Síntese, caracterização e estudo da regeneração do silicoaluminofosfato-11 (SAPO-11)

heterogeneous catalyst such as a silicoaluminophosphate, molecular sieve with AEL (Aluminophosphate eleven) structure such as SAPO-11, was synthesized through the hydrothermal method starting from silica, pseudoboehmite, orthophosphoric acid (85%) and water, in the presence of a di-isopropylamine organic template. For the preparation of SAPO-11 in a dry basis it was used as reactants: DIPA; H3PO4; SiO4; Pseudoboehmite and distilled water. The crystallization process occurred when the reactive hydrogel was charged into a vessel and autoclaved at 200ºC for a period of 72 hours under autogeneous pressure. The obtained material was washed, dried and calcined to remove the molecular sieves of DIPA. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), nitrogen adsorption (BET) and thermal analysis (TG/DTG). The acidic properties were determined using adsorption of nbutylamine followed by programmed thermodessorption. This method revealed that SAPO-11 shows an acidity that ranges from weak to moderate. However, a small quantity of strong acid sites could be detected there. The deactivation of the catalysts was conducted by artificial coking followed by the cracking of the n-hexane in a fixed bed with a continuous flow micro-reactor coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the regeneration and removal of the coke

Estudos comparativos do ciclo de regeneração de diferentes tipos de silicoaluminofosfatos

Different types of heterogeneous catalysts of the silicoaluminophosphate type, (SAPO-5, SAPO-11, SAPO-31, SAPO-34 and SAPO-41), molecular sieves with a: AFI, AEL, ATO, CHA and AFO structure, respectively, were synthesized through the hydrothermal method. Using sources such as hydrated alumina (pseudobohemita), phosphoric acid, silica gel, water, as well as, different types of organic structural templates, such as: cetyltrimethylammonium bromide (CTMABr), di-isopropylamine (DIPA), di-n- propylamine (DNPA) and tetraethylammonium hydroxide (TEOS), for the respective samples. During the preparation of the silicoaluminophosphates, the crystallization process of the samples occurred at a temperature of approximately 200 ° C, ranging through periods of 18-72 h, when it was possible to obtain pure phases for the SAPOs. The materials were furthermore washed with deionized water, dried and calcined to remove the molecules of the templates. Subsequently the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy in the infrared region (FT-IR), specific surface area and thermal analysis via TG/DTG. The acidic properties were determined using adsorption of n-butylamine followed by programmed termodessorption. These methods revealed that the SAPO samples showed a typically weak to moderate acidity. However, a small amount of strong acid sites was also detected. The deactivation of the catalysts was conducted by artificially coking the samples, followed by n-hexane cracking reactions in a fixed bed with a continuous flow micro-reactor coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the catalysts regeneration and removal of the coke

Photoeletrolytic system applied to remazol red brilliant degradation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Degradação eletroquímica do cloranfenicol em reator de fluxo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Processo eletrolítico usado na degradação de efluentes têxteis e avaliação de seu potencial toxicológico e ecotoxicológico

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Impact of the Textile Dye Acid Blue 40 on the Periphyton of a Simulated Microecosystem

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On-line monitoring of electrochemical degradation of paracetamol through a biomimetic sensor

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electrolysis applied for simulated textile effluents degradation containing acid red 151 and acid blue 40

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Residence Time Distribution Models Derived from Non-Ideal Laminar Velocity Profiles in Tubes

The theoretical E-curve for the laminar flow of non-Newtonian fluids in circular tubes may not be accurate for real tubular systems with diffusion, mechanical vibration, wall roughness, pipe fittings, curves, coils, or corrugated walls. Deviations from the idealized laminar flow reactor (LFR) cannot be well represented using the axial dispersion or the tanks-in-series models of residence time distribution (RTD). In this work, four RTD models derived from non-ideal velocity profiles in segregated tube flow are proposed. They were used to represent the RTD of three tubular systems working with Newtonian and pseudoplastic fluids. Other RTD models were considered for comparison. The proposed models provided good adjustments, and it was possible to determine the active volumes. It is expected that these models can be useful for the analysis of LFR or for the evaluation of continuous thermal processing of viscous foods.

