Eugenol antioxidant and antibacterial properties have suggested its use as a natural preservative for food matrices. Eugenol application is compromised due to its high volatility and sensibility to external agents, such as light, heat, oxygen, and moisture. Thus, microencapsulation is viable to increase the eugenol stability. Results have showed that carrageenan combined with rice protein and bovine albumin allow high-quality eugenol microcapsules. These materials show excellent properties, favoring the microcapsules use in food matrices. This study aimed to optimize microcapsules formulation by spray drying, using a simplex-centroid mixture design. Blends of low-lactose whey protein (WP) and/or rice bran protein (RBP) and/or bovine serum albumin (BSA) with carrageenan were used as wall materials. Blends influenced the eugenol retention, microencapsulation efficiency, and size. Pure WP was not efficient for eugenol encapsulation. The highest eugenol retention values, 89.7% and 86.5% were obtained by combining carrageenan with RBP or BSA. RBP and BSA binary interaction with carrageenan showed the highest encapsulation value (80.5%). Scanning electron microscopy, infrared spectroscopy, and thermogravimetry confirmed eugenol inside the microcapsules.

Abstract Virgin polystyrene (PS) composites were reinforced with medium density fiberboard (MDF) residue, considering the influence of fiber content. The composites were evaluated for their morphology, identification of functional groups and thermal behavior. Mechanical tests and a degradation study under ultraviolet radiation (UV) were also performed. The results showed that the best properties were obtained for composites with 4% by mass of MDF waste. The addition of residue was found to increase thermal stability of polystyrene compared to its pure form. The morphology of the composites showed homogeneity of the material. In the degradation tests under ultraviolet (UV) radiation, it was found that the presence of MDF residue slows down the matrix degradation process when evaluated by means of tensile strength. Polystyrene composites reinforced with MDF residues showed good mechanical properties and can be applied in the development of materials that do not need a good appearance.

Abstract The use of araucaria pine nut shell in polymer composites may increase the pine nut value and help protec araucaria (Araucaria angustifolia) itself, which is an endangered species. The aim of this work is to study the influence of the size of pine nut shell fiber on the mechanical properties of composites made of this shell and polyurethane derived from castor oil. Composites with different polyurethane contents were manufactured with dried untreated pine nut shell sieved through 30 and 50 mesh sieves (0.6 and 0.3 mm, respectively). Composites were shaped by mechanical mixing of the components followed by hot pressing. Properties such as density, water absorption, and flexural strength were measured. Specimens were also characterized by SEM, FTIR, and TGA. The flexural strength of PU/0.3mm pine nut shell composites with 30% PU (wt%) was 57.7 MPa, and their water absorption was 7.37% after 24 hours of immersion.

Resumo Os efluentes das indústrias têxteis são conhecidos pela dificuldade de tratamento, constituindo um campo de aplicação de tecnologias alternativas para o tratamento. Neste contexto, um sistema de tratamento híbrido, composto por eletrocoagulação associada à adição de coagulante natural (extrato de sementes de Moringa oleífera lam), visa utilizar condições de operação mais suaves, que proporcionem eficiência de tratamento, com menor demanda de energia elétrica e coagulante. Assim, a remoção do corante reativo Azul 5G de soluções aquosas foi estudada. Foram avaliados os efeitos dos fatores: intensidade da corrente elétrica, concentração de coagulantes naturais e tempo de retenção hidráulica. Um modelo quadrático foi ajustado e validado no nível de significância de 5%. A otimização global resultou em condições de 0,28 A para intensidade de corrente elétrica, 1000,00 mg L-1 de extrato aquoso de Moringa oleífera lam e 5 min para tempo de retenção hidráulica. Operando em condições ótimas, observou-se 71,38% de remoção de cor e 5,22 mg L-1 de concentração residual de ferro.

Abstract Wastewaters from textile industries are known for their difficulty to treat, several alternative technologies are applied for their treatment. In this context, the study examined a hybrid treatment system, composed of electrocoagulation combined with a natural coagulant (extract of Moringa oleífera lam seeds) to remove reactive dye Blue 5G aqueous solutions. The work evaluated the use of milder operating conditions to improve the efficiency of treatment, with reduced demands for electrical power and coagulant. The following factors were evaluated: electric current intensity, natural coagulant concentration and hydraulic retention time. A quadratic model was adjusted and validated at a 5% significance level. The overall optimization resulted in conditions of 0.28 A for electrical current intensity, 1000.00 mg L-1 of aqueous extract of Moringa oleífera lam and 5 min for hydraulic retention time. While operating under optimal conditions, the removal of 71.38% of color and 5.22 mg L-1 of iron residual concentration was achieved.

ABSTRACT The water treatment process generates a residue called water treatment plant (WTP) sludge, which needs to be correctly characterized to ensure appropriate disposal or reuse. This study aimed to characterize the centrifuged sludge produced at the Tamanduá WTP, Iguaçu Falls City, Brazil, and considered opportunities for its reuse in the production of concrete for the civil construction industry. Wet sludge (sludge in its natural form) analysis included the determination of total solids, moisture content, density, pH, and inorganic parameters (As, Al, Ba, Cd, Pb, Cr, F, Hg, Ag, and Se) through thermogravimetric analysis, X-ray diffraction, and chemical analysis by X-ray fluorescence and loss ignition. For calcined WTP sludge, chemical and mineralogical composition and laser granulometry were evaluated. The results indicated that calcined sludge had the potential to be used in the production of cement materials; conversely wet sludge did not reach the appropriate safety standards due to the high quantity of organic matter.