<b>Photodegradation of sugarcane vinasse: evaluation of the effect of vinasse pre-treatment and the crystalline phase of TiO₂

Abstract

ABSTRACT. In this work, the effect of vinasse pre-treatment and anatase content in the photocatalytic degradation of sugarcane vinasse was evaluated. The in nature vinasse was pretreated by coagulation/flocculation using vegetal tannin as coagulant and diluted 1: 2 with deionized water. The photocatalytic tests with in nature, pretreated and diluted vinasse were performed for 48 hours under UV radiation using 1 g of catalyst: TiO 2 Kronos calcined at 300 o C (100% anatase) and 1000 o C (34% anatase) and TiO 2 P25 (87% anatase). The process of coagulation/flocculation removed about 50, 85 and 97% of COD, color and turbidity of in nature vinasse, respectively. The results showed that despite the slight COD decrease of in nature vinasse, its toxicity was significantly reduced after photocatalytic treatment, especially when TiO 2 -34 and TiO 2 -87 were used. This behavior shows that the mixture of anatase and rutile phases showed a positive synergistic effect. Regarding pre-treatment of vinasse, the coagulation/flocculation process was more efficient, promoting the greatest reductions of COD (67%) and toxicity (up to 10 times).Keywords: vinasse, coagulation/flocculation, photocatalysis, toxicity.Fotodegradação da vinhaça: avaliação do efeito do pré-tratamento da vinhaça e da fase cristalina do TiO 2 RESUMO. Neste trabalho, foi avaliado o efeito do pré-tratamento da vinhaça e do teor de anatase na degradação fotocatalítica da vinhaça. A vinhaça in natura foi pré-tratada por coagulação/floculação usando tanino vegetal como coagulante e diluição 1:2 com água deionizada. Os testes fotocatalíticos com a vinhaça in natura, pré-tratada e diluída foram realizados durante 48h sob radiação UV utilizando 1 g de catalisador: TiO 2 Kronos calcinado a 300 o C (100% anatase) e a 1000 o C (34% anatase) e TiO 2 P25 (87% anatase). O processo de coagulação/floculação removeu cerca de 50, 85 e 97% de DQO, cor e turbidez da vinhaça in natura, respectivamente. Os resultados mostraram que apesar da pequena redução de DQO da vinhaça in natura, sua toxicidade foi reduzida significativamente após tratamento fotocatalítico, principalmente quando TiO 2 -34 e TiO 2 -87 foram utilizados. Esse comportamento evidencia que a mistura das fases anatase e rutile apresentou efeito sinérgico positivo. Em relação ao pré-tratamento da vinhaça, o processo de coagulação/floculação se mostrou mais eficiente, promovendo as maiores reduções de DQO (67%) e toxicidade (até 10 vezes).Palavras-chave: vinhaça, coagulação/floculação, fotocatálise, toxicidade.

Enhanced Removal of Endocrine-Disrupting Compounds from Wastewater Using Reverse Osmosis Membrane with Titania Nanotube-Constructed Nanochannels

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Color Image Landscape Photo Hand-Painted Effect Evaluation with PFA Algorithm

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Mycoremediation of vinasse by surface response methodology and preliminary studies in air-lift bioreactors

“…In view of the widespread contamination of the environment by persistent and toxic chemical pollutants from industrial wastewater, it is essential to develop economical methods for their remediation. One of the major problems of the sugar and alcohol industries is the large volume of waste generated, mainly vinasse, which represents a potential pollutant when inadequately administered (Ferreira et al, 2010;Colin et al, 2016;Souza et al, 2016;Hoarau et al, 2018). Sugarcane vinasse is an effluent that can present variation in its composition, depending on the raw material used and the process used in the distillation of ethanol.…”