Waste High-density Polyethylene Research Articles

Response surface design, modelling and analysis on pyrolysis of waste high-density polyethylene (HDPE)

Response surface design, modelling and analysis on pyrolysis of waste high-density polyethylene (HDPE)

Dynamic properties of high-density polyethylene–sand by large-scale direct shear experiments

Recycling and reuse of plastic waste in civil projects is one way to reduce its negative impacts on the environment. High-density polyethylene (HDPE) is a highly abundant plastic waste found widely and in high volumes worldwide. Although sand has a relatively high frictional resistance, if its dynamic parameters are improved, it can be used in geotechnical projects that require higher dynamic parameters than those of pure sand. This study aimed to investigate the dynamic properties of sand mixed with crushed HDPE waste and its application to mitigate its negative environmental impacts. Crushed HDPE was added to sand at 0, 4 and 8% by weight. Under three vertical stresses and two shear amplitudes, the dynamic parameters of the mixture, including damping and shear stiffness, were investigated by conducting a large-scale cyclic direct shear test under ten cycles and are discussed. The results showed that with increasing HDPE percentage, the damping ratio rose and the shear stiffness decreased compared with those of pure sand due to the elasticity, deformation, tensile properties and high potential of HDPE for energy absorption. Furthermore, the rise in shear amplitude decreased the dynamic shear stiffness and raised the damping ratio of the mixtures.

Preparation and Characterization of High-Density Polyethylene (HDPE) Waste filled with Rice husk Silica (RHS) Composites in Gwagwalada metropolis, Abuja, Federal Capital Territory, Nigeria

The adverse effects of use of plastics by human beings are on the increase and become challenging with the growing population. The non-degradability of plastics products such as bottles, cans, cups, bags which resulted into blockage of culverts, drains, suffocating animal’s life. This research focused on recycling of high density polyethylene (HDPE) plastic waste with rice husk silica (RHS) from agricultural waste of rice husks to form eco-friendly polymer composites. Different proportions of 0.5 to 3.0 % rice husk silica (RHS) as filler were melt mixed with maleic anhydride grafted high density polyethylene (HDPE) material and the composite analyzed for tensile and flexural strengths. The tensile strengths ranged values from 10.49 to 13.02 MPa for the resin (vHDPE) and the recycled (rHDPE) composites presented values from 8.30 and 12.41 MPa for 0.5and 3.0% filler loading, respectively. The peak flexural strengths recorded for recycled (rHDPE) and resins (vHDPE) composites are 12.19 MPa and 12.05 MPa for 0.5 and 3.0% filler loading, respectively. The tensile strength of rice husk silica (RHS) filled HDPE waste composites are higher than that of the waste HDPE (control) and thus, the filler reinforced the HDPE. The composite prepared is suitable for use as tiles in building application to solve leaching problems associated with paint coating.

Selected properties of MDF boards bonded with various fractions of recycled HDPE particles

Selected properties of MDF boards bonded with various fractions of recycled HDPE particles.The substitution of non-renewable, formaldehyde-based amine wood binders in the wood-based composites industry is one of the main directions of trials and research. On the other hand, a bigger effort should be put into carbon capture and storage (CCS) activity, especially in the case of oil-based plastics, to extend their life in the products. The aim of the research was to use waste high-density polyethylene (HDPE) in MDF panels and determine their selected properties, including modulus of elasticity in bending, bending strength, internal bond, thickness swelling, water absorption, screw withdrawal resistance, density profile when referred to the fraction of used HDPE.The panels were created in laboratory conditions with a 50% weight content of HDPE particles of different fractions (<1 mm, <2 mm, <4 mm, and a mixed fraction containing 25% of each fraction and unsorted waste). The results show that the highest strength and modulus of elasticity were obtained for panels with plastic fractions below 1 mm. This fraction also achieved the lowest results for water absorption and thickness swelling. The fraction of the used plastic has no significant effect on screw withdrawal resistance. The negative impact of using larger fractions in the board is noticeable, however, for the mixed fraction, the results are similar to the finest fraction in terms of the internal bond, thickness swelling, and water absorption. The addition of HDPE can have a beneficial effect on the parameters of MDF panels. It is possible to create fibreboards from wasted plastic, store carbon dioxide in them, and upcycle them. In the discussed panels, the only binder for wood fibres was HDPE, so panels should not emit formaldehyde from the binder.

