Carpet Waste Research Articles

Process parameter interaction study for mechanical strength of r-HDPE filled calcium carbonate composites

Abstract The increasing issue of plastic waste disposal has drawn attention to the urgent requirement for sustainable solutions. At the heart of this problem is polyethylene, a crucial industrial resin that has significant implications for recycling. This study aims to explore the feasibility of using recycled high-density polyethylene (rHDPE) derived from waste carpet as a sustainable alternative material for structural applications that undergo mechanical loads. The primary focus of this research is to incorporate calcium carbonate an easily obtainable and cost-effective inorganic mineral filler into the rHDPE. This will enhance mechanical strength. Calcium carbonate (CaCO3) is widely recognized for their reinforcing properties in various polymer composites, and in addition not only improves the mechanical strength of the blend but also reduces the environmental impact associated with plastic and waste carpet disposal. Our experimental approach involves preparing samples with varying compositions of rHDPE and calcium carbonate. This includes carefully considering extrusion process parameters such as screw speed and melting temperature. Mechanical testing was performed using a universal testing machine following the ASTM standard. The findings of this research are expected to open up new avenues for innovative strategies in reducing plastic waste and promoting the sustainable utilization of waste carpets thereby contributing to the broader field of environmental sustainability

Enhancement of concrete performance and sustainability through incorporation of diverse waste carpet fibres

Carpet fibres have demonstrated the potential to mitigate early-age cracking and improve tensile properties in concrete. However, a detailed analysis of the varied types of standard carpet fibres in reinforced concrete has been lacking. This study aims to bridge this gap by investigating the performance of concrete reinforced with widely used waste carpet fibres, namely Nylon, Polypropylene, Polytrimethylene terephthalate, and Polyester. The study employs fibres at 0.3 % and 0.5 % volume fractions with a 12 mm length. The research examines mechanical properties, shrinkage and cracking behaviour, pore structure, microstructure, and the ITZ. Results show that 0.3 % fibre volume yielded optimal performance based on GRA analysis. All fibre types reduced shrinkage compared to the control with no fibres. Nylon T1 at 0.3 % achieved a 22.3 % reduction at 90 days. Furthermore, fibre inclusion enhanced flexural and splitting tensile strengths up to 12 % and 39 % respectively due to fibre bridging, pore refinement, and reduced porosity. Notably, individual fibre mechanical properties influenced concrete performance significantly. Hydrophilic fibres exhibited a thinner 10 µm ITZ compared to 15 µm for hydrophobic fibres, contributing to denser interfacial regions and improved bonding. This study demonstrates the potential of carpet fibre-reinforced concrete as a sustainable solution, offering enhanced mechanical properties, shrinkage mitigation, and effective utilization of carpet waste, addressing critical issues in construction and waste management sectors.

Sustainable biocomposites from pyrolyzed lignin and recycled nylon 6 with enhanced flame retardant behavior: Studies on manufacturing and quality performance evaluation

AbstractThe recycled nylon (RN)‐based biocomposites were fabricated by adding 25% lignin biocarbon. Lignin was pyrolyzed at 300, 600, and 900°C to produce Lig300, Lig600, and Lig900 biocarbon (BioC) samples, respectively. Higher functionality of Lig600 (unlike Lig900) allowed for improved interfacial interaction with the polar nylon matrix. Mechanical properties were further enhanced for RN_Lig600 composite with enhanced flexural and tensile strength by 18% and 8%, respectively, compared to neat polymer (RN). RN_Lig900 composite showed enhancement in tensile and flexural modulus by 32.6% and 51.1%, respectively, compared to RN. Incorporation of Lig900 in RN matrix resulted in 77.9% reduction in burning rate compared to RN. These results show the potential of lignin BioC as a filler in RN composites for flame retardant applications and mechanical enhancement, such as in the automotive industry.Highlights Effect of pyrolysis temperatures (300, 600, and 900°C) on lignin biomass. Composites prepared from recycled polyamide 6 from carpet waste and biocarbon. Improved interfacial adhesion of 600°C biocarbon with recycled nylon matrix. Enhanced thermal, mechanical properties, reduced flammability of biocomposites. Sustainable biocomposites with 900°C biocarbon reduced burning rate by 78%.

