Synthesis and Characterization of Modified Magnetic Nanoparticles for Removal of Dispersed Oil in Water

This paper proposes the synthesis of materials capable of sorption oil dispersed in water. From the production of magnetic iron oxide nanoparticles, more specifically magnetite, inorganic modifications were performed using quartz and silicaalumina, in order to identify their properties and sorption capabilities of oil. The produced materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), x-ray diffraction (XRD), sorption and magnetic force tests. At the end of the characterizations and tests, it was concluded that the magnetic nanoparticles were successfully modified. Regarding magnetite, the sorption capacity was outstanding, while the modifications had the same sorption capacity. And the statistical calculations obtained by ANOVA and Tukey's method, proved the difference in the sorption of the samples. In addition, it was evidenced that the higher the magnetic force, the greater is the ability to collect the spot/nanoparticle using a magnet

Production of Portland Cement Loaded with Polyaniline and Evaluation of Sulphidric Gas Sorption Capacity

Cements are materials based on clay and limestone. Its origin was about 4500 years ago and it is believed that they were the basis for the construction of the pyramids in Egypt. As time went by, limestone was calcined, giving origin to the Portland Cement most used today. Its applications are diverse, ranging from the construction industry to the production of sustainable materials. In this sense, this work aims to produce composites of cement loaded with polyaniline and exposure to hydrogen sulfide gas to assess the sorption capacity of this contaminant, present mainly in sewage treatment. The composites were analyzed by resistivity analysis, in order to investigate the influence of PAni in the geopolymer matrix and its ability to conduct electrical energy, after H2S sorption and gravimetry, aiming to observe the increase in mass (g) during the sorption process. All tests were performed in triplicate and the mean, standard deviation and confidence limit were calculated to obtain the reliability of the results

Correlations between physical and chemical characteristics of Cortibel guava (Psidium guajava L.) fruits grown in the Brazilian Cerrado

The correlation between physical and chemical attributes of fruits can serve as indicators for the ideal harvest time and function as selection criteria to enhance the management and productivity of crops. This study aimed to investigate the correlations among physical and chemical properties of Cortibel guava fruits grown in the Brazilian Cerrado. Parameters assessed included skin and pulp color, weight, diameter, length, total soluble solids, titratable acidity, and the ratio of these characteristics. Data were analyzed using Pearson's linear correlation with a significance level of P < 0.05. Several physical and chemical properties of the fruits exhibited significant correlations. The highest correlation coefficients were observed between weight and fruit diameter, as well as between hue angle of the skin and skin lightness. The properties of Cortibel guava fruits cultivated in the Brazilian Cerrado exhibit significant correlations. These findings enable the utilization of straightforward parameters in the selection processes of Cortibel guava for breeding objectives. Highlights: Guava is a significant crop with high economic value. The characterization of fruits assists in selecting genotypes with desirable commercial properties. Cortibel guava fruits exhibited significant correlations between some physical and chemical characteristics. The correlations between the physical and chemical characteristics of the fruits allow the selection of materials of interest for breeding.The correlation between physical and chemical attributes of fruits can serve as indicators for the ideal harvest time and function as selection criteria to enhance the management and productivity of crops. This study aimed to investigate the correlations among physical and chemical properties of Cortibel guava fruits grown in the Brazilian Cerrado. Parameters assessed included skin and pulp color, weight, diameter, length, total soluble solids, titratable acidity, and the ratio of these characteristics. Data were analyzed using Pearson's linear correlation with a significance level of P < 0.05. Several physical and chemical properties of the fruits exhibited significant correlations. The highest correlation coefficients were observed between weight and fruit diameter, as well as between hue angle of the skin and skin lightness. The properties of Cortibel guava fruits cultivated in the Brazilian Cerrado exhibit significant correlations. These findings enable the utilization of straightforward parameters in the selection processes of Cortibel guava for breeding objectives. Highlights: Guava is a significant crop with high economic value. The characterization of fruits assists in selecting genotypes with desirable commercial properties. Cortibel guava fruits exhibited significant correlations between some physical and chemical characteristics. The correlations between the physical and chemical characteristics of the fruits allow the selection of materials of interest for breeding

