Ivana Cesarino

An additional tool towards overcoming absence of specificity of carbon nanostructure-based electrochemical sensors—application to estriol and estradiol detection and distinction

The tristimulus analysis was applied in differential pulse voltammetry experiments to detect and distinguish two substances using a set of three sensors that respond to both substances, aiming at the development of an additional tool to overcome the absence of specificity of the sensor to a single chemical species. The sensors are based on carbon nanostructures (graphene oxide, reduced graphene oxide, and reduced graphene oxide modified with antimony nanoparticles) and are applied to estriol and estradiol detection in water, which constitutes an environmental problem. We show that apart from substance identification, the method can be used to quantify the relative concentration of the substances in a solution.

Studies of lignin as reinforcement for plastics composites

Abstract The growing environmental concerns and depletion of fossil fuels resulted in an increased interest in environmentally friendly materials based on natural polymers. Efforts are being made to introduce the lignin in plastic composites such as polypropylene, with the aim of producing bio-based materials with desirable mechanical characteristics. In this study, blends of lignin powder and polypropylene were extruded and testing samples were produced by injection molding process. The produced materials were tested for physical, mechanical and thermal properties. The results showed that the incorporation of the lignin powder in polypropylene matrix resulted in a composite with suitable property application for various industrial fields, especially those were mechanical features are crucial, such as the replacement of engineering plastics.

Evaluation of graphene oxide and reduced graphene oxide in the immobilization of laccase enzyme and its application in the determination of dopamine

Bioelectrodes were developed based on a simple deposition of graphene oxide (GO) or reduced graphed oxide (rGO) and laccase (Lac) on a glassy carbon (GC) electrode surface. The morphology and electrochemical behavior of the biosensors were characterized by scanning electron microscopy and cyclic voltammetry. These results demonstrated that only rGO was successfully applied for the immobilization of the laccase enzyme, improving the analytical signal for the determination of dopamine. The GC/rGO/Lac biosensor was applied to the detection of dopamine in synthetic urine and plasmatic serum samples, achieving a detection limit of 91.0xa0nmolxa0L−1.

Second-generation ethanol from pineapple leaf fibers

ABSTRACT The use of different lignocellulosic residues for the production of cellulosic ethanol is an alternative for the expanding demand of this fuel without increasing the planting area of traditional carbohydrate crops. One of the proposed alternatives is the use of pineapple leaf fibers (PALF) residues, which is a material rich in cellulose that can be used as raw material for second-generation (2G) ethanol production. In this study, the PALF was pretreated using an alkaline medium combined with a steam explosion and the 2G ethanol produSction was analyzed by two-way processes to enzymatic hydrolysis using separated hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF). Using SHF, the alcoholic fermentation process with addition of molasses provided good fermentability and can handle larger loads of carbohydrate in shorter fermentation time. The SSF was a better method for 2G ethanol production from PALF yielding 96.12%. Therefore, PALF is presented as good raw material for production of 2G ethanol, with all the environmental and social advantages of such approach.

Water hyacinth second-generation ethanol production: a mitigation alternative for an environmental problem

ABSTRACT Natural fibers are very abundant, especially those derived from water plant as water hyacinth. The water hyacinth, which is rich in cellulosic fiber content, has a great ability to adapt itself to harsh conditions and at very high growth rate. Therefore, it is considered a pest due to environmental and economical damage to water bodies. A proposed alternative to mitigate the excessing water hyacinth problem is to use its biomass aiming the production of second-generation ethanol (2G), using cellulose as feedstock. It was been implemented different methods to optimize the production of 2G from water hyacinth. Two approaches were considered: a separate chemical pretreatment process and two-way processes to enzymatic hydrolysis using separated hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF). The chromatography analysis showed that the hydrogen peroxide hydrolysis is the more effective pretreatment and that SSF has the highest productivity. The ethanol output can minimize the water hyacinth removal cost through some economical and environmental return.

Innovation Under the Bioeconomy Context in Brazil

This chapter discusses the possibilities of using biomass for several industrial applications, including biopolymers, bio-based materials and biofuel. It also covers the potential conflict between materials/energy and food, cascading concept of biomass utilization and the use of residues. Finally, it discusses the state of art of biomass and agriwastes utilization in Brazil, going from chemical feedstock, biofuels to bio-based materials, at macro, micro and nanoscales.

Characterization of the pre-treated biomass of Eichhornia crassipes (water hyacinth) for the second generation ethanol production

ABSTRACT Eichhornia crassipes (water hyacinth), is considered an aquatic pest. An alternative to solve the excess water hyacinth problem is to use the biomass for second generation ethanol. This process can be divided into: collection of biomass pre-treatment, enzymatic hydrolysis, fermentation and distillation. Some chemical processes for pre-treatment of biomass water hyacinths were evaluated to determine which procedure degrades the greater amount of lignin and hemicellulose which least affects the cellulose. Characterization was made from the analysis techniques: TG-DTA, XRD and FTIR. The results revealed that the biomass to water hyacinth the most efficient pre-treatment is chemical hydrolysis with sulfuric acid.