Decomposition Of Plastics Research Articles

Combined use of Bacteria and Enzymes in the Degradation of Polymer Materials

The development of the plastics industry, pro-ecological directives and environmental problems related to the decomposition of biodegradable plastics create necessity to develop a way to properly manage waste from materials that should not be deposited in the environment. A bioproduct has been developed to be used for accelerating the biodegradation of polymer materials. The bioproduct includes carefully selected microorganisms and enzymes. It has been observed that metabolic activity of selected bacteria increases significantly in the presence of plastic material, causing degradative changes. In addition, enzymes were used that also stimulate the decomposition of polymer materials. Impact of bacteria and enzymes on polymer biodegradation was analyzed using different methods: BOD, mass loss, SEM-EDX and FTIR-ATR. Also the effect on plant growth was examined. Five bacterial strains were selected as the active ingredients of the bioproduct, including two bacterial strains from the designated collection and three isolated from environment. Four hydrolytic enzymes have been selected that have the potential to accelerate the decomposition of polymer materials. Keywords: bacteria, enzymes, biodegradation, polymer materials

Preparation of 97% pure nickel-cobalt alloy from waste Ni-MH batteries by using waste glass as a fluxing agent

With the e-waste growing rapidly all over the globe due to growing demand of electronics, smartphones, etc., coming up with an efficient and sustainable recycling process is the need of the hour. The present work reports a novel and sustainable process of manufacturing Ni alloy by bringing together three major waste streams such as waste Ni-MH batteries, e-waste plastics, and waste glass. The chosen temperature (1550 °C) favours the reduction of nickel-oxide by e-waste plastic as the reductant and sends rare earth elements present in the waste Ni-MH battery as oxide mixture to the slag phase. Waste glass powder used in this process functions as the fluxing agent, hence not requiring any additional flux. The reduction mechanism is gas-based, controlled mainly by hydrogen and carbon monoxide gases released as a result of decomposition of e-waste plastic as reaction commenced from cold zone (∼300 °C) to hot zone (1550 °C) in the horizontal tubular furnace. Formation of nickel alloy and enrichment of slag with mixture of rare earth oxides were confirmed by XRD, SEM-EDS, and Rietveld refining analysis performed on the XRD spectra of slag phase. ICP-OES (Inductively coupled plasma optical emission spectroscopy) and LIBS (laser induced breakdown spectrometer KT-100S) confirmed the high metal content in the alloy, thereby emphasizing the purity (∼98%) which is close to the composition of nickel super alloy. A maximum of 61% by weight REO enrichment was achieved in the slag phase, having La2O3:44.6%, Pr2O3:14.8%, and Nd2O3: 1.6% under optimised experimental conditions (1550 °C, 15 min, and 20% waste glass powder). This scientific investigation evinces a promising route for efficient utilisation of waste streams emanating from e-waste, thereby devising a sustainable recycling technique and protecting the environment, too.

Simulation investigation on heating characteristics of catalysts under microwave irradiation for decomposition of waste plastic

Microwave heating is a promising technique for heterogeneous catalytic reactions in plastic decomposition. The microwave-insensitive plastic material requires microwave-absorbing catalysts to facilitate catalytic-assisted decomposition and synergistic heating. However, the heating characteristics of catalyst particles within the microwave system is still unclear. In this study, the effects of particle size, particle arrangement direction, and particle shape on the microwave heating behavior of particles was investigated, and the model was experimentally validated and analyzed using infrared temperature data. The simulation results indicated that the heating rate increased as the particle size enlarged, with an average heating rate of 5.56 °C/s for the particle with a radius of 5 mm in comparison to 4.29 °C/s for that of 1 mm. Additionally, when particles were aligned parallel to the applied electric field, the electric field was intensely focused at the interparticle area, with a maximum electric field strength difference of 2.2 × 104 V/m in the samples. In contrast, the horizontal placement resulted in reduced electric field intensity (4.7 × 103 V/m) and lower temperatures (62 °C) near the areas adjacent to the particles compared to the maximum values in the particles. With respect to particle shape, cylindrical particles possessing larger aspect ratios exhibited superior heating performance due to the extended span of intraparticle microwave transmission aligned with the electric field direction but also resulted in increased thermal field distribution inhomogeneity. The research offers theoretical guidance to prevent catalyst sintering and promote microwave-assisted catalytic plastic decomposition.

