ELECTROCHEMICAL TREATMENT OF OILFIELD PRODUCED WATER

Oil production generates wastewater bearing oily hydrocarbons, referred to “produced water” (PW). PW from a heavy-oil field has been treated with stainless steel (SS) cathode and dimensionally stable anodes – passivated titanium and graphite. In the electrolytic cells with these electrodes, electrooxidation (EO) accompanied by electroflotation (EF) are the main processes leading to pollutants removal. An oxidation by in situ generated oxidizing agents is found as the most plausible mechanism for decomposition of oily hydrocarbons in the PW containing high concentration of chloride ions. Total oily hydrocarbons (TOH) content and chemical oxygen demand (COD) as integral parameters and gas chromatography / mass spectrometry as analytical method were used to evaluate the efficiency of the treatment. At the optimal conditions, 15 mA/cm2 and 15 min, 92.5 % removal of TOH and 25 % removal of COD have been achieved through energy consumption 2.218 kWh per kg removed TOH by the EO. Additionally, the treatment of PW in a cell having SS cathode and iron as sacrificial anode has been performed, where electrocoagulation (EC) supplemented by electroflotation cause decrease of organic contaminants concentration. At the optimum conditions, current density 10 mA/cm2 applied for 10 min (energy consumption 0.603 kWh/kg) or current density 8 mA/cm2 applied for 15 min (energy consumption 0.629 kWh/kg) the TOH removal of 95.4 % and 96.4 % respectively have been determined. EC/EF has been found to be more effective than the EO/EF for treating the PW polluted by high-molecular alkanes. The EC/EF is an environmentally friendly and efficient method

Comparative Study of Physicochemical and Antibacterial Properties of ZnO Nanoparticles Prepared by Laser Ablation of Zn Target in Water and Air

Here, we report on ZnO nanoparticles (NPs) generated by nanosecond pulsed laser (Nd:YAG, 1064 nm) through ablation of metallic Zn target in water and air and their comparative analysis as potential nanomaterials for biomedical applications. The prepared nanomaterials were carefully characterized in terms of their structure, composition, morphology and defects. It was found that in addition to the main wurtzite ZnO phase, which is conventionally prepared and reported by others, the sample laser generated in air also contained some amount of monoclinic zinc hydroxynitrate. Both nanomaterials were then used to modify model wound dressings based on biodegradable poly l-lactic acid. The as-prepared model dressings were tested as biomedical materials with bactericidal properties towards S. aureus and E. coli strains. The advantages of the NPs prepared in air over their counterparts generated in water found in this work are discussed

VEGFC acts as a double-edged sword in renal cell carcinoma aggressiveness

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