Thermal degradation of virgin and waste plastics: Estimation of kinetic and thermodynamic parameters using model‐free iso‐conversional methods

AbstractKinetic triplets—apparent activation energy (Ea), pre‐exponential factor (A), and the reaction model—were estimated for the thermal degradation of three primary virgin and waste plastics, as well as mixed plastics waste. Model‐free iso‐conversional FWO, KAS, Starink, Kissinger and Vyzovkin and Friedman methods were employed for the kinetic analysis. The apparent activation energy was determined by the integral methods as 206.5‐209.1 kJ mol−1 and 195.6‐198.8 kJ mol−1 for the virgin and waste high‐density polyethylene (HDPE), 211.6‐214.1 kJ mol−1 and 183.1‐186.6 kJ mol−1 for the virgin and waste polypropylene (PP), 144.0‐163.1 kJ mol−1 and 159.7‐167.1 kJ mol−1 for the virgin and waste polystyrene (PS), and 173.6‐178.9 kJ mol−1 for the mixed plastics waste respectively. Ea was found to follow the trend HDPE > PP > PS with higher values for HDPE and PP virgin samples than that for their waste and marginally smaller for the virgin PS than its waste. Degradation of all plastic samples followed Avrami‐Erofeev equation with n varying between 1.0 and 1.8. The effect of conversion on Ea suggested the degradation of both virgin and waste HDPE to consist of multiple parallel reactions while that of others to be more complex. FTIR analysis of the evolved gases was used to explain the possible reaction mechanism. A small difference between the enthalpy change and the apparent activation energy (6‐7 kJ mol−1) for all plastic samples indicated favourable pyrolysis reactions. The estimated kinetic parameters and thermodynamic properties showed the stability of different plastics as HDPE > PP > PS.

Screening of modified kaolin catalysts in the catalytic pyrolysis of waste high-density polyethylene: Kinetics and thermodynamic analysis, Artificial Neural Network prediction, batch pyrolysis study and characterization of liquid fuel

Plastic waste has become a major hurdle in achieving a pollution-free environment for humans to live in. So, recycling used plastic is essential to protect the environment from degrading further. High-density polyethylene is a widely available plastic among the several types of plastics used every day. In the present study, waste HDPE was catalytically pyrolyzed utilizing different acids and alkali-activated kaolin catalysts in batch pyrolysis studies to screen the catalyst and optimize temperature for greater condensable oil output. The HNO3-treated kaolin gives comparably highest oil output with the least reaction time among all catalysts used in the experiment. Kinetics and thermodynamics of HNO3-catalysed pyrolysis of waste HDPE were analyzed from the thermogravimetric data at three heating rates. ANN modelling accurately simulated the TGA data as the value of R2 was near to one. The liquid fuel produced from HNO3-treated kaolin was then analyzed for composition by FTIR, GC-MS and fuel properties. The analysis report confirms the presence of saturated and unsaturated alicyclic hydrocarbons with carbon composition C10-C25. From the composition and fuel properties, it can be concluded that the oil obtained in the catalytic pyrolysis could be used as a feedstock to the petroleum refining industry for obtaining transportation-grade fuels.

Supercapacitor Performance of NiO, NiO-MWCNT, and NiO-Fe-MWCNT Composites.

