This paper aims to synthesize zero-valent iron nanoparticles (nZVI) supported on SBA-15 nanosilica. The nanosilica generate in the system by polymer reaction with hydrochloric acid under controlled temperature. After, the iron nanomaterial was obtained by sodium borohydride reduction as described in this work. Afterward the synthesis of the nanoparticles contained iron supported on silica SBA-15, the material was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, zeta potential and X-ray fluorescence spectroscopy. The results indicated that nanomaterial obtained was in nanometric scale, by TEM results, and showing characteristic peaks at EDS results, with 11.9% iron and 14.0% silicon content, respectively, and containing 73.0% and 27.0% of their respective oxides through X-ray fluorescence spectroscopy. The isoelectric potential of the sample was around 2.0, close to the value reported for silica, due to the higher percentage of silica in the sample when compared to iron. The obtained material can be used, for some cases, as an possible alternative, to the Fenton reaction for the degradation of xenobiotic compounds or other applications in the groundwater and wastewater treatments

Brazil is the second largest producer of electronic waste in the Americas, with a production that grows each year and only 10% of it being treated in its own way. Additionally, given the typical chemical composition of this type of residue, it can be possible to recover valuable metals, such as copper, gold, silver, and platinum. Presently, Brazil does not have an industrial plant devoted to such extractive activity using electronic waste, with most of its treatment carried out abroad. The research hypothesis of this manuscript is that universities and their communities could develop sources of raw materials for such extraction processes and, therefore, deserve attention for the creation of collection points and partnerships. In this context, there is a need to understand this community behavior regarding the acquisition, storage, and disposal of electronic equipment, as well as information about topics related to electronic waste management and recycling. To implement such a study for the higher education community in Rio de Janeiro, a form was created covering several topics on the subject, which was disseminated among the teachers, students, employees, and family members of two main state universities. It was determined that the studied group has more than 16.96 million mobile phones in hibernation, in addition to other equipment, with an estimated stockpile value of USD 67.45 million for the studied group in the metropolitan area of Rio de Janeiro. If extrapolated to all of Brazil, this could be as high as USD 797.50 million for the studied group. This information will be used in future projects to assess the economic potential of an industrial plant dedicated to metal recovery in Brazil. However, the present study also identified an important lack of knowledge regarding proper waste disposal and solid waste policies among this well-educated group. It became clear that without appropriate information regarding collection points and knowledge on how to deal with obsolete devices, the access to this source of raw material could be a hinderance to future extraction projects in the area.

With a generation of more than 2 million metric tons per year, Brazil is the largest producer of waste electrical and electronic equipment in Latin America. However, Brazil does not have its own way for treating printed circuit boards, a key component present in this type of waste. In this context, the processing of these components would allow the extraction of metals with high added value, mainly copper, silver, gold, and palladium. The purpose of this research is to design a conceptual treatment route, based on the integration of technologies described in the literature. After creating the route design, a mass and energy balances were performed, considering two printed circuit board source as raw material: (Case A) Wasted equipment in general; (Case B) Using only cell phones. For both cases, the treatment of 2 t·h⁻¹ was considered. In addition, cost estimates and plant sensitivity analysis were carried out. For 15 years of plant production, the calculated Capex was USD 2,002,682, where an internal return rate of 140.1% and 3933.0% was obtained for Case A and B, respectively, and a net present value of USD 44,403,373 and USD 3,210,393,496 for Case A and B, respectively. Additionally, it was observed that Case A has a great sensitivity to the variation of the processing volume. Based on the present findings, this theoretical research has the potential to be a nucleation point in the design of a future industrial plant dedicated to the recycling of printed circuit boards, as well as to understand the key variables for the processing these components, based on Brazilian circumstances. Additionally, the project presents the hypothetical investment required for the creation of such conceptual plant, which is a crucial piece of information for potential investors.

In 2018, a research study was conducted at a Public University in Brazil to investigate the quantity of chemical residues produced during laboratory activities in undergraduate engineering courses. Data was collected from control documents maintained by the institution responsible for recording waste quantities. The results showed that 383.2 liters of solutions were generated with varying compositions. Inorganic solutions without heavy metals produced the highest volume of waste, while halogenated organic solutions produced the smallest. The study highlights the need for better waste segregation and disposal methods to reduce laboratory waste. To minimize the environmental impact of laboratory activities, implementing measures such as proper waste storage, waste exchange, recycling, reverse logistics, and life cycle assessment is essential. Educational institutions need to develop better waste management practices to reduce the amount of waste in landfills.

Objective: The main aim of this work is to analyze how environmental factors can influence the atmospheric dispersion of ammonia in different simulation scenarios of a possible accidental release, using the ALOHA simulator. Theoretical Framework: Ammonia is a hazardous product widely used in fertilizer. Production risks are necessary due to the risk of toxic vapor dispersion, explosions, and fires, requiring attention and care to prevent leaks from ammonia tanks. Using simulators with different contamination plume dispersion models enables the adoption of action strategies for accident simulations to mitigate the impacts of accidents, fatalities, environmental damage, and social effects. Method: Different atmospheric conditions, such as relative humidity, cloud cover, wind speed, and temperature, were considered to simulate the dispersion of a specific pollutant plume into the atmosphere, using the ALOHA simulator at a specific location. Two scenarios were simulated: one involving an instantaneous release of ammonia into the atmosphere and the other involving a storage tank explosion. Results and Discussion: It was observed in the study that in the instantaneous release model of the tank contents, cloud cover directly influenced the dispersion of the gas, while in the BLEVE model, the variation in the relative humidity of the atmosphere had a greater impact on the simulation, while cloud cover for this type of model was not significant. Research Implications: Demonstrate that fatal accidents can be prevented by using the ALOHA simulator for different scenarios on an industrial scale, in a real-world setting in Brazil. The simulation results enable safer and more predictive decision-making for the substance in question, which is highly reactive and explosive. Originality/Value: Considering the potential risk of ammonia use in different industrial sectors, this study sought to address the use of a free simulator to predict the effects of adverse situations, such as explosions, leaks, and releases of ammonia into the atmosphere, allowing for the development of emergency action plans to remedy and reduce the potential impacts generated in a given location.

The degradation of persistent organic pollutants reduces their harmful effects on the environment. Various treatment techniques are employed to remediate these pollutants, and among them, advanced oxidative processes are effective for breaking down recalcitrant compounds. This manuscript investigated the degradation of the dye RED 243 using PMS in combination with zero-valent iron particles of different sizes. The reduction in the dye’s colorimetric intensity occurred rapidly, within a few seconds. The results indicated that the reduction in colorimetric intensity ranged from 62 to 83% by the end of the tests when PMS was used with ZVI at various temperatures. It examined several types of acids to assess the impact of anions on the degradation process and found that organic acids were more efficient. The optimal reaction conditions, which minimized reagent usage, occurred at the original sample pH, 313 K, 25 mg L⁻¹ PMS, and 100 mg L⁻¹ micrometric zero-valent iron. Under these conditions, we achieved a degradation efficiency of 83% in colorimetric intensity. The dye degradation reaction followed pseudo-first-order kinetics with respect to dye concentration, yielding activation energies of 39.77 kJ mol⁻¹ for micro-sized iron and 55.67 kJ mol⁻¹ for nano-sized iron particles. Graphical abstract The alternative text for this image may have been generated using AI.