Phytoremediation is a process that uses plants in situ to promote remediation of environments contaminated by organic or inorganic compounds. Phytoremediating species develop methods such as phytoextraction, rhizofiltration, phytodegradation, and phytovolatilization, which can manifest themselves individually or together in a single plant. This study aims to evaluate, through a systematic review, the potential phytoremediation techniques of the genera Syagrus (Mart.), Nephrolepis, Cyperus (L.), Mimosa (L.), Schinus (L.), Brachiaria, and Eryngium (L.) found in a humid area of Rio Grande do Sul, Brazil. The genera that presented significant numbers in the databases consulted were Cyperus and Brachiaria, followed by Nephrolepis. The first two are considered the most promising for phytoremediation processes. The other genera mentioned obtained favorable results for organic contaminants. The studies around these genera are still recent. It is necessary, in research, to highlight which phytoremediation processes the plants exert in relation to the contaminant of the place. In addition, priority should be given to native species that can establish themselves in the environment and that would not unbalance and harm the surrounding biota and ecosystem. The research presents a survey of two decades in four multidisciplinary and international databases, identifying the limitation of research related to volatile and semi-volatile organic compounds, as well as contributing to the identification of native plant species that perform phytoremediation mechanisms.

The increasing world population boosted the demand for basic needs such as energy, water, and food. In turn, agricultural production has increased, generating a large amount of agro-industrial waste every year. Globally, Brazil is the seventh-largest rice producer, and the State of Rio Grande do Sul is responsible for 70% of the rice production in Brazil. Rice husks are composed of organic compounds (cellulose, hemicellulose, lignin, and extractives) and inorganic elements that include potassium, calcium, magnesium, and sulfur. These inorganic elements are essential nutrients in the soil. Since natural degradation is slow due to the aromaticity of lignin, rice husk (RH) waste accumulates and poses an environmental threat, causing air and water pollution. In this context, in order to return the biochar to the soil, the properties of rice husk and rice husk biochar were evaluated. Parameters such as pH, true density, bulk density, porosity, identification of the composition and concentration of the elements, analysis of the functional groups, total carbon (TC), and cation exchange capacity (CEC) were performed on RH biochar samples. These samples were produced in a laboratory-scale pyrolysis rig, under a con-trolled atmosphere of Nitrogen (N), using three peak temperatures (350 °C, 450 °C, and 550 °C) and three soak times (30, 60, and 120 min).Based on the results obtained in the characterization analyses of the biochar, as well as the yield values found, it is concluded that the best pyrolysis temperature for the production of biochar from rice husks, for application in soils, is 550 °C.

Mais cimento não necessariamente melhora a qualidade do concreto ou agiliza os cronogramas de construção. Em contraste, o concreto com menor teor de cimento pode durar mais e atingir resistência suficiente a tempo para evitar atrasos na construção. As normas técnicas exigem o superdimensionamento do concreto por décadas, mas estudos que avaliam as magnitudes do superdimensionamento real são raros. Este estudo experimental teve como objetivo identificar o teor de materiais cimentícios necessário para atender ao superdimensionamento requerido com base em 958 ensaios de resistência à compressão (σ) representando 8200 m³ de concreto para construções comerciais. O superdimensionamento real do concreto parece ser 7 a 21% acima do necessário. O conteúdo de materiais cimentícios deve ser reduzido entre 6 e 17% para que o concreto possa atingir a resistência à compressão requerida (f’cr) sem excesso de cimento. O nível do superdimensionamento excessivo aumentou significativamente com o aumento da resistência à compressão especificada (f’c), indicando que os produtores de concreto parecem ser mais cautelosos quando o f’cr é maior. Pesquisas adicionais são necessárias para expandir a gama de aplicações e teor de materiais cimentícios.

Este trabalho teve como objetivo comparar o efeito da adição de dois biocarvões diferentes em um substrato no desenvolvimento de mudas de alface (Lactuca sativa L.). Os biocarvões foram obtidos a partir da pirólise de resíduos de cascas de arroz e cascas de coco verde, realizada em forno mufla na temperatura de 450 °C. Os experimentos foram conduzidos na Universidade do Vale do Rio dos Sinos, Campus São Leopoldo, RS. As sementes de alface foram plantadas em 3 amostras, que consistiram de tubetes contendo: somente substrato; amostra utilizando 95 % de substrato incorporados a 5 % de biocarvão, produzido a partir da carbonização de cascas de arroz; e amostra contendo 95 % de substrato incorporados a 5 % de biocarvão produzido a partir da carbonização de fibras de cascas de coco verde. As mudas foram cultivadas durante 6 semanas e após este período analisadas quanto ao número de mudas germinadas, crescimento das mudas, potencial hidrogeniônico, tamanho dos poros e área superficial.

The study consists of adsorption tests on two samples of biochar, obtained from rice husk and coconut fiber biochar biomass, as well as a sample of charcarbon, both prepared under different conditions: macerated and non-macerated; impregnation with and without HCl and H3PO4; and washing or not with deionized water after impregnation. The test was performed in duplicate, for 30 min, with masses of 0.5 g; 0.3 g; 0.1 g; and 0.05 g, and an initial methylene blue concentration of 0.01 g∙L-1. The study was carried out with the objective of identifying, in the analyzed samples, the material with the greatest adsorption capacity of methylene blue dye, comparing the data with commercial activated carbon. The results identified removal above 70 % in both types of biochars, suggesting the feasibility of application as an adsorbent material to remove organic contaminants. The sample that most closely resembled the removal percentage of commercial activated carbon (98.84 %) was that of biochar obtained from coconut fibers, with 91.71 %. Thus, the research showed promise in studying the application and valorization of biochars, produced from agro-industrial waste, in adsorption processes.

LED lamps, widely consumed and necessary for society, impact the environment and contribute to the growing generation of electronic equipment waste. When discarded, they can be considered secondary sources of critical materials, which makes it necessary to think about ways of returning them to the production chain. The removal of LEDs from the module is the most complex step of the process. This work aimed to study a separation method for LEDs, with the goal of better metal recovery. The methodology involved obtaining LED modules, removal in a heating plate at different temperatures, grinding, and chemical characterization. After the tests, different compositions of the solder were identified in the LED-Plate connections. Some modules (removed at 150°C) had led in them, while others did not (removed at 200°C). This last case meets international standards, which restrict its use.