Estudo combinado de eletrocoagulação : flotação seguido de fotocatálise em efluentes de indústria de papel e celulose, e de indústria de fármacos e comésticos

• Ano de defesa: 2007
• Autor(a) principal: Boroski, Marcela
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual de Maringá; Brasil; Programa de Pós-Graduação em Química; UEM; Maringá, PR; Departamento de Química
• Palavras-chave em Português: Eletrocoagulação; Química; Efluentes industriais; Descontaminação; Indústria de papel e celulose; Tratamento de efluentes; Indústria farmacêutica; Fotocatálise; Dióxido de titânio; Flotação; Fotocatálise heterogênea; Indústria de fármacos e cosméticos; Efluente.; Electrocoagulation; Flotation; Heterogeneus photocatalysis; Paper industry; Pharmaceutical industry; Effluent.; Ciências Exatas e da Terra
• Link de acesso: http://repositorio.uem.br:8080/jspui/handle/1/3882

The aim of the present work is to treat two distinct matrices effluent whose wastewater usually promote natural water pollution: effluent proceeding from an industty of paper and pulp, and from industry of pharmaceutical and cosmetics, through two combined methods, the electrocoagulation - flotation (EF) followed by heterogeneous photo-catalysis. To the paper industry the samples were collected after the fibers bleaching step, while in the pharmaceutical industty, the samples were withdraw from the last lagoon of the biological treatment system. In EF the effect of the initial pH and re-action time were studied using iron electrodes (anode and cathode), represented as EF/Fe, however for the paper industty effluent, additionally aluminum electrodes was employed (anode and cathode), both EF/Fe and EF/Al. In the studies of heterogeneous photo-catalysis the UV/TiO2/H2O2 system was employed vatying pH, reaction time, TiO2 and H2O2 concentrations. To evaluate the treatments efficiency level analytical determinations were performed and for the statistical data analysis the software Statistica® 5.0 was used (Tuckey test P<0.05). To the wastewater of paper industry, after 30 min of EF/Fe at initial pH 6.0 the turbidity reduction was greater man that with EF/Al; additionally the COD was reduced to 50 - 60 % (in comparison on in natura sample) and for inorganic compounds like sulphates and nitro-compounds the reduction was higher than 60 %. For the pharmaceutical industry wastewater, afier 90 minutes of reaction employing EF/Fe, the COD reduction was 80 90 % (compared to in natura) and was; observed a high reduction of nitro compounds percentage. In the sequence after the EF treatment, tor both industrial effluents was applied the heterogeneous photo-catalysis process using UV/TiO2. For the effluent from the paper industty was applied 0.25 g L-1 de TiO2, pH 3.0, 50 mmol L-1 of H2O2 and 4 h of irradiation, which resulted in 80 % of COD reduction. The diminution of contaminants levels based on COD values and a formation of 26 % of sulphate suggests that the photo-catalysis is a good method to led organic substanees to mineralization. For the wastewater of pharmaceutical industry, the optimized experimental conditions were 0.25 g L-1 of TiO2, pH= 3.0 and 10 mmol L-1 of H2O2. For example, the COD of the sample after 90 minutes of EC was 97 mg L-1 and in this sample submitted to the combined treatment the COD was reduced to 50 mg L-1. Therefore the combination of these two aqueous effluent treatments demonstrated high efficacy to diminish organic substances and bio-refractive compounds of wastewater from both industries. To the effluent of paper industty the biodegradability index increased from 0.15 (sample in natura) to 0.48 after EF and 0.89 after the combined treatments; bioassays of water toxicity with Artemia salina micro-crustaceous reinforced that the treated effluent became less polluted/toxic, reducing the percentage of crustaceous death, which were: 97 % (value for effluent in natura), 33 % after EF and 19 % after 6 h of photo-catalysis. For effluents of industry of paper it was also investigated the effect of the sodium chloride concentration in the EF process; to reach the same treatment level the time of EF was reduced from 30 min to 10 min after addition of 5 g L-1 of salt. This work shows that the association of these two processes, EF followed by photo-catalysis, is an interesting methodology to treat wastewater effluent from both industries.