Maximizing polypropylene recovery from waste carpet feedstock: a solvent-driven pathway towards circular economy

A novel approach for the efficient recovery of polypropylene from waste carpet feedstock utilising a solvent based method.

High-quality separation and recovery of nylon and dyes from waste carpet via non-destructive dissolution and controlled precipitation for sustainable recycling

Pure recycled nylon fibers were developed for the first time from carpets without environmentally irresponsible dye destruction and costly polymer degradation. The lack of economically viable separation technology has resulted in more than 97 % of carpets ending up in landfills, posing severe environmental and health concerns. A sustainable and cost-effective separation and purification technology is the key to successful carpet recycling on a large scale. Impurities removal via depolymerization, although technically feasible, faces intolerable economic challenges, limiting its large-scale application. Cost-effective spinning of dye-containing nylon into fibers did not work since acid dyes considerably lowered the crystallinity and mechanical properties of re-spun fibers. Here, we present a closed-loop recycling approach involving controlled dissolution and precipitation (ReNylon via D&P), allowing for the complete separation of nylon and dyes without damaging their chemical structures. The non-destructive dissolution in butanediol completely removed the colored nylon fibers from both the face and back of carpets. The temperature-induced precipitation resulted in colorless amorphous nylon separated from acid dye solution. Recycled colorless fibers from purified nylon demonstrated the same quality as fibers before the recycling. Acid dyes from carpet were redyed onto nylon in an energy-conservative butanediol-based solution and showed identical dyeability and colorfastness to virgin dyes. The overall costs based on preliminary estimation to produce nylon fibers via our recycling is less than 23 % of that via the petroleum-based method, indicating a high economic viability of the recycling. This clean recycling process minimized waste generation by recovering more than 99 % of biodegradable and low-toxic butanediol. The recycling technology could also apply to other textile blends for closed-loop circulation.

Investigating the Resistance Properties of Concrete Containing Waste Carpet Fibers

Investigating the Resistance Properties of Concrete Containing Waste Carpet Fibers

Utilizing industrial wastes as compost in wheat-rice production to improve the above and below-ground ecosystem services

The prime objective of this study was to enhance the ESs and achieve sustainability in the wheat (Triticum aestivum L.)–rice (Oryza sativa L.) production system (WRPS). The study was conducted in the split-plot design (SPD). In this study’s results were presented as the 2018–2021 average of the WRPS. As compared to zero fertilization in the main-plot, the applied treatment recommended dose of fertilizer (RDF) 100%+ 5 kg zinc (Zn) + 5 kg iron (Fe) increased grain and straw-based ESs by 50% and 39%, respectively. Similarly, in the sub-plot, the carpet waste +Trichoderma viride (CW+M3) treatment had 24% and 22% more grain and straw-based ESs than the application of the bagasse + Pleurotus sajor-caju (B+M1) treatment, respectively. Furthermore, the grain and straw-based ESs interaction between the applications of RDF 100%+ 5 kg Zn + 5 kg Fe × carpet waste decomposed through Trichoderma viride (CW+M3) was significant and observed that the maximum monetary value was US$ 2638 and 557 ha−1 year−1, respectively. There was also 64% more carbon (C) flow and 144% higher soil fertility than those in zero fertilization × B+M1 treatment. While based on other indices in the main-plot, among the different RDF levels, the zero-fertilization plot had the maximum sustainable value index (SVI) (0.880 and 0.985) and sustainable yield index (SYI) (0.977 and 0.983) of wheat and rice in an average of the system for 2018–2021 of WRPS. Furthermore, the sub-plot B+M1 had wheat's highest SVI (0.865) and SYI (0.958). Moreover, in the case of rice, the maximum SVI (0.928) and SYI (0.952) were observed in the pressmud + Pleurotus sajor-caju (PM+M1). All the variables are positively correlated except total, and partial factor productivity. Based on the regression study, the C flow-based ESs contributed to 99.9% variability in grain-based ESs. Based on the above results, this experiment provides unique and distinct information for above and below-ground ESs in WRPS and using IWs to maintain a long-term sustainable food system. The experiment hypothesized that using the IWs as a nutrient source will enhance nutrient use efficiency (NUE), reduce reliance on chemical fertilizers and maintain yield sustainability, improve ESs in WRPS, improve soil health, and ensure a green-sustainable food production system. Additionally, it is an assessable and practical method of sustainably managing waste that correlates well with green economic sustainability to meet the United Nations Sustainable Development Goals (UNSDGs).