The NiO-CNT and NiO-Fe-CNT composites that have been prepared from waste high density polyethylene plastic and their carbon nanotube (CNT) quality-dependent supercapacitance tuning have been reported here. Multiwalled CNT (MWCNT) formation has been confirmed from TEM and Raman spectra with an ID/IG ratio of 0.77, which stands for high graphitization. The specific surface area (SSA) of MWCNTs in the NiO-Fe-CNT composite was 87.8 m2/g, while in the NiO-CNT composite, it was 25 m2/g. NiO-Fe-CNT displayed higher specific capacitance and energy density (1360 Fg-1 and 1180 W h kg-1) than NiO-CNT (1250 Fg-1 and 1000 W h kg-1), which may be due to the presence of higher-quality MWCNTs in the NiO-Fe-CNT composite. NiO-Fe-CNT displayed higher contributions of electric double-layer capacitor (59%) behavior compared to NiO-CNT (38%) and represented a hybrid supercapacitor. NiO-Fe-CNT also displayed a capacitive retention of 96% after 1000 charge-discharge cycles. Furthermore, studies in acidic electrolytes revealed higher performance of NiO-Fe-CNT than NiO-CNT, displaying specific capacitances of NiO-Fe-CNT to be 1147 Fg-1 in 2 M H2SO4 and 943 Fg-1 in 2 M HCl. It has been qualitatively explored that the quality of CNTs, SSA, and quantum confinement effects in the composites may be the factors responsible for the performance difference in NiO-Fe-CNT and NiO-CNT. The present work is geared toward the low-cost fabrication of high-quality CNT composites for supercapacitors and energy storage applications. The present work also contributes quantitatively to the understanding of CNT quality as an important parameter for the performance of CNT-composite-based supercapacitors.

Exploring the recycling potential of HDPE films reinforced with flax fiber for making sustainable decorative tiles

The goal of the research was to assess the recycling potential of waste high-density polyethylene (HDPE) films taken as reinforcement with natural fibers to fabricate decorative tiles with improved mechanical properties. Initially, the density of the composite was determined. Further, hardness, quasi-mechanical and impact properties were evaluated for the HDPE/natural fiber composite samples by testing the composites tensile, flexural loads and impact. In addition, to evaluate the thermal characteristics of the composite, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) study were performed. Water absorption and sound absorption properties were determined for industry specific applications. Scanning Electron Microscopic analysis (SEM) was performed for analyzing the microstructure and also HDPE matrix and natural fibers bonding exists in the composite. The findings confirmed that adding natural fibers to the HDPE matrix impressively increased both tensile and flexural strengths by up to 25%. The impact strength was also enhanced by up to 38%, whereas the hardness and density values remained relatively unchanged. Improved interfacial bonding between the HDPE matrix and natural fibers had been identified by SEM analysis, which was a factor in the composite material's enhanced mechanical characteristics. These findings suggest that waste HDPE films/natural fibers composite can be effectively recycled to fabricate decorative tiles with improved mechanical properties, thereby offering a sustainable and eco-friendly alternative to traditional decorative tile materials.

Performance Evaluation of Waste High Density Polyethylene as a Binder Modifier for Hot Mix Asphalt

Performance Evaluation of Waste High Density Polyethylene as a Binder Modifier for Hot Mix Asphalt

Production of gasoline octane booster aromatics benzene, toluene and ethylbenzene from multiphase catalytic pyrolysis of mixed waste expanded polystyrene and high density polyethylene

