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1.
PLoS One ; 17(5): e0267284, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35503782

RESUMEN

Despite significant investment to increase recycling facilities and kerbside collection of waste materials, plastic packaging is frequently discarded as litter, resulting in significant environmental harm. This research uses qualitative methods to explore the contextual and psychological factors that influence plastic waste disposal behaviour from the perspectives of consumers. This research also reports key results from a brief online survey exploring consumer perspectives toward plastics and plastic recycling. A total of N = 18 adults living in Northern Ireland (NI) participated in a semi-structured interview and N = 756 adults living in NI took part in an online survey. Interview data was analysed via a semi-directed content analysis approach, using the COM-B behaviour change model as a guiding framework. Survey data underwent descriptive and frequency analysis. Collectively, the findings suggest that environmental concern exists among consumers generally, but there is a degree of ambivalence toward recycling that reflects a gap between intentions to recycle and actual recycling behaviour. Plastic recycling behaviour is hindered by three common barriers: 1. confusion and uncertainty about which plastic materials can be recycled (exacerbated by the abundance of plastic products available) 2. perceiving plastic recycling to be less of a personal priority in daily life 3. perceiving that local government and manufacturers have a responsibility to make plastic recycling easier. As recycling is simply not a priority for many individuals, efforts should instead be placed on providing greater scaffolding to make the process of recycling less tedious, confusing, and more habitual. Visual cues on product packing and recycling resources can address ambiguity about which plastic materials can/cannot be recycled and increasing opportunities to recycle (via consistent availability of recycling bins) can reduce the physical burden of accessing recycling resources. Such interventions, based on environmental restructuring and enablement, may increase motivations to recycle by reducing the cognitive and physical burden of recycling, supporting healthier recycling habits.


Asunto(s)
Eliminación de Residuos , Administración de Residuos , Adulto , Humanos , Plásticos , Embalaje de Productos , Reciclaje
2.
Comput Intell Neurosci ; 2022: 6145755, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35528368

RESUMEN

Railway engineering generates large amounts of construction and demolition waste (CDW). To quantify the amount of CDW generated from railway engineering projects throughout the whole life cycle, a process-based life cycle assessment model is proposed in this paper. The life-cycle CDW is divided into four parts: CDW from off-site transportation of construction materials (OSTCM), CDW from site operation wastage of construction materials (SOWCM), discard ballast from roadbeds, stationyard, bridges and tunnels (DB), and CDW from reparation and renewal of aging components (RRAC). Yun-Gui Railway is selected as a case study to validate the developed model, and an uncertainty analysis is conducted with Oracle Crystal Ball software. The results show that between 175 and 311 million tons of CDW is generated throughout the whole life cycle of Yun-Gui Railway. DB is the largest component of the life-cycle CDW from railway engineering projects. This indicates the negative environmental impacts of railway construction can be significantly mitigated by optimizing the location of ballast disposal sites and developing suitable landfill proposals. Also, the CDW generated by wastage of construction materials during off-site construction and site operation is important in waste management in railway engineering projects, in which rubble, sand, and cement have the high potential for waste reduction. Findings from this study can contribute to the knowledge body as well as the engineering practice in green railways.


Asunto(s)
Industria de la Construcción , Administración de Residuos , Animales , Industria de la Construcción/métodos , Materiales de Construcción , Estadios del Ciclo de Vida , Reciclaje/métodos , Administración de Residuos/métodos
3.
Int J Mol Sci ; 23(7)2022 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-35408966

RESUMEN

Plastic pollution is currently one of the most pressing environmental problems, especially in countries with a low recycling rate that is mainly due to the insufficient collection of plastic waste [...].


Asunto(s)
Administración de Residuos , Embalaje de Medicamentos , Plásticos , Embalaje de Productos , Reciclaje
4.
Artículo en Inglés | MEDLINE | ID: mdl-35457426

