Waste High-density Polyethylene Research Articles

Prolonged Lifespan of Superhydrophobic Thin Films and Coatings Using Recycled Polyethylene.

High-density polyethylene (HDPE) waste poses a significant environmental challenge due to its non-biodegradable nature and the vast quantities generated annually. However, conventional recycling methods are energy-intensive and often yield low-quality products. Herein, HDPE waste is upcycled into anti-aging, superhydrophobic thin films suitable for outdoor applications. A two-layer spin-casting method combined with heating-induced crosslinking is utilized to produce an exceptionally rough superhydrophobic surface, featuring a root mean square (RMS) roughness of 50 nm, an average crest height of 222 nm, an average trough depth of -264 nm, and a contact angle (CA) of 148°. To assess durability, weathering tests were conducted, revealing the films' susceptibility to degradation under harsh conditions. The films' resistance to environmental factors is improved by incorporating a UV absorber, maintaining their hydrophobic properties and mechanical strength. Our research demonstrates a sustainable method for upcycling waste into high-performance, weather-resistant, superhydrophobic films.

Revitalizing high-density polyethylene (HDPE) waste: from environmental collection to high-strength hybrid yarns

AbstractPlastic products are used in large quantities. However, the fact that plastics do not degrade in nature for many years causes environmental pollution. Addressing this issue, the study focuses on recycling the widespread high-density polyethylene (HDPE) plastic waste. In this study, HDPE waste was collected randomly from the environment, mirroring real-world scenarios. Then, the waste was transformed into granules. Afterward, washing and drying processes were carried out. HDPE filaments of different linear densities were successfully produced from the waste plastic granules. Tensile tests revealed that the breaking strength of the filaments from waste plastic was lower than that of virgin HDPE filaments, highlighting the challenges of recycling. Hybrid yarns were formed by twisting the filaments with cotton yarn to improve the mechanical properties of the filaments from waste plastic. Remarkably, statistical analysis demonstrated that the breaking load values of the hybrid yarns from waste plastic were statistically equivalent to those made from virgin polymer. This outcome indicated that the hybrid yarns made from waste HDPE plastic were as strong as those made from virgin HDPE polymer. In addition, both hybrid yarns exhibited a breaking load 36% higher than the reference extra-twisted cotton yarn. The hybrid yarn formation made filaments produced from waste plastic a valuable component of the high-strength hybrid yarn. Overall, this study shows that recycling HDPE plastics can lead to the production of high-strength hybrid yarns, which can contribute to reducing plastic waste pollution.

Performance evaluation of SBS-modified asphalt mixtures incorporating waste tire rubber and HDPE

Based on the functional complementarity of waste tire rubber (WTR) and waste high-density polyethylene (HDPE) in asphalt, this study presents a novel approach that simultaneously utilizes WTR and HDPE for modification and substitution of styrene-butadiene-styrene (SBS) modified asphalt. Through experiments on three major indicators, the dosage ratios of the three polymers are scientifically designed using the response surface methodology, and four different ratios of SBS-HDPE-WTR are selected to prepare modified asphalt mixtures. Performance evaluations are conducted on various pavement properties, including high-temperature stability, low-temperature crack resistance, water stability, fatigue resistance, and aging resistance, by comparing them to the reference 4% SBS-modified asphalt mixture. The results demonstrate that the addition of WTR significantly improves the elastic properties and fatigue resistance of the mixture, while the addition of HDPE enhances its high-temperature stability and aging resistance. The SBS-HDPE-WTR asphalt mixtures, designed with appropriate ratios, exhibit superior high-temperature stability, low-temperature crack resistance, and fatigue resistance. Therefore, the use of these waste materials in asphalt mixtures offers a sustainable and environmentally friendly solution for the construction industry.

Studies on partial replacement of waste high density polyethylene (HDPE) and polypropylene (PP) plastic with fine aggregate (FA) on mechanical, durability and thermal properties of M30 and M40 grade concrete

