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1.
J Environ Manage ; 268: 110734, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32510454

RESUMO

Oily sludge is the main hazardous waste produced by the petroleum industry, and its harmless disposal and recycling have become urgent problems. In this study, the pyrolysis technique was used to prepare oily sludge biochar at different temperatures (400 °C, 500 °C, 600 °C, and 700 °C). The characteristics of the biochar, including weight reduction, elemental composition, and molecular structure, were comprehensively investigated. From the perspective of the electrochemical properties of biochar, the relationship between the structure of the biochar and the redox capacity was discussed, and the feasibility of biochar as a battery cathode material was explored. The results suggested that the improper pyrolysis temperature could reduce the content of the quinone structure which was related to the redox capacity, the biochar prepared at 600 °C should have the strongest electron transfer capability. Moreover, the highest degree of condensation and aromaticity of pyrolysis products could be obtained at a higher pyrolysis temperature (700 °C), which might result in the relatively high discharge-charge capacity and good cycle performance of biochar which was used as an electrode material of a battery. This study explored the feasibility of pyrolysis as a disposal route for oily sludge waste and provided a reference for the electrochemical application of biochar prepared from oil sludge waste.


Assuntos
Pirólise , Esgotos , Carvão Vegetal , Óleos
2.
Mar Pollut Bull ; 152: 110893, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32479280

RESUMO

The studies of the formation of oil-Suspended Particulate Matter (SPM) aggregates (OSAs) have advanced significantly in the scientific community, however there is a need to accelerate oil biodegradation that was dispersed by the formation of OSAs. The present research presents a pioneering character regarding the addition of nutrients as biostimulus for autochthonous hydrocarboclastic bacteria in the biodegradation of Total Petroleum Hydrocarbons (TPH) dispersed by the formation of OSAs. Water aliquots were taken over 60 days from eight bioreactors to perform ionic species analysis, pH, salinity and temperature monitoring, liquid/liquid extraction, serial dilution methodology and filter membrane. TPH quantification was performed on the gas chromatograph with a flame ionisation detector (GC-FID). The addition of nutrients contributed positively to the rate and extent of biodegradation of TPH in association with field-collected SPM. The best result found was with the lowest nutrient concentration (Bio 1) with an average of 98.65% of TPH reduction.


Assuntos
Poluição por Petróleo/análise , Petróleo , Biodegradação Ambiental , Hidrocarbonetos , Óleos
3.
J Environ Manage ; 269: 110741, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32560985

RESUMO

In this study, a mixture of waste plastics and papers were pyrolyzed under mild conditions in batch and tubular reactors. The decomposition reactions were enhanced by the use of synthetic zeolite-based catalysts to obtain a higher yield of volatiles and modifying the product composition. Especially the decomposition reactions and the product properties obtained from the different reactors were compared. Gases were analysed by GC-FID and GC-TCD. This fraction contains hydrogen, carbon-monoxide, carbon-dioxide and hydrocarbons. The pyrolysis oils have oxygen-containing compounds, such as alcohols, aldehyde, ketones, carboxylic acids or phenol and its derivative. Not only the reactor configurations but also the catalysts had an effect to the product properties, because the catalysts with alkali characters showed advanced behaviour in the reduction of oxygenated hydrocarbons, while high synthetic zeolite catalysts can increase the saturation and isomerization reactions. The long-term behaviour of the pyrolysis oils was followed by an accelerated aging test at 80 °C till 7 days. The catalysts can effectively reduce the rate of density and viscosity increase during the aging and the alkali catalysts showed beneficial properties in reducing the acidic components. In general, the aging properties were more favorable for pyrolysis oils obtained from the tubular reactor compared with the results in batch reactor.


