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Journal ArticleDOI

Thermolysis of waste plastics to liquid fuel: A suitable method for plastic waste management and manufacture of value added products—A world prospective

TL;DR: A review of the available literature in this field of active research and identifies the gaps that need further attention can be found in this article, where a number of pilot, demonstration and commercial plants processing various types of plastic wastes in Germany, Japan, USA, India, and elsewhere.
Abstract: The present rate of economic growth is unsustainable without saving of fossil energy like crude oil, natural gas or coal. Thus mankind has to rely on the alternate/renewable energy sources like biomass, hydropower, geothermal energy, wind energy, solar energy, nuclear energy, etc. On the other hand, suitable waste management strategy is another important aspect of sustainable development. The growth of welfare levels in modern society during the past decades has brought about a huge increase in the production of all kinds of commodities, which indirectly generate waste. Plastics have been one of the materials with the fastest growth because of their wide range of applications due to versatility and relatively low cost. Since the duration of life of plastic products is relatively small, there is a vast plastics waste stream that reaches each year to the final recipients creating a serious environmental problem. Again, because disposal of post consumer plastics is increasingly being constrained by legislation and escalating costs, there is considerable demand for alternatives to disposal or land filling. Advanced research in the field of green chemistry could yield biodegradable/green polymers but is too limited at this point of time to substitute the non-biodegradable plastics in different applications. Once standards are developed for degradable plastics they can be used to evaluate the specific formulations of materials which will find best application in this state as regards their performance and use characteristics. Among the alternatives available are source reduction, reuse, recycling, and recovery of the inherent energy value through waste-to-energy incineration and processed fuel applications. Production of liquid fuel would be a better alternative as the calorific value of the plastics is comparable to that of fuels, around 40 MJ/kg. Each of these options potentially reduces waste and conserves natural resources. Plastics recycling, continues to progress with a wide range of old and new technologies. Many research projects have been undertaken on chemical recycling of waste plastics to fuel and monomer. This is also reflected by a number of pilot, demonstration, and commercial plants processing various types of plastic wastes in Germany, Japan, USA, India, and elsewhere. Further investigations are required to enhance the generation of value added products (fuel) with low investments without affecting the environment. The paper reviews the available literature in this field of active research and identifies the gaps that need further attention.
Citations
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Journal ArticleDOI
TL;DR: This study studied the survival and fitness of the earthworm Lumbricus terrestris exposed to microplastics in litter at concentrations of 7, 28, 45, and 60% dry weight, percentages that, after bioturbation, translate to 0.2 to 1.2% in bulk soil.
Abstract: Plastic debris is widespread in the environment, but information on the effects of microplastics on terrestrial fauna is completely lacking. Here, we studied the survival and fitness of the earthworm Lumbricus terrestris (Oligochaeta, Lumbricidae) exposed to microplastics (Polyethylene, <150 μm) in litter at concentrations of 7, 28, 45, and 60% dry weight, percentages that, after bioturbation, translate to 0.2 to 1.2% in bulk soil. Mortality after 60 days was higher at 28, 45, and 60% of microplastics in the litter than at 7% w/w and in the control (0%). Growth rate was significantly reduced at 28, 45, and 60% w/w microplastics, compared to the 7% and control treatments. Due to the digestion of ingested organic matter, microplastic was concentrated in cast, especially at the lowest dose (i.e., 7% in litter) because that dose had the highest proportion of digestible organic matter. Whereas 50 percent of the microplastics had a size of <50 μm in the original litter, 90 percent of the microplastics in the casts was <50 μm in all treatments, which suggests size-selective egestion by the earthworms. These concentration-transport and size-selection mechanisms may have important implications for fate and risk of microplastic in terrestrial ecosystems.

754 citations

Journal ArticleDOI
TL;DR: The existing techniques of pyrolysis, the parameters which affect the products yield and selectivity and the influence of different catalysts on the process are presented and major research gaps in this technology are identified.

687 citations


Cites background or methods from "Thermolysis of waste plastics to li..."

  • ...The typical pyrolysis temperature range for thermal processes (non-catalytic) is between 350 and 900 C, which alongside type of feedstock, reaction time and gas media; controls the products obtained from the process (Panda et al., 2010; Lettieri and Al-Salem, 2011; Kunwar et al., 2016)....