RESUMEN

Plastic consumption increases with the growing population worldwide and results in increased quantities of plastic waste. There are various plastic waste management strategies; however, the present management progress is not sustainable, and plastic waste dumping in landfills is still the most commonly employed strategy. Being nonbiodegradable, plastic waste dumping in landfills creates several environmental and human health problems. Numerous research studies have been conducted recently to determine safe and ecologically beneficial methods of plastic waste handling. This article performed a bibliographic analysis of the available literature on plastic waste management using a computational approach. The highly used keywords, most frequently cited papers and authors, actively participating countries, and sources of publications were analyzed during the bibliographic analysis. In addition, the various plastic waste management strategies and their environmental benefits have been discussed. It has been concluded that among the six plastic waste management techniques (landfills, recycling, pyrolysis, liquefaction, road construction and tar, and concrete production), road construction and tar and concrete production are the two most effective strategies. This is due to significant benefits, such as ease of localization, decreased greenhouse gas emissions, and increased durability and sustainability of manufactured materials, structures, and roadways. Conversely, using landfills is the most undesirable strategy because of the associated environmental and human health concerns. Recycling has equal benefits and drawbacks. In comparison, pyrolysis and liquefaction are favorable due to the production of char and fuel, but high energy requirements limit their benefits. Hence, the use of plastic waste for construction applications is recommended.


Asunto(s)
Plásticos , Administración de Residuos , Humanos , Pirólisis , Reciclaje , Instalaciones de Eliminación de Residuos
5.
J Environ Manage ; 315: 115118, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35472828

RESUMEN

Construction and demolition waste are one of the largest waste streams generated in the EU by volume. They consist of materials such as concrete, bricks, gypsum, wood, glass, metals, foams, plastics, solvents, asbestos, asphalt, and excavated soil. Nowadays, many of them can be recycled, some even endlessly. This research attempts to contribute to the non-destructive characterization of such a waste with a novel method using terahertz radiation. By combining terahertz imaging and spectroscopy, we performed analytical characterization of selected building materials. The results demonstrate that terahertz technology allows an inside view into some of the non-conducting building materials. THz imaging can detect and visualize the organic solvents in the insulation material, which are often disposed of together with construction and demolition waste. It can also visualize the content of foreign objects or hazardous and toxic substances, which is important for their separation in the recyclate according to the type of the material. Furthermore, THz spectra reveal some spectral lines that can differentiate between different plastics and polymers within the frequency range of 1.0-4.5 THz due to different material structures and chemical compositions. Such results significantly contribute to the decision of which product meets all the standards, which can be returned to the production process due to irregularities or may be disposed of as waste. The only way to reduce construction and demolition waste in the future is to encourage the adoption of innovative technologies like terahertz spectroscopy in combination with traditional methods. This approach can bring some changes also to the construction design philosophy toward more sustainable buildings with minimum end-of-life demolition.


Asunto(s)
Industria de la Construcción , Administración de Residuos , Industria de la Construcción/métodos , Materiales de Construcción , Residuos Industriales/análisis , Plásticos , Reciclaje , Solventes , Tecnología
6.
Sci Rep ; 12(1): 6683, 2022 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-35461320

RESUMEN

Rubber waste, in the form of granules of styrene butadiene rubber and ethylene-propylene-diene-monomer with a particle size of 0.5 to 4 mm, is broadly used for the construction of synthetic surfaces of sport fields. This method of recycling may be significantly limited due to the restrictions on polycyclic aromatic hydrocarbons (PAHs) content in rubber granules in the European Union since 2022. This also applies to the recommendations of the European Chemicals Agency in relation to the identification of other hazardous chemicals in this waste, including metal elements. The scope of the research included the identification of organotin compounds, PAHs content and 18 elements leached from recycled rubber granules in terms of substances harmful to human health and to natural environment. The research covered 84 samples of rubber granules collected from the surface of football pitches or supplied by recyclers in Poland. The test results showed an over-standard content of PAHs in rubber granules. This result confirms the need to develop alternative directions of rubber granules application: construction and hydro construction, reinforcing soil and roadsides, asphalt pavements, making retaining walls, anti-shock and anti-vibration slabs, soundproofing and damping screens, paving stones and landscaping elements.


Asunto(s)
Fútbol Americano , Hidrocarburos Policíclicos Aromáticos , Sustancias Peligrosas/análisis , Humanos , Hidrocarburos Policíclicos Aromáticos/toxicidad , Reciclaje , Goma/química
7.
Artículo en Inglés | MEDLINE | ID: mdl-35457363

RESUMEN

Construction and demolition waste treatment has become an increasingly pressing economic, social, and environmental concern across the world. This study employs a science mapping approach to provide a thorough and systematic examination of the literature on waste management research. This study identifies the most significant journals, authors, publications, keywords, and active countries using bibliometric and scientometric analysis. The search retrieved 895 publications from the Scopus database between 2001 and 2021. The findings reveal that the annual number of publications has risen from less than 15 in 2006 to more than 100 in 2020 and 2021. The results declare that the papers originated in 80 countries and were published in 213 journals. Review, urbanization, resource recovery, waste recycling, and environmental assessment are the top five keywords. Estimation and quantification, comprehensive analysis and assessment, environmental impacts, performance and behavior tests, management plan, diversion practices, and emerging technologies are the key emerging research topics. To identify research gaps and propose a framework for future research studies, an in-depth qualitative analysis is performed. This study serves as a multi-disciplinary reference for researchers and practitioners to relate current study areas to future trends by presenting a broad picture of the latest research in this field.