Production of waste carpet fiber-reinforced concrete as sustainable material

Waste materials evolve from various processes in industries that require efficient management for their disposal to ensure a cleaner environment. Disposing of solid waste, such as carpets, to sites has grown challenging since the development and management of sites are very costly. There is a dire need to manage such a vast amount of carpet waste efficiently. This study examines certain mechanical properties and durability characteristics of concrete incorporating discarded carpet threads and silica fume (SF). Initially, six different concrete mixes were produced, with 0.25%–1.0% waste carpet fibers by concrete volume and 10% SF by weight of cement. Then samples were tested for mechanical strength, i.e., compressive strength, tensile strength, and flexural strength. The durability characteristics, such as water absorption, rapid chloride penetration test, drying shrinkage, and freeze-thaw action, were also determined. The study shows that the abandoned carpet waste threads and SF (an industrial waste) in concrete significantly increase tensile and flexural strengths and various other durability characteristics. The further increase in fiber content resulted in a lowering of mechanical strengths and workability. Experimental results show the increase in tensile and flexural strengths of the concrete by waste carpet fibers (0.25%) and SF (10%) by 16.5% and 34%. SF and waste carpet fibers improve other durability characteristics, reducing freeze-thaw, drying shrinkage, and chloride ion permeability coefficient by up to 47%, 79%, and 50%. Additionally, using waste carpet fibers to ameliorate concrete properties instead of fresh fibers helps conserve natural resources. It leads to the conservation of resources, sustainability, recycling of wastes, and a circular economy.

Carpet fiber recycling in regular-use concrete mixtures and associated life cycle analysis

This paper reports the characterization of post-consumer carpet fibers and optimization of concrete mixtures containing high volumes (2.5% and 5% as compared to ≤ 2% reported in past work) of carpet fibers, in an effort to contribute to the efficient management of such wastes. This study identifies the different fiber types in a typical post-consumer carpet bale using Fourier transform infrared (FTIR) spectroscopy and the range of tensile strengths demonstrated by the fibers. In order to quantify the sustainability of concretes containing carpet fibers, a cradle-to-gate life cycle analysis is carried out. The results demonstrate that the use of carpet fibers along with fly ash helps reduce the CO2 emission potential by ∼ 12.5% compared to conventional concrete, in addition to saving critical land area that would otherwise be needed to dispose of the ever-increasing amounts of carpet waste. Notable reductions (of up to 10%) in other environmental impact categories (e.g., acidification, eutrophication, etc.) are also observed with respect to conventional concrete. Even with the additional energy required to process the fibers, the overall energy consumption to produce carpet fiber reinforced concretes is similar to that of conventional concretes. The conditions under which carpet fibers become an environmentally sustainable approach for concretes designed to achieve a particular compressive strength are also outlined. It is expected that this work will pave the way for the management and beneficial utilization of otherwise landfilled shredded carpets in concrete applications such as slabs-on-grade.

Simultaneous optimization of carbon yield and iodine adsorption of ACFs derived from carpet wastes

AbstractRecycling post‐consumer carpet waste is a critical consideration for decreasing the environmental hazard of non‐biodegradable plastics. Therefore, the manufacturing of activated carbon fibres (ACFs) from post‐consumer carpet waste treated with KOH was modelled and optimized by the response surface methodology (RSM). The simultaneous effects of carbonization rate, pyrolysis temperature, and activation time on the performance of carpet waste‐based ACFs were studied. Box–Behnken design (BBD) was applied to study the influence of three significant processing parameters on the carbon yield and iodine adsorption of synthesized ACFs. The RSM analysis established that pyrolysis temperature was the most important parameter affecting the ACFs' performance. The optimum settings that led to the production of high carbon yield and iodine adsorption of ACFs were a carbonization rate of 5.4°C/min, pyrolysis temperature of 705.7°C, and activation time of 83 min. The carbon yield and iodine adsorption under the above conditions were obtained at 49.8 ± 0.9 wt.% and 1351 ± 45 mg/g, respectively. BBD has been established to be a powerful approach in modelling and optimization to achieve high‐quality of iodine adsorbents from carpet wastes.