Assuntos
Plásticos , Pirólise , Catálise , Temperatura Alta , Hidrocarbonetos , Óleos
4.
Waste Manag ; 113: 62-69, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32505976

RESUMO

In this paper, the waste fried oil was used to remove the unburned carbon in coal fly ash during flotation process, and found that the waste fried oil could be a novel collector for the removal of carbon from coal fly ash. The results implied that the wetting rate of the fly ash after treated by waste fried oil was decreased, meanwhile the contact angle was increased. A significant decrease in wetting heat was observed, which indicated a weaker interaction between deionized water and fly ash after treatment with waste fried oil. Flotation tests showed that the content of unburned carbon could be reduced effectively through froth flotation when took waste fried oil as collector. FTIR analysis testified that waste fried oil had abundant oxygen-containing groups that could be adsorbed in a carbonaceous matter to achieve hydrophobization. X-ray photoelectron spectroscopy, scanning electron microscope, and energy dispersive analyses showed that the main compositions of flotation concentrate products were unburned carbon, whereas the tailing products consist of aluminum and silicon, which confirmed the superior separation performance when the waste fried oil was used as a collector in coal fly ash flotation. This investigation provides an approach to remove the unburned carbon in coal fly ash based on the principle of "waste control through waste", which can solve the environmental problems brought by large amounts of both coal fly ash and waste fried oils.


Assuntos
Cinza de Carvão , Carvão Mineral , Carbono , Óleos , Material Particulado , Água
5.
J Environ Manage ; 267: 110647, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32421677

RESUMO

Commercial kitchen wastewaters are typically strong organic and fat-rich effluents, often identified as major contributors to fatberg formation and associated blockages in sewers. Experimental trials were done using synthetic kitchen wastewater to understand the complex reactions involved in microbial remediation in grease traps/separators prior discharge in sewers. The principle organic components (FOG, carbohydrate and protein nitrogen), were varied using ranges observed in a previous study on real kitchen wastewater characterisation. A model bacterium, Bacillus licheniformis NCIMB 9375, was used to evaluate microbial utilisation of the different organic fractions in relation to fat, oil and grease (FOG) degradation. Novel results in the treatment of these effluents showed that, the presence and concentration of alternative carbon sources and the ratio of carbon to nitrogen (COD:N) had great influence on FOG-degradation response. For example, FOG removal decreased from 24 to 10 mg/l/h when glucose was substitute for starch at equivalent concentrations (500 mg/l); and from 26 to 5 mg/l/h when initial COD:N increased from 45:1 to 147:1. The dominant influence of COD:N was validated using a commercial bioadditive and real kitchen wastewater adjusted to different COD:N ratios, confirming the strong influence of kitchen wastewater composition on bioremediation outcomes. These results can therefore have major implications for biological management of FOG in kitchens and sewers as they provide a scientific explanation for bioremediation success or failure.


Assuntos
Óleos , Águas Residuárias , Biodegradação Ambiental , Hidrocarbonetos
6.
Sci Total Environ ; 730: 138643, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32402958

RESUMO

The petrochemical industry and urban activities are widely recognized worldwide as a source of pollution to mangrove environments. They can supply pollutants such as trace elements that can modify the ecosystem structure and associated services, as well as human populations. Through geochemical data, multivariate statistical analysis and pollution indices such as the enrichment factor (EF), geo-accumulation index (Igeo), adverse effect index (AEI) and the pollution load index (PLI), we evaluated the factors that control trace element distribution, punctual sources and determined the pollution level of sediments and their potential biological impact in the mangrove ecosystem of Isla del Carmen, Mexico. The factor and cluster analysis highlighted that the distribution of trace elements is influenced by the mineralogy, texture as well as urban derived sources. The pollution indices showed values in the punctual sources from the urban area of EF > 10, Igeo > 3, AEI > 3, PLI > 1 by Cu, Zn and Pb. Finally, the results revealed that mangroves from Isla del Carmen has a major influence from urban activities and natural sources rather than oil industry and also indicate a degraded environment as a result of anthropogenic activities that could have knock-on effect for human health if polluted marine organisms derived from the urban mangroves are consumed. CAPSULE ABSTRACT: Surface sediments show the influence of point sources on selected trace element concentrations correlated with human activities within the mangroves of Isla del Carmen, Mexico.


