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Sugarcane bagasse (SB) is a by-product of ethanol production obtained in large quantities worldwide, including Brazil. Lignin is one of SB components, and its extraction is of great interest due to its vast potential for use. In this study, sugarcane bagasse was subjected to two methods of lignin extraction to obtain: Klason lignin (LKL) and milled wood lignin (MWL). The syringil/guaiacyl ratio of the lignin obtained from sugarcane bagasse was 1.67. Thermogravimetric analysis showed that LKL is more resistant to thermal degradation than MWL. According to the FTIR spectra, LKL yields a more oxidized lignin, presenting greater changes in its structure than MWL. Thus, this study provides information on the changes caused by different extractions and strengthens future studies on the transformation of lignin into products of high added value.

This study aimed to evaluate the effect of nanocellulose addition on the physical–mechanical properties of the paper produced from different fiber blends, besides comparing two nanocellulose addition methods. Three different fibers were used for fiber blending (eucalyptus, sisal, and pine). Handsheets were formed based on the mixing of all possible combinations at a 45/55 ratio in 2% consistency and 60 g/m2. Handsheet reinforcements were performed by two methods: The mixture method (MT) was a mixture of nanocellulose along with pulp during paper formation in 3, 5, and 10% addition; the coating method (CT) was the superficial coating of dry formed papers in 10% addition. Nanocellulose was produced by mechanical microfibrillation of sisal pulp. Handsheets were evaluated by physical and strength properties. Nanocellulose addition increased thickness, volume, grammage, apparent density, opacity, roughness, tensile strength, tensile index, stretch, bursting index, tear index, and fold endurance by 8.7, 8.8, 10.4, 2.1, 4.1, 23.2, 45.7, 31.8, 20.1, 14.2, 21.1, and 271.6% but reduced bulk, brightness, and air permeance by 1.9, 3.4, and 71.7%, respectively. The reinforcement methods presented distinct results. In physical properties, an increasing tendency toward nanocellulose (MT) increase was observed in thickness, grammage, and apparent density despite the decreasing trend in air permeance. No tendency was observed in other physical properties. In general, CT presented higher values of thickness, grammage, bulk, and brightness but lower values of apparent density and opacity, compared to MT. The mixture method showed an increasing tendency in strength properties with the increase of nanocellulose content. CT obtained fewer strength properties compared to MT.

O cártamo (Carthamus tinctorius L.)é uma espécie que tem grande potencial de inserçãoem regiõesque sofrem com o estresse hídrico, devido suas condições de adaptabilidade,qualidadeseaplicações. Nesse sentido, este estudo objetivouidentificar acessos de cártamo compotenciais de adaptações às condições edafoclimáticas norte-mineiras, visando fomentar um programa de melhoramento.Paraisso, 10 acessos docártamoforam avaliadospor caracteres morfoagronômicos.Os caracteres avaliados foram a altura de plantas,matéria seca da parte aérea, diâmetro do caule,ramificação primariaesecundária,inflorescência,produçãode grãosea produção de óleo.Os dados experimentais foram submetidos à análise de variância,ao teste Scott-Knott,correlação linear de Pearsone agrupamento de otimização de Tocher. A herdabilidade (H²),os coeficientes de variação ambiental (Cve) e genética(Cvg) e a e relação Cvg/Cveforam estimados. Foipossível avaliar o potencial de produçãodas variedadesde cártamoe obter aseleção das variedadesdemaior potencial produtivopara as principais características. Tambémfoi possível selecionaroscaracteres com maior potencial ao melhoramento genético. O cártamo pode ser inseridonas condições norte-mineiras e se tornar uma espécie de importância econômica. Safflower(Carthamus tinctorius L.) is aspecies that has great potential forhydrical stressregions,due to its adaptability, qualities and applications.Therefore, this study aimed to identifysaffloweraccess with potential for adaptationat soil and climatic conditionsin northern Minas Geraisforfostering a breeding program.Thereunto, 10saffloweraccesswere evaluated bymorphoagronomic characters. Characters were plant height, shoot dry matter, stem dimeter,primary andsecondary branching, inflorescence, grain yield and oil production.The experimental data were submitted to analysis of variance,Scott-Knott,linear correlation of Pearson and Tocher optimization grouping.The heritability(H²), coefficients of environmentaland genetic variationand Cvg/Cve ratio were estimated. Evaluate the production potential of safflower varietiesandobtain the selection of the varieties with the greatest productive potential for the main characteristicswaspossible. Also,characters with the greatest potential for genetic improvement.Safflowercan be inserted at North ofMinasconditions and become aneconomic importancespecies.

