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.

The current study, conducted over a year, involved a comprehensive analysis of water samples from the Rainha River. This river crosses the Pontifical Catholic University of Rio de Janeiro Campus to assess water quality and potential applications. The samples underwent rigorous physical–chemical tests, including metal concentrations, pH, turbidity and toxicity assessments. The water collected and analysed by the standards proposed by CONAMA was found to be below the limit of regulation, classified at class 1, and requiring only a simplified treatment to remove microorganisms and achieve potability. Toxicity tests using Saccharomyces cerevisiae were performed to examine biological effects, revealing no significant toxicity. The next step was to design a water treatment plant, following the viability, water studies and identification. The process involved designing a block diagram and, later, the process flow diagram (PFD). The processes consist of getting water, passing through microfiltration, decontaminating it with hypochlorite, and using adsorption methods to turn it into a potable and useable on campus, thereby ensuring a safe and sustainable water supply for the university community.

Dye removal from manufacturing and textile industry wastewater is one of the biggest challenges in plants. The improper disposal of water with residual dyes can contaminate effluents and fresh water sources. In this work, filtration membranes based on reduced graphene oxide (rGO) were fabricated by the spray coating method, and its capability to remove dyes from water was evaluated. Graphene oxide was prepared by a modified Hummers method and posteriorly reduced with ascorbic acid; a simple and fast spray coating fabrication method was employed to produce stable membranes, which were analyzed in a home-made permeation cell. Raman spectroscopy and scanning electron microscopy (SEM) were able to prove that rGO dispersion was formed by graphene flakes with about 45.9 μm of lateral dimension; X-ray diffraction, SEM and Raman analyses indicate that the spray method was efficient in producing stable and uniform filtration membranes; and UV-vis absorption spectra of feed and permeation solution indicate that rGO membranes were capable in removing dye from water. By the main results, it is possible to affirm that rGO filtration membranes are an efficient, low-cost, scalable and fast way to remove dyes from wastewater.

RESUMO O presente trabalho teve como objetivo sintetizar membranas lamelares de óxido de grafeno reduzido (rGO – reduced graphene oxide) sobre um suporte de acetato de celulose e compará-las quanto à rejeição de azul de anilina, por meio de duas metodologias de produção do rGO: redução agregante e não agregante. Inicialmente foram produzidas dispersões de óxido de grafeno (GO – graphene oxide) por uma modificação do método de Hummers, as quais passaram por tratamento termoquímico para redução do GO e foram utilizadas para deposição sobre um suporte de acetato de celulose, utilizando-se o método de filtração assistida por vácuo. Para caracterização das dispersões e membranas foram utilizadas as técnicas de difração de raios X (DRX) e microscopia eletrônica de varredura (MEV), sendo que nas membranas produzidas foram conduzidos testes de estabilidade em água. Para análise da rejeição de azul de anilina, utilizado como material a ser filtrado, os permeados de cada uma das membranas, bem como do substrato como recebido, foram analisados por espectrofotometria UV-Vis, sendo que a concentração do permeado pôde ser estimada a partir de uma curva de calibração previamente produzida. Foram observadas diferenças de estabilidade da membrana, a depender da metodologia de redução utilizada, bem como expressivo incremento de rejeição de azul de anilina em relação ao substrato como recebido de acetato de celulose.

Anais do Congresso Brasileiro Interdisciplinar em Ciência e Tecnologia (2764-0582) - Projeto Conceitual De Engenharia Para Tratamento De Esgoto Com Biorreator Com Membranas E Osmose Inversa Parcial Visando Remoção De Compostos De Difícil Tratabilidade