The aim of the present paper is to incorporate two different waste plastic materials that is High-Density Polyethylene (HDPE) and Poly-Propylene (PP), were replaced with Fine Aggregate (FA) at a 10% by 2.5% increment. The widespread formation of HDPE and PP waste plastics has become a major environmental issue, endangering ecosystems and human health. Traditional disposal techniques, such as landfills and incineration, lead to pollution and resource depletion. Incorporating these polymers into concrete provides a long-term solution that reduces environmental effect while improving material qualities. The Different tests conducted are compressive strength (3, 7, 28 and 60 days) (150 × 150x150 mm), flexural strength (3, 7, 28 and 60 days) (100 × 100x500 mm), acid attack (28, 56 and 90 days) (100 × 100x100 mm), sulphate attack (28, 56 and 90 days) (100 × 100x100 mm), and thermal conductivity (180 mm dia x 20 mm thick). The compressive strengths of 40.52 MPa and 38.41 MPa for PP and HDPE material were observed in M30-grade concrete, respectively. Similarly, for M40-grade concrete, 43.6 MPa and 41.8 MPa are for PP and HDPE material, respectively. The optimum percentages of 5% and 7.5 for PP and HDPE material, respectively, can be replaced in concrete for flexural strength in both M30 and M40 grades. The least percentage loss in acid attack was observed at 28 days for both HDPE and PP material, but for 56 days and 90 days, the percentage loss of weight was significantly less (< 5%). The sulphate attack for both M30 and M40 grade concrete showed less than 10% percentage loss in weight after 90 days. Thermal conductivity (k) was also reduced by 30–35% for both HDPE and PP material, with 10% replacement in concrete for M30 and M40 grades. The use of Waste HDPE and PP material can be used to improve the mechanical, durability & thermal property of M30 and M40 grade concrete under controlled conditions.

Adsorption of CO2 and H2 on the polymer-based membrane from High-density Polyethylene (HDPE) Plastic

High-density polyethylene (HDPE), a widely used polymer globally, notably found in plastic bags, presents an environmental concern due to its non-biodegradable nature. Transforming non-biodegradable HDPE waste into a valuable resource presents a formidable ecological challenge. This research aims to study CO2 and H2 gases toward HDPE-based membranes through the adsorption process with pressure and temperature variation. The highest CO2 and H2 adsorption capacities of 14.19 mmol.g−1 (62.43 %wt) and 18.04 mmol.g−1 (3.61 %wt) were obtained by pressure feeding 3 bar at 30°C. The adsorption capacity decrease as the temperature increase. At an adsorption temperature of 50°C, the adsorption capacity of CO2 and H2 decrease, respectively by 75.86 % and 69.81 %. The adsorption kinetics were evaluated using pseudo-first order, pseudo-second order, and intraparticle diffusion models. The kinetic study shows that adsorption at 30°C follows the pseudo-second order. The adsorption at elevated temperatures reveals the intraparticle diffusion mechanism, indicating that the gas is adsorbed directly into the polymer matrix. Thermodynamic results include enthalpy of adsorption (ΔH), standard entropy of adsorption (ΔS), energy Gibbs (ΔG), and energy activation (Ea). ΔH CO2 and H2 are -22.339 and -23.654 kJ mol−1, respectively, which indicates that the process is exothermic and physisorption. The ΔS value shows that the irregularity and randomness of gas movement during the adsorption process, with the respective values for CO2 and H2 are -0.069 and -0.072 kJ mol−1K−1, respectively. ΔG for adsorption of CO2 and H2 with increasing temperature becomes less spontaneous, which results in decreased adsorption capacity. Ea of CO2 is greater than H2, so the adsorption capacity of CO2 is smaller than H2. The thermodynamic study shows that the adsorption process is preferable at lower temperatures.

The Role of Zeolite (Microporous Crystalline Aluminosilicates) In Catalytic Pyrolysis of Waste High- and Low-Density Polyethylene Bags for Production of Fuel and Chemicals: A Review

This review provides a state-of-the-art summary of the role which zeolite plays as a catalyst via pyrolysis as a way of recovering fuels and chemicals from waste high and or low density polyethylene bags. It also highlighted the two types of zeolite (natural or synthetic) which are used as a two-stage pyrolysis−catalysis in giving a free waxing product to pure fuel and chemicals which can be subjected to further analyzing and or upgrading. As yield of oil/wax decreased with the addition of a zeolite as catalyst from 44 and 51 wt.%, (depending on the waste high density polyethylene “HDPE” or low density polyethylene bags “LDPE” and other factors). However, the composition of the pyrolysis−catalysis oils significantly increased in aromatic hydrocarbon content accordingly. In addition, the composition of the oils shifted from high molecular weight hydrocarbons (C16+) to fuel range hydrocarbons (C5−C15), with a high content of single-ring aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylenes, and styrene. This process shows great potential for production of fuels or chemicals, and also addresses the urgent issue of waste HDPE and or LDPE disposal.

