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Considering the challenges of urea administration due to the high ureolytic activity of the rumen and the importance of its use, as well as taking into account the relevance of sustainably exploiting the technological potential of biodiversity, this research studies the encapsulation of urea in different clay minerals (palygorskite (Pal), sepiolite (Sep), and Veegum&reg, (V)) as an alternative for use as nonprotein nitrogen (NNP) sources. A method of incorporation was developed in which the encapsulation of urea was proven by X-ray diffraction, fibrous materials, Pal and Sep had similar characteristics due to the decrease in the relative plane intensity (011), suggesting a decrease in the order of their stacking due to the presence of urea on the surface or inside channels. By contrast, V showed a 7.74&deg, reflection shift, suggesting an increase in basal spacing from 11.45 &Aring, in V to 14.88 &Aring, in the sample after urea encapsulation. By thermogravimetry, it was observed that the presence of urea did not change the mass-loss profiles but only increased the percentage of loss in respective events, indicating urea incorporation in the clay minerals. These results provide a promising alternative for administering NNP sources in the ruminant diet.

Annatto dye is a natural organic dye belonging to carotenoids, whose main components are bixin and norbixin. Due to its low stability, it is convenient to protect the dye molecules with other materials. The use of clay minerals is an alternative, which are phyllosilicates with attractive physico-chemical properties, such as high specific surface area, cation exchange capacity, mechanical/chemical stability and non-toxicity. The main purpose of this work was to develop hybrid materials, using annatto dye and clay mineral modified with different inorganic cations, and then, to evaluate the stability of the new pigments. The process of preparing the modified clay minerals involved mixing a synthetic montmorillonite in solutions containing the precursor salts of the metal cations. Subsequently, the dye was dissolved in a solution containing water and alcohol, followed by filtration and mixed with the modified clay, giving rise to the hybrid pigments. Through the characterizations, it was noted that a variety of colors were obtained, and the sample containing aluminum was the one that most adsorbed the dye and showed a significant increase in stability at high temperatures. This hybrid material was better to dye than its pure form. Therefore, the bixin/montmorillonite pigments are promising for replacing artificial colors in practical applications such as in the cosmetics, food or pharmaceutical industries.

Chitosan is a natural polymer with antibacterial property, that is biodegradable, extremely abundant and non-toxic. This study aimed to develop and characterize chitosan hydrogels in combination with nerolidol, in order to optimize the antimicrobial and healing properties. The hydrogels were prepared using a reaction of the chitosan with acetic acid solution, followed by the addition of 2 or 4% of the nerolidol. Using thermogravimetry, differential scanning calorimetry and infrared spectroscopy, the incorporation of nerolidol in the hydrogel was confirmed. Direct contact tests using hydrogels and Staphylococcus aureus showed a synergistic effect in the materials, enabling total inhibition of bacterial growth. The hydrogel containing 2% nerolidol showed excellent healing effects. The beginning of re-epithelialization and reorganization of collagen was already observed on the 7th day of treatment. The material created proofed to be promising as a healing and antibacterial agent.

Cellulose is vastly used in the adsorption of dyes. It can be used in its natural formor with modified surface. This present study aimed at integrating phosphate cellulose with chloroethyl phosphate, value their potential as adsorbents of brilliant green dye, and compare suchresults to those of pure cellulose (Pure-Cel). The phosphatic material (Phosp-Cel) was characterized by XRD, where it was found that the crystallinity of the material was kept; by IV, which showedtwo bands in 1059 and 1027 cm −1 that indicated the presence of the C O P link; by 31 P NMR, which showed a broad signal in 1.86 ppm indicating the presence of a single species of phosphorus in material (P O C); and by thermogravimetry, where Phosp-Cel proved to be more thermally stable than cellulose forerunner. A time of 20 and 120 min was obtained to reach the equilibrium, through the tests of adsorption, for Pure-Cel and Phosp-Cel, respectively. In both cases the system follows the pseudo second order model. The largest removal occurred at pH 10 and the maximum adsorption was 46.7, 58.42 and 90.5 mg g −1 for Pure-Cel, and 113.6, 114.2 and 112.1 mg g −1 for Phosp-Cel at 25 °C, 35 °C and 45 °C, respectively. Pure-Cel experimental isotherms were best fit to the Langmuir model, and Phosp-Cel at 25 °C best fit the Langmuir model; while at 35 °C and 45 °C it best fit the Freundlich model.

Resumo Os fosfatos de cálcio são materiais cerâmicos que apresentam propriedades particulares como biocompatibilidade e similaridade química com os tecidos ósseos e dentários dos seres vivos. Sua morfologia porosa permite que estes se apresentem como material apropriado para a utilização em substituição de pequenas partes de tecido ósseo, já que proporciona o crescimento de canais de sistemas nervosos, suporte para vasos sanguíneos como também suporte para deposição de fármacos. Dentre os fosfatos de cálcio, a hidroxiapatita se apresenta como fosfato mais estável, o qual é encontrado em maior proporção nos tecidos ósseo e dentário no organismo. Este trabalho teve por objetivo buscar nos bancos de artigos e de patentes trabalhos que relacionem a atividade antimicrobiana da hidroxiapatita, dando suporte a pesquisadores que trabalhem com esta cerâmica para aplicações em tecido dentário, como também a utilização da hidroxiapatita focando o suporte para incorporação de fármaco. Os bancos pesquisados foram o Scopus, Scielo e Web of Science para os artigos e USPTO, EPO e INPI para os bancos de patentes. Os critérios de exclusão levaram a 19 artigos que estudaram hidroxiapatita em conjunto com a clorexidina e zero patente encontrado. Dentre os artigos encontrados, a clorexidina é o fármaco mais empregado como agente antimicrobiano, e a bactéria mais utilizada nos testes é a gram-positiva Streptococcus mutans.

The cellulose matrix was chemically modified with cysteamine (CelCTA) and characterized by elemental analysis, and subsequently applied to the removal of copper ion in an aqueous media. The experimental adsorption isotherm obtained for the studied system was adjusted to linear models: Langmuir, Freundlich, and Temkin. Among the proposed models, the Langmuir model was the one with the best linear adjustment to data obtainedexperimentally, with an adsorption capacity of the adsorbent for 0.3292 mmol dm-3.

