Petroleum reserves available worldwide are geologically based mainly on sedimentary and carbonate rocks, and the reservoir performance depends on the intrinsic properties of each rock and their response to changes in wettability. Recently, the change in wettability with low-salinity brine has been used to improve the oil recovery, which is an environmentally friendly and low investment, but there is no unanimity about the mechanisms of oil recovery process. Therefore, the aim of this study is to investigate the process involved in the wettability associated with interactions between the surface of powdered reservoir rock samples and the surrounding fluids. The reservoir rock surface (sandstone, calcite and dolomite) was evaluated under three different conditions. The total amount of adsorbed oil on aged samples was twice as high in carbonate rocks as in sandstone. The thermal gravimetric analysis (TGA) for the desorption steps of the organic fraction on dolomite and calcite indicates that the treatment under high brine concentration favored the oil desorption and the opposite result was observed for sandstone. This behavior suggests that carbonate rocks adsorb more strongly the organic phase compared to sandstone. Recently lowsalinity salinity investment Therefore fluids sandstone, sandstone (sandstone conditions TGA (TGA

Tetracyclines comprise a large group of broad-spectrum antibiotics used in human and veterinary medicine. Its mechanism of action, via oral ingestion, is to inhibit bacterial protein synthesis, but a large amount (70%) is eliminated without being metabolized, which presents a risk for the arising of antibiotic-resistant species. In this study, the degradation of Tetracycline TC by non-thermal plasma NTP and the antimicrobial sensitivity of the treated solution are investigated. The degradation was followed by chromatographic analysis while the efficiency of NTP in inhibiting the action of TC on bacteria was evaluated by antimicrobial sensitivity test by disk diffusion method. The results showed a high rate of TC degradation, over 90%, in 10 min of NTP treatment for a 60 mL (107 mg L-1) sample and very slow increase up to 94% in 30 min. The antimicrobial sensitivity test of TC after degradation by NTP showed no antibiotic activity. Therefore, our findings are encouraging, since the removal efficiency is below the minimum threshold require, to prevent with high probability, outgrowth of antibiotic-resistant bacteria. In addition, the results confirm that the NTP treated solution is safe to the environment.

Processes such as ablation, erosion and corrosion generally create roughness patterns on solid surfaces. Despite the randomness of this phenomenon, some patterns can be described mathematically by studying statistically the mechanisms behind them. This paper reports an experimental study on the temporal evolution of the roughness development of polymer surfaces exposed to argon non-thermal plasma under reduced pressure of 5 mbar and 65 W of applied power. The substrates studied were polypropylene, high density polyethylene, polyamide-6 and poly(ether ether)ketone. The mean roughness data as well as the saturation roughness values showed differences between polyolefin and polymers containing heteroatoms and notably the dependence of the etching on the packing density of the polymer chains. The plasma-etched surfaces were described statistically as self-affine surfaces using scaling law analysis, exhibiting roughness exponents of α ca.0.73 ± 0.2 and growth exponents of β ca. 1.0 ± 0.1. The roughness increases and decreases successively during treatment although presenting a general linear behavior in a non-monotonous way, as a function of time. The models for the shadowing and redistribution of active species can be complemented with the transient crosslinking model of the observed flattening stages.

The present work focused on the mineralization of herbicide glyphosate (N-(phosphonomethyl) glycine) (C3H8NO5P) in aqueous phase by Glidarc plasma following the orthophosphates released and the reduction of the total organic carbon (TOC). Furthermore, the effect of initial concentration, pH and the degradation process of glyphosate in the presence of Fe2+ were also examined. The results showed that the efficiency of degradation increased with the presence of ferrous ions as catalysts in aqueous medium and also the release of orthophosphate is more efficient in acid medium with pH range of 3.5-6.3. The kinetics of the release of orthophosphate and the TOC removal obey the first order rate law. The ninhydrin and orthophosphates tests showed that the degradation of glyphosate in water by Glidarc plasma was mainly by OH and NO attacked with C–N and C–P bond cleavage leading to complete mineralization.

