Preparation, characterization and photocatalytic activity of activated charcoal from microalgae for photocatalytic degradation of rhodamine B dye

Preparação, caracterização e atividade fotocatalítica de carvão ativado a partir de microalgas para degradação fotocatalítica do corante rodamina B

Abstract

The need to adopt measures that reduce the persistence of pollutants in the environment is notorious, in order to promote the correct disposal and treatment of effluents. This study aimed to prepare, characterize, and evaluate the photocatalytic activity of activated charcoal obtained from the residual biomass of Chlorella pyrenoidosa microalgae for Rhodamine B (RhB) dye degradation. The samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, N₂ porosimetry, and zeta potential. To evaluate the photocatalytic activity, experiments were carried out in a stirred batch reactor. The activated charcoal prepared from microalgae biomass showed the better photocatalytic activity in the degradation of the RhB dye of 75.5% under ultraviolet radiation (k=0.0121 min^-1), and 66.5% under visible radiation (k=0.0091 min^-1), while the commercial ZnO achieved 92.5% (k=0.0158 min^-1) and 16.6% (k=0.0032 min^-1) for ultraviolet and visible radiation, respectively. Moreover, the activation/carbonization process used for the preparation of activated charcoal from microalgae biomass promoted changes in the structural, textural, and catalytic properties of the prepared samples.

Keywords:
dyes; heterogeneous photocatalysis; Chlorella pyrenoidosa; degradation