Assuntos
Ecossistema , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Metais Pesados , México , Óleos , Medição de Risco , Oligoelementos , Poluentes Químicos da Água
7.
Chemosphere ; 256: 126996, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32438125

RESUMO

A new method was developed to remove gaseous and particulate pollutants by capturing them in water using microbubbles. The capture efficiency of gaseous toluene and ultrafine carbon particles, which are hydrophobic substances, was remarkably improved compared to water-only conditions by adding a small amount of oily substances (4% volume fraction of water) to the water surface. The physicochemical properties of four types of oily substances were investigated. Rapeseed and mineral oil exhibited good capture efficiency during a capture experiment of high-concentration gaseous toluene for 96 h. Additionally, a long-term continuous capture experiment for 24 days revealed that the capture mechanisms of rapeseed and mineral oil were different. The toluene concentration in rapeseed oil reached saturation in the middle of the experiment while the capture efficiency of mineral oil remained constant. It was also shown that the emulsion formation greatly affected the capture of rapeseed oil. Thus, it is expected that a new gaseous pollutant treatment technology that can capture and remove gaseous/particulate pollutants regardless of their hydrophilic/hydrophobic properties could be developed in the future.


Assuntos
Poluentes Ambientais/química , Microbolhas , Modelos Químicos , Poeira , Gases , Interações Hidrofóbicas e Hidrofílicas , Óleos , Material Particulado/análise , Tolueno/química
8.
Int J Nanomedicine ; 15: 2071-2083, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32273703

RESUMO

Background and Purpose: Adjuvant can reduce vaccine dosage and acquire better immune protection to the body, which helps to deal with the frequent outbreaks of influenza. Nanoemulsion adjuvants have been proved efficient, but the relationship between their key properties and the controlled release which greatly affects immune response is still unclear. The present work explores the role of factors such as particle size, the polydispersity index (PDI), stability and the safety of nanoemulsions by optimizing the water concentration, oil phase and modes of carrying, to explain the impact of those key factors above on adjuvant effect. Methods: Isopropyl myristate (IPM), white oil, soybean oil, and grape-kernel oil were chosen as the oil phase to explore their roles in emulsion characteristics and the adjuvant effect. ICR mice were immunized with an emulsion-inactivated H3N2 split influenza vaccine mixture, to compare the nanoemulsion's adjuvant with traditional aluminium hydroxide or complete Freund's adjuvant. Results: Particle size of all the nanoemulsion formed in our experiment ranged from 20 nm to 200 nm and did not change much when diluted with water, while the PDI decreased obviously, indicating that the particles tended to become more dispersive. Formulas with 80% or 85.6% water concentration showed significant higher HAI titer than aluminium hydroxide or complete Freund's adjuvant, and adsorption rather than capsule mode showed higher antigen delivery efficiency. As mentioned about oil phase, G (IPM), F (white oil), H (soybean oil), and I (grape-kernel oil) showed a decreasing trend in their adjuvant efficiency, and nanoemulsion G was the best adjuvant with smaller and uniform particle size. Conclusion: Emulsions with a smaller, uniform particle size had a better adjuvant effect, and the adsorption mode was generally more efficient than the capsule mode. The potential adjuvant order of the different oils was as follows: IPM > white oil > soybean oil > grape-kernel oil.


Assuntos
Adjuvantes Imunológicos/química , Sistemas de Liberação de Medicamentos/métodos , Emulsões/química , Vacinas contra Influenza/administração & dosagem , Nanoestruturas/química , Adjuvantes Imunológicos/administração & dosagem , Adjuvantes Imunológicos/farmacologia , Animais , Emulsões/administração & dosagem , Emulsões/farmacologia , Feminino , Vírus da Influenza A Subtipo H3N2 , Vacinas contra Influenza/imunologia , Camundongos Endogâmicos ICR , Óleos/química , Infecções por Orthomyxoviridae/prevenção & controle , Tamanho da Partícula , Óleo de Soja/química , Vacinas de Produtos Inativados , Água/química
9.
Mar Pollut Bull ; 154: 111051, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32319893

RESUMO

Laboratory experiments investigated oxygen dynamics in buried oiled sands sampled from areas impacted by the Macondo spill. Measured oxygen fluxes in oil deposits that were permeable to tidal water ranged from 10-3 to 10-4 µmol/cm2-sec, orders of magnitude higher than fluxes in non-permeable deposits (10-6 to 10-7 µmol/cm2-sec). Oxygen dynamics were well described by 1-d models that represent increased oxygen consumption in oiled sands. Experiments demonstrated that when oxygen is present and the oil deposit is permeable to tidal water, biodegradation of alkylated phenanthrenes and dibenzothiophenes proceeded over time scales (i.e., weeks) to have a significant impact on the mass and quality of buried oil. For this biodegradation process to proceed, two independent conditions must be met, a source of oxygenated water has to be present (e.g., tidal flushing in the intertidal zone) and the oiled deposit has to be permeable to water (i.e., pores cannot be completely saturated with oil).