The main objective of this study is to enhance the valuable octane booster aromatics benzene, toluene, and ethylbenzene (BTE) and reduction of styrene in the fuel oil obtained from the pyrolysis of equally mixed waste expanded polystyrene (WEPS) and waste high density polyethylene (WHDPE). This research article, demonstrated the pyrolysis of equally mixed (50 wt.%:50 wt.%) waste expanded polystyrene (WEPS) and waste high-density polyethylene (WHDPE) followed by in situ-hydrogenation and aromatization in a small laboratory scale reactor for the production of value added commodity and gasoline octane boosters mainly benzene, toluene, and ethylbenzene (BTE). Three reactor arrangements i.e., liquid phase/L-type, vapour phase/V-type, and multiphase/M-type were used for conducting the catalytic pyrolysis of feedstock using ZSM-5, ammonium powder as a catalyst. The maximum liquid yield of 87.41 wt.% was obtained for thermal pyrolysis at a temperature of 650°C and at a heating rate of 15°C/min. Whereas, the maximum liquid yield of 82.65 wt.% was obtained for liquid phase/L-type catalytic pyrolysis at a temperature of 600°C, and at a heating rate of 15°C/min. On the other side, vapour phase/V-type and multiphase/M-type catalytic pyrolysis produced a maximum liquid yield of 78.62 wt.% and 74.07 wt.%, respectively at a reaction temperature of 550°C and at the same heating rate. The pyrolysis oil obtained from thermal pyrolysis contained lowest BTE content of 10.43 wt.% and highest styrene content of 66.25 wt.%. Whereas, the highest BTE content of 30.16 wt.% and lowest styrene content of 53.32 wt.% was found in pyrolysis oil obtained from multiphase/M-type catalytic pyrolysis. The quantitative measurement of BTE and styrene content in the pyrolysis oil was made by the gas chromatography (GC) in a flame ionization detector (FID) mode.

Effects of using waste high-density polyethylene on the rheological, mechanical, and thermal performance of asphalt materials

Effects of using waste high-density polyethylene on the rheological, mechanical, and thermal performance of asphalt materials

Production of liquid hydrocarbons by thermo-acidic method from waste high-density polyethylene.

The study explains the production of useful liquid hydrocarbons by thermo-acidic catalytic thermal degradation of waste high-density polyethylene. A comparative study of the liquid samples with or without catalysts. Energy demand is high in the world. Waste plastic conversion is nowadays a concern of interest research for scientists. HDPE (High-density polyethylene) is the most common plastic used in households. Different types of catalysts and techniques have been used in the alteration process of waste HDPE. This paper deals with the kandite group of catalyst kaolin and the montmorillonite group of catalyst sodium bentonite in acid-activated mutated form. This paper aims to explore the prominent utilization of kaolin clay and sodium bentonite clay minerals as a catalyst for the alteration of waste HDPE into fuel resources and to develop a cost-effective recycling experimental set-up for plastic waste conversion. Thermo-catalytic acid activation has been done for clay mutation. Hydrochloric acid-activated catalysts have been used in this study. FT-IR (Fourier Transform Infrared Spectroscopy) and GC-MS (Gas Chromatography and Mass Spectrometer) techniques have been used to explore the prominent compounds in the product samples. Maximum energy per photon for RO (Parent Oil/Raw Oil) and AO(Acid treated thermo-catalytic oil) samples are respectively 58034.01×1024 Joules and 59271.40×1024 Joules concerning wave numbers 2921.42 and 2983.71 cm-1. Compounds of functional groups C-CH3, CH2, alkenes, and CH3 have been identified for RO and AO samples. Less gaseous hydrocarbons 31.79% (outcomes) or 29.66 % (production yield) and 150.06 % of increment in wax have been calculated after using acid-treated catalysts. Aliphatic compounds like alkanes and alkenes are present in the samples. A mixture of acid-treated kaolin and acid-treated sodium bentonite as the catalysts for degrading waste HDPE into liquid oil greatly reduces wax formation. Average outcomes and production of liquid hydrocarbons are good results with the acid-treated catalytic degradation of HDPE waste. One remarkable fact is that the yield percentage of liquid products is higher in acid-activated catalytic thermal degradation.

Strength Properties of Recycled Waste Plastic and Quarry Dust as Substitute to Coarse Aggregates: an Experimental Methodology

Plastic waste disposal is a significant environmental concern due to its low degradability and management practices, especially in developing countries. Plastic recycling is considered the most effective disposal method, which minimizes environmental impacts. This paper discusses the use of poly(ethylene terephthalate) (PET), high-density polyethylene (HDPE), and polypropylene (PP) plastic as aggregates in the concrete industry by incorporating quarry dust as a base material. An experimental mix design series was carried out, followed by a deoxygenated heat treatment on each mixture for optimum bonding. Compressive strength, specific gravity and water absorption properties were then investigated in each mixture. Although the specific gravity of PET plastic was 30% lower than the natural aggregates, the specific gravity of PET plastic aggregates was higher than the HDPE or PP waste plastic aggregates. Therefore, the proposed method is ideal for low-strength concrete components.

