Redução da carga orgânica de efluentes provenientes da produção de biodiesel por processos oxidativos avançados

• Autor(a) principal: Almeida, Priscila de Freitas
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMT
• Texto Completo: http://ri.ufmt.br/handle/1/4964
• topic: Fotoeletrocatálise; Fotocatálise; Coagulação - floculação; DQO; Ácidos graxos; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA; Photoelectrocatalysis; Photocatalysis; Coagulation - flocculation; COD; Fatty acids

Several techniques have been studied to treat effluents from the biodiesel production process, with the aim of minimizing the possible environmental impacts that such residues can cause. These effluents basically contain residues of sodium or potassium soaps, alcohols, glycerin, fatty acids and a high chemical oxygen demand (COD), which can harm aquatic life. The objective of this work was to evaluate the efficiencies of advanced oxidative processes in the degradation of effluents from biodiesel producing industries located in Mato Grosso using Ti/TiO2 nanotube electrodes. For this purpose, electrodes were made from pure Ti/TiO2 nanotubes and impregnated with Au nanoparticles (Ti/TiO2-Au) and composite g-C3N4 (Ti/TiO2/g-C3N4). The characterization of the electrodes was carried out using the techniques of scanning electron microscopy, X-ray energy dispersive, X-ray diffraction and photoactivity measurements. For the studies, effluents pre-treated by coagulation-flocculation and facultative pond were used. The best conditions for photoelectrocatalytic degradation of effluents were previously studied, namely: support electrolyte Na2SO4 0,05 mol L-1 , without pH adjustment, applied potential of +1,5 V vs. Ag/AgCl (KCl 3 mol L-1 ) and Ti/TiO2-Au electrode, which allowed a removal of COD to the pre-treated effluent by coagulation/flocculation and facultative pond of 60% and 98%, respectively, after 8 h of degradation. The Ti/TiO2/g-C3N4 electrode showed the highest velocity constant and the highest percentage of organic charge removal. The techniques of photolysis, electrocatalysis and photocatalysis were also analyzed. Pretreatment in a facultative pond coupled with Advanced Oxidative Processes brought promising results, with photocatalysis showing a percentage of COD removal of 99% after 8h. 98%, 97% and 95% COD removals were obtained using photoelectrocatalysis, electrocatalysis and photolysis, respectively.