Uso da glicerina oriunda da síntese do biodiesel em sistemas microemulsionados visando aplicação de herbicidas

The program PROBIODIESEL from the Ministry of Science and Technology has substantially increased glycerine, obtained as a sub-product of biodiesel production process, making it necessary to seek alternatives for the use of this co-product. On the other hand, herbicides although play a role of fundamental importance in the agricultural production system in force, have been under growing concern among the various segments of society because of their potential environmental risk. In this work, we used glycerin in microemulsion systems for application of herbicides, to improve efficiency and lower environmental pollution caused by the loss of those products to the environment. To obtain the systems of microemulsinados were used Unitol L90 NP and Renex 40 as surfactants, butanol as co-surfactant, coconut oil as oil phase and aqueous phase as we used solutions of glycerin + water. Through the determination of phase diagrams, the microemulsion region was found in the system E (L90 Unitol, coconut oil and glycerin + water 1:1). Three points were chosen to the aqueous phase rich in characterization and application in the solubilization of glyphosate and atrazine. Three experiments were performed in Horta, Department of Plant Sciences, Plant Science Sector, UFERSA, Mossoró-RN. The first experiment was conducted in randomized complete blocks with 20 treatments and four replications. The treatments consisted of five doses of the herbicide glyphosate (0.0, 0.45, 0.9, 1.35 and 1.8 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity of Brachiaria brizantha was measured at 7, 14, 28 and 60 DAA (days after application). At 60 DAA, we evaluated the biomass of plants. The second experiment was developed in randomized complete blocks with 20 treatments and four repetitions. The treatments consisted of five doses of the herbicide atrazine (0.0, 0.4, 0.8, 1.6 and 2.4 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity on Zea mays and Talinum paniculatum was evaluated at 2, 7, 20 DAA. The experiment III was developed in randomized complete blocks with 16 treatments and three repetitions. The treatments consisted of 16 combinations among the constituents of the microemulsion: Unitol L90 surfactant (0.0, 1.66, 5.0, 15 %) and glycerin (0.0, 4.44, 13.33 and 40.0 %). The phytotoxicity on Zea mays was evaluated at 1, 7 and 14 DAA. At 14 DAA, we evaluated the biomass of plants. The control plants using the microemulsions was lower than in the water due to the poisoning caused by the initial microemulsions in the leaves of the plants, a fact that hinders the absorption and translocation of the herbicide. There was no toxicity in Zea mays plants caused by the herbicide, however, were highly intoxicated by microemulsions. T. paniculatum was better controlled in spraying with the microemulsions, regardless of the dose of the herbicide. The glycerine did not cause plant damage. Higher poisoning the plants are caused by tensoactive Unitol L90 and higher rates occur with the use of higher concentrations of surfactant and glycerin, or microemulsion. The microemulsions used hampered the action of glyphosate in controlling B. brizantha and caused severe poisoning in corn, and these poisonings attributed mainly to the action of surfactant

Síntese e caracterização de tensoativos e estudo de equilíbrio de fase dos sistemas CnH2n+2/H2O/CnH2n+1COONa/But-OH

The growing utilization of surfactants in several different areas of industry has led to an increase on the studies involving solutions containing this type of molecules. Due to its amphiphilic nature, its molecule presents one polar part and one nonpolar end, which easily interacts with other molecules, being able to modify the media properties. When the concentration in which its monomers are saturated, the airliquid system interface is reached, causing a decrease in interfacial tension. The surfactants from pure fatty acids containing C8, C12 and C16 carbonic chains were synthesized in an alcoholic media using sodium hydroxide. They were characterized via thermal analysis (DTA and DTG) and via infrared spectroscopy, with the intention of observing their purity. Physical and chemical properties such as superficial tension, critical micelle concentration (c.m.c), surfactant excess on surface and Gibbs free energy of micellization were determined in order to understand the behaviour of these molecules with an aqueous media. Pseudo-ternary phase diagrams were obtained aiming to limit the Windsor equilibria conditions so it could be possible to understand how the surfactants carbonic chain size contributes to the microemulsion region. Solutions with known concentrations were prepared to study how the surfactants can influence the dynamic light scattering spectroscopy (DLS) and how the diffusion coefficient is influenced when the media concentration is altered. The results showed the variation on the chain size of the studied surfactant lipophilic part allows the conception of surfactants with similar interfacial properties, but dependent on the size of the lipophilic part of the surfactant. This variation causes the surfactant to have less tendency of microemulsionate oil in water. Another observed result is that the n-alcanes molecule size promoted a decrease on the microemulsion region on the obtained phase diagrams