Kinetische Untersuchungen zur Synthese von Blockcopolymeren mit Methacrylatsegmenten durch neue anionische Polymerisationssysteme

Ein metallfreies Reaktionssystem mit Bis(triphenylphosphoranyliden)ammonium-Kationen als Gegenionen sowie das Additiv Lithium-2-methoxyethoxid wurden auf ihre Eignung zur anionischen Synthese von Blockcopolymeren mit (Meth)acrylatsegmenten bei moderaten Temperaturen im Strömungsrohr-Reaktor untersucht. Das metallfreie System ist zur lebenden Polymerisation von Methacrylaten in THF mit engen Molekulargewichtsverteilungen bei Reaktionszeiten < 1 s bis zu Temperaturen von 0 °C geeignet. In Gegenwart von Metallionen (Li+) findet eine Verlangsamung der Polymerisation unter Verlust der Reaktionskontrolle statt, Lithiumenolate verursachen nun breite, multimodale Molekulargewichtsverteilungen. Eine lebende Polymerisation von Acrylaten ist nicht möglich, massenspektroskopische Untersuchungen der Produkte weisen auf einen komplexen Reaktionsmechanismus mit Abbruch- und Übertragungsreaktionen hin. Die Synthese von Poly(styrol)-block-Poly(1,4-butadien)-block-Poly(methylmethacrylat)-Copolymeren in Toluol ist mit Lithium-2-methoxyethoxid als Additiv für die MMA-Polymerisation bei moderaten Mischtemperaturen (T < 0 °C) im Strömungsrohr-Reaktor möglich, die Effektivität des Wechselschritts von Polybutadien zu PMMA beträgt im Durchschnitt ca. 50 %. Untersuchungen verschiedener Reaktionsparameter, wie z.B. der Endfunktionalisierung des Polybutadiens mit 1,1-Diphenylethylen und der Temperatur während der Verkappung und der MMA-Polymerisation, geben keine eindeutigen Hinweise auf die Ursache dieses Phänomens. MALDI-TOF-Massenspektren des unreagierten Polybutadien Precursors zeigen die Anlagerung von 1-3 Molekülen Methylmethacrylat und keinen Abbruch durch Backbiting, was auf die Ausbildung stabiler Aggregate hindeutet.

Synthese C-glycosidischer und N-methylierter Glycosylaminosäuren für den Aufbau von Mimetika tumorassoziierter MUC1-Glycopeptidantigene unter Verwendung mikrostrukturierter Reaktoren

Zur Synthese hydrolysestabiler MUC1-Antitumorvakzine wurde im Rahmen dieser Arbeit zunächst ein Verfahren zur effizienten N Methylierung von Fmoc-Aminosäuren entwickelt. Die Synthese erfolgte in einer zweistufigen Umsetzung über Oxazolidinone unter Verwendung eines Tube-in-Tube-Durchflussreaktors mit einer semipermeablen Membran aus Teflon® AF 2400. In diesem Tube-in-Tube-Reaktor wurde in der ersten Stufe das Modellsubstrat Fmoc-Alanin bereits nach 2 h annähernd quantitativ in das entsprechende Oxazolidinon umgesetzt. In der zweiten Stufe wurde mit TFA erstmals eine Flüssigkeit durch eine solche Membran des Tube-in-Tube-Reaktors eingeleitet und lieferte innerhalb einer Stunde zahlreiche aliphatische, aromatische und funktionalisierte N-Methylaminosäuren in hohen Ausbeuten.rnDes Weiteren wurden erstmals sensible Glycosylaminosäuren, darunter auch TN Antigen-Strukturen, N-methyliert. Sie dienen als Bausteine für die Synthese von MUC1-Antitumorvakzinen. Neben Fmoc-N-Methyl-TN-Threonin konnten die Fmoc-geschützten N-Methyl-TN-Serin, N-Methyl-Sialyl-TN-Threonin sowie zwei N-Methyl-C Glycosylaminosäuren und in guten Ausbeuten erhalten werden. Anschließend wurde das N methylierte TN-Threonin gezielt in die tandem repeat-Sequenz des MUC1 in einer Festphasenpeptidsynthese eingebaut. Um einen direkten Vergleich bezüglich der N Methylierung im MUC1-Glycopeptide und dem darauf folgenden Einfluss auf die Tumorselektivität der resultierenden Vakzine erhalten zu können, wurde zudem ein Referenzpeptid aufgebaut. Zur Vollendung der Vakzinsynthese erfolgte die Konjugation beider Glycopeptidantigene an die jeweiligen BSA- und TTox-Proteine. rnEin alternativer Zugang zu hydrolysestabilen Glycopeptidbausteinen wurde im letzten Teil der Arbeit über die Synthese von α C Glycosylaminosäuren erarbeitet. Der entwickelte Syntheseweg basiert auf einer Ugi-Vier-Komponenten-Reaktion aus Aldehyd, Amin, Nitril und Carbonsäure. Als benötigte Aldehydkomponenten wurden ein einfaches Galactose- sowie ein Galactosamin-Derivat verwendet. Zum Aufbau des C-glycosidischen Grundgerüsts wurde eine Mikrowellen-unterstützte C-Allylierungsvariante im Durchfluss realisiert. Die Galactose- und Galactosaminaldehyde wurden danach mit chirale Glycosylaminen umgesetzt.

