Hydrogen production from water splitting is a widely used technique and hematite is one of the most used semiconductors in these processes due to its favorable characteristics such as: adequate band gap, visible light absorption, high chemical stability, abundance in nature, among others. Research on hydrogen fuel production from ammonia instead of water is still very limited. Ammonia is a contaminant normally found in wastewater and annualy tons of ammonia or effluents containing this contaminant are thrown into the environment, making it an ideal reagent to produce hydrogen in a clean environmental process. Based on this knowledge, this work proposes the comparison of the photoelectrochemical performance of hematite doped with structural cations (zinc, copper, cobalt, and nickel) in the molecular fragmentation of water and ammonia to produce hydrogen. A structural characterization of the materials used and tests for PEC activity were performed. Pure hematite doped with ammonia as a substrate presented higher electrical current and it was not activated by visible light. When under visible light hematite‐Co presented a discrete increase in the electrical current and, consequently, a small increase in the hydrogen production from water, whereas in the tests with ammonia, the copper‐doped hematite was responsible for a slight increase in the electrical current.

There is a growing number of studies related to computational fluid dynamics for the construction and optimization of equipment, machines, and systems. In this work, the main knowledge needed to perform an analysis of computational fluid dynamics in airlift-type bioreactors for ethanol production will be addressed.

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Biofuels are present in the global scenario as an energy source derived from organic biomass, representing an economic and environmental alternative. They are a renewable source of energy with low rates of pollutants emissions and, consequently, less carbon dioxide is released into the atmosphere. The obtaining of bioethanol is originated from a fermentation process, in which a multi-component mix is generated and the anhydrous bioethanol is separated. To obtain such compounds, some operations are required, such as extractive distillation, where solvents are added in order to "break" the ethanol-water azeotrope. In the present work two solvents were used: Glycerol and the ionic liquid [BMIM][BF4]. Starting from a multi-component mixture composed by ethanol, water, acetic acid and isoamyl alcohol, the bioethanol purification process was simulated using the computational tool Aspen Plus® simulator. Through a comparative analysis, it was possible to determine which solvent presented the best performance, where operational parameters such as the reflux ratio, distillate rate and the solvent flow were analyzed. The purity degree of 99.7% in mass and an approximate production of 2764 kg/h of anhydrous bioethanol were fixed and the results showed that glycerol was the solvent that presented greater economic and environmental viability for the process, considering the operational parameters mentioned above.

The discovery of the environmental impacts caused by petroleumbased polymers has led to the use of natural polymers gaining more and more space. Naturally occurring polymers, also known as biopolymers, are chemical compounds produced by living things or raw materials from renewable energy sources. Their main advantage is decomposition, while polymers from fossil and non-renewable energies can take hundreds of years to decompose, biopolymers have significantly shorter life cycles. In this study, a study of the application of the biomass of the microalgae Spirulina platensis in biodegradable films with corn starch was conducted, aiming for the development of a functional film with rapid degradability. Approximately 48 biofilms were produced in varying concentrations (w/v), where the visual characteristics of each were observed and the ones that presented the greatest resemblance to conventional plastics were selected, being Trial 4 (T4) and Trial 46 (T46), composed of 2 and 70% v/v of microalgae, respectively. The other tries were discarded due to cracking, high fragility, and very gelatinous or very rigid appearance. The morphological characteristics of T4 and T46 biofilms were analyzed by Scanning Electron Microscopy (SEM) and compared to those of a conventional plastic bag and a commercially available biodegradable plastic bag, where it was possible to prove that the biofilms produced presented good morphological structure. The Fourier Transform Infrared Spectroscopy (FTIR) analysis provided structural information, proving the presence of polyhydroxyalkanoate in the biofilms produced. Two degradability tests were performed with satisfactory results obtained, proving the rapid degradation of the biopolymers produced. It was possible to prove that the biofilms under study present great potential for replacing conventional polymers.