Low Density Polythene Research Articles

Recycling, thermophysical characterisation and assessment of low-density polythene waste as feedstock for 3D printing

Low-density polyethene (LDPE) is extensively used in single-end-use food packaging and contributes significantly to global waste plastic. This study addresses this challenge by introducing a sustainable approach to reclaim and valorise waste LDPE from milk packaging by converting them into 3D printing filaments. The process involves extruding shredded LDPE pouches into continuous filaments using a modified thermal extruder. The research comprehensively investigates the effects of two key extrusion parameters, nozzle temperature and screw speed, on the resulting filament's physical and mechanical properties. Characterisation efforts include dimensional analysis, morphological evaluation, chemical integrity assessment, thermal stability analysis, and tensile testing. The results show that filaments remain consistently close to 1.75 mm diameter, which is required by most commercial FDM 3D printers. The filaments are chemically intact, thermally stable, and have high toughness across the range of extrusion parameters. The results and a preliminary demonstration of 3D printing indicate that the LDPE waste can be effectively transformed into consistent filaments that have the potential for 3D printing. A carbon footprint assessment underscores the environmental benefits of this approach, showing substantial reductions in estimated CO2 emissions compared to conventional filament production methods. While challenges related to the quality of printed parts remain, the research opens avenues for optimizing 3D printing parameters and exploring multiple recycling cycles. This work represents a step towards sustainable plastic waste management and offers insights into transforming single-use plastic items into valuable resources.

Precision Nutrition – Evaluating Dietary Protein and Amino Acid Intake among Children Using Duplicate Dietary Samples

Introduction: Precision nutrition, at the intersection of science and health, offers tailored dietary intervention, particularly vital for vulnerable populations like children. Focusing on protein and essential amino acids (AA), crucial for health, personalized approaches are keys for addressing deficiencies, and moving beyond generalized methods. While research on the dietary duplication technique has explored various nutrients, but there is a gap in understanding its use for assessing protein and amino acid intake, especially in children. Aim: The study aims to use the dietary duplication technique to assess the precise dietary intake of protein and AA in children, focusing on determining their exact portions and analyzing duplicate samples for content. Methods: A cross-sectional study in Chennai involved 12 children aged 4–9 years. Duplicate food portions for a day were collected from mothers in low-density polythene bags. Samples were analyzed for protein and amino acid content in a National Accreditation Board for Testing and Calibration Laboratories-accredited laboratory. Results: Girls exhibited deficient levels of histidine, lysine, phenylalanine, threonine, and tryptophan, while isoleucine met the Recommended Dietary Allowances threshold. A t-test showed significant differences in threonine levels among 4–6-year-old children, with no notable variations in 7–9-year-old children. Conclusion: This study emphasizes the importance of precise nutrition, particularly protein and essential AA, crucial for children’s health. Addressing undernutrition is crucial, and highlighting the urgency of this concern.

Valorisation of low-density polythene (LDPE) waste into fuels and chemicals through alkane hydroxylase and microbial treatment

Polythene exhibits low reactivity and slow biodegradability due to its highly reduced hydrocarbon structure. In this study, a process has been developed for the transformation of polythene waste into fuel and its precursor molecule by microbial and enzymatic treatments. In first step polythene was pretreated with Paenibacillus alvei. Through fermentation process for 15 days and products released after fermentation were subsequently bio-transformed into alcohols and acids corresponding to its hydrocarbons, employing Alkane hydroxylase (AlkB). On fermentation using Paenibacillus alvei, 16.8% weight loss was observed after 15 days and surface modification was analyzed through AFM and SEM. The major products released during microbial pretreatment analyzed through Chromatography–High-Resolution Mass Spectrometry (GC-HRMS) were pentane, hexane, heptadecane, dodecane, tetracontane, bromotetradecane, methyl esters, hexadecane, etc. which were converted in second step into hexadecanol, octadecanol, octadecanoic acid, and heptadecanoic acid, etc. with the help of Alkane hydroxylase on enzymatic transformation. These findings suggested that the microbial pretreatment results in a release of alkanes, some fatty acids, and esters using Paenibacillus alvei Among these, AlkB facilitated the transformation of C16 and C15 hydrocarbons into hexadecanol, and pentadecanol respectively. This process holds the potential as an alternative to traditional fuels, and an optimization process can be pursued to enhance the overall yield.