Catalyst-mediated pyrolysis of waste plastics: tuning yield, composition, and nature of pyrolysis oil

With ever-increasing plastic waste, a robust and sustainable methodology to valorize the waste and tweak, the composition of the value added product is the need of the hour. The present study describes the effect of different heterogeneous catalyst systems on the yield, composition and nature of the pyrolysis oil produced from various waste polyolefins like high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and polypropylene (PP). The waste polyolefins were subjected to thermal as well as catalytic pyrolysis. Liquid, gas, and solid products were obtained during the pyrolysis. Various catalysts such as activated alumina (AAL), ZSM-5, FCC catalyst, and halloysite clay (HNT) were used. Usage of catalysts has reduced the temperature of the pyrolysis reaction from 470 to 450°C with better liquid product yield. PP waste generated higher liquid yield compared to LLDPE and HDPE waste. The highest liquid yield of 70.0% was achieved with PP waste using AAL catalyst at 450°C. The sulfur and chloride content was found to be < 10 and < 20ppm respectively in all the pyrolysis liquid. Pyrolysis liquid products were analyzed using gas chromatography (GC), nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray fluorescence (XRF) spectroscopy, and gas chromatography coupled with mass spectrophotometry (GC-MS). The obtained liquid products consist of paraffin, naphthene, olefin and aromatic components. Catalyst regeneration experiments with AAL showed that the product distribution profile remains the same up to three cycles of regeneration.

Development and Performance Evaluation of a Fixed Batch-type Pyrolysis Reactor for Bio-oil Production from Plastic Wastes

A fixed bed batch-type bioreactor for pyrolyzing used or discarded plastic wastes was developed and its performance was evaluated. This research explored the option of converting the high-density polyethylene (HDPE) category of plastic wastes into useful bio-oil in the developed pyrolysis fixed-bed batch reactor. The developed 5 kg batch-type pyrolysis system powered by liquified petroleum gas (LPG) was designed and simulated with SolidWorks computer software to confirm its functionality, fabricated with locally sourced materials, and evaluated with HDPE plastic wastes sorted from dumpsites within the Akure metropolis. The developed reactor evaluation result justified that the pyrolysis reactor has the potential to produce 1.4575 kg of bio-oil per kilogram of liquefied petroleum gas (LPG) consumed. The pyrolytic oil obtained at pyrolysis temperature between 280oC-520oC in this work was thereafter assayed for its composition and fuel properties analyses. The results of the characterization indicated that the pyrolysis of plastic HDPE wastes is a good source of alternative fuel as it shows proximity to the physiochemical characteristics of conventional diesel.

Conversion of waste polyolefins to polyethylene wax via pyrolysis

ABSTRACT Waste polyolefins can be converted into value-added products like oils and chemical waxes by a process called pyrolysis. In the present study, conversion of waste polyethylene to polyethylene (PE) wax was carried out via pyrolysis using a ZSM 5 (zeolite based) and Luperox as catalysts. The effect of pyrolysis residence time, catalyst type, loading on the yield, and properties of the PE wax were investigated. Further, a comparison of the properties of PE wax obtained via pyrolysis and the market sample of PE wax was made to optimize the reaction conditions of pyrolysis. It was observed that with an increase in the catalyst loading and residence time, not just the yield of PE wax reduced but it also led to the degradation in the properties of PE wax. The waxes produced via pyrolysis at residence time of 90 min for waste low-density polyethylene and 150 min for waste high-density polyethylene exhibited properties comparable to that of the market sample of PE wax. The PE wax thus obtained has application in textile coatings, plastic processing, and printing inks.