Caracterização e aplicação de sistemas micelares e microemulsionados como inibidores de corrosão

Corrosion is an important phenomenon that frequently occurs in the oil industry, causing surface ablation, such as it happens on the internal surfaces of oil pipes. This work aims to obtain new systems to reduce this specific problem. The surfactants SDS, CTAB, and UNITOL L90 (in micellar and microemulsionated systems) were used as corrosion inhibitors. The systems were obtained using a C/S ratio of 2, butanol as cosorfactant, kerosene as oil phase and, as water phase, NaCl solutions of 0.5M with pH = 2, 4, and 7. Microemulsion regions were found both for direct and inverse micelles. SDS had the higher microemulsion region and the area was not dependent of pH. The study of micellization of these surfactans in the liquid-gas interface was carried out via the determination of CMC from surface tension measurements. Regarding microemulsionated systems, in the case of CTAB, CMC increased when pH was increased, being constant for SDS and UNITOL L90. Concerning micellar systems, increase in pH caused decrease and increase in CMC for SDC and CTAB, respectively. In the case of UNITOL L90, CMC was practically constant, but increased for pH = 4. The microemulsionated systems presented higher CMC values, except for UNITOL L90 L90. The negative values of free energy of micellization indicated that the process of adsorption was spontaneous. The results also indicated that, comparing microemulsionated to systems, adsorption was less spontaneous in the case of SDS and CTAB, while it did not change for UNITOL L90. SAXS experiments indicated that micelle geometry was spherical, existing also as halter and flat micelles, resuting in a better inght on the adsorption at the liquid-solid interface. Efficiency of corrosion inhibition as determined by electrochemical measurements, from corrosion currents calculated from Tafel extrapolation indicuting heat showed surfactants to be efficient even at low concentrations. Equilibrium isotherm data were fitted to the Freundlich model, indicating that surfactant adsorption occurs in the form of multilayers

Estudo da digestão de sedimento de curtume visando a extração do cromo por microemulsão

Leather tanneries generate effluents with high content of heavy metals, especially chromium, which is used in the mineral tanning process. Microemulsions have been studied in the extraction of heavy metals from aqueous solutions. Considering the problems related with the sediment resulting from the tanning process, due to its high content in chromium, in this work this sediment was characterized and microemulsion systems were applied for chromium removal. The extraction process consists in the removal of heavy metal ions present in an aqueous feeding solution (acid digestion solution) by a microemulsion system. First three different solid sludge digestion methods were evaluated, being chosen the method with higher digestion capacity. For this digestion method, seeking its optimization, was evaluated the influence of granule size, temperature and digestion time. Experimental results showed that the method proposed by USEPA (Method A) was the most efficient one, being obtained 95.77% of sample digestion. Regarding to the evaluated parameters, the best results were achieved at 95°C, 14 Mesh granule size, and 60 minutes digestion time. For chromium removal, three microemulsion extraction methods were evaluated: Method 1, in a Winsor II region, using as aqueous phase the acid digestion solution; Method 2, in a Winsor IV region, being obtained by the addition of the acid digestion solution to a microemulsion phase, whose aqueous phase is distilled water, until the formation of Winsor II system; and Method 3, in a Winsor III region, consisting in the formation of a Winsor III region using as aqueous phase the acid digestion solution, diluted in NaOH 0.01N. Seeking to optimize the extraction process only Method 1 (Systems I, II, and VIII) and Method 2 (System IX) were evaluated, being chosen points inside the interest regions (studied domains) to study the influence of contact time and pH in the extraction percentiles. The studied systems present the following compositions: System I: Surfactant Saponified coconut oil, Cosurfactant 1-Butanol, Oil phase Kerosene, Aqueous phase 2% NaCl solution; System II: Aqueous phase Acid digestion solution with pH adjusted using KOH (pH 3.5); System VIII: Aqueous phase - Acid digestion solution (pH 0.06); and System IX Aqueous phase Distilled water (pH 10.24), the other phases of Systems II, VIII and IX are similar to System I. Method 2 showed to be the more efficient one regarding chromium extraction percentile (up to 96.59% - pH 3.5). Considering that with Method 2 the microemulsion region only appears in the Winsor II region, it was studied Method 3 (System X) for the evaluation and characterization of a triphasic system, seeking to compare with a biphases system. System X is composed by: Surfactant Saponified coconut oil, Cosurfactant 1-Butanol, Oil phase Kerosene, Aqueous phase Acid digestion solution diluted with water and with its pH adjusted using 0.01N NaOH solution. The biphasic and triphasic microemulsion systems were analyzed regarding its viscosity, extraction efficiency and drop effective diameter. The experimental results showed that for viscosity studies the obtained values were low for all studied systems, the diameter of the drop is smaller in the Winsor II region, with 15.5 nm, reaching 46.0 nm in Winsor III region, being this difference attributed to variations in system compositions and micelle geometry. In chromium extraction, these points showed similar results, being achieved 99.76% for Winsor II system and 99.62% for Winsor III system. Winsor III system showed to be more efficient due to the obtaining of a icroemulsion with smaller volume, with the possibility to recover the oil phase in excess, and the use of a smaller proportion of surfactant and cosurfactant (C/S)