Biodegradation of low-density polythene (LDPE) by a novel strain of Pseudomonas aeruginosa WD4 isolated from plastic dumpsite.

The present study was proposed with the idea to screen and isolate efficient low-density polyethylene (LDPE) degrading novel bacterial strains from the plastic-contaminated dumping site. The identification of the bacterial isolate was performed with the help of microbiological and molecular characterization approaches. The screening of the best isolate was performed based on its growth in Bushnell-Hass broth supplemented with LDPE sheets as the sole carbon source. The molecular characterization revealed that the isolate WD4 showed a similarity with the Pseudomonas aeruginosa species. A comparative analysis of Pseudomonas aeruginosa WD4 identified in the current study with Pseudomonas putida MTCC 2445 strain was performed. The present study demonstrated that the bacterial isolate showed 9.2% degradation of LDPE films while Pseudomonas putida revealed a 6.5% weight reduction after 100days of incubation at 37°C. The end products of the LDPE degradation were analysed using Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS). The LDPE degradation products eluted include fatty acids such as octadecanoic, hexadecanoic acid, dodecanal, and octyl palmitoleate, alkanes, and some of the unknown compounds after 100days of microbial treatment with the isolated strain. The detailed analysis of the by-products generated in the current study indicates their contribution to the biochemical pathway of LDPE degradation. The profound scope lies in the scalability of these bacterial strains at the industrial level to combat the LDPE waste and similar plastic garbage problems, globally.

Biodegradation of Low-Density Polythene (LDPE) by Microbes Isolated from Plastic Polluted Sites Majorly Consisting of Laboratory Waste

Biodegradation of Low-Density Polythene (LDPE) by Microbes Isolated from Plastic Polluted Sites Majorly Consisting of Laboratory Waste

Theoretical investigation of combustion and emissions of CI engines fueled by various blends of depolymerized low-density polythene and diesel with co-solvent additives

The depletion of fossil fuels and the accumulation of plastic waste are both serious issues facing the world today. This study investigated the potential use of plastic waste as an alternative fuel by utilizing diesel (D) to depolymerize low-density polyethylene (LDPE) in the presence of co-solvents. Several co-solvents were examined: a-pinene, toluene, and o-xylene, with ratios of 10% weight in the LDPE/diesel blend. The blends were theoretically tested in a diesel engine to investigate the impact on the combustion characteristics and emissions. According to tested data, the in-cylinder peak pressure and temperature decreased within the blend of D/LDPE in comparison to diesel at all engine loads. However, when co-solvents were added to the D/LDPE blend, in-cylinder pressures increased during the combustion at all loads, with improvements of 0.48%, 0.5%, 0.6%, and 0.4% for the blends of D/LDPE (10% toluene and 1 bar), D/LDPE (10% a-pinene and 1 bar), D/LDPE (10% xylene and 1 bar), and D/LDPE (10% xylene and 10 bar), respectively, in comparison with diesel at 100% load. Co-solvent additions such as a-pinene and o-xylene to the plastic/diesel blend resulted in a substantial and gradual increase in the heat release rate at high loads. In respect to emissions, carbon monoxide, unburnt hydrocarbon, and soot levels were raised by adding LDPE plastic to D and reduced by adding co-solvents. The most effective co-solvents for decreasing carbon monoxide, unburnt hydrocarbon, and soot emissions were pinene, followed by xylene.

A landfill serves as a critical source of microplastic pollution and harbors diverse plastic biodegradation microbial species and enzymes: Study in large-scale landfills, China

