Recycling, Volume 5, Issue 4 (December 2020) – 10 articles

In this work, different thermal analysis methods have been used to study the co-pyrolysis of low-density polyethylene (LDPE) and motor oil. Two kinds of motor oil were considered, a fresh one and a used one. Through the comparison of experimental curves and so-called “theoretical curves”, high-resolution thermogravimetry experiments allowed highlighting interactions between the LDPE and each of the two oils, when they are co-pyrolyzed. While thermogravimetry coupled with mass spectrometry did not give any insights into these interactions, pyrolysis coupled to gaseous chromatograph and mass spectrometry allowed identifying aldehydes in the products of the co-pyrolysis of LDPE and each of the two oils. These aldehydes were not observed during the pyrolysis of the LDPE or the oils alone. On the basis of these results, various explanations for the formation of these aldehydes are proposed. Full article

Despite technological developments, modern methods for the disposal of end-of-life tires most often involve either their incineration in cement kilns or the destruction of tires in special landfills, demonstrating a lack of sustainable recycling of this valuable material. The fundamental role of recycling is evident, and the development of high-efficiency processes represents a crucial priority for the European market. Therefore, the investigation of end-of-life rubber processing methods is of high importance for both manufacturers and recyclers of rubber materials. In this paper, we review existing methods for processing of end-of-life tires, in order to obtain rubber crumb, which can later be used in the production of new industrial rubber goods and composites. We consider processes for separating end-of-life tires into fractions (in terms of types of materials) using chemical, mechanochemical, and mechanical methods to process the materials of used tires, in order to obtain crumb rubber of various fractions and chemical reactivities. Full article

While the increasing rate of urbanisation is a critical concern for socio-environmental reasons, this also leads to more extraction of natural raw materials and the generation of significant quantities of construction and demolition (C&D) waste. Although the use of recycled C&D waste products is technically feasible and regulated, and positive application examples are evident, it is still unclear how to engage key stakeholders to leverage this opportunity in construction projects. Previous research has shown that there is some level of resistance to the reuse of recycled C&D waste products in construction projects. This highlights a critical need to identify the roles of key stakeholders and the barriers they face when using recycled C&D materials. This paper therefore investigates the type of stakeholders influencing the use of recycled C&D waste products and the main factors affecting stakeholders’ decisions to use recycled C&D waste products through a systematic literature review. The authors present an emergent enablers and barriers for recycled C&D waste products model and provide commentary on how stakeholders’ perceptions, decision and behaviour influence the use of recycled C&D waste products. The authors also contribute to the body of knowledge with insights into the factors that various stakeholders believe influence the market for recycled C&D waste products and provides a reference point for authorities to consider these behavioural insights for policy reform. Full article

Styrofoam fish containers (fish boxes) are ideal for transporting fresh fish because of their light weight and insulation properties. However, due to fish-like odors, fish boxes are simply thrown out after use and are limited to low-grade recycling in Japan. To improve their recyclability, we investigated trimethylamine, which causes fish-like odor, to ascertain whether it is soluble in vegetable oil using the Hansen solubility parameter (HSP). At present, the Oshima College method (OCMT), which is used to reduce the volume of styrofoam, uses heated vegetable oil and can potentially remove the fish-like odor. In addition, the solubility of dimethyl sulfide, which causes the sea-like smell in styrofoam found drifting on shores, in vegetable oil was investigated. Our results conclude that OCMT can remove the fish- and sea-like odors found in waste styrofoam and thus improve its recycling potential. Full article

This study investigates the performance of biodiesel produced from distilled waste tire pyrolytic oil through transesterification as a lubricant additive for aqueous drilling fluid systems. Aqueous-based drilling fluids have a high coefficient of friction as compared to oil-based drilling fluids. The inclusion of a biodiesel additive was for smooth application/operation. The friction-reducing physicochemical properties of the additive were analyzed and compared with the guidelinesof the United States specification (ASTM Standard) and the European specification (EN Standard). The chemical structure of the produced biodiesel was analyzed using gas chromatography–mass spectrometry (GC-MS). The results show that the distilled waste tire pyrolytic oil contains aliphatic, naphthenic, and aromatic hydrocarbons. The free fatty acid value reduced from 5.6% (for pyrolytic oil) to 0.64% after the transesterification process. A saponification value of 203.36 mg/g was recorded for the pyrolytic oil, and this value was also reduced to 197.35 mg/g after the transesterification process. The kinematic viscosity was reduced from 11.2 to 5.3 mm²/s for the obtained biodiesel, and this value is within the ASTM D6751 and EN 14214 standard values (1.9 to 6 and 3.5 to 5 mm²/s, respectively). The cetane number (47.75) was obtained for the biodiesel, and this is within the minimum range stipulated in ASTM D6751 guidelines. The produced biodiesel’s chemical structure analysis using GC-MS shows that it comprises of decanoic acid methyl ester and methyl ester. Furthermore, comparative analysis of the quantified friction-reducing physicochemical properties of the additive shows that the biodiesel produced from the distilled pyrolytic oil is a suitable additive for the improved lubrication of the friction-prone metallic parts of drill bits when water-based drilling fluids are employed for drilling oil and gas wells. Full article

