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Biopolymers are sustainable materials derived from renewable sources that have relevant and industrially attractive properties such as biodegradability, biocompatibility and antimicrobial effect. Thus, these were the target of several experimental studies, widely published in the literature and used in our daily lives. This paper presents a preliminary investigation on the polyesterification of a malic acid/glycerol mixture in order to obtain the poly(glycerol-co-malic acid) to be evaluated as a bioadhesive. For this, different reaction conditions were evaluated by varying the concentrations of malic acid, glycerol and zinc chloride(II) as catalyst, carried out according to the central composite rotatable design. The polymerizations were monitored by acidity index, hydroxamic acid test and conversion rate and the obtained materials characterized by FTIR. Poly(glycerol-co-malic acid) was obtained in yields of 38 to 68% which show that such method is promising for obtaining this new biopolymer aimed as bioadhesive.

The main objective of this study is the degradation of a synthetic solution of atrazine by a modified vermiculite catalyzed ozonation, in a rotating packed bed (RPB) reactor. A 0.5 L RPB reactor was used to perform the experiments, using a Central Composite Design (CCD) response surface to construct the quadratic model based on the factors: pH, catalyst concentration and reactor rotation frequency. The response variable was the removal of the organic load measured in terms of Chemical Oxygen Demand (COD). After the complete quadratic model was constructed through the response surface, the COD degradation process had an optimal removal of 41% under the following conditions: pH 8.0, rotation of 1150 rpm and catalyst concentration 0.66 g L

One of the main problems that affects Ruhrstahl-Heraeus (RH) degasser circulation rate is the obstruction of the gas-injection nozzles. This study aims to elucidate the effects of obstructions in quantity and location using a physical model that depicts 16 injection nozzles on the up-leg distributed symmetrically in 2 rings (8 nozzles/ring). We simulated six, symmetric and nonsymmetric, obstruction conditions to gas flow. The gas-flow rate was varied from 30 to 130 NL/min. The results for symmetric obstructions when the gas-flow rate is kept constant, indicates that the circulation rate in the equipment does not significantly change. However, when these obstructions are non-symmetric, the circulation rate varies drastically, even when the gas-flow rate is kept constant. The analysis of the experimental data generated from this study allowed to determine an equation for the circulation rate that takes into consideration the number and distribution of blocked nozzles.

The search for a renewable source as an alternative to fossil fuels has driven the research on new sources of biomass for biofuels. An alternative source of biomass that has come to prominence is microalgae, photosynthetic micro-organisms capable of capturing atmospheric CO2 and accumulating high levels of lipids in their biomass, making them attractive as a raw material for biodiesel synthesis. Thus, various studies have been conducted in developing different types of photobioreactors for the cultivation of microalgae. Photobioreactors can be divided into two groups: open and closed. Open photobioreactors are more susceptible to contamination and bad weather, reducing biomass productivity. Closed photobioreactors allow greater control against contamination and bad weather and lead to higher rates of biomass production; they are widely used in research to improve new species and processes. Therefore, many configurations of closed photobioreactors have been developed over the years to increase productivity of microalgae biomass.

