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Polystyrene is commercial polymer of extensive use in industrial scale due to great physical and chemical properties and low cost. Lifespan of polymer materials can be changed by incorporation of additions to polymeric matrix.The present study aimed to evaluate the influence of crystal violet dye in polystyrene matrices when irradiated by visible radiation. The samples were studied in the form of films, in which solution of crystal violet (5.0x10-4mol.L-1) was added to the PS solution (8% w / w). The films were irradiated with commercial lamp for 150 hours and analyzed with UV-Vis and FTIR. The results showed that the dye degraded at a rate of 16%, however the FTIR analysis revealed that polystyrene did not degrade under the conditions studied, since no formation of carbonyl compounds was observed.

The immobilization of catalyzers is an alternative to aid the process of photocatalysis. The clays are compounds of high porosity and abundant in nature, therefore, this work aimed at carrying out a prospective study of the use of palygorskite as catalytic support for TiO2on the degradation of the bentazone herbicide. The bibliographic search on the database (Scopus, Web of Science and SciELO) and patent base (EPO, USPTO and INPI). The results showed that the published articles address the synthesis with excellent results on the degradation of different pollutants. With regard to the patents, it could be observed that some palygorskite-based materials have already been patented. The results show that palygorskite is an excellent alternative for obtaining materials with photocatalystic activity.

The resistance of some compounds to conventional treatments engenders the search for alternative methods, such as photo-oxidation. Antibiotics and photo-producers are found in the environment, indicating that these compounds are persistent. This work had as its goal to investigate the photo-oxidation of the antibiotic named tetracycline hydrochloride adsorbed in montmorilloniteclay (VHS) and into aqueous suspension. In order to irradiate the interaction products 0,03g were weighed and put in a petri dish to be collected on pre-determined times. The extraction of the drug was made by adding 10 mL of distilled water and put on the ultrasound for 2 hours. The suspensions were prepared by using 200 mL of the concentration from 25mgL-1of tetracycline in 1gL-1g of clay in a borosilicate reactor. This system was stirred in the dark during 1 hour in order to achieve its balance. The samples were radiated by using an Ultra-Vitalux UV lamp, with 300 W for 2 hours. The kinetics were followed through UV-Vis spectroscopy, monitored in 359 nm, in the maximum wavelength of the drug. The suspensions showed a degradation twice as fast when compared to the interaction product, for the rate of degradation of this system was 24%. This decrease on the concentration may have been caused by the hydroxyl radicals generated by the photolysis of the iron hydroxide II. Hence, one concludes that in the case of the system in suspension it was more effective to the photo-oxidation of this antibiotic. Although, there is the need for increasing the exposure time of the interaction product in order to verify possible structural changes of this system by DRX.

There are reports that the production of panels with various mixtures is quite feasible. However, the knownlogment of production of panels with other residues is litle, except wood. The objective of this work was to evaluate the effect of water absorption on panels produced with elephant grass (Pennisetum purpureumSchum.) andEucalyptussp. leaves, Consolidated with urea-formaldehyde adhesive. For the production of the panels, the elephant grass (CA) was used, without particle size reduction, andEucalyptussp. (EU), freshly collected and crushed as powder. Two panels were produced, one consisting of 100% elephant grass (CA) and another in the proportion (1: 1, from CA: EU), with urea-formaldehyde adhesive. From each panel, 4 specimens were removed and the water absorption test was carried out for 2 hours, in addition to the determination of the apparent density. Panel test specimens (CA) showed, on average, an initial apparent density of 0.5953 g.cm-3and final (water absorption) of 0.5465 g.cm-3, while those of CA + EU showed an apparent density of 0.5478 g.cm-3and 0.6881 g.cm-3. The panels (CA) and (CA + EU) produced showed good consolidation after pressing, but It was verified that there are possibilities of improvement in order to minimize water absorption and improve the stability of this product.

Soil-cement bricks are sustainable and economically viable alternatives due to the possibility of residue utilization. CNSL (Cashew nut shell liquid ) is an example of residue from the cashew industry that can be reused in many applications. Therefore, the present work had as its objective to produce soil-cement bricks having CNSL as a constituent of the formulation. The samples were obtained from the mixture of pure CNSL, soil and cement (1:10). The soils used in the research were extracted from the south of the state and the mixture was pressed in a modular manual press. The samples were submitted to resistance and permeability tests and the results related to resistance and compression showed that the bricks presented an average of 2,3 MPa and were in accordance with what is suggested by NBR 8491/12. The presence of CNSL also altered the permeability of the material which was obtained. Hence, one may conclude that the presence of CNSL satisfactorily influences upon the properties of soil-cement bricks.

The use of salts on the degradation of toxic substances may cause the acceleration or delay of radicals production originating from the degradation process. This work had as its objective to investigate the presence and absence of potassium sulphate salt on the photocatalysis of Bentazone using TiO2 as a catalyzer. The effect of the sulphate ion on the photodegradation of the Bentazone herbicide was studied using concentrations of 0,05; 0,10 and 0,20 g L-1 with 0,5 g L-1 of TiO2, in suspension of 180 mL from bentazone solution (3,0x10-5 mol L-1). The samples were analyzed through UV-Vis spectroscopy. The presence of sulphate ions presented a difference of 3,3% on the degradation of bentazone in comparison to TiO2 alone.

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.

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.