Batik has become more desirable in the current fashion mode within the global market, but the environmental damage induced by this fabric’s synthetic dye practices is a matter of concern. This study aimed to discuss the application of organic materials as natural dyes in the clean production of textiles to maintain the environment. The research was a case study from the community services program in Kampung Malon, Gunungpati, Semarang City, Indonesia, focused on the batik home industry of the Zie Batik fabric. Furthermore, natural pigments from various plant organs (stem, leaves, wood, bark, and fruit) of diverse species, including Caesalpinia sappan, Ceriops candolleana, Maclura cochinchinensis, Indigofera tinctorial, I. arrecta, Rhizopora spp., Strobilantes cusia, and Terminalia bellirica were used for this type of material. These pigments are more biodegradable, relatively safe, and easily obtained with zero liquid waste compared to the synthetic variants. The leftover wastewater from the coloring stages was further utilized for other processes. Subsequently, the remaining organic waste from the whole procedure was employed as compost and/or timber for batik production, although a large amount of the wastewater containing sodium carbonate (Na₂CO₃), alum (KAl(SO4)₂·12H₂O), and fixatives (Ca(OH)₂ and FeSO₄) were discharged into the environment during the process of mordanting and fixating, with the requirement of additional treatment. Full article

Since the beginning of the first cases of the new coronavirus, opinions and laws on the use of plastic materials have been questioned around the world. Their importance in the manufacture of hospital devices and personal protective equipment (PPE) is unquestionable, as they contribute largely to the reduction of the virus spread, helping health systems from all edges of the world and, most importantly, saving lives. However, the same material that is a protector, becomes a polluter when inadequately disposed of in the environment, generating or worsening socio-environmental problems, such as pollution of water bodies by plastic. A critical overview of the role of plastic during the COVID-19 pandemic is provided in this paper. A future panorama is attempted to be outlined. The real possibility of the virus spread from the use of plastic is discussed, as well as the recycling of plastic during the pandemic, correlating its use with problems that it may cause. Full article

The lithium-ion battery is the most powerful energy storage technology for portable and mobile devices. The enormous demand for lithium-ion batteries is accompanied by an incomplete recycling loop for used lithium-ion batteries and excessive mining of Li and transition metals. The hyperaccumulation of plants represents a low-cost and green technology to reduce environmental pollution of landfills and disused mining regions with low environmental regulations. To examine the capabilities of these approaches, the hyperaccumulation selectivity of Alyssum murale for metals in electrode materials (Ni, Co, Mn, and Li) was evaluated. Plants were cultivated in a conservatory for 46 days whilst soils were contaminated stepwise with dissolved transition metal species via the irrigation water. Up to 3 wt% of the metals was quantified in the dry matter of different plant tissues (leaf, stem, root) by means of inductively coupled plasma-optical emission spectroscopy after 46 days of exposition time. The lateral distribution was monitored by means of micro X-ray fluorescence spectroscopy and laser ablation-inductively coupled plasma-mass spectrometry, revealing different storage behaviors for low and high metal contamination, as well as varying sequestration mechanisms for the four investigated metals. The proof-of-concept regarding the phytoextraction of metals from LiNi_0.33Co_0.33Mn_0.33O₂ cathode particles in the soil was demonstrated. Full article

Municipal solid waste collection and transport are functional activities in waste management, with a significant energy and carbon footprint and a significant effect on the urban environment. An issue related to municipal solid waste collection and transport is their regional and municipal implementation, affected by sorting and recycling strategies at local level. An efficient collection is necessary to optimize the whole recycling process. The present paper shows the results of an energy, environmental, and economic evaluation of a case study, analyzing the fleet used for municipal solid waste collection and transport in 10 municipalities in Central Italy. The current scenario was compared with alternative scenarios on the basis of some parameters for performance evaluation: vehicles’ energy consumption, carbon footprint, routes, and costs. Results show that for passenger cars, the alternative scenario based on an entire fleet of dual compressed natural gas (CNG) vehicles led to a reduction of the CO₂ emissions (−2675 kg_CO2eq) in the analyzed period (January–August 2019) and a reduction of the energy consumption (−1.96 MJ km⁻¹). An entire fleet of CNG vehicles led to an increase of CO₂ emissions: +0.02 kg_CO2eqkg_waste⁻¹ (+110%) for compactors (35–75 q) and +0.09 kg_CO2eqkg_waste⁻¹ (+377%) for compactors (80–180 q). Moreover, both categories report a higher fuel consumption and specific energy consumption. For waste transport high-capacity vehicles, we propose the installation of a Stop-Start System, which leads to environmental and energy benefits (a saving of 38,332 kg_CO2eq and 8.8 × 10⁻⁷ MJ km⁻¹kg_waste⁻¹). On three-wheeler vehicles, the installation of the Stop-Start System is completely disadvantageous. Full article

In this study, cellulose was obtained from the residues of pineapple crown by means of simple acid pretreatment and subsequent alkaline treatment. The pretreatment consisted of washing, drying, and chopping with high shear at pH = 5 under heating. The content of cellulose, hemicellulose, and lignin in the pineapple crown was determined by chemical methods. The cellulose obtained was compared with commercial cellulose by Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis, and X-ray diffraction (XDR). Thus, from the obtained fiber cellulose, a food container was prepared, and its physical-mechanical properties were determined. Then, after alkali treatment, the purity of cellulose was 84.7% from the pineapple crown (56.0%) and was compared with commercial cellulose (95%). FTIR results confirmed the removal of the non-cellulosic compounds after alkali treatment. The maximum pyrolysis temperature increased to 356 °C, higher than the original fiber (322 °C), indicating greater thermal stability after chemical treatment. Furthermore, the crystallinity increased to 68% with respect to the original fiber (27%). The physical properties of the container showed a decrease in the parameters in wet 95% RH, as expected, thus facilitating its reuse. These results indicate that the pineapple crown cellulose can be obtained with significant purity, from a single chemical treatment. In addition, this polymorphous cellulose can be used to make ecofriendly reusable food containers. Full article