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1.
J Environ Manage ; 344: 118680, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37531671

RESUMO

Plastic wastes have become one of the biggest global environmental issues and thus recycling such massive quantities is targeted. Thermal pyrolysis has been the most suitable approach to convert the waste plastic into a source of energy. This study aims to compare the thermal pyrolysis of waste plastic with that of the modal plastic compounds in a fixed bed reactor. The liquid oil, obtained from the thermal pyrolysis of HDPE, LDPE, PP and PS wastes were characterized using FT-IR, GC-MS and 1H NMR. Also, their fuel properties such as viscosity and calorific values were characterized using parallel plate rheometer and bomb calorimeter respectively. C10-C44 paraffins and C10-C22 olefins were obtained along with aromatics and alcohols in different type of plastic waste pyrolysis oil. The viscosity of the plastic oil is within kerosene and diesel range. The calorific values of the oils are at par with the Petro fuels.


Assuntos
Plásticos , Pirólise , Plásticos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Óleos/química , Alcenos
2.
J Environ Manage ; 302(Pt B): 114046, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34775338

RESUMO

This paper reviews the new progress, challenges and barriers on production of pyrolysis oil from the plastic waste. Among the different processes thermal and catalytic are the potential methods to produce oil. Since the global plastic production increased over years the accumulation of plastic waste increases. Thus, converting the waste plastics into useful energy is very essential to avoid the environmental concerns. Initially the thermal pyrolysis process and its advantage on production of pyrolysis oil were discussed. During the thermal decomposition the waste plastic had been converted into the products such as gas, crude oil and solid residues. Secondly, the catalytic process and its recent trends were discussed. In addition, the factors affecting the catalytic pyrolysis process had been evaluated. Furthermore, the optimized concentration of catalyst subjected to the higher yield of fuel with low hydrocarbon content was found. The pyrolysis oil produced from the catalytic process has higher heating values, lower density and lower viscosity compared to thermal process. In addition, the application of pyrolysis oil on the diesel engines had been discussed. The effects of pyrolysis oil on combustion and emission characteristics were observed. This review summarizes the potential advantages and barriers of both thermal and catalytic process. Further, the optimized solutions and applications of pyrolysis oil are suggested for sustainability of the process. Besides the introduction of the pyrolysis oil were viable without making major modification to the existing engine design.


Assuntos
Plásticos , Pirólise , Catálise , Hidrocarbonetos
3.
Chemosphere ; 350: 141045, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38154671

RESUMO

Supercritical water (SCW) treatment of plastics is a clean technology in the 'waste-to-energy' path. In this work, PP and PET plastics were processed by sub-/supercritical water. The results showed that temperature was the most important factor of the PP and PET degradation. The influence of factors on the degradation of plastics follows the following order: temperature > residence time > plastic/water ratio. These factors influenced the yield of gas products by promoting or inhibiting various reactions (such as reverse water gas shift reaction, methylation reaction, and Fischer-Tropsch synthesis reaction). Besides, the composition of liquid oil was also analyzed. The main composition of the liquid oil produced by PET was benzoic acid and acetaldehyde, which were generated from the decarboxylation of terephthalic acid (TPA) and dehydration reaction of ethylene glycol (EG). The liquid oil from PP was mainly long-chain olefins, long-chain alkanes, cycloalkanes, etc., which were formed by the interaction of various methyl, alkyl, hydroxyl, and other free radicals. This study could build fundamental theories of plastic mixture treatment.