The presence of dyes in colored polymers can cause a series of reactions that promote their photodegradation under irradiation. The aim of this study was to investigate the kinetic behavior of the photodegradation of poly (sodium 4-styrenesulfonate) (PSS) in aqueous solution or in the presence of thioxanthone (TX) under UV radiation in different atmospheres. These systems were monitored by SEC. The polydispersity decreased in all systems studied indicating that there was a breach of the polymer main chain. Only the PSS / TX / air atmosphere system peaked, which occured at 43h of irradiation. However, this system showed slower kinetics of polymeric scission due to the dye suppressing a transfer of energy from the triplet state to the polymer. The photodegradation of solutions of PSS / air atmosphere showed higher efficiency under ultraviolet radiation in relation to the PSS in the presence or absence of the dye under an inert atmosphere.

The constant search for the removal of organic and inorganic pollutants has been largely intensified lately, as has the search for efficient techniques. With that, this work aims to test two filter papers of different origins to identify their interaction with the bright yellow dye and to determine the adsorption capacity of each paper. Various parameters were studied (pH, time, temperature, and concentration) and it was possible to verify that the best interaction conditions between the material and the dye were 180 minutes, pH 2, and temperature of 298 K, with a maximal capacity at approximately 7 mg of dye per gram of material, with a kinetic adjustment to the pseudo-second-order model. Thus, these results prove that the paper interacts with the dye, and it can be used as an adsorbent.

Degradation of yellow bright anionic dye under ultraviolet radiation was studied using attapulgite (ATT) as a support in the immobilization of the photocatalyst semiconductor, titanium dioxide, TiO2. The photocatalytic performance of the corresponding catalyst was evaluated using the 1.0x10-4 mol L-1 concentration of the dye. The samples were irradiated with UV light for 120 minutes. The kinetics were monitored by UV-Vis spectrophotometry. The spectra absorption showed that the increased amount of photoactive material in the reaction system maximizes the efficiency of the photocatalytic process.

The palygorskite or attapulgite is a mineral clay of fibrous habits, a phyllosilicate 2:1, presented by the formula Mg5[Si8O20](OH)2(OH2)4.4H2O. Taking advantage of this natural resource available in the State of Piauí, this research aims at incorporating the zirconium oxide to the surface of this clay, through the sol-gel method, in order to evaluate the photoactivity of the composite. The material was characterized by the X-ray diffractometry (XRD), indicating the presence of the zirconium oxide, with the emergence of peaks in 30.8° and 60.9°. It was observed the incorporation of zirconium on the clay by transmission electron microscopy (TEM) and verified the fibrous habit and the presence of ZrO2 on the surface of the clay with 1.35% of incorporated zirconium and 127.4 m2 g-1. The rate of degradation of the Remazol Blue dye was 93.5% when using the composite.

A novel chitosan derivative was prepared through direct reaction of pure chitosan with acetylacetone in the absence of a solvent, and it was characterized by elemental analysis, Fourier transform infrared spectrometry (FTIR), and 13C Nuclear Magnetic Ressonance (NMR) spectroscopy. Moreover, the antibacterial properties of the new biomaterial were tested by the direct contact method against multi-drug resistant strains of Staphylococcus aureus and Escherichia coli. The results from the characterization were consistent with the modification of the chemical structure made. The new derivative showed a better antibacterial activity than raw chitosan against E. coli strains, indicating that incorporation of imine link (Schiff base) enhanced its antibacterial activity against Gram-negative bacterium. On the contrary, this chemical change did not decrease its antibacterial activity against Gram-positive bacterium.

The cellulose phosphate used for this work was obtained by a reaction between cellulose and sodium trimetaphosphate (STMP) at pH 10. The material obtained was characterized by 31P nuclear magnetic resonance (31P NMR) spectrometry and energy-dispersive X-ray spectroscopy (EDS). In the 31P NMR results, the two peaks at 2.05 and 7.96 ppm are related to phosphorous. The EDS indicated the presence of 5.47% of incorporated phosphorus which proved the modification. The material obtained was applied in the removal of the pharmaceutical drug acetaminophen (acetaminophen) from aqueous media. The maximum adsorptions of the drug in the cellulose phosphate was 60.7, 56.7, and 60.0 mg g-1 at the temperatures 298 K, 308 K, and 318 K, respectively, in 120 minutes at pH7. The plot traced from the data best aligns with the pseudo-second order kinetic model and with the physical-chemical model proposed by Freundlich.

The polystyrene (PS) has a variety of applications. Many mechanisms have been proposed for the degradation of the polymer, but a consistent mechanism does not exist yet in the literature due to the complexity of the kinetics and formation of photoproducts that depend on various conditions photodegradation. The aim of this study was to investigate the kinetic behavior of the photodegradation of PS films photosensitized by thioxanthone (TX) under UV, Vis and xenon radiation. Changes in chemical structure caused by photo-oxidation in the films were verified by FT-IR. The photodegradation of polystyrene films sensitized by thioxanthone showed greater efficiency in the formation of carbonyl group under Vis radiation and xenon when compared to pure PS. However, in the ultraviolet films system PS and PS / TX exhibited similar kinetic behavior.

The objective of this study was to determine the content of free formaldehyde contained in panels of Acacia mangium clippings. The results of the analysis show that the best temperature for a Hantzschen reaction is 60°C. The panels had a linear behavior over the course of the exposure time (168 hours), whereas samples with a lower surface area showed linearity starting at 72 hours. Thus, it is possible to quantify the emission of formaldehyde panels, thereby supporting research to create measures that minimize its release.

Soil-cement bricks are good examples of environmentally friendly products. This brick is the combination of soil with compacted cement with no combustion in its production. In this work the physical chemical characteristics of the soil from Piaui for producing this material were investigated. Samples of the soil were collected in three potteries from the county of Bom Jesus and pH analysis were carried out, as well as the rate of organic matter, texture, particle density, limits of liquidity and plasticity rates. The results have shown that the soils have acid tones (pH 5,49 a 6,11), which can be neutralized by adding cement, and organic matter percentages up to 1%. The samples have shown predominantly clay-rich textures with adequate plasticity limits, however, values of liquidity limits and particle density above recommended. Altogether, these soils tend to present viability concerning soil-cement brick production, provided that corrections with additives are made in order to minimize this effect.