A Fourier Transform Infrared Spectroscopy Investigation on Faecal Matter of Galleria mellonella Larvae fed with Beeswax and Low-Density Polyethylene

The growing production and consumption of plastics, coupled with their poor recyclability and non-degradability, pose significant environmental risks. Insects including the greater wax moth (Galleria mellonella) have been identified as capable of ingesting and degrading plastics through microorganisms in their gut, thereby reducing the environmental impact. The insect that's accountable for degrading down low-density polyethylene has been depicted. The purpose of this study was to analyse the faeces of G. mellonella larvae in order to determine the chemical makeup of their digested products. The chemical structures and functional groups of the faecal matter of G. mellonella larvae fed on LDPE and beeswax were evaluated using Fourier Transform Infrared Spectroscopy. The findings shed light on the potential role that G. mellonella larvae may play in the decomposition of plastic by identifying unique patterns in the chemical makeup of the faecal matter of larvae fed LDPE.

USE OF PLASTICWASTE AS AN AGGREGATE IN CONCRETE

Significant growth in the consumption of plastic products is observed all over the world in recent years; this has contributed to increasing the production of plastic waste. Disposal of plastic is a challenging task. Because plastic waste can take anywhere from 20 to 500 years to decompose, and eventhen, it never fully disappears; it just get smaller and smaller. Hence it is necessary to reduce the amount of production of plastic as well as disposal and reuse of plastic is mandatory. As decomposition of plastic is a serious problem as it takes very long time and adversely affection the environment in many ways so reuse of plastic waste in the production of concrete or mortar appears as an environmentally friendly solution for getting rid of plastic waste, due to its ecological and economic advantages and we can use it in construction, where we need life of structure to be improved. Furthermore, it leads to a decrease in plastic waste in landfills. Several studies presented the properties of cementitious composites (mortar and concrete) containing different types of (PWD) Usage of these plastic waste materials helping in dual role by minimizing of concrete and by using the waste materials that are affecting the environment. The other advantage of using these waste materials is that they are helping improving the properties of concrete.This study summarizes the previous studies until 2019, discussing the use of recycled plastic aggregate as aggregates in cementation composites and its impact on the compressive strength. In this study we are going to replace the fine aggregate and coarse aggregate by plastic aggregate with 2.5%, 10% and 25%, then specimens are tested and compared with a control specimen of 0% plastic in terms of compressive strength. We will also do the comparative study of replacement of fine and coarse aggregateand going to find that which replacement is better. Keywords: plastic waste, plastic aggregate, environmentally friendly solution

Synergistic interactions between cellulose and plastics (PET, HDPE, and PS) during CO2 gasification-catalytic reforming on Ni/CeO2 nanorod catalyst

CO2 gasification-reforming is a promising approach for the transformation of carbonaceous materials into CO-rich syngas. Within municipal solid waste and agricultural waste streams, plastics are commonly found intermixed with biomass waste. This study delves into the CO2 gasification-reforming of biomass (cellulose) and various plastics (PET, HDPE, and PS) using a self-built online weighing fixed bed reactor and a two-stage fixed bed reactor. During the gasification-reforming of cellulose-plastic mixtures without the catalyst, the experimental gas production rate of cellulose slightly decreased, with the peak of gas production migrating to a higher temperature range. This phenomenon can be attributed to the molten plastic adhering to the cellulose surface, which impeded heat and mass transfer essential for cellulose decomposition. Furthermore, the gas production from plastics was suppressed in the mixtures, likely due to the interference of cellulose char in the decomposition of plastics. The incorporation of 2%Ni/CeO2 catalysts not only augmented gas yields and production rates but also emphasized the synergistic interactions. For the cellulose-HDPE mixture, the total gas yield was reduced by 14.9 mmol gsample−1 relative to the theoretical value. Given that HDPE possessed the highest decomposition temperature, the synergistic interaction was predominantly driven by the inhibitive nature of cellulose char. In contrast, the total gas yields for cellulose-PET and cellulose-PS mixtures increased by 8.7 mmol gsample−1 and 13.3 mmol gsample−1, respectively. The free radicals emanating from cellulose could trigger the decomposition of volatile components from plastics. Concurrently, the decomposition products of plastic could serve as hydrogen donors to stabilize the volatiles of cellulose. The interactions primarily affect the volatiles and tar components of the mixtures. The catalysts amplified gas yields by facilitating the CO2 reforming of tar, therefore, the synergistic interaction became evident upon catalyst addition. Gas chromatography-mass spectrometry analyses of the tar also corroborated the described interaction mechanisms between cellulose and plastics. Thermogravimetric analysis of used catalysts indicated that the synergistic action between cellulose and plastic could effectively diminish coke deposition, thereby preventing swift catalyst deactivation.