Physical and mechanical properties of synthetic beams from high density polyethylene waste

Improper processing of plastic waste can cause several environmental problems, such as air pollution, soil damage, respiratory diseases, and others. This research utilizes high density polyethylene (HDPE) waste as a basic material for synthetic beams. The manufacture of synthetic beams goes through several stages, such as washing, drying, crushing, chopping, and melting HDPE waste, as well as moulding into a block. The physical properties examined in this study include compressive strength, flexural strength, density, and ductility which refer to SNI 03-3958-1995 and SNI 03-3959-1995 codes. From the test results, it was obtained that the average compressive strength and flexural strength of synthetic beams were 1.52 – 2.53 MPa and 0.61 – 0.95 MPa, respectively. Synthetic beams have an average modulus of elasticity of 109.4 MPa, and a density of 834.8 kg/m3. The test results from this study indicate that the strength of synthetic beams from HDPE is low and does not meet the requirements for use as a construction material. In further research, innovation is needed to obtain stronger synthetic beams.

Production and characterization of liquid oil from the pyrolysis of waste high-density polyethylene plastics using spent fluid catalytic cracking catalyst

Production and characterization of liquid oil from the pyrolysis of waste high-density polyethylene plastics using spent fluid catalytic cracking catalyst

Performance of a membrane fabricated from high-density polyethylene waste for dye separation in water.

Industrial growth can have a good impact on a country's economic growth, but it can also cause environmental problems, including water pollution. About 80% of industrial wastewater is discharged into the environment without treatment, of which 17-20% is dominated by dyes, such as methylene blue (MB) and methyl orange (MO) from the textile industry. Only about 5% of a textile dye is used in the dyeing process and the rest is discarded. This problem, of course, requires special handling considering the harmful effects to health. On the other hand, the abundance of plastic waste is increasing by 14% or 85 000 tons per year. This problem must be solved due to its film-forming properties. High-density polyethylene (HDPE) is one type of plastic used as a membrane material. Therefore, in this study, HDPE plastic waste was utilized as a membrane for dye removal. In this study, HDPE plastic waste was fabricated via a thermal-induced phase-separation method using mineral oil as a solvent at various concentrations of 8%, 10%, 13%, and 15% (w/w). All the membranes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and contact angle measurements. The results showed that the HDPE membrane at a concentration of 15% displayed the best performance compared to the others in terms of MB rejection. The negative charge (-36.9) of the HDPE membrane was more effective for cationic dye removal compared to the anionic dye. The flux and rejection of HDPE 15% for 100 ppm MB and MO removal were 2.71 and 4.93 L m-2 h-1, and 99.72% and 89.8%, respectively. The pure water flux of the membrane was 15.01 L m-2 h-1 and the tensile strength was 0.3435 MPa.

Experimental Investigation on Pyrolysis of Domestic Plastic Wastes for Fuel Grade Hydrocarbons

Plastics usage is rising daily because of increased population, modernization, and industrialization, which produces a lot of plastic garbage. Due to their various chemical structures, long chain polymeric compositions, and thermal/decomposition behavior, it is challenging to recycle these plastic wastes into hydrocarbon fuels. In the current work, domestic plastic waste was pyrolyzed at 473 to 973 K in a fixed bed reactor and compared with the three virgin plastics LDPE (low-density polyethylene), HDPE (high-density polyethylene), and PP (polypropylene), as well as a mixture of the three (virgin mixed plastics). The pyrolysis results showed that maximum liquid hydrocarbons obtained from HDPE, LDPE, PP, mixed plastic, and domestic waste were 64.6 wt.%, 62.2 wt.%, 63.1 wt.%, 68.6 wt.%, and 64.6 wt.% at 773 K, respectively. The composition of liquid fuels was characterized using FTIR and GC-MS, which showed a wide spectrum of hydrocarbons in the C8–C20 range. Furthermore, liquid fuel characteristics such as density, viscosity, fire and flash point, pour point, and calorific value were examined using ASTM standards, and the results were found to be satisfactory. This study provides an innovative method for recycling waste plastics into economical hydrocarbon fuel for use in transportation.