Hélcio José Izário Filho

Scale-up of diluted sulfuric acid hydrolysis for producing sugarcane bagasse hemicellulosic hydrolysate (SBHH)

Sugarcane bagasse was pretreated with diluted sulfuric acid to obtain sugarcane bagasse hemicellulosic hydrolysate (SBHH). Experiments were conducted in laboratory and semi-pilot reactors to optimize the xylose recovery and to reduce the generation of sugar degradation products, as furfural and 5-hydroxymethylfurfural (HMF). The hydrolysis scale-up procedure was based on the H-Factor, that combines temperature and residence time and employs the Arrhenius equation to model the sulfuric acid concentration (100 mg(acid)/g(dm)) and activation energy (109 kJ/mol). This procedure allowed the mathematical estimation of the results through simulation of the conditions prevailing in the reactors with different designs. The SBHH obtained from different reactors but under the same H-Factor of 5.45+/-0.15 reached similar xylose yield (approximately 74%) and low concentration of sugar degradation products, as furfural (0.082 g/L) and HMF (0.0071 g/L). Also, the highest lignin degradation products (phenolic compounds) were rho-coumarilic acid (0.15 g/L) followed by ferulic acid (0.12 g/L) and gallic acid (0.035 g/L). The highest concentration of ions referred to S (3433.6 mg/L), Fe (554.4 mg/L), K (103.9 mg/L). The H-Factor could be used without dramatically altering the xylose and HMF/furfural levels. Therefore, we could assume that H-Factor was directly useful in the scale-up of the hemicellulosic hydrolysate production.

Cadmium quantification in Brazilian mothers colostrum: a regional study

OBJECTIVES: to estimate the amount of cadmium in human colostrum of mothers from Taubate. METHODS: it was a cross-sectional study with mothers who delivered in University Hospital of Taubate, in year 2003. The colostrum was collected in special tubes, one day after the delivery and frozen at -200 C. The independent variables were maternal age, birthweight, gestational age, parity, dietary habits, smoking report and maternal occupation. Cadmium was quantified by atomic absorption spectrometry. It was used Mann-Whitney non-parametric approach to compare mean values; Pearson correlation was also used to verify associations. The level of significance was alpha = 5%. RESULTS: the mean value of cadmium was 54.5 mg/L (sd=381.0 mg/L). Cadmium was detected in 18 out of 58 samples (31.0%). There was neither correlation nor differences between the cadmium values and the independent variables maternal age, birthweight, gestational age, parify and smoking report. CONCLUSIONS: these values are above those the amounts described in other papers and it is important to identify the possible sources of this heavy metal in maternal environment.

Microalgal Feedstock for Bioenergy: Opportunities and Challenges

The utilization of algal feedstock for bioenergy can be considered as one of the greatest challenges for biosystems engineering in the near future. Some species of microalgae show high potential for oil accumulation and further utilization of its biomass for biogas generation, pyrolysis, ethanol production, and even as fertilizer. Microalgae can utilize CO2 as carbon source and can also be grown on nonagricultural environments, such as wastewater facilities, industrial effluents, freshwater, and marine water habitats. The vast research field on microalgae engineering is due to the facts that it can be a source of energy and act as an air and water pollutants removal. There have been considerable advances in engineering its growth, in bioreactor designs, and on lipid accumulation due to chemical, biochemical, and genetic studies. Despite that, there are still some fundamental processing aspects that are considered challenges, either economical, ecological, or technical, such as biomass harvesting and the competition with the higher value products produced from algae, as proteins.

Evaluation of sample preparation methods and optimization of nickel determination in vegetable tissues

Nickel, although essential to plants, may be toxic to plants and animals. It is mainly assimilated by food ingestion. However, information about the average levels of elements (including Ni) in edible vegetables from different regions is still scarce in Brazil. The objectives of this study were to: (a) evaluate and optimize a method for preparation of vegetable tissue samples for Ni determination; (b) optimize the analytical procedures for determination by Flame Atomic Absorption Spectrometry (FAAS) and by Electrothermal Atomic Absorption (ETAAS) in vegetable samples and (c) determine the Ni concentration in vegetables consumed in the cities of Lorena and Taubate in the Vale do Paraiba, State of Sao Paulo, Brazil. By means of the analytical technique for determination by ETAAS or FAAS, the results were validated by the test of analyte addition and recovery. The most viable method tested for quantification of this element was HClO4-HNO3 wet digestion. All samples but carrot tissue collected in Lorena contained Ni levels above the permitted by the Brazilian Ministry of Health. The most disturbing results, requiring more detailed studies, were the Ni concentrations measured in carrot samples from Taubate, where levels were five times higher than permitted by Brazilian regulations.

