De resíduo a insumo: a construção do caminho para uma química mais limpa através de um projeto de ensino

The discussion among teachers, students, and technicians about the destination of residues from chemistry laboratories led to a research project whose results were incorporated into a course in its daily practices. The treatment of the residues from argentimetric practices allowed us to establish cognitive relations of technological basis and of those related to the rising of the level of awareness about environmental aspects and social responsibility of chemistry professionals. The techniques and the results, from the economic point of view, namely that of value aggregation (metallic silver) and the conversion of the residue into input (potassium chromate solution) are shown.

La diversidad cultural y la cooperación en el centro educativo

Artículo que se propone mostrar la experiencia vivida con todo un colectivo femenino de una misma escuela (alumnas, madres y profesoras), que ha permitido mejorar la autoestima y la integración social de un grupo de mujeres inmigrantes. La finalidad de esta intervención es ayudar a despertar el interés de las madres inmigrantes por el saber, como un bien con el que favorecer su dignidad personal y llegar a participar activamente en la sociedad

Caracterização e classificação de resíduo sólido "pó de rocha granítica" gerado na indústria de rochas ornamentais

The ornamental rock industry generates huge amounts of wastes during the process of extraction and sawing of rock blocks. The ornamental rock powder waste is a non-biodegradable material, which represents the increase in environmental problem. The waste was collected from a granitic rock sawing plant located in Santo Antônio de Pádua, Rio de Janeiro. The chemical-environmental characterization and classification of the waste were done according to ABNT standards. The results showed that the granitic rock powder waste should be classified as Class II A - "No Inert", because of its high concentrations of lead, chrome, iron and manganese.

Repensando la formación inicial del profesorado para abordar el tratamiento a la diversidad cultural y lingüística en el aula = Rethinking initial teacher education for linguistic and cvltural diversity in the classroom

In recent decades, European educational systems are facing many challenges related to the treatment of cultural and linguistic diversity. The need to address this diversity requires new approaches to education; this in turn requires changes in the way we prepare teachers for the new reality they face in their classrooms. In this article we highlight some of the major problems that initial teacher training has to address in order to enable teachers to deal effectively, respectfully, and fairly with students whose linguistic and cultural background is different from their own. We also present several models for teacher education from Europe and North America based on clearly identified teacher competences for linguistic and cultural diversity

Competència cultural i artística

Partim de la convicció basada en les evidències que la competència cultural i artística és fonamental en la formació dels estudiants. A més, aquesta competència no es pot garantir sense que els docents estiguin preparats en aquestes competències: cultural (intercultural), emocional/sensible, crítica, investigadora, comunicativa, creativa, didàctica i inclusiva de l’art (des de l’art, per mitjà de l’art i per l’art). És per aquest motiu que encetem el discurs «entre la realitat i el desig», sintetitzant en poques pàgines no pas allò que és, sinó més aviat allò que podria ser: renunciar a disgregar i jerarquitzar els sabers, i apostar per un paradigma educatiu que valori les competències que transcendeixen una disciplina. La competència cultural i artística està connectada necessàriament amb les altres competències bàsiques: la lògica/matemàtica (representació de l’espai, com a mínim), la comunicativa (de què forma part i molt vinculada a la tecnològica), i, com és obvi, les de l’àmbit de valors personals i de ciutadania i les de l’àmbit cultural i social. Perquè tot això pugui materialitzar-se, també hi ha algunes condicions elementals i relativament fàcils d’oferir que tot just apuntem

Metodologias para reutilização do resíduo de terra diatomácea, proveniente da filtração e clarificação da cerveja

The earth diatomite is a material used by the industries in the filtration process and clarification of the beer. This material presents a reduced useful life due to the blockages of their pores during the filtration process. The objective of this work was to reactivate the properties of filtration of the earth diatomite, saturated with organic matter during the filtration stage, starting from a controlled thermal treatment. The obtained results demonstrated that the earth diatomite saturated with organic matter submitted to a controlled thermal treatment has their filtration properties reactivated, could be reused in the beer production process.

