Photocatalytic degradation of 2,4-dichlorophenoxyacetic acid - A comparative study in hydrothermal TiO_2 and commercial TiO_2

摘要

Photoremediation of pesticides under natural sunlight will not be distant a dream any more due to rapid development in the field of catalysis and its related technology. 2,4-dichlorophenoxyacetic acid (2,4-D) is a common broad-leaved weeds, found in surface and groundwater at concentrations above the maximum containment level, is chosen as model pollutant in this study. Hydrothermal synthesis of TiO2 under sol-gel route resulted in altered band gap material with good crystallinity and particle size. Further, the overview of its degradation is compared with commercial TiO2 such as P25, Hombicat UV-100 and commercial brand of TiO2 (C-TiO2). More importantly, commercial viability of the catalyst was assessed in natural sunlight for its photocatalytic activity and selectivity. The chosen catalyst was characterized using XRD, SEM, EDAX, Raman spectroscopy, FTIR and DRS-UV for its structural, functional and electronic properties. Hydrothermal catalyst (H-TiO2) showed degradation of 96% under UV light and 83% under solar light due to its altered band gap (3.16 eV), selective anatase phase ratio appending to similar particle size and crystallinity as that of P25. The major intermediates of 2,4-D degradation were identified for H-TiO2 and its selective degradation mechanism was highlighted. Thus, this work not only puts forward the importance of material characteristics for mitigation of model pollutant but also its feasibility for practical implication under natural sunlight. (c) 2018 Elsevier B.V. All rights reserved.