Background: Blended paper can present suitable mechanical properties due to sirnergetic effect. However, regarded to physical properties, few studies are conducted. This study aimed to evaluate optical, structural, interfiber bonding, and other physical properties from blended paper and try to understand how these properties can affect applications. The eucalyptus, sisal, and pine pulp were used for handsheet forming. Pulps were disintegrated, refined, and blended two by two in 5/95%, 25/75%, and 45/55% ratios. Also, virgin pulps (100% of each pulp) were used for handsheet forming. Handsheets were formed and evaluated by bond strength, cobb test, air permeance, roughness, optical, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Results: Treatments differed statistically in bond strength, cobb test, optical, air permeance, and roughness. Generally, treatments with eucalyptus presented higher bond strength, brightness, and air permeance. Treatments with sisal presented the highest opacity and roughness. Spectra of virgin handsheets presented differences in 2170-2000 and 2360 cm-¹ bands, probably related to residual lignin content. SEM images revealed structural differences between blended and virgin pulps. Conclusion: Treatment T15 (45S 55P) presented the best results, suggesting better physical-mechanical properties. Blended handsheets presented better properties than virgin handsheets on most properties, evidencing a synergetic effect.

The use of biomass for biochar production is already a reality. However, little is known about its structure and composition, mainly due to the changes occurred during the heat treatment. This information is crucial since it will have an immediate impact on the quality and applicability of the material produced. Therefore, this study aimed to analyze different biomasses, characterizing their potential for biochar production. Woods from Eucalyptus urophylla and Corymbia citriodora and coffee husk were assessed. The biomass was ground and sieved, and then stored under controlled conditions of temperature and humidity. Subsequently, the material characterizations were performed through proximate analysis, elemental analysis, thermogravimetric analysis and Fourier transform infrared spectroscopy (FTIR). In general, all biomasses presented potential to be used in the production of biochar, where low H/C and O/C ratios were found. The coffee husk has higher lignin, extractives, ash and fixed carbon contents, which certainly contributed to its greater thermal stability. The FTIR analysis showed the presence of bands related to recalcitrant chemical groups such as carboxylics and phenolics in the spectra of all biomasses. The thermogram profiles of the C. citriodora and E. urophylla wood were similar to each other, and different from that of the coffee husk, which showed higher thermal stability. RESUMO A utilização da biomassa para produção de biocarvões já é uma realidade. Porém, pouco se sabe sobre a sua estrutura e composição, principalmente, mediante as transformações ocorridas durante o tratamento térmico. Estas informações são fundamentais, uma vez que terão impacto imediato na qualidade e aplicabilidade do material produzido. Portanto este trabalho objetivou analisar diferentes biomassas, caracterizando-as como potenciais para produção de biocarvões. Foram utilizadas madeiras de Eucalyptus urophylla e Corymbia citriodora e cascas de café. As biomassas foram moídas e peneiradas e, em seguida, armazenadas sob condições de temperatura e umidade controlada. Posteriormente realizou-se a caracterização dos materiais, por meio de análise química, química imediata, elementar (CHNS-O), térmica (TGA e DTA) e de espectroscopia vibracional na região do infravermelho (FTIR). De forma geral, todas as biomassas apresentaram potencial para serem utilizadas na produção de biocarvão, no entanto, a casca de café apresentou maiores teores de lignina, extrativos, cinzas e carbono fixo, o que, certamente, contribuiu para que a mesma apresentasse maior potencial de utilização como condicionador de solos. Com relação à análise de FTIR, observou-se a presença de bandas referentes aos grupos químicos recalcitrantes, como os carboxílicos e fenólicos nos espectros de todas as biomassas. O perfil dos termogramas de C. citriodora e de E. urophylla foram semelhantes entre si e diferentes da casca de café, que apresentou maior estabilidade térmica.

Activated carbons (AC) are high porosity and adsorptive carbonaceous materials. These adsorbents can be produced using different organic materials. Precursor material properties may impact their quality. This study aimed to produce activated carbon from Tectona grandis wood wastes, besides determining efficiency in adsorption of different pollutants. Chemical activation, with ZnCl2 (AC_ZnCl2) and CuSO4 (AC_CuSO4), and physical activation, with CO2 (AC_CO2) were performed. Activated carbons were characterized by FTIR, surface functional groups (Boehm) and surface area analysis. Moreover, ACs were tested regarding adsorption capacity of methylene blue (MB), phenol and Cr+6 ions in aqueous medium. Higher total pore volume (0.62 cm³ g-¹), micropore volume (0.31 cm³ g-¹) and surface area (524.50 m² g-¹) were obtained in AC_ZnCl2, which was also the most effective in MB and phenol adsorption. AC_CuSO4 obtained high adsorption capacity for phenol and presented functional groups different from the other AC. AC_CO2 was the second with better adsorption performance for all pollutants. Keywords: Activation process. Adsorbent. Forest wastes. Raw material.