Can We Find a Way to Solve Microplastic Pollution?

The issue of microplastic pollution has escalated in significance and urgency due to the global infiltration of minuscule plastic particles into terrestrial and marine ecosystems. Microplastics are generated through a variety of processes, including the decomposition of larger plastics, industrial operations, and the incorporation of microbeads into personal care items. These substances have been detected in sediments, lakes, rivers, oceans, and even the air we breathe. The detrimental impacts of microplastics on the well-being of wildlife are extensively documented. These particles present hazards to marine organisms such as seabirds, fish, and sea turtles via ingestion or entanglement. Moreover, they might function as vectors through which detrimental substances infiltrate the food chain. To adequately tackle this matter, it is imperative to adopt a multidisciplinary strategy that encompasses policy interventions aimed at restricting plastic production and consumption, advancements in waste management technologies, public awareness initiatives promoting sustainable lifestyles, and ongoing research to comprehensively comprehend the problem's magnitude and ecological repercussions. The assurance of a cleaner environment for future generations is contingent upon our collective efforts to mitigate microplastic pollution.

Adsorption performance of nanoplastics in carbon filtration column

ABSTRACT Nanoplastics (NPs) are usually formed by the decomposition of large plastics, which will cause water pollution after entering the water body. Carbon filter column is used to adsorb and remove polystyrene nanoparticles (PSNPs). The influence of experimental conditions on adsorption was investigated and fitted by kinetic model. The results show that increasing the height of carbon filter column and decreasing the initial concentration of PSNPs and water flow rate can prolong the breakthrough time of carbon filter column. When the initial concentration of PSNPs is 0.8 mg L−1, the influent flow rate is 4 mL min−1 and the height of carbon filter bed is 8.5 cm, the removal effect is the best, and the depletion point of carbon filter column is extended to 48 h. Adams-Bohart model is suitable for describing the initial stage of adsorption. Thomas and Yoon-Nelson models can well describe the whole dynamic adsorption process of PSNPs, and Yoon-Nelson model can accurately predict the time required for 50% PSNPs to penetrate the carbon column. The adsorption mechanism of NPs by carbon filter column is mainly through the attachment sites and pore retention provided by particles on the surface of activated carbon. This study can provide new technical and theoretical support for the removal of NPs.

Microbial decomposition of biodegradable plastics on the deep-sea floor

Microbes can decompose biodegradable plastics on land, rivers and seashore. However, it is unclear whether deep-sea microbes can degrade biodegradable plastics in the extreme environmental conditions of the seafloor. Here, we report microbial decomposition of representative biodegradable plastics (polyhydroxyalkanoates, biodegradable polyesters, and polysaccharide esters) at diverse deep-sea floor locations ranging in depth from 757 to 5552 m. The degradation of samples was evaluated in terms of weight loss, reduction in material thickness, and surface morphological changes. Poly(l-lactic acid) did not degrade at either shore or deep-sea sites, while other biodegradable polyesters, polyhydroxyalkanoates, and polysaccharide esters were degraded. The rate of degradation slowed with water depth. We analysed the plastic-associated microbial communities by 16S rRNA gene amplicon sequencing and metagenomics. Several dominant microorganisms carried genes potentially encoding plastic-degrading enzymes such as polyhydroxyalkanoate depolymerases and cutinases/polyesterases. Analysis of available metagenomic datasets indicated that these microorganisms are present in other deep-sea locations. Our results confirm that biodegradable plastics can be degraded by the action of microorganisms on the deep-sea floor, although with much less efficiency than in coastal settings.