Photocatalysts based on SrSnO3 and SrSnO3@ZrO2 were prepared by the modified-Pechini method and applied in the photocatalytic degradation of a textile azo-dye under UV radiation. The photohydroxylation of terephthalic acid and scavengers were employed in order to evaluate the participation of each active species, such as hydroxyl radical, and photogenerated electrons and holes on the photocatalytic process. The band gap structure was evaluated using the Mott Schottky method in combination with UV–visible spectrophotometry. Both samples had high photocatalytic activity, although SrSnO3@ZrO2 showed the best decolorization performance ranging from 32% to 98%. This behavior was assigned to the best dispersion of the active phase on the support and to the Sn(II) reduced states, observed by XPS. The participation of hydroxyl radicals in the reaction was confirmed when terephthalic acid was used as probe and by using isopropanol as hydroxyl radical scavenger, which resulted in the inhibition of the photocatalytic process.

For many years research has focused on the development of new carriers for controlled release of drugs.

In the context of mitigating the harmful impacts caused to the environment, in particular the water pollution, by the indiscriminate discharge of anionic dyes, this work reports the use of sodium titanate nanotubes (NaTiNTs) functionalized with amine group (NaTiNTs-NH2), obtained from the reaction of nanotubes with 3-aminopropyltrimethoxysilane (APTMS), as adsorbent. The physicochemical characterizations showed that APTMS interacts covalently with the surface of NaTiNTs and the proposed adsorbent, NaTiNTs-NH2, retained morphological and crystalline structure after the functionalization. Remazol blue R (RB) was used as the model molecule of anionic dye and the adsorption tests were carried outin the aqueous solution, which showed that the matrix NaTiNTs-NH2 presents very high adsorption capacity of RB dye (435.68 ± 6.05 mgg−1) and the process occurs at monolayer by chemisorption. The adsorption process is thermodynamically favorable and exothermic in nature and. These results suggest that NaTiNTs-NH2 can be used as an alternative adsorbent material for the removal of anionic dyes in aqueous medium.

Hydroxyapatite (HAp) is a ceramic material composing the inorganic portion of bones. Ionic substitutions enhance characteristics of HAp, for example, calcium ions (Ca2+) by cerium ions (Ce3+). The use of HAp is potentialized through biopolymers, cashew gum (CG), and gellan gum (GG), since CG/GG is structuring agents in the modeling of structured biocomposites, scaffolds. Ce-HApCG biocomposite was synthesized using a chemical precipitation method. The obtained material was frozen (&ndash, 20 &deg, C for 24 h), and then vacuum dried for 24 h. The Ce-HApCG was characterized by X-Ray diffractograms (XRD), X-ray photoemission spectra (XPS), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy (EDS). XRD and FTIR showed that Ce-HApCG was successfully synthesized. XRD showed characteristic peaks at 2&theta, = 25.87 and 32.05, corresponding to the crystalline planes (0 0 2) and (2 1 1), respectively, while phosphate bands were present at 1050 cm&minus, 1 and 1098 cm&minus, 1, indicating the success of composite synthesis. FESEM showed pores and incorporated nanostructured granules of Ce-HApCG. The mechanical test identified that Ce-HApCG has a compressive strength similar to the cancellous bone&rsquo, s strength and some allografts used in surgical procedures. In vitro tests (MTT assay and hemolysis) showed that scaffold was non-toxic and exhibited low hemolytic activity. Thus, the Ce-HApCG has potential for application in bone tissue engineering.

A nanoheterostructure of titanate nanotubes decorated with anatase nanoparticles (TiNT@AnNP) was synthesized for the first time by a microwave-assisted hydrothermal one-pot reaction. Characterization by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, selected-area electron diffraction, and X-ray photoelectron spectroscopy showed highly crystalline and nanometer-sized TiNT@AnNP. The synthesized TiNT@AnNP degraded an anionic dye (Remazol blue) more efficiently under UV-visible light (380–780 nm) than a commercial anatase-TiO2 precursor. We correlated this increased efficiency of photodegradation to the large surface area and the efficient separation of photoinduced electron-hole pairs. Finally, we propose a mechanism to highlight the influence of a microwave-assisted hydrothermal synthesis in the production of TiNT@AnNP for environmental applications.

Resumo A hidroxiapatita (HAp) está presente no organismo humano nos tecidos ósseos e dentários, em que do total da massa de cada tecido 30 a 70% correspondem a HAp, podendo ser aplicada como revestimentos de próteses ou até substituição de pequenas partes ósseas. Assim, o objetivo foi sintetizar HAp por precipitação, incorporar clorexidina (CHX) e avaliar as propriedades microbianas. A caracterização foi realizada por DRX, FTIR, TG/DTG, MET e MEV. A CHX foi incorporada à HAp por adsorção, variando a quantidade incorporada. O difratograma apresentou picos em 25,9º, 31,5°, 32,2º e 32,7º (2θ) referentes aos planos (002), (211), (112) e (300) da HAp. O espectro de FTIR mostrou banda em 1050 cm-1 correspondente à deformação dos grupos fosfatos e deformações de grupos CH2 em 1485 e 1445 cm-1 da clorexidina, que apresentou morfologia porosa e cilíndrica. O biomaterial apresentou excelentes propriedades antimicrobianas frente a Streptococcus mutans, Staphylococcus aureus e Escherichia coli.

