Influence of bio-precursor upon the adsorption and solar photodegradation of methylene blue on TiO2@C

MATOS, J.; CHURIO, G.; POON, P.; ANIA, C.:
Proceedings of 41ª RIA (Reunión Ibérica de Adsorción), España 2018.

Introduction

Methylene blue (MB) is a common dye extensively used in several industrial applications. Unfortunately, the discharged of this dye in water effluents has been continuously increasing in the last years. For that reason, different technologies to remediate MB wastes have received an increasing attention, mainly by adsorption and photocatalytic degradation. In both cases, both surface pH and the porous framework of the materials play the main role for the MB adsorption following degradation. A large surface area composed both by micro- and mesopores is required because the cross section for the MB is ca. 1.2 nm2 indicating than not only micro- but also mesopores are fundamental for the effective diffusion of MB from solution to the pore framework of the adsorbent or photocatalysts. In this sense, hybrid materials with bifunctional behavior as adsorbent and photocatalysts, would be of great interest to simultaneously perform the adsorption of MB following its photodegradation. In a recent work, our group has reported the synthesis of a TiO2-based material characterized mainly by a mesopore framework and with a moderate photoactivity toward refractory molecules such as phenol, imidacloprid and dichloroacetic acid. The main objective of the present work is to evaluate the capacity of adsorption and photodegradation of MB on three different series of TiO2@C nanostructured hybrid materials varying the biogenic carbon precursor (furfural, chitosan, and saccharose) as co-adsorbent or doping element of TiO2. Correlations between textural, surface pH and the crystalline phases of TiO2 with the adsorption capacities adsorption according to Langmuir and Freundlich models and with the photocatalytic activity.

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