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  • ...Such methods include glycolysis (Simon et al., 2014; Sharma and Bansal, 2016), hydrolysis (Campanelli et al., 1993; Evans and Chum, 1991; Panda et al., 2010), pyrolysis (Williams, 2013; Williams and Brindle, 2002; Danon et al., 2015a, 2015b), aminolysis (Goje et al., 2004; Sinha et al., 2010;…...

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  • ..., 2014; Sharma and Bansal, 2016), hydrolysis (Campanelli et al., 1993; Evans and Chum, 1991; Panda et al., 2010), pyrolysis (Williams, 2013; Williams and Brindle, 2002; Danon et al....

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Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the co-pyrolysis process through several points of view, including the process mechanism, feedstock, exploration on co- pyrolyisation studies, co-PyROlysis phenomena, characteristics of byproducts, and economic assessment.

605 citations

Journal ArticleDOI
TL;DR: The authors in this paper reviewed the history of the circular economy (CE) concept to provide a context for a critical examination of how it is applied currently and highlighted the variability in CE project success and failure over time and by region.
Abstract: The challenges of balancing industrial development, environmental and human health, and economic growth in China and elsewhere in the world are drivers for recent resource use and low-carbon development strategies that include the application of the circular economy (CE) concept. A central theme of the CE concept is the valuation of materials within a closed-looped system with the aim to allow for natural resource use while reducing pollution or avoiding resource constraints and sustaining economic growth. The objectives of this study are (1) to review the history of the CE concept to provide a context for (2) a critical examination of how it is applied currently. Thematic categories are used to organize the literature review results including policy instruments and approaches; value chains, material flows, and products; and technology, organizational, and social innovation. The literature review illustrates the variability in CE project success and failure over time and by region. CE successes, key challenges, and research gaps are identified. The literature review results provide useful information for researchers as well as multi-stakeholder groups who seek to define the CE concept in practical terms, and to consider potential challenges and opportunities it presents when implemented.

552 citations

Journal ArticleDOI
TL;DR: In this article, the progress and challenges of the catalytic pyrolysis of plastic waste along with future perspectives in comparison to thermal pyrolynsis are reviewed. And the recommended solutions for these challenges include exploration of cheaper catalysts, catalyst regeneration and overall process optimization.

546 citations

References
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Journal ArticleDOI
TL;DR: In this article, the authors tried to describe perhaps the most important solid acids based on inorganic oxides, going from their preparation procedures and characterization, to their catalytic activity for a series of hydrocarbon reactions.
Abstract: It is possible to say that solid acid catalysis involves the largest amounts of catalysts used and the largest economical effort in the oil refining and chemical industry. In this review the author has tried to describe perhaps the most important solid acids based on inorganic oxides, going from their preparation procedures and characterization, to their catalytic activity for a series of hydrocarbon reactions. The review starts with an introductory part in where the nature of the acid sites and their physicochemical characterization is described. Then the classification to the different catalysts is initiated with the older amorphous silica-alumina and aluminum phosphates and followed by catalysts with more interest at present which are discussed in order of increasing acid strength: zeolites, heteropoly acids, and sulfated metal oxides. The aim of this review is to present an extended summary of the state of the art and the current and the future tendencies in the field. 720 refs.

2,804 citations

Journal ArticleDOI
TL;DR: In this paper, the authors have discussed various types of polymeric degradations along with their mechanisms, which include photo-oxidative degradation, thermal degradation, ozone-induced degradation, mechanochemical degradation, catalytic degradation and biodegradation.

1,054 citations

Journal ArticleDOI
TL;DR: In this article, infrared spectroscopy and temperature-programmed desorption have been used to investigate the acidic properties of ZSM-5-type zeolites, showing that the most active acidic sites are located at the channel intersections, and the weaker acidic sites correspond to terminal silanol groups on the external surface of the zeolite or possibly nonzeolitic impurities.

577 citations

Journal ArticleDOI
TL;DR: Analysis of the derived gases and oils showed that pyrolysis gave a mainly aliphatic composition consisting of a series of hydrocarbons (alkanes and alkenes), with a great potential to be recycled back into the petrochemical industry as a feedstock for the production of new plastics or refined fuels.

540 citations

Journal ArticleDOI
01 Jul 2001-Fuel
TL;DR: In this paper, the pyrolysis characteristics of 11 different components, representing the dry cellulosic fraction and plastics of municipal solid waste (MSW) have been investigated at a constant heating rate of 10°C/min in an inert atmosphere.

490 citations