Microplastics (MPs) are emerging pollutants. Landfills store up to 42% of worldwide plastic waste and serve as an important source of MPs. However, the study of MPs distribution and the plastic biodegradation potential in landfills is limited. In this study, the distribution of abundance, size, morphology and polymer type of MPs and plastics biodegradation species in refuse samples along landfill depths were extensively investigated within a large-scale landfill in Shenzhen, China. In addition, plastics biodegradation enzymes were evaluated in seven Chinese large-scale landfills leachate. MPs distribution pattern was investigated in all refuse samples. The abundance of MPs in refuse samples varied between 81 and 133 items/g. The size of MPs in all samples varied between 0.03 and 5 mm, and the average sizes were 1.2 mm ± 0.1 mm. The main morphology and polymer type were fragments and cellophane, respectively. Landfill depth was significantly negatively correlated with the relative abundance of MPs size 1–5 mm (p < 0.05) and was positively correlated with the relative abundance of MPs size < 0.2 mm (p < 0.05), suggesting that plastics were broken down during municipal solid waste decomposition. The multiple regression on matrices analysis further showed the landfill depths and plastic morphology significantly impact the MPs distribution. The strains, Lysinibacillus massiliensis (with relative abundance of 1.8%) for low-density polyethylene and polystyrene biodegradation, and Pseudomonas stutzeri (0.1%) for low density polythene and polypropylene biodegradation, were detected on the plastic surface with high relative abundance. Furthermore, 75 plastic degradation species and their associated 31 enzymes (breakdown 24 plastics) were discovered in seven landfills leachate samples.

Low-temperature diesel-induced depolymerization of waste polyethylene

Plastic waste poses a significant threat to the environment due to its slow degradation and low recyclability. In recent years, thermochemical and biological processes for turning plastic waste into useful fuel and chemicals have been developed, but multiple processing steps and susceptibility to contaminants have so far prevented their widespread deployment. This study reports the diesel-induced depolymerization process for low density polythene (LDPE) at a low temperature to produce easily separable liquid and solid products. The produced liquid stream can be utilized as an alternative fuel, due to its chemical compatibility with diesel. The LDPE was dissolved in diesel at a range of temperatures (80–165 °C), reaction times (0.5–10 h), and ratios of LDPE to diesel under inert atmosphere. It was found that the LDPE/diesel weight ratio was the most significant process variable, with up to 95 wt% of the LDPE being converted into liquid phase and blended with the diesel fuel. The temperature at which the dissolution took place also played a role in the LDPE conversion; a higher temperature led to a greater degree of LDPE dissolution. The solubility of LDPE was not significantly affected by the reaction time. The dissolution of LDPE in diesel fuel led to a rise in the kinematic as well as the dynamic viscosity. The resulting liquid diesel/LDPE mixture also exhibited an increased high heating value (HHV). The measured HHV was 45.2439 MJ/kg for pure diesel, 45.5247 MJ/kg for diesel mixed with LDPE at 135 °C, and 45.9247 MJ/kg for diesel mixed with LDPE at 165 °C.

Development and quality evaluation of rice-wheat composite flour cake using special rice variety BR14

The study was conducted to develop and evaluate the nutritional, physical and sensory quality along with storage attributes of cake enriched with a special rice variety released from Bangladesh Rice Research Institute, BR14. The percentages of rice flour used in the cake formulations were 20%, 50%, and 100% to replace wheat flour. The moisture, protein, fat, ash, crude fiber and carbohydrate content of composite flour cake samples were found in the range of 21.67-28.33%, 5.60-6.50%, 14.41-21.07%, 0.95-1.02%, 0.49-1.27% and 49.81-54.03% respectively. The composite flour cake samples with different level of rice flour were found nutritionally better than the control sample although there were remarkable changes in specific volume, crumb and the crust color with different levels of rice flour supplementation. In addition, a significant variation in color, flavor, texture, taste and overall acceptability of cake samples were also observed. Cake sample with 50% rice flour substitution was the most acceptable in terms of color, flavor, texture and overall acceptability compared to other samples. The cake samples were packed in low density polythene bags and changes in moisture content were evaluated storing in room temperature (250 C). Thus, acceptable cake formulations in comparison with wheat flour cake were developed with special rice flour supplementation

Effects of storage conditions on the different attributes of deoiled rice bran incorporated extruded product

The purpose of this study was to develop extruded snack product using optimized formulation of rice flour, corn flour and deoiled rice bran. The properties like lateral expansion (LE), bulk density (BD), water absorption index (WAI), water solubility index (WSI) and hardness of the optimized extruded product were investigated.The storage studies of quality extruded product showed greater changes to moisture content and hardness packed in low density polythene in comparison to aluminium laminated pouches kept under ambient and accelerated conditions. Higher variation in quality parameters was observed at accelerated storage condition. Therefore, it was suggested that aluminium laminated packaging materials can store extruded product for a longer time period than low density polythene packs in both storage conditions.