Assuntos
Polietilenotereftalatos , Polipropilenos , Plásticos , Temperatura , Polietileno
4.
Sci Total Environ ; 829: 154692, 2022 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-35318056

RESUMO

The massive generation of medical waste (MW) poses a serious risk to the natural environment and human health. The pyrolysis technique is proposed as a potential treatment for MW to tackle the associated environmental issues and produce value-added products. In this work, medical waste pyrolysis has been conducted at various temperatures using a fixed bed reactor with a 20 °C·min-1 heating rate and nitrogen was used as a career gas with a flow rate of 100 ml·min-1. In addition, the effect of temperature on products yield and chemical composition of MW pyrolysis have been investigated. The maximum yield of 57.1% for liquid oil was observed from the mixed MW pyrolysis at 500 °C. The gas and char yield were found between 26.5-37.3% and 24.2-12.4%, respectively, for the pyrolysis temperature of 450 °C to 600 °C. According to GC analysis, the concentration of the main gaseous products such as CH4, H2, and C2H4 was increased with increasing temperature, while CO and CO2 experienced a decreasing trend. The results of GC-MS analysis revealed that the main components of MW pyrolysis oil were aromatic hydrocarbons, cyclic hydrocarbons, aliphatic hydrocarbons, alcohol, carboxylic acids, and their derivatives. The aromatic and cyclic hydrocarbons content increased up to 38.2% at a pyrolysis temperature of 600 °C. As pyrolysis oil tends to have more long-chain hydrocarbons therefore carbon distributions from C7 to C35 were observed. The ultimate analysis of oil and char revealed that the increased temperature enhanced the carbon content up to 78.6% and 68.0%, respectively. Furthermore, the higher heat values of 41.8, 24.4, and 52.7 MJ·kg-1 were reported for oil, char, and gas, respectively.


Assuntos
Resíduos de Serviços de Saúde , Pirólise , Carbono , Gases , Temperatura Alta , Humanos , Hidrocarbonetos , Temperatura
5.
J Pharm Sci ; 108(6): 2136-2142, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30721711

RESUMO

Many new therapeutic candidates and active pharmaceutical ingredients (APIs) are poorly soluble in an aqueous environment, resulting in their reduced bioavailability. A promising way of enhancing the release of an API and, thus, its bioavailability seems to be the use of liquid oil marbles (LOMs). An LOM system behaves as a solid form but consists of an oil droplet in which an already dissolved API is encapsulated by a powder. This study aims to optimize the oil/powder combination for the development of such systems. LOMs were successfully prepared for 15 oil/powder combinations, and the following properties were investigated: particle mass fraction, dissolution time, and mechanical stability. Furthermore, the release of API from both LOMs and LOMs encapsulated into gelatine capsules was studied.


Assuntos
Portadores de Fármacos/química , Composição de Medicamentos/métodos , Óleos/química , Água/química , Disponibilidade Biológica , Cápsulas , Química Farmacêutica , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Gelatina/química , Pós , Solubilidade , Fatores de Tempo
6.
Waste Manag ; 69: 66-78, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28882427

RESUMO

This study aims to examine the catalytic pyrolysis of various plastic wastes in the presence of natural and synthetic zeolite catalysts. A small pilot scale reactor was commissioned to carry out the catalytic pyrolysis of polystyrene (PS), polypropylene (PP), polyethylene (PE) and their mixtures in different ratios at 450°C and 75min. PS plastic waste resulted in the highest liquid oil yield of 54% using natural zeolite and 50% using synthetic zeolite catalysts. Mixing of PS with other plastic wastes lowered the liquid oil yield whereas all mixtures of PP and PE resulted in higher liquid oil yield than the individual plastic feedstocks using both catalysts. The GC-MS analysis revealed that the pyrolysis liquid oils from all samples mainly consisted of aromatic hydrocarbons with a few aliphatic hydrocarbon compounds. The types and amounts of different compounds present in liquid oils vary with some common compounds such as styrene, ethylbenzene, benzene, azulene, naphthalene, and toluene. The FT-IR data also confirmed that liquid oil contained mostly aromatic compounds with some alkanes, alkenes and small amounts of phenol group. The produced liquid oils have high heating values (HHV) of 40.2-45MJ/kg, which are similar to conventional diesel. The liquid oil has potential to be used as an alternative source of energy or fuel production.


