Green synthesized nano-TiO2 from Tamarindusindica leaf extract for photo-degradation of combination of dyes by suspension and immobilization on inert supports

The present study aims to use green synthesized TiO 2 as a photocatalyst in suspended and immobilized form under UV light to efficiently degrade a combination of reactive dyes, namely titan yellow, methyl orange, rhodamine B, and methylene blue. TiO 2 nanoparticles (NPs) were synthesized using Tamarindus indica leaf extract and were utilized to parametrically study photo-degradation at room temperature. The green synthesized NPs were characterized by Powder XRD, SEM, and FTIR techniques to understand the crystalline phase/purity, morphology, and functional groups respectively. The TiO 2 in suspension under UV light showed >90% degradation towards a 10 ppm composite dye at a loading of 1.5 gL −1 , pH 7, and an irradiation time of 120 min. Subsequently, TiO 2 was further immobilized in-situ, on inert supports of perlite granules and glass and studied for catalytic activity in batch and continuous modes. The TiO 2 nanoparticles immobilized on perlite granules and glass showed 59 and 48% degradation in batch operation under the same conditions as in suspended form. In continuous mode, the highest degradation activity was recorded at 2 Lh −1 after 4 passes. Further, kinetic studies reveal that the degradation reaction is best described by Langmuir Hinshelwood kinetics for both suspended and immobilized TiO 2 .