Made available in DSpace on 2021-06-25T11:22:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Microalgae have received special attention due to the biotechnological potential of their biomass, which can be used to produce biofuels, food formulations and pharmaceutical products. In order to improve biomass productivity, the present work proposes an internal light integrated photobioreactor (ILI-PBR), which integrates two configurations of photobioreactors (PBRs) already consecrated and widely used (tubular and bubble column) in a single system, combining the benefits of each configuration in a single PBR. To evaluate the applicability of ILI-PBR, a comparative test was conducted with the internal light bubble column photobioreactor (ILBC-PBR); both PBRs were illuminated with blue light-emitting diodes (LED).The PBR's performance was evaluated in terms of specific growth rate (mu(max)) and cell productivity (P-X) of the microalgae Chlorella minutissima. The mu(max) and P-X in ILI-PBR were at least 42.85 and 58.06 % higher than ILBC-PBR, respectively. ILI-PBR was 36 % more efficient in terms of electricity consumption than ILBC-PBR. Univ Fed Ouro Preto, Inst Exact & Biol Sci ICEB, Dept Chem, Lab Technol & Environm Chem, Campus Univ Morro Cruzeiro, Ouro Preto, Brazil Univ Sao Paulo, Sch Engn Lorena EEL USP, Lorena, SP, Brazil Ctr Fed Educ Tecnol Celso Suckow Fonseca CEFET R, Angra Dos Reis, RJ, Brazil Univ Fed Sao Joao del Rei UFSJ, Campus Ouro Branco, Ouro Branco, MG, Brazil Sao Paulo State Univ, Fac Engn Guaratingueta, Ave Doutor Ariberto Pereira da Cunha 333, BR-12516410 Guaratingueta, SP, Brazil Sao Paulo State Univ, Fac Engn Guaratingueta, Ave Doutor Ariberto Pereira da Cunha 333, BR-12516410 Guaratingueta, SP, Brazil

This work studies low-cost coagulants and flocculants with satisfactory efficiency, using the flower from Musa sp. as raw material. Many coagulants already used in the market, have high application cost and they may also be polluters. The tannins, natural biocoagulants, coming from the secondary mechanism of plants, are somewhat chemically reactive and they have already been used in processes. The present work has the objective of obtaining tannins using hot percolation as the extraction method, with the following factors: extraction solvent type, batch extraction number and percolation time. To evaluate the best extraction condition, a response surface methodology characterized by a Central Composite Design (CCD) was used, which could analyze each of the respective factors in five levels. The optimization of the model generated from the response surface aiming at a higher concentration of tannins was done using the Generalized Reduced Gradient (GRG) algorithm. Under these conditions, the tannin concentration was 0.93 μg/mL in the experimental conditions defined by the following factors: acetic acid solution 12.5% v/v, 6 batch with 45 min each. Under these conditions, the efficiency of the extract in the coagulation and flocculation of sludge from the mining industry was 98.78% for turbidity removal and 99.24% for solid removal.

Tannins condensed and hydrolyzable, extracted from the flower of Musa sp. was used in the process of reducing turbidity of effluents from the processing of iron ore. A great deal of attention has been given to coagulation and flocculation processes in the separation of the ore fines that remain adhered to silica after processing, aiming at the reuse of process water and the iron itself with percentages between 15 and 35%. The coagulation and flocculation tests were performed in a jar test, verifying the influence of the factors: pH, coagulant volume and frequency of agitation aiming at turbidity reduction. Response surface methodology was used to construct a model and verify the influence of the levels of each of the factors on the turbidity reduction. From the constructed model, it was possible to optimize the turbidity removal through the generalized reduced gradient algorithm (GRG) leading to an initial turbidity reduction of 86500 NTU in 97.58%.

This paper presents the multiobjective optimization of methyl orange treatment with ozone using Normal Boundary Intersection and response surface models of rotated principal component factor scores for the expected value E[f(x)] and prediction variance Var[f(x)] of dye removal (Y 1 ) and chemical oxygen demand removal (Y 2 ). The innovation and the main contribution of this paper consists of building a 2-dimensional equispaced and convex Pareto Frontier for rotated factor scores representing the original multivariate set, reducing the number of objective functions without inverting the correlation among the original responses. Furthermore, this proposal provides a practical way to generate the narrowest possible prediction confidence intervals for a desired optima using the fuzzy membership function criterion in order to select the best compromise solution between E[f(x)] and Var[f(x)]. To illustrate the proposal's feasibility, a central composite design for the ozonation process of methyl orange solution with three factors (x 1 = pH, x 2 = air flow and x 3 = ozone dosage) was run. The optimization results showed a maximum dye removal of 94.1% ± 4.3 with a respective chemical oxygen demand removal of 88.4% ± 5.3 obtained at x* = [9.5; 7.1 l.min-1; 18.4 g h −1 ]. However, this point have presented the largest 95% prediction confidence interval. Based on the fuzzy membership of Pareto set it was possible to select the narrowest 95% confidence intervals with maximum removal rates (Y 1 = 90.5 ± 2.2 and Y 2 = 88.3 ± 2.7), obtained at x* = [7.9, 5.6 l min −1 , 18.4 g h −1 ]. Confirmation runs and comparisons among several optimization methods were done and indicated that the results fell within the respective confidence intervals for predictions, which corroborates the good adequacy of the proposal.