Assuntos
Biodegradação Ambiental , Poluição por Petróleo , Petróleo , Fenantrenos , Poluentes Químicos da Água , Óleos
10.
J Environ Manage ; 261: 109911, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32148250

RESUMO

The leaking of harmful organic liquids into water resources has had hazardous impacts on living organisms. Herein, we demonstrated the fabrication of hybrid sorbents using s-PPG and organosilane cross-linker. The final product exhibited high, quick absorption capacity, great reusability and excellent oil separation performance from wastewater. They also selectively absorb different oils from the bottom and surface of water without any capacity change, even in harsh conditions like wavy and sub-zero water environment. Experimental results demonstrated that the obtained sorbents are efficient to successfully remove oil from water surface, even at harsh conditions, and float on the water surface before and after oil sorption without any capacity loss and structural change. Simple preparation by avoiding time consuming multistep process, initiator, solvent, activator free reaction medium, high and selective sorption characteristics and great reusability could make these sorbents a promising candidate for the cleaning of water from harmful organic liquids, by absorbing them.


Assuntos
Poluição por Petróleo , Poluentes Químicos da Água , Purificação da Água , Adsorção , Óleos , Águas Residuárias
11.
Chemosphere ; 251: 126348, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32146185

RESUMO

Due to the variety of oily wastewater and complexity of separation system, it has put forward new challenge and requirement to separation materials for on-demand separation of various oil/water mixtures. Here, we reported a facile waste-to-resource strategy to rationally fabricate hierarchical ZnO nanopillars coating onto the surface of waste brick grains (ZnO/WBG) via simple physical process and in-situ growth technique. Specifically, the directly as-prepared ZnO/WBG possess superhydrophilic/underwater superoleophobic (UWSOB) properties and modified ZnO/WBG by organosilicon reagent possess quasi superhydrophobic/superoleophilic (SHOBI) properties. It is also worth noting that this discrete ZnO/WBG with opposite wettability can be accumulated into ZnO/WBG layer with numerous tortuous channel structure, making it feasible for on-demand separating various oil/water mixtures whether immiscible light- and heavy-oil/water mixtures or oil-in-water and water-in-oil emulsions. It has been demonstrated that the filter layers with opposite wettability exhibit high separation efficiency and flux, excellent chemical stability and admirable recyclability. Thus, this novel and cost-effective ZnO/WBG layer holds great promise for large-scale and versatile oil/water separation. Additionally, this work presents a sustainable perspective of effectively utilizing waste brick to construct workable functionalized materials with tremendous application potential, showing far-reaching value and significance in fundamental research and environmental protection.


Assuntos
Purificação da Água/métodos , Emulsões , Interações Hidrofóbicas e Hidrofílicas , Óleos/química , Águas Residuárias , Água/química , Molhabilidade
12.
Waste Manag ; 106: 21-31, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32179418

RESUMO

The elution of metallic content from cotton stalk (CS) and its co-pyrolysis with waste tires (WT) was investigated in fixed bed reactor. Hydrochloric acid (HCl) was used for leaching and successful removal of metals from cotton stalk was observed. Removal efficiencies of 86%, 58%, 48%, 58% and 35% for potassium, calcium, magnesium, sodium, and iron metals were achieved, respectively. Pyrolysis and co-pyrolysis using various mixing ratios of raw (R-CS) and acid washed cotton stalk (W-CS) with waste tire were carried out at 550 °C. Co-pyrolyzing W-CS with WT not only resulted in increased liquid yield with reduced char and gas yields, but also improved the quality of pyrolytic oil evincing the occurrence of strong positive synergistic effect. The addition of WT reduced oxygenates, density and water content of oil whilst pH and calorific value are increased compared to both, R-CS and W-CS pyrolytic oils. Relative percentage area of hydrocarbons increased to 65% in co-pyrolysis of WT with W-CS as compared to 47% for that of R-CS at optimum blend ratio (CS:WT 1:3). Likewise, 19% higher reduction in oxygenated compounds was observed in W-CS and WT co-pyrolytic oil. Co-pyrolyzing WT with R-CS and W-CS resulted in improved quality of oil. However, the synergistic effect was less significant for R-CS suggesting that the presence of intrinsic metals in R-CS hampered the occurrence of synergistic effects.