Photocatalytic degradation of low-density polythene using protein-coated titania nanoparticles and Lactobacillus plantarum

ABSTRACT The biodegradation of low-density Polyethylene (LDPE) is usually time-consuming, In the presence of Titania-nanoparticles, LDPE is photocatalytically degraded in smaller fragments afterward the bacteria can effectively degrade polyethylene. In the current study, potent polyethylene degrading bacteria were screened from the soil of the local dumpsite and identified using 16s rRNA sequencing. The protein-coated titania nanoparticle (TNPs) was synthesized using Sol-gel Method and characterized by XRD, and SAED-HRTEM. The photocatalytic biodegradation of LDPE (30 microns) in presence of 1M NaOH was studied by exposing it to UV irradiation, visible light, and high temperature (50°C) for 21 days separately and photocatalytic biodegradation was assessed by monitoring % weight loss at every 7 days’ time interval, tensile strength, and FTIR. After 21 days of photocatalytic biodegradation, LDPE film containing both TNPs and Lactobacillus plantarum along with 1M NaOH in presence of visible light was unveiled oxidation and enumerated via the occurrence of strong absorptions band of the carbonyl group (C=O) and also the breaking and weakening of existing absorptions bonds along with the new carbonyl functional group formation. The decline in tensile strength was measured at 21% after 21 days. Thus, experimental results on LDPE after exposure to visible irradiation along with Lactobacillus plantarum and 5% protein-coated TNP showed improvement in degradation rate and elongation 59 % and 51% within 21 days, respectively in comparison to another study (49 % Weight loss and 12% elongation after 45 days). An excellent application of this research is significantly reduced plastic waste via a maintained procedure.

Energy, exergy and techno-economic analysis of novel solar stills for sea coastal area

This paper presents the energy, exergy, and economic analysis of conventional solar still (CSS) and Modified solar still integrated with sand bed earth (MSSIE). The energy analysis has been done with the help of Dunkle and Kumar & Tiwari after using modified relations of Tsilingiris. Throughout the experimentation, the internal efficiency of MSSIE is higher than CSS (viz. 14.67%). The MSSIE shows a 41.9% higher value of exergy efficiency after 14:00 h than CSS. The distillate yield recorded from MSSIE is 12.64% higher than CSS. The AWC has been evaluated as 1.2, 1.33, 1.47 and 1.29, 1.44, 1.59 INR/l at an interest rate of 8, 10 and 12% for CSS and MSSIE with GI tray, respectively. Whereas, AWC for MSSIE get reduced by 9.2, 8.3 and 8.8% compared to CSS for the same rate of interest without GI tray.Abbreviations: AC: Total annual cost (INR); AMC: Annual maintenance cost (INR); ASV: Annual Salvage value (INR); AWC: Annual water cost (INR/l); CRF: Capital recovery factor; FAC: First Annual Cost (INR); GI: Galvanised Iron; INR: Indian National Rupee; LLDPE: Linear low density polythene; SFF: Sinking fund factor

A Study on Comparison of Efficiency of Low-Density Polythene (LDPE) Degradation Under Aerobic and Anaerobic Conditions by Microorganisms Isolated from Soil