Test of polystyrene toxicity on Aeromonas-sobria and staphylococcus-homini bacteria

The spread of nano-plastic particles arising from the decomposition of plastic has become a global problem because it poses a threat to primary products in food chains, and thus threatens the entire system. We tested the apparent effects on the metabolism of Gram-negative and Gram-positive bacteria after exposure to nano-plastics (nanocpolystyrene) by using carbon as an energy source. After diagnosis bacteria samples and then exposed to nanopolystyrene solution with different concentrations (200, 500 and 1000) ppm. Biology Eco Microplate (BEMP) was used to determine changes in bacteria after uptake of a carbon source. Average well-color development (AWCD) was used for data analysis, the result showed there are increase in size of bacteria and in absorption of carbon sources.

Microwaves assisted deconstruction of HDPE waste into structured carbon and hydrogen fuel using Al2O3-(Ni, Zn, Mg)Fe2O4 composite catalysts

Plastic waste management is becoming an issue of global concern due to the excessive consumption of plastics with one-time use. The decomposition of plastic into valuable products by catalytic pyrolysis has gained significant attention as a promising method of valorizing plastic waste. This paper demonstrates the microwave-assisted decomposition of plastic waste materials for carbon nanotubes (CNTs) and high H2 production using magnetic-based catalysts via in-situ exsolution. Magnetic-based catalysts, namely Al2O3-NiFe2O4, Al2O3-ZnFe2O4, and Al2O3-MgFe2O4 were prepared using aluminum oxide, iron nitrate, zinc nitrate, and magnesium nitrate. CNTs and H2 were produced from the decomposition of wasted HDPE using the prepared catalysts. The Al2O3-NiFe2O4 catalyst showed better formation of CNTs and gas due to its low dielectric loss factor. The high surface area and magnetic-support interaction also promoted the catalytic activity of the catalyst. The oil byproduct mainly contained C8-C16 compounds, showing better selectivity for small molecules in the tested process. Conclusively, Al2O3-NiFe2O4 produced CNTs with good structural properties and fewer impurities than Al2O3-ZnFe2O4 and Al2O3-MgFe2O4 composites. The Al2O3-NiFe2O4 catalyst showed 90% hydrogen composition in evolved gases. In all cases, almost 90% of the hydrogen evolved from the feedstock within the first 2 min of the processing time.

Evidence of plasma‐driven decomposition of common plastics exposed to an atmospheric nonthermal discharge

AbstractA nonthermal, pulsed spark discharge is applied to three polymer powders in Ar and Ar– gas mixtures. Hydrogen is introduced to assess plasma‐driven decomposition. Gaseous decomposition products, including methane, acetylene, and ethylene, are observed with Fourier‐transform infrared (FTIR). Surface modifications are observed on the residual polymer via attenuated total internal reflection‐FTIR. Time‐averaged rotational, vibrational, and excitation temperatures are characterized in the discharge. The plasma density is found to be around , with rotational and vibrational temperatures ranging from 1500 to 2200 K and an excitation temperature of 1–2 eV. While spark properties did not change with either gas composition or polymer composition, it was determined that the addition of hydrogen promoted higher concentrations of gaseous phase products (promoting hydrogenolysis).

Microplastics cause hepatotoxicity in diabetic mice by disrupting glucolipid metabolism via PP2A/AMPK/HNF4A and promoting fibrosis via the Wnt/β-catenin pathway.

In recent years, microplastics (MPs) have gained significant attention as a persistent environmental pollutant resulting from the decomposition of plastics, leading to their accumulation in the human body. The liver, particularly of individuals with type 2 diabetes mellitus (T2DM), is known to be more susceptible to the adverse effects of environmental pollutants. Therefore, to investigate the potential impact of MPs on the liver of diabetic mice and elucidate the underlying toxicological mechanisms, we exposed db/db mice to 0.5 μm MPs for 3 months. Our results revealed that MPs exposure resulted in several harmful effects, including decreased body weight, disruption of liver structure and function, elevated blood glucose levels, impaired glucose tolerance, and increased glycogen accumulation in the hepatic tissue of the mice. Furthermore, MPs exposure was found to promote hepatic gluconeogenesis by perturbing the PP2A/AMPK/HNF4A signaling pathway. In addition, MPs disrupt redox balance, leading to oxidative damage in the liver. This exposure also disrupted hepatic lipid metabolism, stimulating lipid synthesis while inhibiting catabolism, ultimately resulting in the development of fatty liver. Moreover, MPs were found to induce liver fibrosis by activating the Wnt/β-catenin signaling pathway. Furthermore, MPs influenced adaptive thermogenesis in brown fat by modulating the expression of uncoupling protein 1 (UCP1) and genes associated with mitochondrial oxidative respiration thermogenesis in brown fat. In conclusion, our study demonstrates that MPs induce oxidative damage in the liver, disturb glucose and lipid metabolism, promote hepatic fibrosis, and influence adaptive thermogenesis in brown fat in diabetic mice. These findings underscore the potential adverse effects of MPs on liver health in individuals with T2DM and highlight the importance of further research in this area.