A reforma de fontes de carbono por plasma térmico de argônio de elevada capacidade calorífica é um dos métodos mais promissores na síntese de novos materiais. Um método para a obtenção de negro de carbono e nanotubos de carbono através da pirólise do metano por plasma térmico de corrente contínua é relatado no presente trabalho. A reforma foi realizada na ausência de oxigênio utilizando um jato de plasma gerado por uma tocha de plasma de argônio. O produto sólido foi caracterizado por espectroscopia Raman e microscopia eletrônica de varredura e transmissão. Os resultados mostraram que nanotubos de carbono foram produzidos na presença de catalisadores metálicos, enquanto que a formação de negro de carbono ocorreu na ausência de catalisadores no reator. A relação I D/I G obtida a partir dos espectros Raman indicou que a amostra obtida usando o catalisador 5%Ni/Al2O3 apresentou nanotubos de carbono com maior pureza em relação aos outros catalisadores (10%Ni/Al2O3 e 10%Ni-5%Ce/Al2O3) testados.

Thermal plasma processing of carbon sources using a plasma jet with high heat capacity is one of the most promising methods for the synthesis of new materials. A method for obtaining carbon black (CB) and carbon nanotubes (CNT) through the pyrolysis of methane using a thermal plasma direct current (DC) system is reported herein. The cracking operation is performed in the absence of oxygen using an external power source, i.e., a plasma jet generated by an argon plasma torch. The obtained carbonaceous materials were characterized by Raman spectroscopy, scanning, and transmission electron microscopy. The results showed that CNT are produced in the presence of a catalyst while CB formation occurs without a catalyst. The Raman I D/I G ratio indicated that the sample obtained using a 5%Ni/Al2O3 catalyst contains a higher quantity of pure CNT than the other catalysts tested (10%Ni/Al2O3 and 10%Ni-5%Ce/Al2O3).

Este estudo investigou o efeito da temperatura da solução sobre a descoloração do azul de metileno em um reator de plasma de descarga elétrica do tipo ponta-plano. Os resultados mostraram um aumento da porcentagem inicial de descoloração do corante com o aumento da temperatura da solução de 4 para 28 ºC, mas de 28 para 37 ºC não houve alteração. Entretanto, quando a temperatura foi elevada para 47 ºC a porcentagem de descoloração inicial do corante diminuiu. A formação de peróxido de hidrogênio em água durante o tratamento por plasma diminuiu com o aumento da temperatura de 4 para 47 ºC. A reação de descoloração ocorreu por um complexo mecanismo onde processos de zero e primeira ordem ocorreram numa mesma temperatura, seguindo ordem zero no início do processo e primeira ordem com o progresso da reação. A energia de ativação envolvida no processo de primeira ordem foi de 13,09 kJ mol-1.

This study investigates the effect of bath solution temperature on methylene blue decolorization in a point-to-plate electrical discharge plasma reactor. The results show an increase in the initial percentage of dye decolorization with an increase in the bath solution temperature from 4 to 28 ºC, but from 28 to 37 ºC there was no change. However, when the temperature was raised to 47 ºC the initial dye decolorization percentage decreased. The hydrogen peroxide (H2O2) formation in water during the plasma treatment decreased as the bath temperature increased from 4 to 47 ºC. The dye decolorization reaction occurred via a complex mechanism where zero- and first-order processes took place at the same temperature, following zero-order in the initial step and first-order with the progress of the reaction. The activation energy involved in the first-order process was 13.09 kJ mol-1.

O presente trabalho consiste no desenvolvimento de uma tocha de plasma de corrente contínua com eletrodos de grafite e sistema de nebulização integrada para a eliminação de resíduos líquidos organoclorados (tetracloreto de carbono) em pequena escala. Os gases resultantes da pirólise do tetracloreto de carbono pelo plasma foram coletados e identificados por cromatografia gasosa acoplada ao espectrômetro de massa (GC-MS) e monitorados por cromatografia gasosa com detecção por ionização de chama (GC-FID). Observou-se que a tecnologia do plasma térmico elimina tetracloreto de carbono, caracterizando-se por baixo custo, simplicidade operacional e dimensões reduzidas, apresentando-se como uma alternativa ambientalmente correta, pois reduz a emissão total de gases organoclorados.

This work describes the development of a continuous flow plasma torch with graphite electrodes and an integrated nebulization system for the elimination of organochlorine liquid waste (carbon tetrachloride) on a small scale. The gases resulting from the pyrolysis of the carbon tetrachloride by the plasma were collected and identified by gas chromatography, coupled with mass spectrometry (GC-MS). Monitoring was carried out by gas chromotography with flame ionization detection (GC-FID). It was observed that the thermal plasma technique eliminated the carbon tetrachloride completely, being characterized by low cost, operational simplicity and reduced dimensions. This technique presents a suitable environmentally correct alternative, since it reduces the total emission of organochlorine gases.