Plastic has many desirable properties and thus, possesses several varied applications. This has led to a rise in its production and over the years, it has caused plastic pollution. Biodegradation is an affordable and more environment-friendly method compared to the other techniques currently available to eliminate plastic. The aim of this study was to isolate LDPE degrading microbes from soil samples that were collected from 4 different sources in Mumbai and compare their respective LDPE % degradation rates. Isolation of potential plastic degraders was carried out on Bushnell Haas agar that was overlaid with LDPE strips. The final biodegradation rate was calculated by the weight loss reduction method after an incubation period of one month under aerobic and anaerobic conditions. For identification of the bacteria, gram staining and Matrix Assisted Laser Desorption/Ionization- Time of Flight (MALDI-TOF) Mass Spectroscopy were performed and several colony characteristics were studied. For identification of fungi, Potato Dextrose agar containing chloramphenicol was used as the selective media, and Lacto Phenol Cotton Blue staining was performed. Two facultative anaerobic bacterial isolates, Bacillus sp. and Staphylococcus cohnii ssp. urealyticus with LDPE degradation rates of 9.8% and 5.57% respectively, and a highly aerobic fungus, Aspergillus niger, with a degradation rate of 12.13% were found. Fungi showed the maximum rate of biodegradation. Bacillus species exhibited an almost double degradation capacity as compared to that of Staphylococcus species. To improve the biodegradation capacity, the optimum conditions for microbial growth and enzyme production can be assessed and these findings can be applied commercially on a larger scale.

Biosurfactants as facilitators in Biodegradation of Low-Density Polyethylene (LDPE)

Low density polythene (LDPE) is amongst the highest produced synthetic plastic and also largely plagued with ineffective disposal management. Strategies to remedy its ineffective disposal have been underway and at the forefront is biodegradation due its positive environmental impact. This study reports on the preliminary investigation into surface chemistry using biosurfactants as facilitators for the biodegradation process of LDPE. Synthesized biosurfactants from isolated soil microbes, Bacillus subtilis and Pseudomonas aeruginosa were used in the biodegradation study along with pure cultures of the organisms themselves. 0.84mg/ml was the highest amount of biosurfactant synthesized under static conditions at 25°C. Supplementing with biosurfactants increased the biodegradation efficiency by at least 1.2 % compared to using the microbes alone during a 30 d incubation period. Percentage weight loss of LDPE bags was used as a measure of biodegradation in this study and 3.3% weight loss was the highest observed for a single organism when augmented with biosurfactants compared to 1.9% when used alone.

Polyethylene degradation by Ralstonia sp. strain SKM2 and Bacillus sp. strain SM1 isolated from land fill soil site

Low-Density Polyethylene (LDPE) is often widely used in packaging and wrapping because of its stability and durability. For decades, the plastic or synthetic polymer persists without deterioration in the soil. The aim of this analysis was to separate the bacteria from the soil of landfill and to evaluate the microbial degradation of the sheet of low-density polythene (LDPE) for 180 days. The microbial degradation was characterized by weight loss, alteration of pH in the media, Fourier Transform Infrared Spectroscopy (FTIR) and microscopic view. Molecular identification of bacteria was confirmed by phylogenetic analysis using 16SrRNA gene sequence. The bacteria were identified as Ralstonia sp. strain SKM2 and Bacillus sp. strain SM1. The weight loss in LDPE sheet by Ralstonia sp. strain SKM2 and Bacillus sp. strain SM1was 39.2%and 18.9%respectively The pH of media was reduced from 7.12 to 6.67 for Ralstonia sp. strain SKM2 bacterium and 7.12 to 7.03 for Bacillus sp. strain SM1 bacterium. Clearly noticeable structural changes such as blackness, shrinkage, cracks, pits, and roughening of LDPE sheet surface were detected by microscope. FTIR also observed changes in the carbon bonds (especially alcohol), ether and alkane groups of LDPE sheet.Thus, the Ralstonia sp. strain SKM2 and Bacillus sp. strain SM1 could be used as LDPE degrading microorganisms.

Impact of Processing Techniques and Packaging Materials on some Functional Properties of Soybean Flour

This study investigated some functional properties of soya bean flour produced from steeping and gelatinization techniques and stored in different packaging materials. The freshly harvested soya bean seeds used for the study were cleaned and soaked for five different durations (6, 9, 12, 15, and 18 hours); cooked at five different cooking times (20, 25, 30, 35 and 40mins); packaged in five different materials (paper bag, low density polythene bag, composite bag, high density polythene bag and plastic) and stored for five different periods (20, 40, 60, 80 and 100 days). A Response Surface Methodology, Central Composite Experimental Design was used. The samples of flour were then subjected to functional analysis. All experiments were carried out in triplicates. Data obtained was analyzed using Design Expert 11.0 statistical software tool; the Analysis of Variance (ANOVA) was conducted and empirical models developed. Statistical analysis shows that the gelatinization duration, and packaging materials had significant effect (P≤0.05) on the oil absorption capacity of the flour sample at P-value of 0.044 for gelatinization duration, 0.012 for packaging material, and water absorption capacity of the flour samples was significant with effect to storage duration P= 0.001, packaging material of 0.015 p-value. Bulk density of the processed flour was not significantly affected by processing techniques, packaging materials and storage duration employed in this study. Numerical optimization conducted on the experimental factors shows best desirability constraint of 0.60 point at steeping and gelatinization duration of 13.03 minutes and 25minutes respectively.