RESUMO A carnaúba (Copernicia prunifera) é uma espécie vegetal comum no Nordeste do Brasil e possui grande importância comercial no que se refere a exploração/exportação da cera extraída de suas folhas. Assim, visando o pleno aproveitamento dos resíduos gerados na cadeia produtiva da carnaúba, neste trabalho é apresentada a caracterização da palha e do talo “in natura”, bem como pós densificação (produção de briquetes), com o objetivo de investigar a possível aplicação como biocombustíveis. A metodologia experimental envolveu a determinação dos teores de umidade, cinzas, voláteis, carbono fixo, poder calorífico superior, ensaios de resistência ao impacto, compressão diametral e termogravimetria. A análise elementar (CHNS/O) também foi realizada. Com relação ao teor de voláteis os valores obtidos foram 70,89% e 81,12% para a palha e o talo in natura e 70,02% e 80,41%, para os briquetes de palha e talo. Para carbono fixo obteve-se 19,98% e 16,08 % para a palha e o talo in natura e 20,9% e 16,8%, para os briquetes de palha e talo, respectivamente. Quanto ao conteúdo energético, a palha in natura obteve poder calorífico superior da ordem de 17,51 MJ/kg e o talo in natura 17,29 MJ/kg. No que se refere a densidade energética, a produção dos briquetes proporcional aumentos da ordem de 328,9% (2,98 para 12,78 kJ/cm3) para a palha e de 292% (2,89 para 11,33 kJ/cm3) para o talo. Quanto ao ensaio de resistência mecânica, o briquete de palha apresentou uma resistência de 0,1 MPa e o briquete de talo de 0,3 MPa. Diante do exposto, pode-se inferir que a palha e o talo de carnaúba possuem potencial para utilização como biocombustíveis. ABSTRACT The carnauba (Copernicia prunifera) is a common plant species in Northeast Brazil and has a great commercial importance due to exploration/exportation of the wax extracted from its leaves. Therefore, aiming the use of the residues derived from carnauba's production chain, this work shows the characterization of the stalk and straw "in natura", and after densification (briquettes production), with the aim to investigate the possible application as biofuels. The analyses involved the determination of moisture, ash, volatile matter, fixed carbon, gross calorific value, impact resistance, diametrical compression, and thermogravimetry. Elemental analysis (CHNS/O) was also performed. In relation to the volatile matter the carnauba's straw and stalk "in natura" obtained 70.89% and 81.12% while carnauba briquettes of straw and stalk showed 70.02% and 80.41%, respectively. For the fixed carbon - a calculated value - the results were 19.98% for the straw and 16.08% for the stalk. After briquettes production were obtained 20.9% and 16.8% for the straw and the stalk, respectively. In relation to the gross calorific value, the carnauba's straw and stalk "in natura" obtained 17.51 MJ/kg and 17.29 MJ/kg. For the energetic density, briquettes' production provided an increase of 328.9% (2.98 to 12.78 kJ/cm3) for the straw and 292% (2.89 to 11.33 kJ/cm3) for the stalk. The mechanical resistance test for the carnauba's straw briquette showed 0.1 MPa and the carnauba's stalk briquette showed 0.3 MPa. According to the results, it can be inferred that the carnauba's straw and stalk have the potential for use as biofuels.

The heterogeneous photocatalysis combined with the use of nanostructured materials has proven to be a viable and highly efficient technology in the degradation of numerous organic compounds. This chapter present the fundamental aspects of nanometric semiconductors related to photodegradation and their treatment conditions for effluents contaminated. The role of the predominant species involved in each process has been studied using radical scavengers. In photocatalytic studies, clay minerals have recently been used as supports for the anchoring of semiconductors, developing photocatalysts with appropriate crystalline structure, which are more ecologically compatible and also have a high surface area. Additionally, the operational devices and influence on the degradation effectiveness such as dyes, pesticides and drugs were discussed for environmental treatment.

Chitosan has become promising as a biomaterial because of its biocompatible, biodegradable nature and non-toxic. The biochemical and antioxidant properties of chitosan modified with acetylacetone and ethylenediamine (Cacen) or diethylenetriamine (Cacdien) associated with ceftazidime (F) were investigated. Chitosan was characterized using Elemental Analysis (CHN), Thermal Analysis (TG/DTG/DSC), X-Ray Diffractometry (XRD), and was investigated an in vitro hemolytic cytotoxicity test, Artemia saline larvae for toxicity and in vitro antioxidant activity by DPPH (2,2-diphenyl-1-picrylhydrazyl). The chemical modification was confirmed by CHN, XRD and TG. The Cacen, Cacdien, CacenF and CacdienF derivatives presented high percentages of nitrogen (7.6%, 7.9%, 14.1% and 19.2%, respectively), confirming the modification and drug adsorption. The average molecular weight of chitosan and its derivatives were 132 kDa, with very few variations after modification. This incorporation decreased in the crystallinity index of Cacen (7.1%) and Cacdien (4.3%), as well as the incorporation of the drug (CacenF 0.3% and CacdienF 3.4%). FTIR spectra showed bands at 1580–1654 cm−1 referring to carbonyl and imine group and bands at 3500–3300 and 1462–1264 cm−1 related to vibration and deformation the amine group. 13C NMR spectroscopy was observed new peaks in carbonyl and imine regions (170–200 ppm). The thermal stability of the derivatives without the drug improved according to TG/DTG/DSC analysis, however there were decreased in the derivatives with the drug. The biocompatibility of the derivatives was confirmed by the low hemolytic rate ( 3000 ppm), and significant index (1–34%) of antioxidant activity. The results demonstrated that chitosan and its derivatives are promising biomaterials.

Adsorption has been researched attempting to minimize the pollution caused by dyes, which represents a serious environmental problem as contamination of surface and ground water. Therefore, cellulose and its modified forms with amine and thiols groups constitute a class of versatile adsorbents for the removal of anionic dyes in aqueous solution. In this context, this work reports the preparation of cellulose modified by ethylene sulfide and ethylenediamine (Cel-ESEN), through the reaction of the cellulose modified by ethylene sulfide (CEL-ES) and ethylenediamine (EN). Materials were characterized by elemental analysis, which showed in the Cel-ESEN matrix 10.12 ± 0.10%, 5.52 ± 0.06% of sulfur and nitrogen, respectively. Nuclear magnetic resonance in the solid state of 13C (13C NMR) showed, for the Cel-ESEN matrix, a peak related to CH2 groups from the molecules incorporated in the cellulose biopolymer. Crystalline Index obtained by X-ray diffraction (XRD) was in the order pure Cellulose > Cel-Cl > Cel-ES > Cel-ESEN. The adsorbent matrix (Cel-ESEN) was used in the removal of the remazol yellow GR (RY) dye in aqueous medium. Data obtained experimentally from kinetic study had the best adjustment to the proposed pseudo-second-order model. The adsorption process occurs in monolayer, is endothermic and thermodynamically favorable. Adsorption capacity of the modified material became 118 times higher than the starting material. These results suggest that the obtained biopolymer can be used as an alternative material to remove RY in aqueous solution.

