Effect of temperature on methylene blue decolorization in aqueous medium in electrical discharge plasma reactor

Abstract

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 o C, mas de 28 para 37 o C não houve alteração. Entretanto, quando a temperatura foi elevada para 47 o C 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 o C. 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 o C. 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 .

Isolation, screening and molecular identification of novel bacterial strain removing methylene blue from water solutions

“…Where the temperature required to the maximum rate of color removal tends to correspond with the optimum bacterial growth tempera- ture of 30°C (60.3%). This result is in concordant with Benetoli et al (2011). While Liu et al (2014) suggested that the maximum dye removal is achieved at 40°C.…”

“…On the other hand, much higher temperatures also weaken the decolorization, which may be due to inactivation of intracellular enzymes assisting in the active transport of the bacteria, reducing the bacterial activity. Appropriately, raising the temperature could enhance the bacterial adsorption activity, thereby improving the decolorization efficiency (Benetoli et al 2011). Bacterial culture generally exhibits maximum decolorization at pH 5 (59.6%) whereas the rate of color removal tends to decrease rapidly at highly acidic or alkaline pH.…”

Microwave Plasma Jet in Water: Characterization and Feasibility to Wastewater Treatment

“…In fact, the induced chemistry in such a medium is very wide, and many other species that can contribute to MB degradation can be produced. For instance, water temperature increases significantly (to ~70 °C), and it has been observed, by Benetoli et al [37], that dye decolorization increased with an increase in solution temperature. Also, other oxidizing species, such as peroxonitrous acid (ONOOH), can be produced in our conditions (e.g., H + + NO2‾ + H2O2 → ONOOH + H2O) and can contribute to MB degradation [38].…”

Degradation of bromophenol blue molecule during argon plasma jet irradiation

“…One of the most interesting topics, in recent years, has been studying degradation of different materials in aqueous solution such as degradation of methyl orange [18], methyl violet [19], phenol [20], methanol [21], diuron [22], 1-naphthylamine [23], pharmaceutical compound pentoxifylline [24], organophosphate pesticides [25], antibiotics [26], textile dyes [27], etc. In such studies, scientists are interested in investigating the effects of various parameters such as pH [28] and temperature [29] on the plasma-treatment process. The degradation process of some materials such as bromophenol blue during plasma irradiation has not been investigated; some studies concerned the degradation of bromophenol blue without using plasma irradiation [30][31][32][33].…”