Pechini method was applied for the first time to synthesize CeNb3O9 perovskite at different calcination temperatures (600, 800 and 1000 °C). A solution of water, citric acid, ethylene glycol, ammonium niobium oxalate and cerium ions was polymerized and calcined at 300 °C for 2 h. The precursor gels were submitted to a second calcination at 600, 800 and 1000 °C to obtain perovskite at different temperatures. These materials were characterized through X-ray diffraction (XRD), thermogravimetric analysis (TGA), N2 physisorption, scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), diffuse reflectance spectroscopy (DRS-UVvis) and Fourier transform infrared spectroscopy (FTIR). Results showed the formation of perovskite only at 1000 °C and Nb2O5-CeO2 mixed oxides at lower temperatures with some interesting characteristics. Pechini technique allows the synthesis of cerium niobate perovskite at lower temperatures than those presented in the literature (prepared by different methods).

Ozone and a Fe2+/TiO2-based catalyst were examined in the degradation of a synthetic solution of benzene toluene and xylene (BTX) in an advanced oxidation process (AOP). The catalyst beads were made from the slurry waste of aluminum production process, by inserting the TiO2 content and subsequent calcination. The reduction of the BTX concentration load was monitored by the reduction of chemical oxygen demand (COD) and BTX concentration. Different levels were used on factors: pH, time of treatment, initial concentration of BTX, and percentage of TiO2. The process was conducted in a bubble column reactor with the insertion of catalyst beads. A response surface methodology technique (CCD) was used to build a model based on COD reduction results. The model was optimized using the normal-boundary intersection (NBI) algorithm to maximize COD reduction and minimize the variance attributed to the process. Optimization led to COD reductions of 80% in 2 h of experiment. Correlation analysis of coefficient models from experimental data R2adj was 0.9966, showing a good fit of model data. In the optimized conditions, the possible increase of the biodegradability ratio of the BTX solution, through the biochemical oxygen demand (BOD) and COD, was also analyzed. Under pre-treatment conditions, the BOD/COD ratio was 0.13. After the treatment, it increased to 0.56.

