RESUMO O Pinus elliottii Engelm. possui uma vasta possibilidade de aplicações, porém, apresenta características indesejáveis às quais podem ser atenuadas com a adoção dos tratamentos de termorretificação e a furfurilação. Assim, este trabalho analisou a influência que os tratamentos de furfurilição e termorretificação exerceram em propriedades tecnológicas da madeira de Pinus elliottii. Para tanto, confeccionaram-se corpos de prova com dimensões de 15 x 15 x 250 mm (tangencial, radial e longitudinal), distribuídos igualmente em 5 tratamentos: controle, furfurilação com carga de 25% de álcool furfurílico (T F25%) e termorretificação em diferentes temperaturas (T 180°C, T 200°C e T 220°C). Avaliaram-se a variação da massa (ΔM) segundo adaptação da norma ASTM D 2017 (2005), à massa específica aparente ao teor de umidade de 12% (ρ12%), os módulos de elasticidade (MOE) e ruptura (MOR) obtidos pelo ensaio de flexão estática conforme a norma ASTM D 143 (2014), e a variação colorimétrica da madeira em conformidade com as recomendações do sistema CIE-L*a*b*. Verificou-se que o tratamento com furfurol provocou: aumentos significativos na massa, ρ12%, MOR, e causou o escurecimento da madeira, não afetando significativamente o MOE, em 5% de probabilidade de erro. Os tratamentos de termorretificação afetaram significativamente a perda de massa, contudo a maior diferença foi observada no tratamento T 220°C, o qual acarretou redução significativa no MOR em relação ao grupo controle, destacando-se que tal tratamento deixou a madeira com coloração semelhante aquela adquirida pela madeira tratada com furfurol. Conclui-se que ambos os tratamentos causaram o escurecimento da madeira de Pinus elliottii agregando assim valor estético, sendo que o tratamento à base de furfurol, com carga de 25%, ocasionou melhora nas propriedades tecnológicas da madeira. Apesar dos tratamentos de termorretificação terem aumentado o MOE, geraram perda de massa significativa, principalmente nos tratamentos mais agressivos, comprometendo assim possíveis usos da madeira com finalidade estrutural.

This study aims to compare the resistance against subterranean termites of wood–polymer composites produced by in situ polymerization. The biological tests were carried out by choice and no-choice feeding tests. Poly (furfuryl alcohol), poly(styrene) and poly (methyl methacrylate) were studied here. They were impregnated into a Brazilian fast-growing pine wood using a vacuum:pressure method and then cured under simple heating. These treatments were evaluated using chemical (by infrared spectroscopy) and morphological (by scanning electron microscopy) analyses. The termite attack was evaluated by mass loss determination and photography. In general, all the treatments were effective in protecting the fast-growing pine wood. Results obtained by no-choice tests indicated that the treatment solution with 75% of furfuryl alcohol was less effective than the others, which indicates that both choice and no-choice tests may be important in a comprehensive study on the termites resistance of solid woods.

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This study addresses changes in aesthetical features of bio-based polyurethane (PU) foams filled with four forest-based particles (namely wood flour, wood bark, kraft lignin, and paper sludge), which were decayed by two wood-rot fungi. White-rot and brown-rot fungi were inoculated on these foams and further characterization results were obtained using colourimetric parameters measured according to the CIELab method. The fungi penetrated into both intra and intercellular spaces into the PU foams, although it neither changed the foam weight nor chemically interacted with the polymer cell wall. These fungi changed overall the appearance of the foams, which indicates that a protective strategy against these microorganisms may be of interest, especially for foam parts used in contact with wood products. The neat PU presented smaller colour stability if compared to the filled foams. Among the fillers, powdered kraft lignin stood out and can be indicated to produce valuable darkened PU parts with stable colour patterns.

Industrial effluents containing heavy metals can have harmful effects on organisms and the ecosystem. Silver is a waste from textile, galvanic and photographic industries, and when released into the environment, it can harm human health and cause biological modification. Removal of metals, such as silver, has been traditionally carried out using physicochemical methods that produce a high concentration of sludge and expend a significant amount of energy. Researchers are seeking innovative technologies for more efficient removal of silver or for using this heavy metal to obtain new products. The use of microalgae is a promising alternative to traditional remediation methods because several species can absorb and assimilate heavy metals. When exposed to toxic substances, microalgae excrete molecules in the medium that induce the reduction of silver particles to nanoparticles. Biosynthesized silver nanoparticles (AgNPs) can be used in medicine, food packaging, the production of cosmetics and pharmaceuticals, civil engineering, sensors and water purification. Thus, microalgal biosynthesis of metal nanoparticles has the capacity to bioremediate metals and subsequently convert them into non-toxic forms in the cell. In this context, this review addresses the use of microalgal biotechnology for industrial waste remediation of silver, which includes the simultaneous biosynthesis of AgNPs. We also discuss the potential applications of these nanoparticles.