Comparing non-biodegradable plastic with environmentally friendly natural fibre composite on car front bumpers design

Production of plastic is growing, and plastics are used in a variety of products. However, plastics are not biodegradable and do not decompose easily. To overcome the problems in decomposition of plastics, the use of a specific type of natural fibre composite (NFC) material for front-bumper in cars is considered in this investigation. NFCs have the advantages of being environmentally friendly, light weight and high strength. The use of jute fibre is adopted for the design of a car front bumper and compared with the plastic bumper through Finite Element Analysis. The aim is to identify their performances in terms of impact energy, strength and resilience. The results show that when both materials were simulated under the same impact force, jute fibre has a lower equivalent stress with 177.1 MPa compare with 293.18 MPa on plastic material. This finding indicates that jute fibre has greater yield limit and more resilient to fracture. The simulation result also shows that jute fibre has a higher equivalent stress of 65.55 MPa on the front bumper compare with a lower equivalent stress of 39.94 MPa on plastic. This suggests that plastic material will yield soon when an impact force is higher. The total deformation after the same impact force in jute fibre is 2.1 mm, which is significantly less than the deformation in plastic with 11.7 mm. Therefore, this research concludes that jute fibre can potentially replace plastic as a green composite material application to minimise environmental damages.Graphical abstract

Experiment on Concrete by Adding Steel Fibers and Plastic Waste to Reduce Environmental Issues and Adding Strength to Concrete

Abstract: Concrete is the most commonly used material for construction in civil engineering. The project involves the proposed concrete which is made up of adding plastic in concrete may help to reuse the plastic as one of the constituent material of concrete. Due to rapid industrialization the amount of use and decomposition of plastic has increased. If we are able to utilize this waste under proper conditions as addition to concrete it will reduce the plastic waste up to some extent. By adding the steel fibers to the above mix it will increase the compressive strength of the concrete. M40 grade concrete is used in the whole procedure. Here, we used 4 different percentages of plastic waste (i.e., 0.6%, 1.2%, 1.8%, and 2.4%) of weight of cement and by taking quantity of steel fiber as constant (i.e., 2%) of weight of cement, and the aspect ratio of steel fibers is 60. The concrete cube of size 150mm×150mm ×150mm are prepared and tested at 3days, 7days, 14days and 28 days. The resulting data has been analyzed and compared with controlled specimens.

Earthworms facilitated pepper (Capsicum annuum L.) growth via enhancing the population and function of arbuscular mycorrhizal fungi in a low-density polyethylene-contaminated soil

Microplastics (MPs) produced by the decomposition of plastics exist persistently, interfering with soil fertility and plant nutrition. Both arbuscular mycorrhizal (AM) fungi and earthworms are beneficial in terrestrial ecosystems, but their interactions under MPs contamination are unclear so far. Here, the influences of inoculating earthworms (Eisenia fetida) on indigenous AM fungi and pepper (Capsicum annuum L.) growth were investigated in a vegetable soil treated with 0.1% low-density polyethylene (LDPE), while the specific interactions of earthworm and AM fungus (Funneliformis caledonium) under LDPE contamination were further resolved in another experiment using sterilized soil. Inoculation of earthworms shifted soil AM fungal community structure, replacing the predominant genus Glomus by Paraglomus, and increased the abundance, diversity (i.e., Shannon) index, and root colonization rate of AM fungi by 108, 34.6 and 45.0%, respectively. Earthworms also significantly decreased soil pH, and significantly increased soil alkaline phosphatase (ALP) activity, shoot biomass and fruit yield of pepper by 394, 82.8 and 188%, respectively. In the sterilized soil, both E. fetida and F. caledonium improved pepper growth, while the latter noticeably increased phosphorus (P) translocation efficiency from root to shoot, and the combination induced the highest soil ALP activity and pepper fruit yield. Furthermore, the significantly interactive effects between earthworm and AM fungus were observed in soil pH and available P concentration, as well as in shoot P concentration and fruit yield of pepper. This study revealed the interaction between earthworms and AM fungi under MPs contamination conditions for the first time, indicating that earthworms could facilitate vegetable growth via enhancing the propagation and P-promoting function of AM fungi in LDPE-contaminated soils.Graphical