Effect of Addition of Carpet Waste Fibres on the Unconfined Compressive Strength of Cohesive Soils Samples from Umutu, Agbor and Obiaruku in Delta State, Nigeria

With the latest trend in the beautification of most homes and offices, there has been a great shift from the use of carpets to floor tile and as such most of these carpets have become waste and causing environmental pollution. Therefore the objective of this paper was to evaluate the effect of adding carpet waste fibre on unconfined comprehensive strength of cohesive soil samples from Umutu, Agbor and Obiaruku in Delta State, Nigeria using standard techniques. The results showed that the maximum dry density (MDD) of the natural soil samples from Umutu, Agbor and Obiaruku were 1.76g/cm3, 1.73 g/cm3 and 1.72 g/cm3 respectively while their respective OMC were 13.6%, 13.86% and 14.2%. The UCS of the natural soil samples were 68.6kN/m2, 73.77kN/m2 and 76.69kN/m2 respectively. The MDD decreased from 1.73 g/cm3 to 1.675g/cm3, 1.72g/cm3 to 1.66g/cm3 and 1.71 g/cm3 to 1.63 g/cm3 when the natural soils from these study areas respectively were compacted with 0.1% to 0.4% fibre content. Also, the OMC from the respective soils-fibre mix increased from 13.8% to 19.0%, 16.0% to 19.6% and 14.9% to 19.2% respectively. The UCS for the respective soil-fibre mix decreased from 60.38kN/m2 to 52.65kN/m2, 66.28kN/m2 to 57.70kN/m2 and72.39kN/m2 to 57.27kN/m2. Hence, the study showed that the addition of fibre to natural soil decreases the strength of the soil.

Utilization of Waste Carpet Fiber to Produce Green Concrete; a Solution to Environmental Issues

Utilization of Waste Carpet Fiber to Produce Green Concrete; a Solution to Environmental Issues

Diversity in the Rice–Wheat System with Genetically Modified Zinc and Iron-Enriched Varieties to Achieve Nutritional Security

The rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system (RWCS) feeds more than 6 billion people in South Asia and across the world. In developing countries, almost 2 billion individuals are suffering from Zn and Fe micronutrient deficiency. This study aimed to adopt genetically enriched varieties of rice and wheat to manage the Zn and Fe deficiency with organic and inorganic fertilization in the food system. The experiment was designed for two years (2018–2019) under the split-plot design and was replicated three times. The results of the study indicate that the highest grain yield of wheat and rice was increased by 67.09 and 58.41 and 44.10 and 33.21% more NPKFeZn in the applied treatments compared to the control treatment during both years, respectively. The treatment carpet waste and Trichoderma viride was performed for higher yields (grain, straw, and biological) as compared to the rest of the treatment. In the main-plot, with application of NPKFeZn, higher Fe and Zn ranges of 54.27 and 52.91 and 35.71 and 34.29 parts per million (ppm), respectively, were recorded during both years. Similarly, the residual effects of NPKFeZn treatment in rice Fe and Zn concentration were recorded at 44.17 and 41.22 and 27.55 and 24.19 ppm during both years, respectively. It was found that there was 49.18 and 42.12 and 25.28 and 19.94% more Fe and Zn content, respectively, in grain as compared to the traditional varieties range of 33 and 14 ppm for Fe and Zn, respectively. Ina sub-plot, for the wheat in carpet waste and Trichoderma viride treatment, the Fe and Zn contents were recorded as 55.21 and 54.62 and 37.05 and 35.53 ppm for the two years, respectively. In the traditional varieties of wheat, the range of Fe and Zn contents was 30 and 32 ppm, respectively. In the sub-plot of succeeding rice in carpet waste and Trichoderma viride treatment contents of Fe and Zn of 43.27 and 40.43 and 26.67 and 23.37 ppm were recorded during both years, respectively. On the basis of the interaction effect, the maximum total Fe and Zn uptake by wheat of 0.84 and 0.50 kg ha−1, respectively, were recorded in the N3 × B1C3 treatments. Likewise, the maximum total Fe and Zn uptakes by rice of 0.62 and 0.39 kg ha−1, respectively, were recorded with the interaction effect of N3 × B1C3 treatments. The hypothesis of the experiment was to manage malnutrition in society by diversifying genetically modified rice–wheat varieties in the RWCS. This research might assist in increasing nutritional security.