The Application of Response Surface Methodology in the Study of Photodegraded Industrial Dairy Effluents by the Photo-Fenton Process: Optimization and Economic Viability

This study presents results from an application of Photo-Fenton process for organic-load reduction in dairy effluents. Process efficiency was evaluated in terms of percentage dissolved organic carbon, chemical oxygen demand, and biochemical oxygen demand (DOC, COD, and BOD, resp.), whose initial values were  mg O2 L−1,  mg O2 L−1, and  mg O2 L−1, respectively. We applied a statistical design represented by Box-Behnken factorial design inclusive of Fentons reagent, the power of applied radiation (W), and pH factors. The set temperature value was 30°C with a reaction time of 60 min. The maximum efficiency obtained was at , Fenton reagent in the proportion of 35 g H2O2  3.6 g Fe2

Predição da demanda química de oxigênio em chorume maduro contendo reagente de Fenton, por meio de modelo matemático empírico gerado com planejamento fatorial completo

COD is an important parameter to estimate the concentration of organic contaminants. The closed system technique with the use of K2Cr2O7 is the most important one, however, it has the inconvenience to suffer positive chemical interferences from inorganic compounds such as Fe2+ and H2O2 (not enough reported in the literature). This paper considers a statistical-experimental set capable to validate a empirical mathematical model generated from a 23 experimental design, in the presence of Fe2+ and H2O2. The t test shows that mathematical model has 99,99999% confidence degree and the experimental validation test indicates absolute mean error of 4,70%.

Semiquantitative analysis of mercury in landfill leachates using double-pulse laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is showing to be a promising, quick, accurate, and practical technique to detect and measure metal contaminants and nutrients in urban wastes and landfill leachates. Although conventional LIBS presents some limitations, such as low sensitivity, when used in the single pulse configuration if compared to other spectroscopic techniques, the use of the double-pulse (DP) configuration represents an adequate alternative. In this work DP LIBS has been applied to the qualitative and quantitative analysis of mercury (Hg) in landfill leachates. The correlation analysis performed between each intensified charge-coupled device pixel and the Hg concentration allowed us to choose the most appropriate Hg emission line to be used for its measure. The normalization process applied to LIBS spectra to correct physical matrix effects and small fluctuations increased from 0.82 to 0.98 the linear correlation of the calibration curve between LIBS and the reference data. The limit of detection for Hg estimated using DP LIBS was 76  mg Kg-1. The cross validation (leave-one-out) analysis yielded an absolute average error of about 21%. These values showed that the calibration models were close to the optimization limit and satisfactory for Hg quantification in landfill leachate.

Modeling the Photocatalytic Process of Variation in Chemical Oxygen Demand via Stochastic Differential Equations

Several papers in the literature on Advanced Oxidation Processes (AOPs) confirm the process as a viable alter- native for the treatment of a variety of industrial effluents. In many of these works, modeling the variations of Chemical Oxygen Demand (COD) as a function of different experimental conditions was performed by techniques such as Design of Experiments, Artificial Neural Networks and Multivariate Analysis. These techniques require both a large number of parameters and a large quantity of experimental data for a systematic study of the model parameters as a function of ex- perimental conditions. On the other hand, the study of Stochastic Differential Equations (SDE) is presently well devel- oped with several practical applications noted in the literature. This paper presents a new approach in studying the varia- tions of COD in AOPs via SDE. Specifically, two effluents, from the manufacture of paints and textiles were studied by combined treatment of the photo-Fenton process and catalytic ozonization.

Catalytic Ozonation Using Fe 2+ in the Treatment of Dairy Effluent in a Semi-Batch Process with Recycle

This work describes the treatment of dairy industry effluent using catalytic ozonation with Fe2+ as its catalyst in a semi-batch process with recycle. A fractional factorial design 24-1 was used with a reduction percentage of total organic carbon (TOCred) as response. Optimal conditions were obtained by the reaction time of 30 min, ozonator power of 35 W, O2 flow rate of 0.125 L min-1, Fe2+ concentration of 1.0 g L-1 and pH 4.0 for a 2 L raw effluent. TOCred of 64.03% represents a decrease in concentration from 473.0 to 170.1 mg L-1, with an estimate cost of US

Deslocamento miscível de um efluente de indústria de explosivo em colunas de solo

0.03 L-1effluent. The treatment performed was not sufficient to discharge it directly on surface water; however, significant reduction of TOCred, among physical and chemical characteristics makes a better product to be proceeded into a biological treatment.