Assuntos
Óleos Combustíveis , Plásticos/análise , Reciclagem/métodos , Resíduos/análise , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos/análise , Polietileno/análise , Poliestirenos/análise , Zeolitas
7.
Waste Manag ; 58: 250-259, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27717700

RESUMO

This paper aims to investigate the effect of temperature and reaction time on the yield and quality of liquid oil produced from a pyrolysis process. Polystyrene (PS) type plastic waste was used as a feedstock in a small pilot scale batch pyrolysis reactor. At 400°C with a reaction time of 75min, the gas yield was 8% by mass, the char yield was 16% by mass, while the liquid oil yield was 76% by mass. Raising the temperature to 450°C increased the gas production to 13% by mass, reduced the char production to 6.2% and increased the liquid oil yield to 80.8% by mass. The optimum temperature and reaction time was found to be 450°C and 75min. The liquid oil at optimum conditions had a dynamic viscosity of 1.77mPas, kinematic viscosity of 1.92cSt, a density of 0.92g/cm3, a pour point of -60°C, a freezing point of -64°C, a flash point of 30.2°C and a high heating value (HHV) of 41.6MJ/kg this is similar to conventional diesel. The gas chromatography with mass spectrophotometry (GC-MS) analysis showed that liquid oil contains mainly styrene (48%), toluene (26%) and ethyl-benzene (21%) compounds.


Assuntos
Poliestirenos/química , Eliminação de Resíduos/métodos , Desenho de Equipamento , Cromatografia Gasosa-Espectrometria de Massas , Projetos Piloto , Tempo de Reação , Eliminação de Resíduos/instrumentação , Arábia Saudita , Resíduos Sólidos , Temperatura , Viscosidade
8.
ACS Appl Mater Interfaces ; 7(26): 14328-37, 2015 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-26107421

RESUMO

The type of material stabilized by four kinds of fluorinated particles (sericite and bentonite platelet clays and spherical zinc oxide) in air-oil mixtures has been investigated. It depends on the particle wettability and the degree of shear. Upon vigorous agitation, oil dispersions are formed in all the oils containing relatively large bentonite particles and in oils of relatively low surface tension (γla < 26 mN m(-1)) like dodecane, 20 cS silicone, and cyclomethicone containing the other fluorinated particles. Particle-stabilized oil foams were obtained in oils having γla > 26 mN m(-1) where the advancing air-oil-solid contact angle θ lies between ca. 90° and 120°. Gentle shaking, however, gives oil-in-air liquid marbles with all the oil-particle systems except for cases where θ is <60°. For oils of tension >24 mN m(-1) with omniphobic zinc oxide and sericite particles for which advancing θ ≥ 90°, dry oil powders consisting of oil drops in air which do not leak oil could be made upon gentle agitation up to a critical oil:particle ratio (COPR). Above the COPR, catastrophic phase inversion of the dry oil powders to air-in-oil foams was observed. When sheared on a substrate, the dry oil powders containing at least 60 wt % of oil release the encapsulated oil, making these materials attractive formulations in the cosmetic and food industries.


Assuntos
Emulsões/química , Compostos de Flúor/química , Óleos/química , Água/química , Silicatos de Alumínio/química , Bentonita/química , Argila , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Esqualeno , Propriedades de Superfície , Óxido de Zinco/química
9.
Bioresour Technol ; 169: 110-118, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25038506

RESUMO

Three species of macroalgae (Ulva lactuca, Laminaria japonica and Gelidium amansii) were converted into liquid oils via deoxy-liquefaction. The elemental analysis, FTIR and GC-MS results showed that the three liquid oils were all mainly composed of aromatics, phenols, alkanes and alkenes, other oxygen-containing compounds, and some nitrogen-containing compounds though there were some differences in terms of their types or contents due to the different constituents in the macroalgae feedstocks. The oxygen content was only 5.15-7.30% and the H/C molar ratio was up to 1.57-1.73. Accordingly, the HHV of the three oils were 42.50, 41.76 and 40.00 MJ/kg, respectively. The results suggested that U. lactuca, L. japonica and G. amansii have potential as biomass feedstock for fuel and chemicals and that deoxy-liquefaction technique may be an effective way to convert macroalgae into high-quality liquid oil.


