Combinación de ozono y nanopartículas magnéticas verdes para la degradación de azul de metileno en agua residual sintética textil

Trabajo de investigaciónSe usaron nanopartículas de magnetita verdes en un proceso de ozonización para remoción del colorante azul de metileno proveniente agua residual sintética textil. La concentración inicial del contaminante fue de 2mg/L. Se obtuvo una capacidad máxima de adsorción sobre el material de 0.0086mg/g debida a la modelación cinética e isotermas. Finalmente se encontró un porcentaje de remoción de 87.02 usando ozonización catalítica.RESUMEN 1. INTRODUCCIÓN 2. PLANTEAMIENTO Y FORMULACIÓN DEL PROBLEMA 3. JUSTIFICACIÓN 4. OBJETIVOS 5. ESTADO DEL ARTE 6. ANTECEDENTES 7. MARCO DE REFERENCIA 8. ALCANCE Y LIMITACIONES 9. METODOLOGÍA 10. RESULTADOS CONCLUSIONES RECOMENDACIONES REFERENCIAS ANEXOSPregradoIngeniero Civi

Polyacrylonitrile membranes for microalgae filtration: Influence of porosity, surface charge and microalgae species on membrane fouling

International audienceA comprehensive study on membrane fouling using polyacrylonitrile (PAN)-based membranes with different properties was performed for 8 microalgae species. Two sets of PAN membranes with different porosity and surface charge were prepared via phase inversion and further hydrolyzed to introduce a negative charge on the membrane surface. These membranes were then used for filtering microalgae which differ in a number of properties and are characterized by their dry weight, size, shape, presence of cell-wall, zeta potential, and transparent exopolymer particles (TEP) content. For most species, more fouling occurred in the more porous membranes. Negatively charged membranes offered species dependent benefits to reduce fouling. Remarkably, this benefit seemed to be partially influenced by TEP concentration, but not by the zeta potential of the microalgae. The results also show that fouling in microalgae filtration is dominated by the formation of a cake layer by the cells which is mainly influenced by cell shape and size, size distribution, and cell-wall rigidity. It was found that microalgae with non-spherical (Scenedesmus and Phaeodactylum), larger size and a rigid cell wall filtered better than those with no cell wall (Isochrysis) or a flexible one (Pseudanabaena), proven by their cake resistance values. © 201

Biofouling in membrane bioreactors nexus between polyacrylonitrile surface charge and community composition

International audienceThe influence of membrane surface charge on biofouling community composition during activated sludge filtration in a membrane bioreactor was investigated in this study using polyacrylonitrile-based membranes. Membranes with different surface properties were synthesized by phase inversion followed by a layer-by-layer modification. Various characterization results showed that the membranes differed only in their surface chemical composition and charge, ie two of them were negative, one neutral and one positive. Membrane fouling experiments were performed for 40 days and the biofouling communities were analyzed. PCR-DGGE fingerprinting indicated selective enrichment of bacterial populations from the sludge suspension within the biofilms at any time point. The biofilm community composition seemed to change with time. However, no difference was observed between the biofilm community of differently charged membranes at specific time points. It could be concluded that membrane charges do not play a decisive role in the long-term selection of the key bacterial foulants. © 2018 Informa UK Limited, trading as Taylor and Francis Group

Sequencing batch membrane photobioreactor for simultaneous cultivation of aquaculture feed and polishing of real secondary effluent

Microalgae technology is attractive for simultaneously treating wastewater and producing valuable biomass. However, biofuel application demands a very low net-energy input that can hardly be fulfilled. Therefore, exploration of a more direct-use of microalgae biomass and selection of appropriate microalgae species are necessary to fine-tune viable applications. This study assesses performance of sequencing batch membrane photobioreactors (SB-MPBRs) for simultaneously polishing secondary effluent by cultivating Staurastrum sp., a species suitable as aquaculture feed. The effect of feed composition (high and low phosphorous, P) on microalgae growth, membrane fouling propensity, nutrient removal, as well as oxygen enrichment capacity were evaluated. Overall results demonstrate the effectiveness of SB-MPBR to cultivate Staurastrum sp. in secondary effluent by achieving biomass concentration of 0.45 and 0.6 g/L and very low nutrients concentrations in the effluents (≈ 0, 10 and 2 mg/L, for chemical oxygen demand (COD), TN and TP respectively). The actual biomass productivity of the SM-MPBRS are 40.0 and 30.0 g/(day m 3 ) for the low-P and high-P feeds, corresponding to production costs of 11.3 and 15.1 $/kg biomass, respectively. Low-P feed results in a slightly higher biomass productivity of 33% compare to high-P feed, but slightly higher fouling propensity. The growth in both SB-MPBRS seems to be limited by the inorganic carbon supply. Too-short HRT leads to nutrients accumulation of the nutrients and eventually reduced their removal efficiencies. Overall results show a new cultivation method for aquaculture feed while at the same time polish secondary effluent and enrich its oxygen concentration