Remoção de frações de óleo leve e pesado de rocha calcária através de sistemas microemulsionados

In this research the removal of light and heavy oil from disintegrated limestone was investigated with use of microemulsions. These chemical systems were composed by surfactant, cosurfactant, oil phase and aqueous phase. In the studied systems, three points in the water -rich microemulsion region of the phase diagrams were used in oil removal experiments. These microemulsion systems were characterized to evaluate the influence of particle size, surface tension, density and viscosity in micellar stability and to understand how the physical properties can influence the oil recovery process. The limestone rock sample was characterized by thermogravimetry, BET area, scanning electron microscopy and X-ray fluorescence. After preparation, the rock was placed in contact with light and heavy oil solutions to allow oil adsorption. The removal tests were performed to evaluate the influence of contact time (1 minute, 30 minutes, 60 minutes and 120 minutes), the concentration of active matter (20, 30 and 40 %), different cosurfactants and different oil phases. For the heavy oil, the best result was on SME 1, with 20 % of active matter, 1 minute of contact time, with efficiency of 93,33 %. For the light oil, also the SME 1, with 20 % of active matter, 120 minutes of contact time, with 62,38 % of efficiency. From the obtained results, it was possible to conclude that microemulsions can be considered as efficient chemical systems for oil removal from limestone formations