Palygorskite, a fibrous clay mineral, exhibits excellent adsorbent properties. This study was conducted to assess the potential activation of palygorskite and to obtain thermally activated samples to use as clarifying agents for soybean oil. Previously, the palygorskite samples were thermally activated at various temperatures in the range of 100–900 °C for 24 h. The natural and activated samples were characterized using the following techniques, XRD, XRF, FTIR, SEM, SSA, CEC and thermal analysis, to observe the structural and morphologic alterations after thermal treatment. These characterizations indicated that the primary changes to the palygorskite surface referred to losses of structural water: physically adsorbed, zeolitic and coordination water molecules. The sample was activated above 700 °C, which potentiated the clarification of the soybean oil by the removal of the carotenoid dye and other pigments, and exhibited higher performance compared with the natural palygorskite.

This study evaluated nutrient accumulation of yellow passion fruit seedlings produced in substrates containing proportions of decomposed buriti (Mauritia vinifera Mart.) stem (DBS) and the boron in this process. Four experiments were conducted in Federal University of Piaui in Brazil. The experimental design was completely randomized in factorial scheme 6 × 2 + 1, referring to the substrates [DBS (100%), soil and sand 1:1 (20%) + DBS (80%), soil and sand 1:1 (40%) + DBS (60%), soil and sand 1:1 (60%) + DBS (40%), soil and sand 1:1 (80%) + DBS (20%), commercial substrate (additional treatment without boron) and soil, sand and manure 1:1:2] with (0.5 mg B.dm−3) and without boron. The following variables were recorded: total nitrogen, total phosphorus, potassium, calcium and magnesium, boron, absorption efficiency index and chlorophyll. No influence concerning the substrate composition was noticed on nutritional status, but boron influenced on K and Mg of yellow passion fruit seedlings.

The presence of organic pollutants, which cannot be eliminated by conventional processes of primary and secondary treatment, can be problematic. Photocatalytic processes offer an efficient breakdown of organic pollutants into non-toxic compounds such as CO2 and H2O. This paper proposes the use of the titanium dioxide embedded in palygorskite as a photoactive material in the degradation of cationic dye, Coomassie Brilliant Blue. The system was irradiated using UV light for a maximum time of 120 minutes. The concentration of the dye used was 1.0x10-4 mol L-1 in 0.5 g L-1 of the photoactive material. The kinetics of the system was monitored by UV-Vis spectrophotometry. In 120 minutes of radiation, the process of photocatalysis reduced the initial concentration of the Coomassie Brilliant Blue dye in half.

Adsorption has been explored to minimize the pollution caused by dyes. This work relates the preparation of diethylenetriamine-modified cellulose (DetaCel) by reacting phthalic anhydride-modified cellulose (PhCel) with diethylenetriamine (Deta). Materials were characterized by Elemental Analysis and results showed a degree of incorporation of 5.55 ± 0.02 mmol of nitrogen per gram of modified material. The main bands observed for DetaCel by Fourier-Transform Infrared Spectroscospy (FTIR) were attributed to C N deformation (1330 cm−1) and N H stretching of amide (3400 cm−1), while Solid State Nuclear Magnetic Resonance of 13C (13C{1H}CP-MAS NMR) showed a signal at 164.6 ppm characteristic of amide group. Crystallinity index (CrI) obtained by X-Ray Diffraction (XRD) was 74.99 (Cel), 58.64 (PhCel) and 46.12% (DetaCel). Adsorbent matrices were employed to remove methyl orange (MO) and eosin (EY) dyes in aqueous medium. Data obtained experimentally from kinetic study had a better fit to the pseudo-first order, thus the adsorption process occurs in monolayer, with MO adsorption capacity by Cel and DetaCel of 2.19 and 65.45 mg g−1, respectively. For EY adsorption by Cel and DetaCel was 1.30 and 56.69 mg g−1, respectively. These results suggest that DetaCel can be used as an alternative potential for removal dyes in aqueous solution.

Microparticles (MPs) with controlled morphologies and sizes have been investigated by several researchers due to their importance in pharmaceutical, ceramic, cosmetic, and food industries to just name a few. In particular, the electrospray (ES) technique has been shown to be a viable alternative for the development of single particles with different dimensions, multiple layers, and varied morphologies. In order to adjust these properties, it is necessary to optimize different experimental parameters, such as polymer solvent, voltage, flow rate (FR), type of collectors, and distance between the collector and needle tip, which will all be highlighted in this review. Moreover, the influence and contributions of each of these parameters on the design and fabrication of polymeric MPs are described. In addition, the most common configurations of ES systems for this purpose are discussed, for instance, the main configuration of an ES system with monoaxial, coaxial, triaxial, and multi-capillary delivery. Finally, the main types of collectors employed, types of synthesized MPs and their applications specifically in the pharmaceutical and biomedical fields will be emphasized. To date, ES is a promising and versatile technology with numerous excellent applications in the pharmaceutical and biomaterials field and such MPs generated should be employed for the improved treatment of cancer, healing of bone, and other persistent medical problems.

The palygorskite is an aluminum-magnesium silicate that has a fibrous morphology. Their physico-chemical characteristics are the result of high surface area, porosity and thermal resistance which make it an attractive adsorbent. Its adsorption capacity can be increased through chemical reactions and/or heat treatments. The objective of this work is to verify the effects of acid activation on the palygorskite, treated with HCl at 90 oC at concentrations of 2, 4 and 6 mol L-1 in 2 and 4 hours, with clay/acid solution ratio 1 g 10 mL-1 and characterized by techniques: XRF, XRD and surface area. A significant increase in specific surface area was observed in the sample treated with HCl at the concentration 6 mol L-1. The changes were more pronounced at stricter concentrations of acidity, with decreasing intensity of reflection of the clay indicated in the XRD. These changes were confirmed in the XRF with the leaching of some oxides and with increasing concentration of SiO2.

