Isolated ultrasonic vibrations were used to treat feed water from a 20 bar steam-producing water tube boiler. Physical treatments such as ultrasounds and reverse osmosis (RO) are recommended as the most eco-friendly for this purpose. A novel bench-scale prototype delivering 6 L/h of treated water was designed and built. The ultrasonic atomization of raw water with 1.7 MHz piezoelectric transducers and subsequent humidification and dehumidification of drag airflow was the innovating sequence of operations used as a treatment technique. To ensure greater humidification capacity to the drag air, the energy available from the thermal inertia of the liquid column (raw water) in the prototype vaporization chamber was used to heat this air flow. After a single pass of raw water through the bench-scale prototype, a 98.0% reduction in conductivity and a 99.0% decrease in the content of total dissolved solids were obtained at a drag air temperature of 70 °C. Compared to RO, two of the main advantages of the proposed ultrasonic wave method are the elimination of the use of chemical agents in the pre-treatment phase and a significant reduction in maintenance costs by membrane replacement.

The growing demand for sustainable industrial practices has driven the search for eco-friendly alternatives in the treatment of brewery effluents. Tannin-derived bio-based coagulants have emerged as promising substitutes for inorganic coagulants, which pose risks to both the environment and human health. This review aims to examine the development of bio-based coagulants through ultrasound-assisted tannin extraction, as well as their application in the treatment of brewery effluents. Studies indicate that ultrasound-assisted extraction is effective in obtaining tannins and yields better performance compared to conventional methods. In the context of breweries, bio-based coagulants have demonstrated high efficiency in turbidity and color removal, with the added advantage of generating biodegradable sludge. Additionally, several native species from the Caatinga biome are known to have potential for tannin extraction, although many remain unexplored for industrial wastewater treatment purposes. It can be concluded that the combination of ultrasound-assisted extraction and the use of bio-based coagulants represents a promising and environmentally friendly strategy for industrial wastewater treatment, with potential for large-scale application. However, further research is required to assess the economic and operational feasibility of these technologies.

This systematic review investigates the application of microbubble technology in aquaculture, emphasizing its effects on water quality, fish health, and sustainable production. As the demand for intensive and environmentally friendly aquaculture systems grows, oxygenation technologies have become critical to improving production efficiency and animal welfare. Following PRISMA guidelines, articles were retrieved from Scopus, Web of Science, and Google Scholar databases using the descriptors “microbubble,” “nanobubble,” and “aquaculture.” After screening for duplicates and evaluating titles, abstracts, and full texts, a final set of relevant articles was selected for in-depth analysis. The findings demonstrate that microbubble and nanobubble systems offer superior oxygen transfer efficiency compared to traditional aeration methods, improving dissolved oxygen levels and promoting fish immunity and stress resistance. Applications in tilapia culture, integrated aquaculture systems, and biofloc environments show enhanced productivity and reduced dependence on antibiotics. Furthermore, microbubble use supports environmental sustainability by improving biodiversity and nutrient cycling. However, barriers such as high initial implementation costs, lack of standardized operational protocols, and limited technical knowledge among producers still hinder widespread adoption. The review highlights the need for economic feasibility studies, producer training, and integration with other sustainable practices to maximize the benefits of this emerging technology. These findings provide valuable insights for researchers, policymakers, and aquaculture practitioners aiming to modernize production systems through sustainable innovation.

This review examines the processes involved in converting gypsum from the Araripe Gypsum Pole (PGA) into commercial hemihydrate, emphasizing dehydration kinetics, calcination technologies, and sustainability challenges. The study explores the influence of operational parameters—such as temperature, residence time, and water vapor control - on phase formation and product quality. Different furnace types are assessed in terms of energy efficiency, emission profiles, and automation potential. Special attention is given to kinetic models, including diffusion-based and nucleation-growth mechanisms, and their applicability in real-time process control. Through a comparative analysis of academic and industrial data, this review identifies key research gaps, such as the need for industrial validation of kinetic models, improved control systems, and adoption of alternative energy sources. The review concludes by proposing future research directions that include the integration of circular economy principles, advanced monitoring techniques, and stronger academia-industry collaboration to enhance the competitiveness and environmental performance of the gypsum industry in the region.

This work presents a study on the catalytic recovery of elemental sulfur from hydrogen sulfide gas (H₂S) using a Fe/EDTA solution assisted by ultrasonic waves in a continuous stirred-tank reactor (CSTR) at bench scale. The introduction of ultrasonic cavitation (1.7 MHz) promoted intense atomization of the catalytic solution, enhancing the gas–liquid interface and conversion efficiency. The determined rate constant was k = 1.4329 L·mol⁻¹·s⁻¹, and the reaction order, n = 1.5, indicating a complex fractional-order kinetics. Experimental optimization identified an ideal molar ratio of H₂S:Fe/EDTA = 1:3 and an average residence time of 19.2 s, resulting in a conversion efficiency above 98%. The process demonstrated high operational stability, with continuous catalyst regeneration and efficient precipitation of high-purity sulfur. The kinetic modeling was simulated in Python, validating the experimental data and reinforcing the potential for industrial scale-up. This study contributes to the development of clean technologies and sustainable biotechnological processes, applicable to biogas purification and mitigation of toxic sulfur compounds.