Assuntos
Biotecnologia/métodos , Óleos/metabolismo , Alga Marinha/metabolismo , Carvão Vegetal/química , Cromatografia Gasosa-Espectrometria de Massas , Gases/análise , Temperatura Alta , Espectroscopia de Infravermelho com Transformada de Fourier
10.
ACS Appl Mater Interfaces ; 6(24): 22585-93, 2014 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-25402002

RESUMO

Our previous work suggested great potential for a phosphonium-organophosphate ionic liquid (IL) as an antiwear lubricant additive. In this study, a set of five ILs were carefully designed and synthesized, with identical organophosphate anions but dissimilar phosphonium cations, to allow systematic investigation of the effects of cation alkyl chain length and symmetry on physicochemical and tribological properties. Symmetric cations with shorter alkyl chains seem to increase the density and thermal stability due to closer packing. On the other hand, either higher cation symmetry or longer alkyl moieties induce a higher viscosity, though the viscosity index is dependent more on molecular mass than on symmetry. While a larger cation size generally increases an IL's solubility in nonpolar hydrocarbon oils, six-carbon seems to be the critical minimum alkyl chain length for high oil miscibility. Both the two ILs, that are mutually oil miscible, have demonstrated promising lubricating performance at 1.04% treat rate, though the symmetric-cation IL moderately outperformed the asymmetric-cation IL. Characterizations on the tribofilm formed by the best-performing symmetric-cation IL revealed the film thickness, nanostructure, and chemical composition. Results here provide fundamental insights for future molecular design in developing oil-soluble ILs as lubricant additives.

11.
ARYA Atheroscler ; 9(1): 29-37, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23696757

RESUMO

BACKGROUND: This study aimed to determine the effects of the interventions of Isfahan Healthy Heart Program (IHHP) on the type of oil consumed at the population level. It also tried to assess how this strategy has been effective as a health policy. METHODS: The IHHP, a six-year community intervention program (2001-07), aimed at health promotion through the modification of cardiovascular disease risk factors. It was performed in Isfahan and Najafabad counties (intervention area) and Arak county (reference area), all in central Iran. This study targeted the whole population of over 2,000,000 in the intervention area. The findings of annual independent sample surveys were compared with the reference area. Dietary interventions were performed as educational, environmental, and/or legislative strategies. RESULTS: From 2001 to 2007, the mean of changes for hydrogenated oil consumption was -3.2 and -3.6, and for liquid oil it was 3.6 and 2.8 times per week in the intervention and reference areas, respectively (P < 0.001). According to Commerce office record, the increase in liquid oil distribution during 2000-2007 was significantly higher in Isfahan than Arak (34% vs. 25%). CONCLUSION: The effects of the simple, comprehensive, and integrated action-oriented interventions of our program could influence policy making and its results at the community level. It can be adopted by other developing countries.

12.
ARYA Atheroscler ; 6(1): 16-22, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-22577408

RESUMO

BACKGROUND: Trans fatty acids are known as the most harmful type of dietary fats, so this study was done to compare the effects of hydrogenated, liquid and ghee oils on serum lipids profile of healthy adults. METHODS: This study was a randomized clinical trial conducted on 129 healthy participants aged from 20 to 60 years old who were beneficiaries of Imam-e-Zaman charitable organization. Subjects were randomly divided into 3 groups and each group was treated with a diet containing cooking and frying liquid, ghee, or hydrogenated for 40 days. Fasting serum lipids, including total cholesterol (TC), triglyceride (TG), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), apoprotein A (Apo A), and apoprotein B (Apo B) were measured before and after the study. RESULTS: TC, TG and Apo B had a significant reduction in the liquid oil group compared to the hydrogenated oil group. In the ghee group TG declined and Apo A increased significantly (P < 0.01). Liquid oil group had a significant reduction in HDL-C, compared to the ghee oil group (P < 0.05). CONCLUSION: It was concluded that consuming liquid oil along with frying oil caused to reduce all serum lipid levels. However, ghee oil only reduced TG and increased HDL-C levels.

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