The present study aimed to synthesize photocatalytic materials using palygorskite (PAL) clays and a layered double hydroxide (LDH) calcined as support for titanium dioxide (TiO2) as an alternative for dye decontamination in aqueous media. The material was synthesized from the co-precipitation of LDH-Mg-Al in PAL and the TiO2 was incorporated using a sol-gel method. The materials were calcined at 400 °C for 2 h for formation of anatase phase of TiO2. The samples were characterized using X-ray diffraction, Fourier Transform Infrared Spectroscopy, Thermogravimetric Analysis, Scanning Electron Microscopy and Diffuse Reflectance Spectroscopy, Specific surface area, and Photoluminescence, which proved the incorporation of TiO2 anatase in the materials, this being responsible for the photocatalytic properties. The photocatalytic activity was measured by monitoring the discoloration of the eosin yellow (EY) dye. The LDH material calcined with TiO2 (CLDHT-400) showed a discoloration rate of 99.08%. The materials made from PAL with TiO2 (PALT-400) and PAL-LDH with TiO2 (PAL-CLDH-T-400) presented discoloration rates of 75.36% and 73.19%, respectively. For all the materials, an efficient photocatalytic was proven even in the process of recycling the photocatalysts with loss of capacity of less than 7.0%, proving that the titanium dioxide remains stable in the structure of the clays. The possible photodegradation mechanism was propused based on the properties of CLDHT-400, scavenger study and the photoproducts.

A novel one-dimensional decorated nano-heterostructure, anatase nanoparticle-decorated titanate nanotubes (TiNT@AnNP), was synthesized from anatase-TiO2 precursor using a fast and economic one-pot microwave-assisted alkaline hydrothermal route. The effect os reaction parameters, such as reaction time and temperature has been investigated in order to identify the best synthesis conditions leading to an improved photocatalyst. It was observed that increasing both the reaction temperature and time lead to complete conversion of the TiO2 precursor to the nano-heterostructures whereas increasing only the reaction time leads to the formation of larger anatase nanoparticles over the surface of the titanate nanotubes. All the samples prepared varying time and temperature showed enhanced discoloration of an anionic dye, remazol blue (RB), under UV–visible light, whereas the samples obtained at 140 °C showed higher photocatalytic efficiency, the best results were obtained for the sample with 2 h of reaction time. In order to investigated the effect of active species on the dye discoloration, a basic scavenger study involving several inhibitors were performed in all samples. It was observed that the singlet oxygen (1O2) was dominant active species for the discoloration of RB. However, the addition of EDTA (scavenger of h+) increased the photocatalytic activity of RB, which may be due to the capture of holes that inhibit the electron-hole recombination, which, in turn facilitates generation of 1O2 the chief reactive oxygen species (ROS).

The present study aimed to investigate the degradation of poly(ethylene oxide) (PEO) in the presence of cationic dye crystal violet irradiated under visible light. The preparation of the samples was done in the form of films obtained by casting. Degradation tests were carried out by 120 hours at room temperature. The degradation kinetics of the dye and polymer were accompanied by UV-Vis spectrophotometry and viscosimetry technique. The UV-Vis Spectra showed 81.2% degradation of the dye. In addition, it was observed a broadening of the absorption band of the polymer and the reduction of its viscosity, which features degradation. In this way, it is possible to affirm that the crystal violet dye, at the studied concentration, contributed to the degradation process of PEO.

Made available in DSpace on 2018-11-26T16:18:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-03-03 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) FAPEPI (Foundation for Research Support of Piaui State) The identification of alternative substrates suitable for seedling production is very important, while boron nutrition is also relevant due to plant requirement and its difficult management. Thus, four experiments were carried out from October 2012 to April 2013 to evaluate the effect of substrates using decomposed buriti (Mauritia vinifera Mart.) stem (DBS) and boron fertilizing for seedling production of yellow passion fruit (Passiflora edulis Sims). The experimental design was completely randomized in factorial scheme 6x2+1, referring to the substrates [S1: DBS, S2: soil and sand 1:1 (20%) + DBS (80%), S3: soil and sand 1:1 (40%) + DBS (60%), S4: soil and sand 1:1 (60%) + DBS (40%), S5: soil and sand 1:1 (80%) + DBS (20%), S6: commercial substrate (additional treatment) and S7: soil, sand and manure 1:1:2] with and without boron. The seedling emergence, emergence rate, plant height, stem diameter, root length, root volume and dry mass of roots and shoots were recorded. The substrates S2 (without B fertilizing) and S4 (B fertilized with 0.5mg dm(-3)) produced seedlings with more than 3.0g of shoot dry mass and at least 30cm in height, and can be used for production of high-quality yellow passion fruit seedlings. Univ Fed Piaui, Dept Agron, Bom Jesus, Brazil Sao Paulo State Univ, Dept Soil & Fertilizers, Jaboticabal, Brazil Fed Univ Sao Francisco Valley, Dept Agron, Petrolina, Brazil Sao Paulo State Univ, Dept Soil & Fertilizers, Jaboticabal, Brazil CNPq: 133781/2010-0 FAPEPI (Foundation for Research Support of Piaui State): 20203.0816/2008

In the last decade, adsorption has been used to minimize the pollution caused by dyes, which represents a serious environmental problem. In this context, this work reports the preparation of phthalic anhydride-modified cellulose (PhCel), through the reaction of cellulose (Cel) with phthalic anhydride (Ph). The efficiency of the reaction was observed by elemental analysis, Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermogravimetry/derivative thermogravimetry (TG/DTG). The adsorbent matrix (Cel and PhCel) was used in the removal of crystal violet (CV) and methylene blue (MB) dyes in aqueous medium. In the kinetic study, the experimental data obtained had the best fit to the pseudo-first-order model. In general, the isotherms obtained at different temperatures had a best fit to the model proposed by Langmuir, and the CV and MB adsorption process in adsorbent matrixes can be favored strictly by hydrogen bonds and/or electrostatic interactions for Cel and electrostatic interactions for PhCel.