Asunto(s)
Industria de la Construcción , Administración de Residuos , Bibliometría , Materiales de Construcción , Humanos , Publicaciones , Reciclaje , Investigadores , Administración de Residuos/métodos
8.
Waste Manag ; 144: 421-430, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35452950

RESUMEN

The study aimed to propose an efficient and eco-friendly strategy to improve the utilization of feather waste and converting it into high-valued antimicrobial products. Under the synergistic effect of instant catapult steam explosion (ICSE) (1.5 MPa-120 s), over 90% of chicken feather powder (CFP) was degraded into soluble peptides via keratinolysis within 3 h, about 90% of which were smaller than 3 kDa, indicating an overwhelming advantage than general proteolysis. Importantly, the keratinolysis hydrolysate of CFP was able to inhibit E. coli growth, among which the fraction < 3 kDa exhibited highest antimicrobial activity with a minimal inhibitory concentration of 30 mg/mL. Compared to other fractions, the fraction < 3 kDa contained higher content of hydrophobic amino acids (364.11 mg/g), in which about 79% of peptides had more than 60% hydrophobic ratio, potentially contributing to its antimicrobial activity. ICSE-keratinolysis process holds potential in reducing both protein resource waste and environmental pollution by valorizing feathers into antimicrobial product.


Asunto(s)
Plumas , Queratinas , Animales , Escherichia coli , Queratinas/química , Queratinas/metabolismo , Péptidos/metabolismo , Polvos/metabolismo , Reciclaje , Vapor
9.
Artículo en Inglés | MEDLINE | ID: mdl-35409874

RESUMEN

The behaviors of urban residents in terms of waste separation at source are crucial to achieve the reduction and recycling of waste in urban governance. In this study, the data were collected from 1008 respondents in Shaanxi province, the host of China's 14th National Games; theoretical and empirical analyses were conducted to determine the factors influencing waste separation behaviors, and specific policy suggestions are proposed. The results show that the waste separation behaviors of urban residents are positively influenced by their cognition of waste pollution, ecological values, sense of social responsibility, perceived knowledge, and perceived utilities of waste separation. Moreover, the residents' waste separation intentions partially mediate the relationships between their cognition of waste pollution, ecological values, perceived utilities, and waste separation behaviors, which almost totally mediate the relationship between their sense of social responsibility and waste separation behaviors. In addition, it was shown that the cost of waste separation can weaken the effect of waste separation intention on behavior, while waste separation facilities, social norms, and the publicity for China's 14th National Games have the opposite effect. Finally, policy suggestions are proposed to encourage urban residents to adopt waste separation behaviors, contributing to transforming Shaanxi into a zero-waste province.


Asunto(s)
Intención , Reciclaje , China , Humanos , Políticas , Población Urbana
10.
Artículo en Inglés | MEDLINE | ID: mdl-35409554

RESUMEN

In recent years, the generation of a large amount of construction and demolition waste (CDW) has threatened the public environment and human health. The inefficient supply chain of CDW resource utilization hinders the green development of countries around the world, including China. This study aims to reveal the impact of information sharing regarding recyclers' market demand forecast on the performance of CDW resource utilization supply chains. Therefore, this paper uses the incomplete information dynamic game method to establish and solve the decision-making model of the construction and demolition waste resource utilization supply chain under the conditions of recyclers sharing and not sharing their information. The paper then obtains the Bayesian equilibrium solution and the optimal expected profit for each party. Finally, a numerical simulation was used in order to verify the validity of the model and conclusions. The main conclusions are as follows. In the CDW resource utilization supply chain, if the recycler is more pessimistic about the market's demand forecast, their information sharing makes the remanufacturer more motivated to improve their level of environmental responsibility. In addition, information sharing by recyclers is always beneficial in increasing the profit of the remanufacturer, but it also may make the recycler lose profit. When the efficiency of the environmental responsibility investment of remanufacturers is in a high range, information sharing increases the profits of recyclers. Conversely, information sharing has no significant effect on the profits of recyclers. The impact on the profits of the entire CDW resource utilization supply chain depends on the intensity of competition among channels, the market share of offline recycling channels and the efficiency of environmental responsibility investments.