Assuntos
Biocombustíveis , Pirólise , Biomassa , Temperatura Alta , Hidrocarbonetos , Óleos
13.
Food Chem ; 320: 126653, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32217430

RESUMO

Curcumin is claimed to have many health benefits, but it has low chemical stability. In this study, the influence of food-grade antioxidants on the chemical degradation of curcumin-enriched oil-in-water emulsions was examined. The curcumin degradation rate and extent depended on antioxidant type. The water-soluble antioxidants were more effective at protecting curcumin from degradation than the oil-soluble ones, which may have been because curcumin degrades faster in water than in oil. Interestingly, the amphiphilic antioxidant was almost as effective as the water-soluble ones. The oil-soluble antioxidant actually slightly promoted curcumin degradation. In summary, curcumin retention after storage declined in the following order: 82.6% (Trolox) ~82.2% (ascorbic acid) >79.5% (ascorbyl palmitate) ≫57.9% (control) >52.7% (α-tocopherol). The effectiveness of ascorbic acid in stabilizing curcumin increased as its concentration was raised (0-300 µM). Our results may facilitate the creation of curcumin-enriched foods and beverages with enhanced bioactivity.


Assuntos
Antioxidantes/química , Curcumina/química , Emulsões/química , Ácido Ascórbico/análogos & derivados , Ácido Ascórbico/química , Cromanos/química , Óleos/química , Solubilidade , Água/química , alfa-Tocoferol/química
14.
J Chromatogr A ; 1620: 460989, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32151414

RESUMO

A GC-MS based analytical method was developed for the profiling of oil-based AAS products using 15 organic constituents as target compounds. A total of 219 compounds were identified in 109 seized AAS products, among them 15 target compounds were selected. The selection was based on each compound's occurrence, reproducibility, and variance between products. The 15 target compounds did not include the active steroid itself, but only compounds found in the carrier oil. The subsequent method validation included assessment of specificity, linearity, precision, robustness and sample stability. The method was finally applied for the classification of a set of 27 seizures of AAS products supplied by the police. The classification was based on the Pearson correlation coefficient using pre-treated peak area data from the 15 target compounds. A successful classification was obtained, with only a small overlap between linked and unlinked samples. A 1% false-positive rate could be obtained at a threshold of 0.625 in terms of the Pearson distance. The present study thus demonstrates that it is possible to profile and classify AAS products with regard to a common origin. As the profiling method is not specific with regards to the steroid content, it may potentially be used to profile and compare other kinds of oil-based liquids.


Assuntos
Anabolizantes/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Óleos/química , Esteroides/análise , Anabolizantes/química , Humanos , Reprodutibilidade dos Testes , Esteroides/química
15.
Waste Manag ; 105: 18-26, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32014796

RESUMO

The co-feeding of scrap tires pyrolysis oil (STPO) on the catalytic cracking of vacuum gasoil (VGO) has been investigated with the aim of exploring the capacity of the refinery fluid catalytic cracking (FCC) unit to upgrade discarded tires at large-scale. The runs have been carried out in a CREC (Chemical Reactor Engineering Centre) riser simulator reactor that mimics the behavior of the industrial unit at the following conditions: 500-560 °C; catalyst/oil ratio, 3-7 gcat goil-1; contact time, 6 s. Obtained results with the blend of 20 wt% STPO in VGO have been compared with those obtained in the cracking of the pure streams, i.e., STPO and VGO, to get a proper idea of the synergetic effects that could be involved in the co-feeding. This way, when the STPO is co-fed with the VGO the production of naphtha (C5-C12) and light cycle oil (C13-C20) lumps are maximized, as the over-cracking reactions that convert them into gaseous products (C1-C4) are mitigated. Consequently, the co-feeding promotes the production of high-interest hydrocarbons for refineries. Additionally, the naphtha obtained in the cracking of the blend shows a lower content of paraffins and naphthenes than that obtained with the VGO, and higher of olefins and aromatics.


