Danyelle Medeiros de Araújo

Decontamination of produced water containing petroleum hydrocarbons by electrochemical methods: a minireview

Produced water (PW) is the largest waste stream generated in oil and gas industries. The drilling and extraction operations that are aimed to maximize the production of oil may be counterbalanced by the huge production of contaminated water (called PW) with pollutants, such as heavy metals, dissolved/suspended solids, and organic compounds. PW is conventionally treated through different physical, chemical, and biological methods. In offshore platforms, because of space constraints, compact physical and chemical systems are used. However, major research efforts are being developed with innovative technologies for treating PW in order to comply with reuse and discharge limits. Among them, electrochemical technologies have been proposed as a promising alternative for the treatment of this kind of wastewaters. Then, this paper presents a minireview of efficient electrochemical technologies used until now for treating PW generated by petrochemical industry.

Understanding the behavior of caffeine on a boron-doped diamond surface: voltammetric, DFT, QTAIM and ELF studies

A cyclic and differential pulse voltammetry analysis by using a boron doped diamond (BDD) electrode to understand the behavior of caffeine on its surface as well as the correlation of experimental figures with theoretical calculations was carried out. Voltammetry results clearly reveal that a direct electron transfer is achieved as the main mechanistic behavior of caffeine on the BDD surface during its electrochemical oxidation. From the information provided by experimental measurements, a cluster of the BDD surface was computationally characterized to verify the interactions of caffeine with the electrode, obtaining thermodynamic parameters and geometric interactions by DFT, QTAIM and ELF calculations. According to the energetic analysis results obtained from DFT, the more and less stable geometries were thermodynamically determined, indicating that the topological data of the geometries of interactions were obtained using QTAIM and ELF to verify the influences that occurred during the interaction and relate it to interaction energy.

Scale-up on Electrokinetic Treatment of Polluted Soil with Petroleum: Effect of Operating Conditions

This study investigates the influence of the scale-up of electrokinetic remediation (EKR) approach in carbonaceus soils. The scale-up study was performed in an electrokinetic lab scale (2.55 dm 3 ) by using two graphite electrodes placed in the cathodic and anodic compartments. The solution used was to humidify the soil were Na2SO4 0.1 M and water. A soil polluted (1.5 Kg) with petroleum (ranging from 500 to 2500 ppm) was treated by applying different currents (ranging from 0.5 A to 0.2 A). The effects such as current, pH, conductivity, z-potential and solution were evaluated to understand the better conditions to remove the organic matter from polluted soil. An increase in scale directly influenced the amount of energy supplied to the soil being treated. As a result, electroosmotic and electromigration flows and electric heating are more intense than in previous study performed where a smaller-scale cell was used.

Improving the catalytic effect of peroxodisulfate and peroxodiphosphate electrochemically generated at diamond electrode by activation with light irradiation

Boron doped diamond (BDD) anode has been used to oxidatively remove Rhodamine B (RhB), as persistent organic pollutant, from synthetic wastewater by electrolysis, photoelectrolysis and chemical oxidation containing sulfate and phosphate as supporting electrolytes. RhB is effectively oxidized by electrolysis and by chemical oxidation with the oxidants separately produced by electrolyzing sulfate or phosphate solutions (peroxodisulfate and peroxodiphosphate, respectively). The results showed that light irradiation improved the electrolysis of RhB due to the activation of oxidants under irradiation at high current densities. Meanwhile, the efficiency of the chemical oxidation approach by ex situ electrochemical production of oxidants was not efficient to degrade RhB.