Evaluation of H2S Sorption Capacity by Geopolymers Produced in Heterogeneous Medium

Geopolymers are composed of aluminosilicates that, upon activation by alkaline solution, form repeated units, and are classified as inorganic polymers. Geopolymers have gained great prominence due to the obtainment of the raw material, which can be natural or residual, the ease of production and low cost. These materials are widely used in civil construction to replace Portland cement and also in the environmental area for the remediation of toxic compounds. However, there is still little in the literature about the applications of these materials. Thus, this work aimed to use geopolymers for hydrogen sulfide gas sorption and it was possible to verify that they are able to adsorb twice its mass in gas

Evaluation of the Electrical Conductivity of Geopolymers Loaded with Carbon Black

Geopolymers are inorganic polymers, composed of aluminosilicates activated with an alkaline solution. This method gives the material three-dimensional networks that are capable of carrying out ion exchange, as well as facilitating the transfer of electric charge through the matrix, when a conductive charge is added. In this sense, geopolymers loaded with carbon black in concentrations of 5, 10, 15 and 20% by weight were produced and the electrical conductivity capacity was verified. The geopolymers were subjected to X-ray Diffraction and resistivity analyzes. The results showed that the geopolymers loaded with carbon black showed a decrease in resistivity due to the concentration of carbon black in the geopolymeric matrix, indicating that with increasing load, less resistive and more conductive. In addition, all analyzes were performed in triplicates, and the calculations of the mean, standard deviation and confidence limit, indicated that in all syntheses the geopolymers remained with the same efficiency

The Importance of Viscosity Analysis in Biodiesel

One of the primary motivations for studying biofuels is to meet global energy needs. Biodiesel, as a promising renewable energy source, has the potential to reduce dependence on fossil fuels if implemented effectively. It is derived from chemical reactions (transesterification) in vegetable oils or animal fats, facilitated by a catalyst that accelerates the reaction. Currently, industrial processes employed by biodiesel plants predominantly utilize homogeneous catalysts. However, heterogeneous catalysts are emerging as promising alternatives in biodiesel production, distinguished by their environmentally friendly nature and the ability to regenerate and be reused. This study aims to investigate the viscosity of biodiesel through the methylic route, employing geopolymers with added magnetic nanoparticles as a heterogeneous catalyst. Kinematic viscosity measurements of biofuels were conducted to assess their impact on combustion efficiency and engine performance. The results obtained indicate that the values fall within the parameters established by the National Petroleum Agency (ANP)

Reaction of Activated Geopolymers in Acid Medium and Application of Polyaniline as a Conductor of Electricity

In 1972, the French chemist Joseph Davidovits named a new class of inorganic polymers, the geopolymers. This was due to his search for flame-resistant materials that were harmless to the environment and human health. These materials were produced by reacting aluminosilicates in alkaline solution. However, over time, it was discovered that it was possible to produce the same material via an acidic route, using phosphoric acid. In this sense, this work aimed the production of geopolymers in acid medium and the insertion of 10%, 25% and 50% of conductive charge to produce a geopolymer capable of conducting electric charge. To verify the conductive capacity of the material, the resistivity test, and Thermogravimetric Analysis (TGA) were performed to investigate the loss of mass as a function of temperature. The tests were performed in triplicates and the data obtained were analyzed by ANOVA and Tukey method and the results showed that the values were different from each other, indicating the domination of resistivity with increasing polyaniline concentration

Assessment of cassava starch biofilm in the quality and shelf life of banana 'prata'