Síntese de nanomateriais de carbono a partir do resíduo de milho (DDGS)

The world's largest ethanol producer (USA) uses corn as feedstock. DDGS (distillers dried grains with solubles) is the main waste generated from this process (around 32 million t/year). DDGS samples were pyrolyzed at 1000 ºC in a furnace with controlled atmosphere. The effluent was channeled to a second furnace, in which catalyst substrates were placed. Chromatographic analysis was used to evaluate the gaseous effluents, showing that the catalyst reduced hydrocarbon emissions. The solid products formed were analyzed by SEM and TEM. Graphitic structures and carbon nanofibers, 50 µm in length and with diameters of 80-200 nm, were formed.

Caracterização de resíduo sólido formado em biodiesel de sebo bovino

The nature of the solid residue formed in beef tallow biodiesel from two commercial producers in Brazil was determined by comparative analytical techniques, namely, gas chromatography with flame ionization detector (GC-FID) and thermogravimetry (TG). Pure monopalmitin and monostearin were used as reference standards for both methodologies. Analyses were carried out before and after filtration of the solids formed, which allowed the observation that the formation of precipitate reduced the levels of monoglycerides in the beef tallow biodiesel. The chromatographic and thermogravimetric results confirmed the nature of the residue as saturated monoglycerides, predominantly monostearin and monopalmitin.

Modificação e caracterização do resíduo pó de aciaria elétrica (PAE) para aplicação em reações de redução de cromo (VI)

In this study, electric arc furnace dust (EAFD) was thermally modified at different temperatures under H2 flow or charcoal in order to obtain reduced iron phases (Fe3O4, FeO and Fe0). The formation of these phases was confirmed by powder X-ray diffraction. The tests performed for reducing Cr (VI) using resultant materials obtained after thermal treatment of the EAFD showed excellent results, with PAE600H (EAFD reduced at 600 ºC under H2 flow) decreasing around 100% of the Cr (VI) in only 10 minutes of reaction. These results indicate the possibility of adding value to the residue, obtaining materials that offer great potential for environmental applications.

Caracterização de membranas assimétricas de acetato de celulose produzidas a partir do aproveitamento do resíduo da palha de milho para uso em ultrafiltração

Cellulose acetates (CA) with different degrees of acetylation were synthesized from cellulose extracted from corn stover. Membranes were prepared for the ultrafiltration process with pure polymers and blend form of CA utilizing a dioxane/acetone system. The membranes were characterized according to their transport properties. The blend form materials presented the best results for application in ultrafiltration experiments. M-TAC/DAC (corn stover triacetate and diacetate) and M-TAC/DAC-Rho (corn stover triacetate and Rhodia diacetate) presented rejection to egg albumin protein of 87.39% and 80.50%, respectively. Thus, MWCO of 45 kDa was determined for these materials.

APROVEITAMENTO DE RESÍDUO DE BIODIESEL PARA PREPARAÇÃO DE CARVÕES ÁCIDOS COM ELEVADA ATIVIDADE CATALÍTICA NA REAÇÃO DE ETERIFICAÇÃO DO GLICEROL

Environmentally friendly acid carbon (CG) catalysts, containing a high amount of sulfonated and oxygenated groups, were prepared from glycerin, a biodiesel waste. CGs were produced by glycerin carbonization in the presence of H2SO4 at 1:3 m:m ratio in a closed autoclave at 180ºC for different times: 0.25; 1; 3 and 6 hours (CG-0.25h; CG-1h; CG-3h and CG-6h, respectively). The catalyst properties for all carbons were evaluated in the glycerol etherification reaction with tert-butyl alcohol (TBA). The yield for mono-tert-butyl glycerol (MTBG), di-tert-butyl glycerol (DTBG) and tri-tert-butyl-glycerol (TTBG) was high and very similar for all CGs, of about 43% and 20% for the MTBG and DTBG + TTBG, respectively. Furthermore, the activity of these catalysts were close to those obtained using a commercial resin, Amberlyst-15, of about 50% and 27% for MTBG and DTBG + TTBG, respectively.