RESUMO O interesse pela síntese de nanopartículas utilizando extratos vegetais vem crescendo nas últimas décadas, devido a não geração de resíduos de químicos tóxicos e condições mais brandas de síntese. O Brasil é um dos líderes em florestas plantadas, principalmente do gênero Eucalyptus, em razão disso o objetivo deste trabalho foi sintetizar nanopartículas de óxido de zinco utilizando extrato etanólico das folhas de Eucalyptus dunnii. As folhas foram secas e moídas para obtenção de pó, 10 g deste foram adicionadas em 100 mL de álcool etílico, a solução foi mantida em banho-maria a 80 ºC por 75 min, a solução foi filtrada para obtenção do extrato. Para a síntese utilizou-se 20 mL de extrato e 1,57 g de acetato de zinco, a solução foi mantida a 80 ºC sob agitação magnética vigorosa por 20 min, transcorrido o tempo foi realizado tratamento térmico em mufla a 500 ºC por 2h. As nanopartículas obtidas apresentaram característica cristalina e diâmetro médio de 32,24 nm. O espectro FTIR do extrato apresentou diversos picos relacionados a compostos redutores capazes de realizar a síntese, enquanto o espectro das nanopartículas demonstrou que mesmo após a calcinação, ainda se detecta a presença de compostos orgânicos que podem ser responsáveis pela estabilização das mesmas. Sendo assim, o extrato etanólico de E. dunnii possui capacidade redutora para realizar a síntese de nanopartículas cristalinas de óxido de zinco.

O objetivo deste trabalho consistiu em analisar a deterioração causada por térmitas em madeiras de Mezilaurus itauba (Meisn.) Taub. ex Mez, Cordia americana (L.) Gottshling & J. E. Mill., Melia azedarach L. e Parapiptadenia rigida (Benth.) Brenan, após ensaio de preferência alimentar. Foram confeccionados 20 corpos de prova de cada espécie, com dimensões de 15 x 15 x 260 mm (tangencial x radial x longitudinal). Os parâmetros tecnológicos avaliados foram a massa específica básica (ρb), a perda de massa (PM), o módulo de elasticidade (MOE) e ruptura (MOR) provenientes do ensaio de flexão estática e a dureza. Finalizado o ensaio, a espécie com menor perda de massa foi a Melia azedarach, possivelmente devido à composição dos seus extrativos. Para as espécies Cordia americana e Parapiptadenia rigida, quanto às propriedades mecânicas, verificou-se redução significativa somente no MOE das amostras deterioradas em comparação com as do grupo controle. Conclui-se, portanto, que, a maior resistência da espécie Melia azedarach está associada à sua composição química, sendo que em quase todas as espécies madeireiras houve decréscimo nos parâmetros mecânicos (MOE, MOR e dureza Janka) devido ao ataque dos térmitas Nasutitermes.Palavras-chave: biodeterioração, cupins, propriedades tecnológicas, espécies florestais. TECHNOLOGICAL PROPERTIES CHARACTERIZATION OF FOUR HARDWOODS DETERIORATED BY GENDER Nasutitermes TERMITES ABSTRACT:The objective of this work was to analyze the deterioration caused by termites in woods of Mezilaurus itauba (Meisn.) Taub. ex Mez, Cordia americana (L.) Gottshling & J. E. Mill., Melia azedarach L. and Parapiptadenia rigida (Benth.) Brenan, after food preference assay. Were made 20 test specimens of each species, with dimensions of 15 x 15 x 260 mm (tangential x radial x longitudinal). The physical parameters were the basic mass (ρb), the mass loss (PM), the modulus of elasticity (MOE) and rupture (MOR) from the static bending test and Janka hardness. After the test, the species with the lowest mass loss was Melia azedarach, possibly due to your extractives composition. For the species Cordia americana and Parapiptadenia rigida, about the mechanical properties, it was observed significant reduction only in the MOE of deteriorated samples compared to the control group. It's concluded that the Melia azedarach specie higher resistance it’s associated with your chemical composition, and in almost all wood species there was a decrease in mechanical parameters (MOE, MOR and Janka hardness) due to attack of Nasutitermes termites.Keywords: biodeterioration, termites, technological properties, forest species.

The technological properties of wood are constituted by parameters, which after being analyzed, make it possible to define an appropriate use for this material. However, the deterioration of the wood due to the attack of termites, which find their food source in the chemical components, ends up altering these original technological characteristics, reducing their useful life and compromising their use. Thus, this study aimed to determine some technological properties of Pinus elliottii, as well as to evaluate the influence of deterioration caused by Nasutitermes termites in this wood. Specimens with dimensions of 20 x 20 x 150 mm (tangential x radial x longitudinal) were used as specimens. The physical properties evaluated were the basic density and linear shrinkage (tangential and radial contractions, and anisotropy coefficient), while the mechanical properties were represented through the Janka hardness test and compression parallel to the fibers. After 40 days of the biodeterioration test with Nasutitermes termites, changes in the equilibrium moisture content, retractability, water absorption rate and mechanical properties were evaluated. While the physical and mechanical properties evaluated showed values similar to those found in the literature, the deterioration caused by termites caused a reduction in hardness and parameters related to compression, increasing the dimensional instability of the wood, represented by the variation in the anisotropy coefficient. This made it possible to conclude that the biodeterioration resulting from the attack of termites directly affected the technological parameters of the wood, and consequently, its quality for the use in the purpose it could initially be destined.