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Made available in DSpace on 2021-06-25T10:52:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) A molecularly imprinted polymer (MIP) sensor was successfully constructed on glassy carbon electrode for the determination of 1-naphthol (1-Nph). The sensor was constructed by electropolymerization on bare GCE in the presence of the target molecule. The recognition of 1-Nph was conducted indirectly using [Fe(CN)6]3−/4− as redox probe. The MIP sensor presented wide linear working range and limit of detection of 1.5×10−9 mol L−1. The MIP sensor was applied for the determination of 1-Nph in oilfield produced water. The results obtained showed good selectivity and sensitivity of the proposed sensor in terms of 1-Nph quantification. National Institute of Alternative Technologies for Detection Toxicological Evaluation and Removal of Micropollutants and Radioactive Substances (INCT-DATREM) São Paulo State University (UNESP), 55 Prof. Francisco Degni St. Analytical Chemistry Department Institute of Chemistry São Paulo State University (UNESP), 55 Prof. Francisco Degni St. National Institute of Alternative Technologies for Detection Toxicological Evaluation and Removal of Micropollutants and Radioactive Substances (INCT-DATREM) São Paulo State University (UNESP), 55 Prof. Francisco Degni St. Analytical Chemistry Department Institute of Chemistry São Paulo State University (UNESP), 55 Prof. Francisco Degni St. CNPq: 143222/2017-1

In general, the oil industry has been searching for ways to alleviate the abundant disposal of oilfield produced water, which contains dissolved hard-removal and highly toxic organic compounds. Advanced oxidative processes (AOPs) have revealed to be effective in the degradation of organic compounds, because they generate hydroxyl radicals with high oxidizing potential which are capable of degrading these compounds. The present study has demonstrated the degradation efficiency of effluents containing organic compounds although the photo-Fenton process using a tubular photochemical reactor under different energy sources. This reactor allowed the use and evaluation of two ultraviolet irradiation sources, the sun and black light lamps, besides other relevant variables to the process, such as reagents concentration and the irradiated area, using a model effluent containing phenol. A sample of oilfield produced water was photochemically degraded through the optimum experimental conditions found for the phenol degradation. Solar irradiation was more efficient than lamplight, and it corresponds an important factor for the reduction of operating costs of this process. The solar reaction system applied to the oilfield produced water showed a removal of organic components up to 76%

International audience; This experimental paper deals with the development of a hybrid biological reactor for the treatment of a synthetic oilfield produced water under an increase in total dissolved solids (TDS) concentration. To comply with strengthening regulations concerning produced water discharge and peculiar produced water compositions, a moving bed biofilm reactor (MBBR) consisting in a combination of free activated sludge and moving biofilm supports was compared to a fixed bed hybrid biological reactor (FBHBR) consisting in a combination of free activated sludge and a fixed biofilm support. After a 216 days experimental period, the MBBR and the FBHBR were efficient to treat a synthetic produced water with chemical oxygen demand (COD) removal rate above 90% under an increase in TDS concentrations from 1.5 to 8 g·L−1. Ecotoxicity measurements on freshwater and marine microorganisms revealed an absence of toxicity on treated waters. A decrease in bacterial diversity indices with respect to the inoculum was observed in both bioreactors. This suggests that the increase in TDS concentrations caused the predominance of a low number of bacterial species.

Despite a declining trend, California remains a significant oil-producing state. For every barrel of crude oil, an average of 15 barrels of oilfield produced water (OPW) is generated, some of which is used to boost freshwater sources for crop irrigation in the agriculturally important Central Valley. OPW is known to contain salts, metals, hydrocarbons, alkylphenols, naturally radioactive materials, biocides, and other compounds from drilling and production processes. Less is known about the potential uptake and accumulation of these compounds in crops and soil irrigated with OPW. In this study, 23 potted mandarin orange plants were irrigated two to three times weekly (depending on season) with water containing three different concentrations of the known OPW heavy metals barium, chromium, lead, and silver. Seven sets of samples of soil and leaves and 11 fruits were collected and processed using microwave-assisted digestion (EPA Method 3051A). Processed samples were analyzed using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Analysis of variance (ANOVA) and covariance (ANCOVA) coupled with Tukey’s honest significant difference test were used to examine the effects of metal concentrations in the irrigation water and number of watering days, respectively, on the metal concentrations in the soil, leaf, and fruit samples. Accumulation of barium in soil and leaves was strongly positively associated with sample and number of watering days, increasing nearly 2000-fold. Lead also showed an upward trend, increasing up to 560-fold over the baseline level. Total chromium showed an increase in the soil that tapered off, but less consistent results in the leaves and fruit. The silver results were more volatile, but also indicated at least some level of accumulation in the tested media. The smallest absolute accumulation was observed for chromium. Concentrations in the fruit were highest in the peel, followed by pith and juice. Accumulation of all heavy metals was generally highest in the soil and plants that received the highest irrigation water concentration. Considering the potential for adverse human health effects associated with ingesting soluble barium contained in food and drinking water, and to a lesser extent chromium and lead, the study signals that it is important to conduct further research into the accessibility and bioavailability of the tested heavy metals in the soil and whether they pose risks to consumers.

Produced water (PW) is the largest waste stream in the oil production process: it contains light polar and aliphatic hydrocarbons, production process compounds, dissolved gases, anions and cations. Disposal of PW is subjected to strict legislations. Oil producing countries are focused on finding effective and economic methods for its treatment. Some physical and chemical methods have been used for treatment of PW and biological treatments have been proven to efficiently remove dissolved hydrocarbon compounds. Coupling of anaerobic biological treatment with electrochemical technology in microbial fuel cells (MFCs) can in principle lead to the production of clean water and electric energy. The suitability of MFCs for improving the treatment of PW was investigated in the present work. For the first time, the simple design of single chamber MFCs fed with real PW (PW-MFCs) was studied, in different configurations: (i) with and without membrane; (ii) with and without Pt cathodic catalyst. The results demonstrate the effectiveness of the membraneless configuration without chemical catalyst at the cathode. Even though the electrical output of PW-MFCs was very low (3 mW m −2 ), it is currently the best reported performance. Furthermore, almost complete hydrocarbon degradation was achieved for each fed-cycle (96.6 ± 1.94%). The Coulombic efficiency was limited by the difficulty to obtain strict anaerobic condition at the anode, since the biocathode of PW-MFCs remained more permeable to oxygen than in acetate-fed MFCs. The DNA sequencing of operating anodic biofilm detected electroactive Desulfobulbaceae mixed to aerobic biodegraders ( Burkholderiales ) likely through cycling sulfur compounds, which enriched from the PW initial pool in the hypersaline environment. Above all, the results pointed to the practical possibility of using a MFC to enhance and monitor the PW biodegradation process. In fact, the MFC electrical output indicated the occurrence of anaerobic degradation, while the electrochemical parameters of cathode (Tafel slope) resulted correlated to aerobic degradation, suggesting the possibility to design an on-line sensor of the biotechnological industrial treatments of PW.