Improvement in biodegradability of paper mill wastewater by anatase TiO2 predominant in {001} facet in the batch and packed bed photoreactor (PBPR).

In this study, the synthesis of the {001} facet of anatase TiO₂ (T-{001}) was hydrothermally carried out by a two-step process (without using fluoride ions as capping agent); the synthesized T-{001} sample was characterized by XRD, FESEM and HRTEM. The T-{001} was used for improvement in biodegradability of paper mill wastewater in the batch and continuous system under UV light irradiation. The performance of T-{001} was compared to commercial TiO₂ (P25). In the batch system, the effect of the pH, time and photocatalyst dosage on the COD removal were investigated. The results showed that alkaline condition enhanced photocatalytic degradation of COD. For batch system, biodegradability index (BOD₅/COD ratio) improved from 0.12 to 0.71 by application of the T-{001}; whereas this improvement was 0.52 for P25 sample. For the continuous system, the TiO₂ samples were immobilized on the glass media and utilized in a packed bed photoreactor (PBPR). The effect of different flowrates on the COD removal was investigated. To investigate the stability of the samples, the photocatalytic experiments were continuously carried out for 3 h; both samples showed considerable stability during this time. The final values of BOD₅/COD ratio at flowrate of the 5.4 ml/min were 0.64 and 0.42 for CT-{001} and CP25, respectively. [ABSTRACT FROM AUTHOR]