Upcycled Polypropylene and Polytrimethylene Terephthalate Carpet Waste in Reinforcing Cementitious Composites

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Waste valorization in sustainable engineering materials: Reactive processing of recycled carpets waste with polyamide 6

Waste resources utilization is of utmost importance today to promote sustainable development and minimize pollution. However, it remains a great challenge to reuse, recycle and turn post-consumer wastes into value-added products. Here, we demonstrate a strategy to reprocess post-consumer recycled carpet waste (PCRC) (containing polyamide, polypropylene and other additives and reinforcing agents) with polyamide 6 (PA 6) at different weight ratios through reactive extrusion. The phase adhesion of the PCRC and PA 6 was improved significantly with the aid of poly(ethylene-octene)-grafted-maleic anhydride copolymer (POE-g-MA) and epoxidized styrene-acrylic copolymer (ESAC). Superior notched impact strength and elongation at break were observed when the blends were modified with POE-g-MA and a small amount of chain extender ESAC (0.5–2 phr). Morphological characterization showed a decrease in PCRC droplets size and enhanced its dispersion in the PA 6. FTIR analysis showed an enhancement of interfacial compatibilization between PA 6 and PCRC by the interaction between maleic anhydride of POE-g-MA and epoxy group of ESAC with polyamide functional group through melt mixing. The effective compatibilization of the blends was also evident from thermal and rheological analysis. The results revealed the possible reuse and utilization of recycled carpet for different polymer blends and composites fabrication with high recycled content for various applications.

Development of waste carpet (jute) and Multi-wall carbon nanotube incorporated epoxy composites for lightweight applications

This work highlights the recycling of waste carpet (Jute) to develop epoxy composites using a modified vacuum-assisted environment. Incorporating Multi-wall carbon nanotube (MWCNT) into the epoxy matrix in different weight percentages improves the physio-mechanical properties. The MWCNT was supplemented at 0.25, 0.5, 0.75, and 1 wt% to investigate the mechanical aspects of composite samples. The nanofiller (MWCNT) dispersion in the epoxy matrix was simulated using X-ray diffraction (XRD) and Energy Dispersive X-Ray Analysis (EDX). The results were compared to the neat (pristine) sample to study the influence of nano-supplement. The Tensile, Flexural, and Impact tests were the selected experiments to assess the material characteristics. The findings show the feasibility of the developed samples for lightweight structural applications such as toy items, wall tiles, roof tiles, sound insulation, and roadside barriers. It could be endorsed as a feasible way to handle the waste issues generated by the carpet and textile sources.

Investigation on the physio-mechanical properties of carpet waste polymer composites incorporated with multi-wall carbon nanotube (MWCNT)

In the structural functions of polymer components, the material's thermal stability and moisture absorption efficiency play a vital role in defining durability and physio-mechanical performance. This article emphasizes the experimental investigation of polymer (Epoxy) composites fabricated from carpet waste and Carbon nanomaterial (CBN). The supplement of Multi-wall carbon nanotube (MWCNT) into the epoxy/carpet waste polymer composites is proposed to enhance the physio-mechanical properties. The experimentation was performed to check the synergistic effect of nanomaterials in five configurations with different wt.% of MWCNT in the proposed composites. The water absorption, swelling rate, fire retardant and compression performance of the discarded carpet polymer composite modified with MWCNT have been investigated. The effect of water dipping and dry condition was completed to evaluate the composite feasibility. In addition, the fire-retardant properties of developed materials were analyzed using the fire (horizontal) setup process. The results found that incorporating the MWCNT nanoparticles into discarded carpet polymer composites can improve the compression strength. It was noticed that the few quantities of water were absorbed with less swelling effect at the 0.25 wt.% of MWCNT. The modified epoxy nanocomposites have higher specific properties values when compared to neat (discarded carpet polymer) composites. The fire retardancy properties have been enhanced remarkably with a supplement of lower nanomaterials wt.%. The findings show that the proposed carpet waste/MWCNT/polymer composites could be recommended for lightweight functions such as roadside barriers, wall tiles, toys, decorative frames, insulating materials, etc.

