https://ri.ufs.br/jspui/handle/riufs/19270 2026-09-26T05:20:49Z 2026-09-26T05:20:49Z Santos, Silvia Vitória Guimarães https://ri.ufs.br/jspui/handle/riufs/26155 2026-09-23T12:15:06Z 2026-07-24T00:00:00Z

Título: Avaliação integrada de íons solúveis em MP10 e variáveis meteorológicas aplicada à qualidade do ar Autor(es): Santos, Silvia Vitória Guimarães Abstract: Inhalable particulate matter (PM₁₀) is an important indicator of air quality, particularly in coastal areas, where marine aerosols and anthropogenic activities contribute to its composition. The aim of this study was to evaluate the composition of water-soluble ions in inhalable particulate matter (PM₁₀) and its relationship with meteorological variables in the city of Aracaju, Sergipe, Brazil, in order to understand the processes influencing air quality and identify potential sources of atmospheric pollution. To ensure reliable determination of ion concentrations, the extraction method was optimized using a 2³ full factorial design, in which the effects of sample mass, extraction time, water volume, and their interactions were evaluated. The results showed that extraction time and sample mass had the most significant effects on ion extraction. The accuracy of the analytical method was evaluated using a certified reference material of urban particulate matter (NIST SRM 1648a), yielding agreement values ranging from 83.6% to 107.0%. Precision was expressed as relative standard deviation (RSD%), with values below 10%. The analytical method showed no lack of fit (ANOVA, p = 0.275) and exhibited a strong correlation between experimental and predicted values (r = 0.97). The method was considered green, with a sustainability score of 0.81 calculated using the Analytical GREEnness Metric (AGREE) software. The ionic composition was dominated by Na⁺, SO₄²⁻, Ca²⁺, and NO₃⁻, suggesting contributions from marine aerosols, secondary aerosol formation, and soil particle resuspension. The maximum daily concentration (53.87 μg m⁻³) and annual mean concentration (6.68 μg m⁻³) fully complied with the Intermediate Standard 2 (IS-2) limits established by CONAMA Resolution No. 506/2024. The enrichment factor (EF) indicated a marine contribution for Mg²⁺ (EF = 0.023), a crustal/construction-related origin for Ca²⁺ (EF = 28.64), and secondary and anthropogenic contributions for SO₄²⁻ (EF = 4.05) and K⁺ (EF = 2.14). The low EF value for Cl⁻ (EF = 0.13), together with its significant negative correlation with NO₃⁻ (r = −0.58), indicated the occurrence of chlorine depletion through ionic substitution in the particulate phase. Meteorological analysis showed that the rainy season favored particle removal through wet deposition, whereas the dry season and the influence of trade winds enhanced atmospheric dispersion and soil dust resuspension. Principal Component Analysis (PCA) explained 75.8% of the total cumulative variance through four components, confirming contributions from marine aerosols, mineral dust, vehicular traffic, and secondary atmospheric reactions. Overall, the results demonstrate the mixed and multifactorial nature of atmospheric pollution in Aracaju, providing essential scientific and methodological support for air quality management.

2026-07-24T00:00:00Z Andonof, Mylena Torres https://ri.ufs.br/jspui/handle/riufs/25250 2026-07-06T19:36:17Z 2025-12-18T00:00:00Z

Título: Tratamento primário da água produzida: coagulação lastreada com microareia e resíduos de crustáceos e moluscos Autor(es): Andonof, Mylena Torres Abstract: Produced water (PW), a byproduct of the oil and gas industry, has high levels of contaminants such as suspended solids, organic compounds, hydrocarbons, and heavy metals, representing a significant environmental challenge. Given legal requirements and growing concern about water pollution, the development of effective and sustainable technologies for its treatment is essential. In this context, this work aimed to evaluate the efficiency of coagulation ballasted with microsand and crustacean and mollusk waste (bioballast). The research was conducted in two stages: first, the produced water was characterized and the most efficient chemical coagulant was selected; second, the selected coagulant was applied to the coagulation/flocculation system with different ballast agents (microsand and bioballast). The produced water showed high concentrations of total suspended solids (TSS) and total oils and greases (TOG), exceeding the limits established by environmental legislation. For the coagulants tested (aluminum sulfate (AS), ferric chloride (FC), and aluminum polychloride (PAC)), aluminum sulfate, at a dosage of 0.2 g/L, stood out with removals of 72.86% for TSS and 91.24% for TOG, in addition to presenting the best cost-benefit ratio. The coagulation process ballasted with microsand (5 g/L) showed similar performance to the conventional process, with 74.35% for TSS and 91.77% for TOG. However, the use of bioballast at the same dosage resulted in a 7.23% increase in TSS removal and a 1.32% increase in TOG removal. Furthermore, metal analysis indicated that the bioballast did not adsorb Ba and Mn. However, bioballast presents itself as a sustainable and promising alternative to replace microsand as ballast, not only in the treatment of produced water, but also in the treatment of water and effluents, promoting the use of crustacean and mollusk waste and contributing to the development of cleaner technologies in effluent treatment.