Bacterial cellulose (BC) is a nanofibrous biomaterial biosynthetized by a series of acetic bacteria with unique properties with application in many tissue engineering purposes. Calcium phosphates (CPs), mainly hydroxyapatite, are bioceramics that possess similar composition of host bones and are able to stimulate osteoconduction and osteointegration to living tissues. Bacterial cellulose-calcium phosphates composites have caught the attention of researchers by their excellent mechanical properties and biocompatibility, being considered an excellent proposal to development of new synthetic grafts to bone tissue engineering. The minireview presented here focuses on various fabrication methods used to prepare and novel applications of BC-CPs composites and their applications in BTE.Keywords

The degradation of imazapyr, an imidazolinone herbicide, in aqueous solution has been investigated with TiO2 slurry as photocatalyst at 30°C under UV radiation. The depletion of imazapyr concentration in an aqueous suspension followed 1st order kinetic behavior. The influence of pH and the charge densities of imazapyr geometries were calculated at the semi-empirical AM1 level, and the effect of temperature was investigated. The addition of electron acceptors such as potassium persulfate and hydrogen peroxide showed that the rate constant doubled at least. At higher persulfate concentrations the herbicide degradation was more efficient in direct photolysis than TiO2-photocatalysis. The degradation rate constant increased by 38% upon variation of the temperature between 20.0 and 50.0°C and displayed non-Arrhenius behavior.

The cellulose is the most abundant biopolymer in the world and presents a higher chemi‐ cal variability for presence of several hydroxyl groups. These hydroxyl groups allow sur‐ face modification of biomaterials, with insertion of several chemical groups which change cellulose characteristics. This natural biopolymer and its derivatives have been used a lot as adsorbent, from several contaminants of aqueous medium due to biocompatibility, chemical degradability, and variability. Therefore, this chapter has the objective to review the literature about several cellulose surfaces or cellulosic material (incorporation of car‐ boxymethyl, phosphorus, carboxyl, amines, and sulfur), presenting the main characteris‐ tics of reactions and showing its adsorption in application of aqueous medium (metals, dyes, and drugs), locating the main interactions between biomaterial/contaminant.

O mecanismo de degradação da solução de poliestirenossulfonato de sódio (PSS) fotossensibilizada por cloreto de 2-hidroxi-3-(3,4-dimetil-9-oxo-9H-tioxanton-2-iloxi)-N,N,N-trimetil-1-propano (QTX) foi investigado. Inicialmente, foi estudada a fotodegradação de QTX em solução aquosa. Os fotoprodutos gerados pela fotólise foram caracterizados em sulfonas e sulfóxidos, que foram identificados por CLAE-EM. A fotodegradação de QTX em solução aquosa foi também acompanhada pelos espectros de absorção UV-Vis, sugerindo a formação de sulfóxidos. As reações elementares de QTX em solução aquosa foram investigadas através da fotólise por pulso de laser. O valor das constantes de supressão do estado triplete de QTX na presença de sorbato de potássio e hidroquinona foram próximas ao valor de constante difusional. A combinação dos resultados obtidos pelas diferentes técnicas possibilitou a proposição do mecanismo para degradação da QTX. A fotodegradação de PSS em solução aquosa na presença e na ausência de QTX foi monitorada por cromatografia de exclusão de tamanho e viscosidade. A fotodegradação de PSS foi observada somente na presença de QTX. Nesta condição uma diminuição de Mw foi observada, que significa quebra de cadeia aleatória. A degradação PSS/QTX também foi investigada na presença do sorbato de potássio, um supressor de triplete. Neste caso, ocorreu um aumento na porcentagem de degradação. Estes resultados sugeriram que o mecanismo de degradação de PSS fotossensibilizada por QTX ocorre principalmente pela QTX excitada no singlete abstrair um hidrogênio do polímero e na presença de oxigênio leva a formação de radicais, que contribuem para o processo de degradação. The poly(styrenesulfonate) (PSS) photosensitised by 2-hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propanium chloride (QTX) solution degradation mechanism was investigated. Initially, the photodegradation of QTX in aqueous solution was studied. The photoproducts generated photolysis were characterized as being sulfones and sulfoxides, which were identified by HPLC-MS. The photodegradation of QTX in aqueous solution was also followed by UV-Vis absorption spectra, suggesting the formation of sulfoxides. The elementary reactions of QTX in aqueous solution were investigated by laser flash photolysis. The quenching rate constant values of the triplet state QTX in the presence of potassium sorbate and hydroquinone were close to the value of diffusion constant. It was possible to propose the mechanism of QTX degradation combining the results from the different techniques. The photodegradation PSS in aqueous solution in the presence and absence of QTX was monitored by size exclusion chromatography and viscosity. The photodegradation of PSS was observed only in the presence of QTX. In this condition a decrease of Mw was observed, which means the random chain scission. The PSS/QTX degradation was also investigated in the presence of potassium sorbate, a triplet quencher. In this case, an increase of degradation percentage occurred. These results suggested that the degradation mechanism of PSS degradation photosensitised by QTX occurs mainly by the singlet excited QTX abstracts a hydrogen from the polymer and in the presence of oxygen leads to radicals formation which contributed to the degradation process.

RESUMO: A longevidade das hastes florais é um dos principais aspectos observados na produção de flores para corte, constituindo-se um pré-requisito para a qualidade do produto e sucesso da comercialização. Nesse sentido, objetivou-se avaliar a conservação de inflorescências de helicônias com ou sem renovação da água de manutenção, previamente adubadas com doses crescentes de nitrogênio e potássio. Foram utilizadas inflorescências de helicônias da espécie Heliconia psittacorum x H. spathocircinata cv. Golden Torch cultivadas a céu aberto no Setor de Floricultura da UFPI, Bom Jesus (PI), sob doses crescentes de adubação com N e K. O delineamento foi em blocos casualizados em esquema fatorial 4 x 4 x 2, correspondendo a: i) doses de N (0, 120, 180 e 240 g de N cova1); ii) doses de K (0, 120, 180 e 240 g de K2O cova-1); e iii) renovação da água de manutenção (sem e com renovação) com três repetições e três hastes cada uma. Fora realizado a avaliação de absorção de água pelas hastes florais, perda de massa fresca das hastes florais, massa seca das hastes florais e longevidade pós-colheita. A dose de 180 g cova-1 tanto de N quanto K proporcionou a maior longevidade das hastes florais com manutenção da qualidade. A absorção de água pelas hastes florais e sua massa seca após a colheita foram influenciadas pela adubação prévia de N e K. A renovação da água de manutenção também influenciou positivamente na longevidade das hastes florais, sendo um manejo indicado para manter a qualidade pós-colheita. ABSTRACT: The post-harvest of floral stems is one of the main features observed in the production of flowers for cutting, becoming a prerequisite for product quality and successful marketing. In this sense, the objective was to evaluate the conservation of heliconias inflorescences with or without renewal of the water maintenance, previously fertilized with increasing doses of nitrogen and potassium. Inflorescences of Heliconia psittacorum x H. spathocircinata cultivar Golden Torch were used and grown in open conditions in the Floriculture area at UFPI, city of Bom Jesus, Piauí State under increasing doses of fertilization with N and K. The stems were harvested in the morning, standardized and placed in containers with 500 mL of water. The design was a randomized block in factorial 4 x 4 x 2, corresponding to: i) N doses (0, 120, 180, and 240 g N hole-1), ii) K doses (0, 120, 180, and 240 g K2O hole-1), and iii) renewing the water maintenance in vase (with and without renewal) with three replicates of three stems each. Some evaluations were observed during the Study, such as: the water uptake by the flower stems; loss of fresh weight of the flower stems, dry weight of the flower stems and post-harvest longevity. The dose of 180 g hole-1 both as N and K provided the longevity of the flower stems with quality maintenance. The absorption of water by the flower stems and its dry mass after harvesting are influenced by previous fertilizer N and K. The renewal of the water maintenance also positively influence the longevity of flower stems and its a management indicated to maintain quality post-harvest.