RESUMO Foram estudados catalisadores a base de níquel (Ni) e cobre (Cu) suportados em Hbeta cuja atividade e seletividade foram avaliadas na reação de Hidrodesoxigenação (HDO) do benzaldeído. Para isso, sintetizaram-se catalisadores com 10,0 % de NiO (em massa) e adicionaram-se diferentes teores de CuO: 2,5 %, 5,0 %, 7,5 % e 10,0 % (em massa). Para efeito de comparação, foram sintetizados, também, os monometálicos NiO 10,0 % e CuO 10,0 % (em massa). A reação foi realizada em reator batelada com agitação magnética a 220 °C. Os catalisadores foram caracterizados pelas técnicas de difratometria de raios X (DRX), fisissorção de N2, redução com hidrogênio à temperatura programada (RTP-H2), espectroscopia por reflectância difusa nas regiões do ultravioleta e do visível (ERDUV-Vis) e análise termogravimétrica (TG/DTG). Pelos resultados de avaliação catalítica observou-se que o benzaldeído foi convertido em álcool benzílico, tolueno e benzeno. O catalisador Ni10Cu7,5/Hbeta apresentou conversão de 84,7 %, com seletividade para tolueno em torno de 91,0 %, apresentando maior seletividade a produtos desoxigenados que o catalisador com maior teor metálico (Ni10Cu10/Hbeta), fato que, possivelmente, possa estar associado à maior quantidade de sítios ácidos no catalisador. Os catalisadores bimetálicos apresentaram-se mais ativos que os monometálicos Ni e Cu. Dessa forma, a adição do Cu pode contribuir para a melhor performance dos catalisadores de Ni/Hbeta na reação de HDO. ABSTRACT The activity and selectivity evaluation of nickel (Ni) and copper (Cu) catalysts supported over Hbeta in the hydrodeoxygenation (HDO) reaction of benzaldehyde were studied. For this purpose, monometallic (10 wt.% of NiO or CuO) and bimetallic catalysts with 10 wt.% of NiO with different CuO (2.5 %, 5 %, 7.5 % and 10 % by wt.) were synthesized. The reaction was carried out in batch reactor with magnetic stirring at 220 °C. The catalysts were characterized by X-ray diffraction (XRD), N2 physisorption, hydrogen temperature programmed (TPR-H2), diffuse reflectance spectroscopy in ultraviolet and visible regions (DRSUV-Vis), thermogravimetric analysis (TG / DTG). Results of the catalytic evaluation showed that the benzaldehyde was converted to benzyl alcohol, toluene and benzene. Ni10Cu7.5/Hbeta catalyst presented a conversion of 84.73 %, with selectivity to toluene around 91 %, presenting higher selectivity to deoxygenated products than Ni10Cu10/Hbeta, which can be related to the higher acidic sites present in the catalyst. The bimetallic catalysts were more active than the monometallic Ni and Cu. Thus the addition of Cu can contribute to a better performance of the Ni/Hbeta catalysts in the HDO reaction.

Amoxicillin is a useful antibiotic to combat bacterial infections. However, this drug can cause serious problems when discarded in waterways due to its great bioaccumulation potential. This compound can be treated via advanced oxidation processes (AOPs), which are capable of converting amoxicillin into carbon dioxide and water. In this context, the use of ozone as an oxidizer has excelled in amoxicillin degradation. This paper aims at treating a synthetic solution of amoxicillin (0.1 g L−1) in a reactor with ozone bubbling. A Design of Experiment (DoE) with a response surface known as Central Composite Design (CCD) was used to optimize the treatment process. In addition, a Normal Boundary Intersection (NBI) method was used in the construction of a Pareto boundary chart. Results after 1-h treatment showed a reduction of 53% of the initial organic matter from a designed model using factors, such as pH, ozone generator power, and O3 flow. A model was built from the CCD with score of 0.9929. Thus, the model was able to represent the real scenario with confidence.

Minimizing the variability of any process can become a way to reduce costs and at the same time keep the process stable. The use of the Normal Boundary Intersection (NBI) algorithm to construct the Pareto frontier can be applied to a better choice of a particular setup that can give the process a better response and less variability. The objective of this research is to propose the modelling and optimization for the maximum removal of the Chemical Oxygen Demand (COD) and the minimization of the variance associated the COD removal, to the UV/TiO2/O3 process, in the treatment of Eriochrome Black T. The factors studied in the COD removal were: pH, ozonator power, ozone flow and reaction time. The process of modelling used the response surface through the Central Compound Design (CCD) arrangement. In addition to the optimization, a Pareto Frontier using the NBI algorithm was utilized. The optimized results showed a COD removal of 33.7 ± 1.29 obtained X* = [7.7; 160 W; 5.6 L min−1; 22.6 min]. The confirmation of this point belonging to the Pareto frontier from the validation of the method was performed within a 95% confidence interval, the number of experiments being determined from the power sample size, comparing the ratio between the variances, weights w1 = 1 and w2 = 0.45.