Blending action of pyrolysis oil/diesel fuel featured with hydrogen on compression ignition engine performance and emission analysis

Waste high-density polyethylene (HDPE) is a non-biodegradable toxic, and harmful material. To maintain environmental sustainability, the waste HDPE involves alternative fuel extraction. The main objective of this study is to extract the alternative oil fuel from the source of the waste HDPE through pyrolysis with a reactor temperature of 300–550 °C and study the compression ignition (CI) engine performance and emission behavior. ASTM standards evaluate the physical and chemical properties of oil fuel, and its results showed that 40 and 43 °C flash and fire point temperatures, better Cetane number of 49, and a good calorific value of 43.17 MJ/kg. The CI engine performance and its emission behavior are experimentally studied with different blending ratios of HDPE oil: hydrogen: diesel fuel like 0:0:100 (D), 0:5:95 (5HD), and 10:5:85 (10B5HD). With this output, results of 10B5HD exhibited better engine performance like better brake power (BP–6.78 kW), optimum brake specific fuel consumption (BSFC-0.52 kg/kWh), improved brake thermal efficiency (BTE-28.78%) and reduced emission behavior including carbon monoxide (CO-0.43%) and carbon dioxide (CO2-24 ppm), hydrocarbon (HC-5.4%) and nitrogen oxide (NOx-760 ppm). Based on these results, 10B5HD performed better than diesel fuel and was utilized in future alternative fuel applications.

An Aspen plus process simulation model for exploring the feasibility and profitability of pyrolysis process for plastic waste management

Plastics, integral to various human activities, have led to a surge in production, posing substantial challenges in waste management. The persistent non-biodegradability of plastics, taking over a century to decompose, necessitates exploration into technologies for their conversion into sustainable fuels. Pyrolysis, an oxygen-free thermal decomposition process, emerges as a promising avenue for producing liquid fuels from plastic waste. This study's primary objective is to create and validate an Aspen Plus simulation model, enabling techno-economic evaluation and sensitivity analysis of pyrolysis for converting waste plastics into liquid fuels. Critical parameters—temperature, retention time, and particle size—are examined for their impact on product yield and quality. The methodology involves model development, validation, and subsequent simulations with various waste plastic types under different pyrolysis conditions. Experimental investigation using waste high-density polyethylene (HDPE) in an auger reactor yielded an oil yield of 61.29%, char yield of 10.98%, and syngas yield of 27.73% at 525 °C. Post-validation against this data, the model explored four plastic types, revealing significant influences of plastic type and reactor temperature on product yields. Polystyrene (PS) at 500 °C produced the highest oil content at 83.69%, with temperature affecting yield before secondary cracking. Techno-economic evaluation for a pyrolysis plant processing 10,000 tons of waste HDPE annually indicated a minimum selling price (MSP) of $302.50/ton, a net present value (NPV) of $12,594,659.7, and a 1.03-year payback period. This study provides crucial insights for designing an economically viable and sustainable pyrolysis process, guiding further research and industrial implementation.

The study of High-Density Polyethylene (HDPE) waste utilization into particle board

This research discusses related to one of the processing of waste, especially HDPE waste. HDPE waste is another alternative besides wood to make particle board. HDPE particle board takes advantage of these properties to provide a strong and durable alternative. The use of HDPE particle board provides significant benefits in the context of sustainability and the environment. In the manufacture of particle board in this study there were differences in temperature variations, so the variable in this study was temperature. Sample A has a temperature of 130° and sample B has a temperature of 160°. The particle board is pressed for 20 minutes using a hot press machine using 1 x 1 m molding. Testing of this HDPE particle board includes testing of physical properties, namely in the form of Density and chemical testing in the form of Acidity resistance and Alkalinity resistance. The standards in this study refer to SNI 03-2105-2006 regarding Particle Boards, SNI 01-7201-2006 regarding Plywood and block boards with beautiful paper faces, and ASTM D543. The density test showed a value of 0.90 gr/cm3 in the average sample A and 0.75 gr/cm3 in the average sample A. The results of the ANOVA analysis on the Density test showed that there was a significant difference between each sample and each treatment. the results of the t-Test showed that the treatment of sample A did not meet the standard, while the treatment of sample B met the SNI 03-2105-2006 standard. The acidity and alkalinity resistance were tested visually with the results that the temperature at 130° was more susceptible to reaction than the temperature at 160° Objectives: To find out the result of Density test, Acidity, and Alkalinity resistance of HDPE Particle Board is it already fulfill the standard ; To determine the temperature that has the most significant impact on the performance of HDPE Particle Board. Method and results: 1) Process of making the Particle Board, the process are include material preparation, material weighing, shredding, cleaning, drying, and pressing. 2) Sample Testing, the treatment that used is about variation of temperature. Variable that be used in this study consist of Density, Acidity, &amp; Alkalinity. 3) Data Analysis, by using ANOVA Single Factor and t-Test. Conclusion: The results of Density test by t-Test analysis showed that the treatment of sample A did not meet the standard, while the treatment of sample B already fulfill the SNI 03-2105-2006. In Acidity and Alkalinity resistance there are indicators according to SNI 01-7201-2006 in the form of softening and open cracks in several samples. Density test results show the variable B (160°) is at 0.75 gr/cm3 and already fulfil the standard. Visual test results of Acidity and Alkalinity resistance show the variable B (160°) is more resistant to the effects of acids and bases. So that the optimal variable is at a temperature of 160°.