Asunto(s)
Industria de la Construcción , Administración de Residuos , Teorema de Bayes , China , Materiales de Construcción , Humanos , Residuos Industriales , Difusión de la Información , Reciclaje/métodos , Administración de Residuos/métodos
11.
Waste Manag ; 144: 376-386, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35452946

RESUMEN

Polyvinyl chloride (PVC)-containing waste streams are difficult to recycle due to high chlorine content in PVC. Toxic dioxins or corrosive hydrogen chloride (HCl) vapor released from improper management of PVC-containing wastes can cause severe environmental pollution and human health problems. While PVC is usually treated as contamination and burden in waste recycling, a novel recycling approach was developed in this study to leverage PVC as an asset. Specifically, red oak and PVC were co-converted in γ-Valerolactone, a green biomass-derivable solvent. During the co-conversion, PVC-derived HCl in the solvent acted as an acid catalyst to produce up to 14.4% levoglucosenone and 14.3% furfural from red oak. On the other hand, dechlorinated PVC hydrocarbons and lignin fraction of red oak reacted each other to form chlorine-free solid fuels with high thermal stability. The higher heating value of the solids was up to 36.2 MJ/kg, which is even higher than the heating value of anthracite coal. After the co-conversion, more than 80% of PVC-contained chlorine turned into chloride ion and the rest formed 5-chlorovaleric acid. 5-chlorovaleric acid crystals were further recovered from the post-reaction liquid with a purity of 91.2%.


Asunto(s)
Cloro , Cloruro de Polivinilo , Carbón Mineral , Humanos , Ácido Clorhídrico , Reciclaje , Solventes , Madera
12.
Waste Manag ; 144: 387-400, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35452947

RESUMEN

Construction and demolition waste (CDW) is identified by multiple circular economy (CE) policies as a key sector for implementing circularity strategies due to the high volume of waste produced and the large consumption of raw materials. However, CE is not widely applied in the sector because of the lack of solid estimations on its environmental and economic viability. The main aim of this study was to propose a set of methodological steps to identify the optimal circularity alternatives for CDW products based on a multicriteria analysis of their environmental and economic performance. This methodology is applied to evaluate concrete waste. In specific, high-grade applications of concrete waste were analyzed comprising the processing into recycled coarse aggregates (RCA) for their use in structural and non-structural concrete. Multiple scenarios with different RCA replacements (20%, 30% and 100%) and different types of sorting and recycling (on-site and off-site) were evaluated in accordance with the specific site conditions of the region of Catalonia, Spain. The Life Cycle Analysis methodology (LCA) was used to perform the environmental analysis, while a detailed cost analysis was conducted for the economic aspect. The multicriteria method VIKOR was used for the selection of alternatives considering three different criteria. The results of this study showed environmental and economic advantages of CE scenarios based on the use of RCA over conventional concrete, mainly due to the influence of landfilling and transport distances. RCA produced on-site showed a better performance than RCA from fixed plants.


Asunto(s)
Administración de Residuos , Materiales de Construcción , Residuos Industriales/análisis , Reciclaje/métodos , España , Administración de Residuos/métodos
13.
Waste Manag ; 144: 454-467, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35462290

RESUMEN

To conserve resources and enhance the environmental performance, China has launched the "Zero waste" concept, focused on reutilization of solid waste and recovery of materials, including copper. Although several studies have assessed the copper demand and recycling, there is a lack of understanding on how different waste management options would potentially reduce primary copper demand and associated environmental impacts in China in the context of energy transition. This study addresses this gap in view of a transition to low-carbon energy system and the optimization of copper waste management combining MFA and LCA approaches. Six types of waste streams (C&DW, ELV, WEEE, IEW, MSW, ICW) are investigated in relation to various "Zero waste" strategies including reduction, reuse (repair, remanufacturing or refurbishment), recycling and transition from informal to formal waste management. Under present Chinese policies, reuse and recycling of copper containing products will lead to a somewhat lower dependency on primary copper in 2100 (11187Gg), as well as lower total GHG emissions (64869 Gg CO2-eq.) and cumulative energy demand (1.18x10^12 MJ). Maximizing such "Zero waste" options may lead to a further reduction, resulting in 65% potential reduction of primary copper demand, around 55% potential reduction of total GHG emissions and total cumulative energy demand in 2100. Several policy actions are proposed to provide insights into future waste management in China as well as some of the challenges involved.