As principais matérias-primas usadas para a produção de celulose e papel no Brasil são madeiras de florestas plantadas. Embora com imenso potencial, o uso de fibras não madeireiras é pouco explorado. Diante disso, esse estudo tem como objetivo avaliar o uso do bagaço de cana e bambu para a produção de celulose e papel a partir da caracterização física, química, anatômica e de índices qualitativos. Para isso, foram realizadas análises anatômicas das fibras (comprimento e largura das fibras e vasos, largura do lume e espessura da parede celular), análise dos componentes químicos (teores de celulose, hemiceluloses, lignina, extrativos e cinzas) e da densidade básica. Além disso, calcularam-se os índices de enfeltramento, Runkel, Mulsteph, Boiler, coeficiente de flexibilidade e fração parede. Os resultados demostraram que os materiais diferiram estatisticamente entre si nas propriedades químicas, com exceção dos teores de lignina, na densidade e nas propriedades anatômicas, excluindo a largura dos vasos e índice de enfeltramento. O bambu apresentou maiores valores de celulose (52,96%), cinzas (2,34%), densidade (0,461 g/cm³), fração parede (67,84%) e índices de Runkel (2,11), Mulsteph (0,90) e Boiler (0,81), enquanto o bagaço de cana apresentou maiores valores de hemiceluloses (17,63%), extrativos (12,81%) e coeficiente de flexibilidade (46,19%). A maioria das propriedades foram similares às observadas em matérias-primas comumente utilizadas para essa finalidade. Portanto, esses dois materiais lignocelulósicos têm potencial para serem usados em indústrias de papel e celulose no Brasil.

Surface modification may lead activated carbon (AC) to take on different properties. This study aimed to promote surface modification of activated carbons using corona treatment (electrical discharge). In this study, powdered commercial activated carbon was used. Activated carbons were subjected to corona treatment at different exposure times (2, 5, 8 and 10 min) at 4.5 cm height from the source. To observe differences promoted by treatment, activated carbons were analyzed by acidity, surface functional groups, Fourier Transform Infrared Spectroscopy (FTIR), elemental analysis (CHN), proximate analysis and thermogravimetry. Corona treatment impacted surface chemistry of activated carbons. There was a trend of increasing surface acidity according to exposure time. There were changes in functional groups, increasing carboxyl acid and decreasing lactone and phenol groups. FTIR analysis showed peaks in the bands at 3500, 1650 and 1300 cm-1. Increase of oxygen content and decrease of carbon content were also found. Immediate analysis followed similar tendency for volatile and fixed carbon content. There were also differences in thermogravimetry analysis. Treated activated carbons were different compared to virgin activated carbon. This difference was performed by surface oxidation. Thus, this study showed that corona treatment caused surface modifications and might impact adsorption process.

Para diversos usos da madeira, como na produção de celulose e papel e do carvão vegetal, a presença da casca é indesejável, podendo comprometer a produção. Desta forma, este trabalho teve como objetivo avaliar a influência de diferentes espaçamentos de plantio nas propriedades da casca de um clone de Eucalyptus grandis x E. camaldulensis aos sete anos de idade em cinco diferentes espaçamentos de plantio. Os discos de madeira foram retirados das árvores nas posições 0, 25, 50, 75 e 100% da altura comercial. Foram feitas análises da espessura, densidade, poder calorífico superior e minerais da casca. Não houve diferenças significativas entre os tratamentos para o poder calorífico e para a espessura da casca. Para a densidade básica da casca, os maiores valores foram encontrados nas árvores plantadas nos maiores espaçamentos e considerando os teores de minerais, houve diferença significativa apenas para P, Mn e Zn. For several wood uses, such as pulp, paper and charcoal, the presence of the bark is undesirable, compromising production. Thus, this study aimed to evaluate the influence of different plant spacings on the properties of the bark of a clone of Eucalyptus grandis x E. camaldulensis at seven years of age at five different plant spacings. The wood discs were removed from the trees at 0, 25, 50, 75 and 100% of the commercial height; then we performed thickness, basic density, gross calorific value and mineral content analysis of bark. There were no significant differences among treatments for the bark gross calorific value and thickness. For the bark basic density, the highest values were found in trees planted in wider plant spacings and considering the mineral content, there was a significant difference only for P, Mn and Zn.