2025-12-18T00:00:00Z Santos, Davi Nascimento dos https://ri.ufs.br/jspui/handle/riufs/25249 2026-07-06T19:33:26Z 2024-08-28T00:00:00Z

Título: Planejamento experimental aplicado à eletrocoagulação para o tratamento de esgoto doméstico Autor(es): Santos, Davi Nascimento dos Abstract: Given the growing need for environmental preservation and sustainable water management, this research addresses the application of electrocoagulation (EC) in the treatment of domestic sewage, focusing on the optimization of operational parameters through experimental design. Additionally, it aimed to evaluate the efficiency of organic matter removal using Central Composite Rotational Design (CCRD) to identify the optimal parameters for current density and pH. The characterization of the sewage was followed by the application of different EC configurations, resulting in significant removals of organic load and turbidity. The tests showed removals of up to 80.07% for BOD and 41.97% for COD in domestic sewage. Economic analysis indicated that the process is viable for smaller volumes of effluent, with a cost per cubic meter treated of $1.23 or R$6.20. The application of the method to different types of sewage demonstrated its robustness and flexibility, reinforcing the viability of EC as an effective and sustainable solution for sewage treatment. It is concluded that electrocoagulation can be an efficient alternative to improve water quality and promote public health in various communities.

2024-08-28T00:00:00Z Santos, Adrielle Silva dos https://ri.ufs.br/jspui/handle/riufs/25248 2026-07-06T19:30:53Z 2026-02-24T00:00:00Z

Título: Otimização do processo de fermentação escura da vinhaça da cana-de-açúcar para produção de hidrogênio de baixo carbono Autor(es): Santos, Adrielle Silva dos Abstract: Sustainable energy production has gained prominence in recent years due to the intensification of climate change resulting from the predominant use of fossil fuels. In this context, the transition toward an energy matrix composed mainly of renewable sources has increased, and among the pathways pursued for this shift, hydrogen production stands out. Hydrogen is considered a clean energy source and a promising energy carrier, especially when produced from organic residues through biotechnological processes. The present study aimed to optimize the dark fermentation process in order to maximize fermentative hydrogen production using sugarcane vinasse as the substrate and sewage sludge as the inoculum. Pretreatments were applied to enhance the activity of hydrogen-producing microorganisms and to maximize the availability of readily fermentable sugars in the reaction system. The substrate was subjected to an acid pretreatment assisted by ultrasound (pH, temperature, and sonication time), while the sewage sludge underwent an acid/thermal pretreatment followed by incubation for 24 hours (pH 3.0 and incubation at 55 °C). Both residues were characterized in terms of their physicochemical parameters. Fermentations were carried out in a 7.5 L anaerobic bioreactor, and a factorial experimental design (2³) was employed to optimize the variables pH, temperature, and substrate/inoculum volumetric ratio. Gas quantification was performed using a gas chromatograph (GC-TCD/FID) based on the chromatographic method developed and validated in this study. The results confirmed the high energy potential of vinasse, resulting from its high load of biodegradable organic matter, as well as the efficiency of the pretreatment in increasing biodegradability and sugar availability. Based on the factorial experimental design, the optimized conditions for the variables were: pH 5.5, temperature 55 °C, and substrate/inoculum volumetric ratio of 50%, resulting in a maximum hydrogen production of 1104.4 N mL H₂ L⁻¹ substrate. Through the validation assay conducted under the optimized conditions, a maximum specific hydrogen production of 1158.6 N mL H₂ L⁻¹ substrate and an accumulated hydrogen production of 3267.6 N mL H₂ L⁻¹ substrate were obtained throughout the reaction process. These results demonstrate that the integration of pretreatments and optimized operational conditions enhances the dark fermentation process and maximizes hydrogen production, indicating that the proposed route can be considered a complementary alternative to the conventional hydrogen production pathway. Keywords: Sustainability, energy transition, biohyd

2026-02-24T00:00:00Z