Development and characterization of k-carrageenan (Kappaphycus alvarezii) incorporated bun

Functional foods with elevated levels of fibre content are of high demand because of its several health benefits. A study was conducted for the development of fibre enriched bakery products. As a part of this study fibre enriched bun was developed using k-carrageenan (Kappaphycus alvarezii) as the source of fibre. The bun was prepared with the incorporation of various concentrations (2-8%) of -carrageenan powder. Comparative analyses of the physical, chemical, textural, structural and sensorial characteristics of bun were conducted. The highest concentration of k-carrageenan that was sensorily acceptable for incorporation in bun was 6 per cent, beyond which sensory parameters like taste and texture showed unacceptability. Radical scavenging activity assays revealed an improved activity with increased concentration of k-carrageenan.The shelf-life analysis of the sample was done after packing in low density polythene (LDPE) pouches. The present study has demonstratedthat k-carrageenan can be used as a competent constituent for the fortification of bun to utilize the health benefits of marine fibre.

Evaluation of Postharvest Shelf Life and Quality of Lemon Treated with Different Coatings during Storage

The effect of edible coatings such as mustard, olive and soybean oils with 1.5% (w/v) sodium alginate (C6H7NaO6)n on the postharvest shelf life and the quality of Jara Lebu (Citrus medica) in 1.5% perforated LDP (low density polythene) bags at 30-32°C and 80-85% relative humidity were evaluated. The changes of physico-chemical attributes like percent weight loss, percent juice yield, pH, Total Soluble Solids (TSS), percent fruit decay, acidity and vitamin C were observed for 18 days of storage. After observing results we found that in controlling percent weight loss, percent juice yield, percent fruit decay, pH and TSS, mustard oil +1.5% sodium alginate coatings showed the best results whereas soybean oil with 1.5% sodium alginate coating showed reverse results. Concerning to the results of preserving acidity and vitamin C, the 1.5% sodium alginate and the mustard oil with 1.5% sodium alginate were found as the most effective coatings on the other hand olive oil plus 1.5% sodium alginate coatings showed slight efficiency in controlling the postharvest quality loss. Though the coating of lemon with mustard oil +1.5% sodium alginate and only 1.5% sodium alginate showed significantly better results with respect to sensory evaluation, the former one eventually performed the best in retaining most of the quality parameters of the samples. This study clearly indicates that mustard oil with 1.5% sodium alginate coating can be used as the best edible coating for preserving almost all the postharvest quality parameters as well as extending the shelf life of Jara Lebu.

Effect of packaging materials on shelf life of dehydrated green chilli

The green chilli was dehydrated in a hot air oven. The dehydrated green chilli samples were packaged in low density polythene (LDPE) pouch, PET jar, and laminated film pouch and stored at room temperature for 28 days for storage study to estimate shelf life. Green chilli samples were evaluated based on sensory score for visual colour, texture, water activity and moisture absorption during storage at a regular interval of 7 days. Since no appreciable change in quality parameters, water activity and moisture absorption were found after 28 days of storage period stored in PET jar and laminated film pouch, dehydrated green chilli were acceptable. The increase in water activity and moisture absorption was high in LDPE pouch in comparison to PET jar and laminated film pouch. From the storage study, it was found that the shelf life of dried green chilli could be increased to more than 28 days.

Blending of Polystyrene and Low Density Polythene to Enhance the Physical Properties by using Compatibilizer-Styrene Ethylene/Butylene Styrene

Blending of Polystyrene and Low Density Polythene to Enhance the Physical Properties by using Compatibilizer-Styrene Ethylene/Butylene Styrene