Assuntos
Pirólise , Rios , Catálise , Óleos , Vácuo
16.
Water Res ; 174: 115600, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32088385

RESUMO

A hierarchically assembled superomniphobic membrane with three levels of reentrant structure was designed and fabricated to enable effective treatment of low surface tension, hypersaline oily wastewaters using direct contact membrane distillation (DCMD). The overall structure is a combination of macro corrugations obtained by surface imprinting, with the micro spherulites morphology achieved through the applied phase inversion method and nano patterns obtained by fluorinated Silica nanoparticles (SiNPs) coating. This resulted in a superomniphobic membrane surface with remarkable anti-wetting properties repelling both high surface tension water and low surface tension oils. Measurements of contact angle (CA) with DI water, an anionic surfactant, oil, and ethanol demonstrated a robust wetting resistance against low surface tension liquids showing both superhydrophobicity and superoleophobicity. CA values of 160.8 ± 2.3° and 154.3 ± 1.9° for water and oil were obtained, respectively. Calculations revealed a high liquid-vapor interface for the fabricated membrane with more than 89% of the water droplet contact area being with air pockets entrapped between adjacent SiNPs and only 11% come into contact with the solid membrane surface. Moreover, the high liquid-vapor interface imparts the membrane with high liquid repellency, self-cleaning and slippery effects, characterized by a minimum droplet-membrane interaction and complete water droplet bouncing on the surface within only 18 ms. When tested in DCMD with synthetic hypersaline oily wastewaters, the fabricated superomniphobic membrane demonstrated stable, non-wetting MD operation over 24 h, even at high concentrations of low surface tension 1.0 mM Sodium dodecyl sulfate and 400 ppm oil, potentially offering a sustainable option for treatment of low surface tension oily industrial wastewater.


Assuntos
Destilação , Purificação da Água , Membranas Artificiais , Óleos , Tensão Superficial , Águas Residuárias
17.
J Environ Manage ; 261: 110112, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32001431

RESUMO

The current energy demand and diminishing conventional fuels have forced researchers to find an alternative source of energy. Waste to energy is the current trend for converting waste materials (plastic waste) into valuable fuels. This article mainly discussed the detailed characterization of the pyrolytic products, their comparative analysis and the reaction mechanism at varying operating temperature. This article is a successor of part 1, which primarily focused on the characterization of different waste plastics, their TG analysis, the effect of reactor temperature on yield analysis in a batch reactor and their detailed degradation mechanism. Furthermore, the results presented in this article report the characterization of products at three processing temperatures of 450, 500 and 550 °C. The pyrolytic oils from all wastes excluding PS show a very low density ranging from 0.71 to 0.76 kg/m3, whereas PS pyrolytic density is reported between 0.86 and 0.88 kg/m3. The viscosity of oils increases with an increase in the processing temperature and is similar to the conventional fuels. The FTIR analysis of the products (oil & gases) obtained from HDPE, PP and mixed plastic waste (MIX) shows a large presence of alkanes and a higher presence of aromatics. PS analysis reported a large presence of aromatics (~75%). The GC-MS analysis of all pyrolytic oils from waste plastics, simulated wastes (virgin plastics) and distilled fraction of MIX pyrolysis oil is compared. The GC analysis of non-condensable gases at all processing temperature reports that MIX produce the maximum H2; HDPE, PS and MIX produces a high amounts of CH4 too. The formation of lower hydrocarbons (C5-C12) in pyrolysis oil shows a trend as MIX > PP > PS > HDPE, while for the heavier hydrocarbons (>C19) it is HDPE > PP > PS > MIX. The potential of the utilization of these products has been discussed in different sectors for future research.