Effects of phosphorus on the growth and nitrogen fixation rates of Lyngbya majuscula: implications for management in Moreton Bay, Queensland

Significant acetylene reduction and therefore N-2 fixation was observed for Lyngbya majuscula only during dark periods, which suggests that oxygenic photosynthesis and N-2 fixation are incompatible processes for this species. Results from a series of batch and continuous-flow-culture reactor studies showed that the specific growth rate and N-2 fixation rate of L, majuscula increased with phosphate (P-PO4) concentration up to a maximum value and thereafter remained constant. The P-PO4 concentrations corresponding to the maximum N-2 fixation and maximum growth rates were -0.27 and -0.18 muM respectively and these values are denoted as the saturation values for N-2 fixation and growth respectively. Regular monitoring studies in Moreton Bay, Queensland, show that concentrations Of P-PO4 generally exceed these saturation values over a large portion of the Bay and therefore, the growth of the bloom-forming L, majuscula is potentially maximised throughout much of the Bay by the elevated P-PO4 concentrations. Results from other studies suggest that the elevated P-PO4 concentrations in the Bay can be largely attributed to discharges from waste-water treatment plants (WWTPs), and thus it is proposed that the control of the growth of L. majuscula in Moreton Bay will require a significant reduction in the P load from the WWTP discharges. If the current strategy of N load reduction for these discharges is maintained in the absence of substantial P load reduction, it is hypothesised that the growth of L, majuscula and other diazotrophs in Moreton Bay will increase in the future.

Computationsl modelling of dimethyl ether separation and steam reforming in fluidized bed reactors

This study presents a computational fluid dynamic (CFD) study of Dimethyl Ether (DME) gas adsorptive separation and steam reforming (DME-SR) in a large scale Circulating Fluidized Bed (CFB) reactor. The CFD model is based on Eulerian-Eulerian dispersed flow and solved using commercial software (ANSYS FLUENT). Hydrogen is currently receiving increasing interest as an alternative source of clean energy and has high potential applications, including the transportation sector and power generation. Computational fluid dynamic (CFD) modelling has attracted considerable recognition in the engineering sector consequently leading to using it as a tool for process design and optimisation in many industrial processes. In most cases, these processes are difficult or expensive to conduct in lab scale experiments. The CFD provides a cost effective methodology to gain detailed information up to the microscopic level. The main objectives in this project are to: (i) develop a predictive model using ANSYS FLUENT (CFD) commercial code to simulate the flow hydrodynamics, mass transfer, reactions and heat transfer in a large scale dual fluidized bed system for combined gas separation and steam reforming processes (ii) implement a suitable adsorption models in the CFD code, through a user defined function, to predict selective separation of a gas from a mixture (iii) develop a model for dimethyl ether steam reforming (DME-SR) to predict hydrogen production (iv) carry out detailed parametric analysis in order to establish ideal operating conditions for future industrial application. The project has originated from a real industrial case problem in collaboration with the industrial partner Dow Corning (UK) and jointly funded by the Engineering and Physical Research Council (UK) and Dow Corning. The research examined gas separation by adsorption in a bubbling bed, as part of a dual fluidized bed system. The adsorption process was simulated based on the kinetics derived from the experimental data produced as part of a separate PhD project completed under the same fund. The kinetic model was incorporated in FLUENT CFD tool as a pseudo-first order rate equation; some of the parameters for the pseudo-first order kinetics were obtained using MATLAB. The modelling of the DME adsorption in the designed bubbling bed was performed for the first time in this project and highlights the novelty in the investigations. The simulation results were analysed to provide understanding of the flow hydrodynamic, reactor design and optimum operating condition for efficient separation. Bubbling bed validation by estimation of bed expansion and the solid and gas distribution from simulation agreed well with trends seen in the literatures. Parametric analysis on the adsorption process demonstrated that increasing fluidizing velocity reduced adsorption of DME. This is as a result of reduction in the gas residence time which appears to have much effect compared to the solid residence time. The removal efficiency of DME from the bed was found to be more than 88%. Simulation of the DME-SR in FLUENT CFD was conducted using selected kinetics from literature and implemented in the model using an in-house developed user defined function. The validation of the kinetics was achieved by simulating a case to replicate an experimental study of a laboratory scale bubbling bed by Vicente et al [1]. Good agreement was achieved for the validation of the models, which was then applied in the DME-SR in the large scale riser section of the dual fluidized bed system. This is the first study to use the selected DME-SR kinetics in a circulating fluidized bed (CFB) system and for the geometry size proposed for the project. As a result, the simulation produced the first detailed data on the spatial variation and final gas product in such an industrial scale fluidized bed system. The simulation results provided insight in the flow hydrodynamic, reactor design and optimum operating condition. The solid and gas distribution in the CFB was observed to show good agreement with literatures. The parametric analysis showed that the increase in temperature and steam to DME molar ratio increased the production of hydrogen due to the increased DME conversions, whereas the increase in the space velocity has been found to have an adverse effect. Increasing temperature between 200 oC to 350 oC increased DME conversion from 47% to 99% while hydrogen yield increased substantially from 11% to 100%. The CO2 selectivity decreased from 100% to 91% due to the water gas shift reaction favouring CO at higher temperatures. The higher conversions observed as the temperature increased was reflected on the quantity of unreacted DME and methanol concentrations in the product gas, where both decreased to very low values of 0.27 mol% and 0.46 mol% respectively at 350 °C. Increasing the steam to DME molar ratio from 4 to 7.68 increased the DME conversion from 69% to 87%, while the hydrogen yield increased from 40% to 59%. The CO2 selectivity decreased from 100% to 97%. The decrease in the space velocity from 37104 ml/g/h to 15394 ml/g/h increased the DME conversion from 87% to 100% while increasing the hydrogen yield from 59% to 87%. The parametric analysis suggests an operating condition for maximum hydrogen yield is in the region of 300 oC temperatures and Steam/DME molar ratio of 5. The analysis of the industrial sponsor’s case for the given flow and composition of the gas to be treated suggests that 88% of DME can be adsorbed from the bubbling and consequently producing 224.4t/y of hydrogen in the riser section of the dual fluidized bed system. The process also produces 1458.4t/y of CO2 and 127.9t/y of CO as part of the product gas. The developed models and parametric analysis carried out in this study provided essential guideline for future design of DME-SR at industrial level and in particular this work has been of tremendous importance for the industrial collaborator in order to draw conclusions and plan for future potential implementation of the process at an industrial scale.