Asunto(s)
Eliminación de Residuos , Administración de Residuos , China , Cobre , Ambiente , Políticas , Reciclaje , Eliminación de Residuos/métodos , Residuos Sólidos/análisis , Administración de Residuos/métodos
14.
Waste Manag ; 144: 479-489, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35462292

RESUMEN

Plastic production and worldwide use of plastic materials have continued to rise due to their convenience and excellent marketing advantages. This is generating an environmental crisis and global scale pollution which is one of the greatest threats to our planet. One of the best responses could be accomplished by improving recycling and waste management strategies. In this paper we conducted Raman analyses of representative stock of plastics aged in terrestrial or aquatic environments spanning in age up to 15 years. We aimed to establish any potential influence of the aging conditions on the Raman signature of specific plastics. This information is further used to build up a Raman logic gate for automatic sorting of plastic waste recovered from environment. Pigments and aging introduced indeed small changes in the Raman signature of the respective plastics. However, we were able to identify unique spectral ranges characteristic for the main plastic types and intensity threshold of fingerprint bands sufficiently strong for building robust Raman barcodes for sorting. Waste plastics Raman data handling and the proposed methodology for sorting complies with the FAIR (Findability, Accessibility, Interoperability and Reusability) principles of scientific data, being useful for researchers, policymakers and stakeholders. Our spectral characterization of solid plastic waste comes in support of improved waste plastic management and could have economic and environmental positive impact.


Asunto(s)
Plásticos , Administración de Residuos , Contaminación Ambiental , Reciclaje , Residuos Sólidos , Tecnología
15.
Waste Manag ; 144: 513-526, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35468449

RESUMEN

The rapid global growth in the production of electric vehicles (EVs) will produce numerous waste power battery modules (WPBMs) in the future, which will create significant challenges concerning waste disposal. Therefore, measures to disassemble and recycle WPBMs before using them in other fixed scenarios provide an opportunity for research. First, considering battery components' hazards and complex properties, a human-machine collaborative cell-level disassembly model of WPBMs is proposed. Second, the WPBMs from the Tesla Model S are selected as the case study to verify reliability and validity. Finally, two different disassembly schemes are obtained by solving the proposed model using NSGA-II based on the actual data from resource-recycling companies. The results show that: 1) The proposed model and method can realize the cell-level disassembly of WPBMs and assign the disassembly tasks of hazard components to robots and the disassembly tasks of complex components to humans. 2) The two disassembly schemes obtained are two solutions that do not dominate each other, and the four objectives (number of workstations, workstation idle time, number of workers, and disassembly cost) are optimized simultaneously. 3) The proposed model can provide decision-makers with additional options when incorporating the number of workers into enterprise risk indicators.


Asunto(s)
Suministros de Energía Eléctrica , Eliminación de Residuos , Electricidad , Humanos , Reciclaje/métodos , Reproducibilidad de los Resultados
16.
Waste Manag ; 144: 533-542, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35487059

RESUMEN

Material recovery facilities (MFRs) play an important role in today's waste management systems to maximize recycling efficiency for several waste materials. These facilities face multiple challenges, often due to a poor understanding of the mechanisms occurring within the sorting equipment. Improving modeling techniques of these unit operations appear to be a promising opportunity to mitigates these challenges. Mechanical sorting efficiency of municipal solid waste is often predicted from simple transfer coefficients, which are obtained for a specific set of operating conditions of the sorting equipment and sorting sequence configuration. When these transfer coefficients are used in situations that are different to those in which they were obtained, poor predictions can be expected. To overcome these limitations, a new predictive tool, based on the integration of mechanistic models and transfer coefficients, is presented. Mechanistic models are developed only for the most influential unit operations in a MRF, in order to predict their sorting efficiency based on the physical phenomena occurring. Integration of these models with the use of transfer coefficients for the other unit operations allows the entire predictive tool to remain as simple as possible while providing high prediction accuracy and flexibility. The use of the tool is validated with a real case study of a material recovery facility. Results indicate a good prediction of the mass flows of the facility. Moreover, a new modeling technique is proposed for the representation of a ballistic separator based on the shape factor of the waste items.