Assuntos
Plásticos , Resíduos , Hidrocarbonetos , Óleos , Temperatura
18.
Sci Total Environ ; 715: 136944, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32014773

RESUMO

Produced water is the largest waste stream associated with oil and gas operations. This complex fluid contains petroleum hydrocarbons, heavy metals, salts, naturally occurring radioactive materials and any remaining chemical additives. In the United States, west of the 98th meridian, the federal National Pollutant Discharge Elimination System (NPDES) exemption allows release of produced water for agricultural beneficial reuse. The goal of this study was to quantify mutagenicity of a produced water NPDES release and discharge stream. We used four mutation assays in budding yeast cells that provide rate estimates for copy number variation (CNV) duplications and deletions, as well as forward and reversion point mutations. Higher mutation rates were observed at the discharge and decreased with distance downstream, which correlated with the concentrations of known carcinogens detected in the stream (e.g., benzene, radium), described in a companion study. Mutation rate increases were most prominent for CNV duplications and were higher than mutations observed in mixtures of known toxic compounds. Additionally, the samples were evaluated for acute toxicity in Daphnia magna and developmental toxicity in zebrafish. Acute toxicity was minimal, and no developmental toxicity was observed. This study illustrates that chemical analysis alone (McLaughlin et al., 2020) is insufficient for characterizing the risk of produced water NPDES releases and that a thorough evaluation of chronic toxicity is necessary to fully assess produced water for beneficial reuse.


Assuntos
Água/química , Animais , Variações do Número de Cópias de DNA , Daphnia , Gases , Mutagênicos , Óleos , Estados Unidos , Poluentes Químicos da Água
19.
Environ Sci Pollut Res Int ; 27(13): 15488-15497, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32077028

RESUMO

Although it is still a great challenge, developing oil-/water-separating membranes that combine the advantages of high separation efficiency, salty environments tolerance, and fouling resistance are highly demanded for marine oil spill cleanups and oil-/gas-produced water treatment. Here, we report a new type of all-inorganic nanostructured membrane, which is composed of titanate nanofibers and SiO2 particulate gel for efficient and stable oil/saltwater separation. The nanoporous and interconnected network structure constructed with titanate nanofibers is the key to ensure the high separation efficiency and high water flux of the new membrane. The SiO2 gel is used as a binder to offer mechanical flexibility and integrity for this type of all-inorganic membrane. The new membrane displays a high oil/water separation efficiency of above 99.5% with oil content in treated effluent lower than US environmental discharge standards (42 ppm) and high water permeation flux of 1600 LMH/bar under low operation pressure. The new membrane also demonstrates outstanding durability in the environment of different salinities, and it has a good resistance for oil fouling due to its excellent underwater superoleophobicity with an oil contact angle above 150 °. Most importantly, the underwater superoleophobic properties can be well maintained after being repeatedly reused. The excellent environmental durability, oil-fouling resistance, high separation efficiency, and facile fabrication process for this new type of membrane render great potential for industrial application in treating produced water.


Assuntos
Nanocompostos , Purificação da Água , Interações Hidrofóbicas e Hidrofílicas , Óleos , Dióxido de Silício
20.
Food Chem ; 312: 126041, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31901829

RESUMO

Effect of fried food, oil type, moisture, fatty acid and molecular distribution on the effectiveness of rapid test of Total Polar Compounds (TPC) in frying oil based on dielectric constant was explored. Effects of all factors were compared and found to be significant (P < 0.05). Throughout the life cycle of frying oil, its rapid results were correlated well with those of conventional chromatography (Y = 0.7625X + 3.681, R2 = 0.8734). But the discrepancy was found within selected TPC ranges of 0%-10% and 20%-30%. According to the definition of TPC, three potential reasons for the high TPC values of fresh oils were discussed. For the deteriorated oils, the triglyceride dimers, mono-unsaturated and di-unsaturated fatty acids were found to be the main compositional factors by stepwise multivariate regression analysis. Pieces of advice about the operation guideline, internal control indices, calibration, reference oil, sensor, and detection range were proposed for instrument users and producers.


Assuntos
Óleos/química , Culinária , Ácidos Graxos/análise , Alimentos , Restaurantes , Fatores de Tempo , Triglicerídeos/análise
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