Ultrasound-assisted extraction of R-phycoerythrin from Grateloupia turuturu with and without enzyme addition

The aim of this study was to compare two processes for the extraction of R-phycoerythrin (R-PE) from the red seaweed Grateloupia turuturu: ultrasound-assisted extraction (UAE) and ultrasound-assisted enzymatic hydrolysis (UAEH). Process efficiencies were both evaluated by the yield of R-PE extraction and by the level of liquefaction. Experiments were conducted at 40 and 22 °C, for 6 h, using an enzymatic cocktail and an original ultrasonic flow-through reactor. R-PE appeared very sensitive to temperature, thus 22 °C is strongly recommended for its extraction by UAEH or UAE. However, the higher processing temperature (40 °C) clearly increased the extraction of water-soluble compounds (up to 91% of liquefaction). These two new processes are thus promising alternatives for the extraction of water-soluble components including R-PE, from wet seaweeds, with extraction yields at least similar to conventional solid–liquid extraction.

Síntese, caracterização e estudo da regeneração do silicoaluminofosfato-11 (SAPO-11)

heterogeneous catalyst such as a silicoaluminophosphate, molecular sieve with AEL (Aluminophosphate eleven) structure such as SAPO-11, was synthesized through the hydrothermal method starting from silica, pseudoboehmite, orthophosphoric acid (85%) and water, in the presence of a di-isopropylamine organic template. For the preparation of SAPO-11 in a dry basis it was used as reactants: DIPA; H3PO4; SiO4; Pseudoboehmite and distilled water. The crystallization process occurred when the reactive hydrogel was charged into a vessel and autoclaved at 200ºC for a period of 72 hours under autogeneous pressure. The obtained material was washed, dried and calcined to remove the molecular sieves of DIPA. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), nitrogen adsorption (BET) and thermal analysis (TG/DTG). The acidic properties were determined using adsorption of nbutylamine followed by programmed thermodessorption. This method revealed that SAPO-11 shows an acidity that ranges from weak to moderate. However, a small quantity of strong acid sites could be detected there. The deactivation of the catalysts was conducted by artificial coking followed by the cracking of the n-hexane in a fixed bed with a continuous flow micro-reactor coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the regeneration and removal of the coke