Water absorption study and characterization of polymer composites developed from discarded nylon carpet

The scientific objective of this work is to reuse the polymer materials generated from carpet waste. The nylon obtained from the discarded carpet was used as reinforcement material into the epoxy matrix phase. A modified approach of Vacuum-assisted resin transfer molding (VARTM) was used to infuse the mixture of epoxy and hardener into the nylon carpet polymer composites. This investigates the water absorption behavior of carpet waste composite. It will justify the application of proposed composites for lightweight structural applications in a moisture environment. The nylon fiber-based-epoxy composite was dipped in water as per ASTM standard for a different duration, namely, 24, 48, 72, 144 hours. The findings demonstrate that it can effectively withstand in moisture environment, and a maximum 4.5% weight of samples increased among all the samples for a different duration. Also, the developed composite showed a lower water diffusion co-efficient than the nail head structure and linden wood. Also, the carpet waste composite samples were investigated for thermal degradation and chemical behavior using X-Ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, respectively. The finding shows that the proposed composite could be used for lightweight components such as dashboard panels, sound absorbers, panel sheets, wall tiles, etc.

Use of discarded carpet material in the development of polymer (epoxy) composites for structural functions

The solid waste generated through the carpet and textile industry produces pollution and health risks in various forms when discharged into the open space. This study aims to utilize post-consumer discarded carpets for the manufacturing of lightweight polymer composites. The waste generated from the carpet industry has been a matter of serious concern for the environment. The average life of a carpet is approximate 8-9 years. After that becomes a non-biodegradable waste that is hazardous for the environment and occupies large landfill areas. In this context, the carpet waste is used to enhance the structural properties of the polymer (epoxy) composite. The epoxy is modified using waste carpet in two separate configurations: back-fiber-fiber-back (BFFB) and fiber-back- back-fiber (FBBF). A modified Vacuum-assisted resin transfer molding (VARTM) has been used to infuse the mixture (epoxy and hardener) into the waste carpet samples. The tensile, compressive, and flexural strength tests of the proposed samples were performed to analyze the mechanical behavior. The Scanning electron microscopy (SEM) outcomes demonstrate a good bonding strength between the epoxy matrix and filler material fabric (waste carpet). The FBBF configuration has comparatively superior mechanical performance than the BFFB. The mechanical testing results indicate that the developed samples can be satisfactorily used for lightweight structural applications such as sound barriers, wall tiles, desk boards, toys components, decorative product parts, etc. The research demonstrates that polymer composite reinforced by carpet waste can be endorsed as an acceptable and cost-effective replacement of structural polymer components. Also, the proposed method is remarked as a feasible solution to utilize the waste carpet into end products.

Synthesis and Characterization of Monetite from Calcium Carbonate Recovered from Carpet Waste

Calcium carbonate (CaCO3) was recovered from the carpet waste by combustion at 500 °C under an air atmosphere. The CaCO3 had a pure calcite phase without detection of other crystalline phases, as confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) measurements. Dicalcium phosphate (CaHPO4) or monetite, which is known as a family of calcium phosphate-based biomaterials, was synthesized by mixing the CaCO3 recovered from the carpet waste with phosphoric acid (H3PO4) solution. The reaction was kept at a constant temperature of 80 °C for 24 h. The XRD and FTIR results demonstrated that the pure monetite phase was successfully formed by the reaction between CaCO3 and H3PO4. The energy-dispersive X-ray spectroscopy analysis confirmed that the monetite was composed of calcium, oxygen, and phosphorus. The results obtained in this work revealed that CaCO3 recovered from carpet waste could potentially be an alternative material for the synthesis of monetite under mild conditions.