The cellulose matrix was characterized by FTIR, 13C NMR, XRD, TG, SEM and applied in the removal of the reactive red RB dye in an aqueous medium, with a capacity of adsorption at a pH of 2.0, and an adsorption equilibrium time which was reached at around 200 mins. The kinetic study for the system followed the Elovich model. The adsorption isotherms for the system at temperatures of 35°C, 45°C, and 55°C were adjusted to the Langmuir, Freundlich, Sips, and Redlich-Peterson non-linear models, with a capacity of adsorption for adsorbent of 5.97 mg g-1, 5.64 mg g-1, and 4.62 mg g-1, respectively. The adsorption occurred by electrostatic interactions and it was favorable and spontaneous, with the influence of temperature.

In this work, the Crystal Violet (CV) dye discoloration was investigated by direct photolysis and photoassisted peroxidation in a reactor open to the atmosphere under UV irradiation, having as source of radiation a lamp without bulb mercury vapor of 125W E27. The optimal range of photolysis of VC dye was 7,0 x 10 -6 mol.L -1 , featuring a percentage of discoloration around 12, 37 and 25% larger compared to the other concentrations, and the monitoring of the variation of the Absorbance x Time (min) through the curves confirmed that in fact this was the concentration that most discolored. The effect of H 2 O 2 on discoloration of the aqueous dye solution at 9,0 x 10 -6 mol.L -1 was analyzed, and it was concluded that the addition of this oxidant it benefited the photolysis process.

Crystalline cellulose chemically modified through a reaction with sodium trimetaphosphate (STMP) in an acidic or basic condition yielded Cel-P4 and Cel-P10. These phosphated solids were characterized by elemental analysis, X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) at the solid state for phosphorus nucleus and dispersive X-ray energy. The elemental results demonstrated that the phosphorylation reaction was more efficient in the basic medium, as supported by the amount of phosphorous content. The synthesized biomaterials decreased in crystallinity in comparison to the precursor cellulose, with an increase in roughness and present two distinct phosphorus environments in the formed structure. The phosphated cellulose in an alkaline condition was applied to sorb the drug ranitidine. This process was applied in varying pH, time, temperature and concentration. The best sorption kinetic model to fit the experimental data was the pseudo-second-order with a coefficient correlation of 0.8976, and the Langmuir isotherm model was the most adjusted to the variation in concentration. The efficient drug sorption has a low dependence on temperature, with maximum values of 85.0, 82.0 mg and 85.7 mg·g−1 for Cel-P10 at 298, 308 and 318 K, respectively. The best sorption occurred at pH = 6 with a saturation time of 210 min.

O objetivo deste trabalho foi avaliar o potencial de plantas de cobertura semeadas em diferentes sistemas de cultivo quanto à produção de fitomassa e acúmulo de nutrientes, no cerrado piauiense. O experimento foi instalado no ano agrícola 2010/2011, na Serra do Quilombo, município de Bom Jesus (Piauí). O arranjo utilizado foi em parcelas subdivididas, com os seguintes sistemas de manejo do solo: preparo convencional e plantio direto avaliados nas parcelas e, nas subparcelas, os sistemas de produção: S1 - Soja no verão em monocultura; S2 - Soja no verão e Penissetum glaucum na safrinha; S3 - P. glaucum pré-soja de verão e sobressemeadura de Urochloa ruziziensis na soja no estádio R5.5; S4 - Soja de verão e sobressemeadura de P. glaucum na soja no estádio R5.5; S5 - Milho verão + U. ruziziensis simultâneo. Utilizou-se o delineamento em blocos casualizados, com quatro repetições. Os sistemas com a sobressemeadura do P. glaucum e do U. ruziziensis na soja e o consórcio de milho + U. ruziziensis destacaram-se na produção de fitomassa seca, cobertura do solo e acúmulo de nutrientes durante a entressafra no cerrado piauiense. Os nutrientes com maior taxa de acúmulo pelas plantas de cobertura foram o nitrogênio e o potássio. The objective of this work was to evaluate the biomass production and nutrient accumulation in potential cover crops sown in different cropping systems in the Brazilian Cerrado of Piauí State. The experiment was conducted in the crop season 2010/2011 in the Serra do Quilombo, county of Bom Jesus, Piauí, Brazil. This study was arranged in split plot scheme, with soil management systems (conventional tillage and no-tillage) evaluated in plots and crop systems in subplots: S1- Soybean monoculture in the crop-season; S2 - Soybean in crop-season and Pennisetum glaucum for off-season; S3 - P. glaucum before soybean crop-season and Urochloa ruziziensis oversown on soybean in the phenological stage R5.5; S4 - Soybean crop-season and P. glaucum oversown on soybean in R5.5; S5 - Maize + U. ruziziensis simultaneously in crop-season. The experimental design was in randomized blocks, with four replications. The crop systems with oversown of P. glaucum and U. ruziziensis on soybean and the consortium maize + U. ruziziensis improved the biomass production, soil coverage and nutrient accumulation during the off-season in the Cerrado from Piauí State, Brazil. The nutrients with greater accumulation rate by cover crops were nitrogen and potassium.