Tratamento de borra de petróleo com sistemas microemulsionados

During the storage of oil, sludge is formed in the bottoms of tanks, due to decantation, since the sludge is composed of a large quantity of oil (heavy petroleum fractions), water and solids. The oil sludge is a complex viscous mixture which is considered as a hazardous waste. It is then necessary to develop methods and technologies that optimize the cleaning process, oil extraction and applications in industry. Therefore, this study aimed to determine the composition of the oil sludge, to obtain and characterize microemulsion systems (MES), and to study their applications in the treatment of sludge. In this context, the Soxhlet extraction of crude oil sludge and aged sludge was carried out, and allowing to quantify the oil (43.9 % and 84.7 % - 13 ºAPI), water (38.7 % and 9.15 %) and solid (17.3 % and 6.15 %) contents, respectively. The residues were characterized using the techniques of X-ray fluorescence (XRF), Xray diffraction (XRD) and transmission Infrared (FT-IR). The XRF technique determined the presence of iron and sulfur in higher proportions, confirming by XRD the presence of the following minerals: Pyrite (FeS2), Pyrrhotite (FeS) and Magnetite (Fe3O4). The FT-IR showed the presence of heavy oil fractions. In parallel, twelve MES were prepared, combining the following constituents: two nonionic surfactants (Unitol L90 and Renex 110 - S), three cosurfactants (butanol, sec-butanol and isoamyl alcohol - C), three aqueous phase (tap water - ADT, acidic solution 6 % HCl, and saline solution - 3.5 % NaCl - AP) and an oil phase (kerosene - OP). From the obtained systems, a common point was chosen belonging to the microemulsion region (25 % [C+S] 5 % OP and AP 70 %), which was characterized at room temperature (25°C) by viscosity (Haake Rheometer Mars), particle diameter (Zeta Plus) and thermal stability. Mixtures with this composition were applied to oil sludge solubilization under agitation at a ratio of 1:4, by varying time and temperature. The efficiencies of solubilization were obtained excluding the solids, which ranged between 73.5 % and 95 %. Thus, two particular systems were selected for use in storage tanks, with efficiencies of oil sludge solubilization over 90 %, which proved the effectiveness of the MES. The factorial design delimited within the domain showed how the MES constituents affect the solubilization of aged oil sludge, as predictive models. The MES A was chosen as the best system, which solubilized a high amount of aged crude oil sludge (~ 151.7 g / L per MES)

Uso da glicerina oriunda da síntese do biodiesel em sistemas microemulsionados visando aplicação de herbicidas

The program PROBIODIESEL from the Ministry of Science and Technology has substantially increased glycerine, obtained as a sub-product of biodiesel production process, making it necessary to seek alternatives for the use of this co-product. On the other hand, herbicides although play a role of fundamental importance in the agricultural production system in force, have been under growing concern among the various segments of society because of their potential environmental risk. In this work, we used glycerin in microemulsion systems for application of herbicides, to improve efficiency and lower environmental pollution caused by the loss of those products to the environment. To obtain the systems of microemulsinados were used Unitol L90 NP and Renex 40 as surfactants, butanol as co-surfactant, coconut oil as oil phase and aqueous phase as we used solutions of glycerin + water. Through the determination of phase diagrams, the microemulsion region was found in the system E (L90 Unitol, coconut oil and glycerin + water 1:1). Three points were chosen to the aqueous phase rich in characterization and application in the solubilization of glyphosate and atrazine. Three experiments were performed in Horta, Department of Plant Sciences, Plant Science Sector, UFERSA, Mossoró-RN. The first experiment was conducted in randomized complete blocks with 20 treatments and four replications. The treatments consisted of five doses of the herbicide glyphosate (0.0, 0.45, 0.9, 1.35 and 1.8 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity of Brachiaria brizantha was measured at 7, 14, 28 and 60 DAA (days after application). At 60 DAA, we evaluated the biomass of plants. The second experiment was developed in randomized complete blocks with 20 treatments and four repetitions. The treatments consisted of five doses of the herbicide atrazine (0.0, 0.4, 0.8, 1.6 and 2.4 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity on Zea mays and Talinum paniculatum was evaluated at 2, 7, 20 DAA. The experiment III was developed in randomized complete blocks with 16 treatments and three repetitions. The treatments consisted of 16 combinations among the constituents of the microemulsion: Unitol L90 surfactant (0.0, 1.66, 5.0, 15 %) and glycerin (0.0, 4.44, 13.33 and 40.0 %). The phytotoxicity on Zea mays was evaluated at 1, 7 and 14 DAA. At 14 DAA, we evaluated the biomass of plants. The control plants using the microemulsions was lower than in the water due to the poisoning caused by the initial microemulsions in the leaves of the plants, a fact that hinders the absorption and translocation of the herbicide. There was no toxicity in Zea mays plants caused by the herbicide, however, were highly intoxicated by microemulsions. T. paniculatum was better controlled in spraying with the microemulsions, regardless of the dose of the herbicide. The glycerine did not cause plant damage. Higher poisoning the plants are caused by tensoactive Unitol L90 and higher rates occur with the use of higher concentrations of surfactant and glycerin, or microemulsion. The microemulsions used hampered the action of glyphosate in controlling B. brizantha and caused severe poisoning in corn, and these poisonings attributed mainly to the action of surfactant