Brazil is now the world's fourth-largest banana producer in the world with an annual production of 6.953,747 tons per year. In Brazil, the banana (Musa spp.) stands out, not only because it is the most widespread, but also because it is the most consumed by all social classes. Cassava is a renewable, almost unlimited resource and one of the most abundant substances in nature. It is one of the most important starchy root crops of the tropics used for food and industrial purposes. The present study evaluated the use of biofilms based on cassava starch in maintaining the quality and shelf life of the 'Prata' banana at room temperature. Initially, filmogenic solutions were produced using the casting technique for two treatments. T1 (2.6% starch / 500 mL of distilled water); T2 (2.6% starch / 500 mL of distilled water + 1 g of gelatin). Additionally, thickness, weight, and, subsequently, the biofilms were applied in the film-forming solution for 1 min and suspended for further drying at room temperature. After this process, were evaluated the loss of fresh mass, pH, and totals soluble solids. The present study revealed the efficiency of biofilm coating with and without gelatin to reduce the rate of enzymatic browning and increase the shelf life of bananas. It was possible to verify a smaller reduction in fresh weight loss in the treatments. Besides, no significant difference was observed in the addition of gelatin to the parameters evaluated in the fruit

Isolamento de Candida spp. de estomatite relacionada à prótese no Pará, Brasil.

The aim of this study was to isolate and identify Candida species from the oral cavity of den-ture wearers with denture-related stomatitis who were attended at the University Federalof Pará (Belém City, Pará State, Brazil). A total of 36 denture wearers with denture-relatedstomatitis were included, and type I (50%), type II (33%) and type III (17%) stomatitis wereobserved. Candida spp. were isolated from 89% of the cases and included five differentCandida species. C. albicans was the most frequently recovered species (78% of the cases),followed by C. famata and C. tropicalis. We observed a significant association between Candidaspecies isolation and unsatisfactory denture condition (p = 0.0017). Our results demonstratedthe highly frequency of Candida species isolation in denture wearers with denture-relatedstomatitis and showed the relationship between these species and poor denture maintence.O objetivo deste estudo foi isolar e identificar espécies de Candida da cavidade oral de usuários com estomatite relacionada à dentadura, atendidos na Universidade Federal do Pará (Cidade de Belém, Pará, Brasil). Foram incluídos 36 usuários de protese com estomatite relacionada à prótese, e foram observadas estomatite tipo I (50%), tipo II (33%) e tipo III (17%). Candida spp. foram isolados em 89% dos casos e incluíram cinco espécies diferentes de Candida. C. albicans, frequentemente recuperada (78% dos casos), seguida por C. famata e C. tropicalis. Observamos uma associação significativa entre o isolamento da espécie Candidas e a condição insatisfatória da prótese (p = 0,0017). Nossos resultados demonstraram a alta frequência de isolamento de espécies de Candida em usuários de próteses com estomatite relacionada à prótese e mostraram a relação entre essas espécies e má manutenção da prótese

Use of Static Method to remove Heavy Metal of the Contaminated Water, using Porous Geopolymer and Magnetically Loaded

Due to several catastrophic fires in France involving flammable organic plastics, Davidovits began his search for new materials resistant to heat, developing an alkaline activated silico-aluminous material, which was called a geopolymer. The polymeric Si-O-Al network gives the geopolymer ion exchange property, allowing the immobilization of heavy and radioactive metals within the material matrix. Due to the geopolymer's characteristic of immobilizing heavy metals in its matrix, this project aims to evaluate the geopolymer's ability to absorb heavy metals in contaminated water. For this, samples of porous geopolymers with magnetic charges in concentrations of 1, 2 and 3% were produced. And, subsequently, toxic metal solutions were made, such as Chromium, Cadmium and Lead at a concentration of 3ppm, then the sorption was carried out using the static method, where 0.5 g of the gepopolymer was dispersed in 25 ml of contaminated water and left stirring for 5 minutes, with the aid of a mechanical stirrer, and left to rest for 24 hours for the geopolymer to settle and the supernatant to be collected (this procedure was performed for geopolymers with and without magnetic charges). Afterwards, the treated water was analyzed by the atomic absorption technique, in order to investigate the geopolymer's sorption capacity. All tests were performed in triplicate and the mean, standard deviation and 95% confidence limit were evaluated to determine the reliability of the results