Dye degradation is a significant topic in environmental science, since dyes can bring several problems to the environment. Activated carbon (AC) is an important material used as adsorbent of these hazardous substances, but need to be improved especially into specific substances. This paper aimed to evaluate the impact of activated carbon surface modified by corona treatment (electric discharge) on adsorption of different dyes. Activated carbons were treated by corona treatment to cause surface modification, modifying exposure time to treatment (2, 5, 8 and 10 minutes). Evaluation of adsorption was performed by adsorption isotherms and kinetic adsorption. Dyes differed in their charge (anionic or cationic) and molecular weight. Dyes used were Methylene Blue (cationic) and Congo Red (anionic). Surface area and Scanning Electron Microscopy (SEM) were also conducted. Surface chemistry was impacted by corona treatment and interfered in dye adsorption. There was decrease of dye adsorption for both dyes according to time exposure. However, the decrease of Methylene Blue (25%) was higher than Congo Red (14%), suggesting that either charge or molecule weight interfere in the adsorption isotherms. In kinetic adsorption, there was no difference between treatments, although there was a difference in adsorption equilibrium. SEM showed that surface was impacted (pore destruction) by corona treatment. Furthermore, estimated surface area was strongly impacted by the treatment, reducing with the increase of time exposure. Thus, textural properties might have contributed to reduce adsorption capacity of both dyes and play a higher role than chemical properties. RESUMO A degradação de corantes é um importante tópico nas ciências ambientais, já que os corantes podem trazer diversos problemas para o meio ambiente. O carvão ativado é um importante material usado como adsorvente dessas substâncias causadoras dos mais diversos danos, mas precisam ser melhoradas especialmente quando envolve substâncias específicas. Este manuscrito tem como objetivo avaliar o impacto da superfície de carvões ativados modificados pelo tratamento corona (descarga elétrica) na adsorção de diferentes corantes. Os carvões ativados foram tratados pelo tratamento corona para promover a modificação na superfície, modificando os tempos de exposição ao tratamento (2, 5, 8 e 10 minutos). A avaliação da adsorção foi realizada pelas isotermas de adsorção e velocidade de adsorção. Os corantes diferiram pelas suas cargas (aniônico e catiônico) e massa molecular. Os corantes utilizados foram o Azul de Metileno (catiônico) e o Vermelho Congo (aniônico). A área superficial e a microscopia eletrônica de varredura (MEV) também foram realizadas. A superfície química foi impactada pelo tratamento corona e interferiu na adsorção dos corantes. Houve decréscimo na adsorção dos corantes para ambos de acordo com o tempo de exposição. No entanto, o decréscimo de Azul de Metileno (25%) foi maior que para o Vermelho Congo (14%), sugerindo que a carga ou a massa molecular interferiram na isoterma de adsorção. Na velocidade de adsorção, não houve nenhuma diferença entre os tratamentos, embora houve diferença no equilíbrio da adsorção. A análise MEV mostrou que a superfície foi impactada (destruição dos poros) pelo tratamento corona. Além disso, a área superficial estimada foi fortemente impactada pelo tratamento, reduzindo com o aumento do tempo de exposição. Assim, a propriedades texturais pode ter contribuído para a redução na capacidade de adsorção de ambos corantes, desempenhando papel de maior importância comparado com as propriedades químicas.

The main and new surface modification methods of activated carbon (AC) and their influence on application (adsorption capacity) were reviewed. Adsorption capacity is an important issue, contributing to hazardous substances environment management. According to literature, it is true that surface chemistry strongly affects adsorption capacity. Surface chemistry can be modified by several methods that lead to different activated carbon properties. Furthermore, adsorbate properties, and their relationships with surface structure, can impact adsorption properties. Surface modifications can be conducted by adding some atoms to the surface structure, making the surface more acidic or basic. Introduction of oxygen and ammonia atoms (chemical modification) are the main processes to make the surface more acidic and basic, respectively, although may bring chemical wastes to environment. Surface modification is done by chemical and physical modifications that lead activated carbons to present different properties. The main and new methods of chemical and physical modifications are compared and presented in this paper. Some new physical methods, like corona treatment, plasma discharge and microwave radiation, can be applied to cause surface modifications. Corona treatment can be a practical and new way to cause surface modification on an activated carbon surface.