqueous extract derived from seeds of Strychnos potatorum was found to be an effective coagulant for the sedimentation of TiO2. Further, the potential for recovery and reuse of the sedimented photocatalysts TiO2, was investigated by photocatalytic degradation of rhodamine B and terephthalic acid tests. The photocatalytic degradation experiments with recovered catalyst obey pseudo first-order kinetics with enhanced photocatalytic activity than that of the pure TiO2. The investigation of recovered catalysts with XRD, BET, SEM etc., suggests that there is no change in surface and morphological properties when compared with pure TiO2 and the recovered catalysts are highly suitable for recycle and reuse.