Effects of waste high-density polyethylene (HDPE) on asphalt binder and airfield mixes

ABSTRACT Flexible airport pavements may require polymer-modified asphalt binder for their asphalt concrete (AC) mixes to withstand heavy gear loading and slow traffic moving in taxiways and aprons. Waste plastics could be repurposed as a possible alternative to Styrene–butadiene-styrene (SBS) modifiers. In this study, the feasibility of using granulated recycled high-density polyethylene (HDPE) waste was evaluated as an asphalt binder modifier for airfield pavements. A base asphalt binder was modified with waste HDPE to obtain a Superpave performance grade (PG) of 70-22. Adding waste HDPE would increase binder’s stiffness and bond to aggregate, it slightly improved ductility and elasticity; but less than SBS polymer-modified binders. The AC mixes prepared with waste HDPE-modified binder showed less potential for rutting and cracking compared control AC mixes with PG 64-22. However, the rutting and cracking potential was higher when compared to their SBS-modified PG 70–22 counterparts. On the other hand, AC mixes containing waste HDPE-modified binder were less susceptible to moisture-induced damage. It appears that using waste HDPE-modified binder is feasible where improving adhesion and resistance to moisture-induced damage AC mixes are needed and embrittlement and elastic recovery are not critical, while meeting rutting and cracking potential regional thresholds.

Comparative Analysis of Kerosene Grade Fuel from Pyrolysis of HDPE and LDPE Waste Plastics

To curb the menace of plastic waste and energy crisis, this study investigated the conversion of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) grades of plastics to kerosene. Plastics sourced from dumpsites within Port Harcourt metropolis in Rivers State, Nigeria were shredded and pyrolyzed (thermally degraded under inert condition at a temperature range of 350-400oC). The obtained hydrocarbon liquid was distilled using distillation column at a temperature range of 150-270oC and characterised to evaluate the physico-chemical parameters such as flash point, density, copper corrosion, and calorific value and compared against the acceptable standard. The result showed that these properties were within the permissible limit. However, the sulphur content and smoke point of HDPE and LDPE were above and below the limits, respectively. The GC-MS and GC-FID results of kerosene samples obtained from both grades of plastics indicates that the product comprised C9 to C17 grades.

Initiative to Increase the Circularity of HDPE Waste in the Construction Industry: A Physico-Mechanical Characterization of New Sustainable Gypsum Products

The annual production of plastic waste worldwide has doubled in just two decades, with approximately 390 million tonnes of plastic waste now being generated. In this context, the construction industry must move towards the development of new, more sustainable materials made under circular economy criteria. In this work, a physico-mechanical characterisation of gypsum composites with the incorporation of high-density polyethylene (HDPE) waste, replacing 2–4–6–8–10% by volume of the original raw material, has been conducted. The results show how the incorporation of these plastic wastes improves the water resistance of the gypsum material without additions, as well as producing a decrease in thermal conductivity and greater resistance to impact. On the other hand, it has been found that, as the percentage of recycled raw material added increases, the mechanical resistance to bending and compression decreases, leading to fracture due to a lack of cohesion between the matrix and the waste. Nevertheless, in all the cases studied, mechanical strengths higher than those established by the EN 13279-2 standard were obtained. Thus, the results confirm the viability of these secondary raw materials to be used in the development of new products for sustainable building, especially in the design of prefabricated panels for false ceilings.

Catalytic pyrolysis of waste high-density (HDPE) and low-density polyethylene (LDPE) to produce liquid hydrocarbon using silica-alumina catalyst

Catalytic pyrolysis of waste HDPE and LDPE polyethylene was successfully carried out using a silica-alumina catalyst at 450 °C under N2 atmosphere. The synthesized silica-alumina is mesoporous and shows type IV isotherm. Thermal pyrolysis (without any catalyst) provided 47% wax-like hydrocarbons at 485 °C. On the other hand, more than 80% liquid yield was achieved using silica-alumina catalysts from waste HDPE and LDPE. The highest liquid yield was obtained from LDPE (87.69%) than HDPE (83.25%) at a catalyst-to-plastic ratio of 1:25. The 1H NMR shows that the liquid product does not contain any aromatic compound. The GC-MS, 1H NMR, and FTIR confirmed that the liquid contains linear and branched alkanes and alkenes. J. Bangladesh Acad. Sci. 47(2); 195-203: December 2023

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 (&lt;1 mm, &lt;2 mm, &lt;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 &gt; PP &gt; 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 &gt; PP &gt; 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.