History of marine mycology – a personal perspective

Abstract This article is a personal impression of the key scientists who contributed to the study of marine mycology over past 174 years, especially those the author met during his career studying this unique group of fungi. Marine mycology has been a journey of discovery from a few species to nearly 2000 taxa in nine fungal phyla. Techniques for their study have advanced from morphological observations, to the use of scanning and transmission electron microscopy, to the development of high-throughput sequencing technology and the unravelling of the genomes of selected species. Thoughts on the conservation of marine fungi, their adaptation to climate change and potential role in the decomposition of plastics are briefly considered.

Mixed Plastics Wastes Upcycling with High-Stability Single-Atom Ru Catalyst.

Mixed plastic waste treatment has long been a significant challenge due to complex composition and sorting costs. In this study, we have achieved a breakthrough in converting mixed plastic wastes into a single chemical product using our innovative single-atom catalysts for the first time. The single-atom Ru catalyst can convert ∼90% of real mixed plastic wastes into methane products (selectivity >99%). The unique electronic structure of Ru sites regulates the adsorption energy of mixed plastic intermediates, leading to rapid decomposition of mixed plastics and superior cycle stability compared to traditional nanocatalysts. The global warming potential of the entire process was evaluated. Our proposed carbon-reducing process utilizing single-atom catalysts launches a new era of mixed plastic waste valorization.

Photocatalytic Hydrolysis-A Sustainable Option for the Chemical Upcycling of Polylactic Acid.

Plastic waste is a critical global issue, yet current strategies to avoid committing plastic waste to landfills include incineration, gasification, or pyrolysis high carbon emitting and energy consuming approaches. However, plastic waste can become a resource instead of a problem if high value products, such as fine chemicals and liquid fuel molecules, can be liberated from controlled its decomposition. This letter presents proof of concept on a low-cost, low energy approach to controlled decomposition of plastic, photocatalytic hydrolysis. This approach integrates photolysis and hydrolysis, both slow natural decomposition processes, with a photocatalytic process. The photocatalyst, α-Fe2O3, is embedded into a polylactic acid (PLA) plastic matrix. The photocatalyst/plastic composite is then immersed in water and subjected to low-energy (25 W) UV light for 90 h. The monomer lactide is produced as the major product. α-Fe2O3 (6.9 wt %) was found to accelerate the PLA degradation pathway, achieving 32% solid transformation into liquid phase products, in comparison to PLA on its own, which was found to not decompose, using the same conditions. This highlights a low energy route toward plastic waste upgrade and valorization that is less carbon intensive than pyrolysis and faster than natural degradation. By directly comparing a 25 W (0.025 kWh) UV bulb with a 13 kWh furnace, the photocatalytic reaction would directly consume 520× less energy than a conventional thermochemical pathway. Furthermore, this technology can be extended and applied to other plastics, and other photocatalysts can be used.

The implementation of microbes in plastic biodegradation

AbstractMost microorganisms are necessary for the decomposition of plastics and the production of bioplastics. It takes plastic materials more than a thousand years to degrade significantly. To degrade solid waste, microorganisms for the degradation of plastics should be configured meticulously. In the manufacture of equipment, a variety of plastic polymers are utilised, focusing on how they will be used. This article reviews about a detailed summary of the microbes that degrade several forms of plastics including polyethylene, polypropylene, polystyrene, polyurethane, polyethylene terephthalate, and polyvinyl chloride also the harmful effects of plastics on humanity.