Asunto(s)
Eliminación de Residuos , Administración de Residuos , Fenómenos Físicos , Reciclaje/métodos , Eliminación de Residuos/métodos , Residuos Sólidos
17.
Waste Manag ; 144: 210-220, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35395506

RESUMEN

The recycling of light-emitting diode (LED) lamps and tubes is becoming increasingly important due to their growing market share as energy-efficient lighting technology. Here we report on the use of high voltage electric-pulse fragmentation to recover elementary components such as LED chips and printed circuit boards (drivers). E27 LED lamps with plastic bulbs, which represent 48% of deposits collected by a French company, are used as a case study. More than 150 lamps were tested on a laboratory reactor for electrodynamic fragmentation. The technological process in which highly energetic electrical pulses were applied to materials immersed in water was studied in order to separate the components of the LED lamps using a minimal specific energy. The estimated energy necessary to achieve total separation assessed at 64%, without grinding pretreatment, was 5.2 ± 0.6 kWh per ton, representing a mass recycling rate of 74%. Based on the disassembled material, the commercial value of the recovered materials was thus estimated. Gold, as the most representative material, was found to represent 0.03% of the mass fraction for 83.6% of the total commercial value. The process disassembling capacity is a key issue to increase the recycling rate of current LED lamps and tubes.


Asunto(s)
Artículos Domésticos , Plásticos , Electricidad , Oro , Iluminación , Reciclaje
18.
Waste Manag ; 144: 221-232, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35397419

RESUMEN

Due to rapid economic development and urbanisation, emerging megacities with dense populations have witnessed a significant increase in waste generation. Megacities face challenges in developing sustainable waste management systems. Considerable heterogeneity exists across megacities in management strategies. The two selected emerging megacities, Singapore (a city-state) and Shanghai, have similar developmental characteristics, but their waste management modes differ strikingly. This study assessed the two modes in terms of management strategies, environmental effects, economic costs, and social outcomes. Environmental footprint analysis and cost quantification were employed for the assessment based on public data. The research results would permit a deeper understanding of the long-term sustainability of each mode while considering the feasibility of implementation across different contexts. It was found that the waste management system in Singapore had a relatively lower environmental impact than Shanghai before Shanghai's new waste segregation and recycling policy in 2019. However, when the effect of fossil fuel substitution is taken into account, the environmental burden in Shanghai can be lowered more substantially than the one in Singapore. Although Shanghai had more economic burden for the waste segregation at source, it tended to implement the circular economy principles (e.g., reduce, reuse, and recycling) better and improve its sense of community significantly. Based on the practical experiences from the two representative megacities, suggestions for better waste management practices were provided for Singapore, Shanghai, and other emerging megacities with similar circumstances. In addition, challenges and opportunities related to household waste segregation and recycling were identified to guide future practices in emerging megacities.


Asunto(s)
Eliminación de Residuos , Administración de Residuos , China , Ciudades , Reciclaje , Singapur , Residuos Sólidos/análisis
19.
Waste Manag ; 144: 294-302, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35427901

RESUMEN

Global tantalum production from mines averages 1800 tons per year and hardly increases, but demand for tantalum in the electronics industry consistently increasing. Globally, 50% of total tantalum produced is being used for tantalum capacitors manufacturing, almost all demand from various industries is mainly met by primary resources only. Tantalum production and supply predominantly dominated by Congo and Rwanda which accounts for > 50%, add disadvantages for the strategic and economic competitiveness of other nations. To address the monopoly dominated by Congo and Rwanda, and the disparity of tantalum primary reserve, exploitation of secondary resources can alternatively address the drawbacks of primary resource distribution. Currently, hardly < 1% of tantalum getting recycled, and the poor recycling rate of tantalum is mainly contributed by the lack of efficient and sustainable valorization technology for recycling tantalum-bearing scraps like electronic capacitors and semiconductor industry tantalum scrap. In the current investigation, a sustainable tantalum extraction process from scrap dominated by hydrometallurgical route has been developed. Tantalum scrap which is passive to leach for tantalum recovery was calcinated for oxidation of TaN content and followed by tantalum has been leached using a mixture of NaF and HCl, a specially developed novel lixiviant for the purpose as an HF substituent. Calcination process parameter like temperature and time requirement for oxidation was optimized varying one parameter at a time. Then, the efficient leaching condition was optimized for quantitative leaching of tantalum. The process can achieve 99.99% efficient leaching, the process can successfully be applied for feasible industrial-scale tantalum scrap recycling. The HF substituent lixiviant can add advantages to overcome occupational and industrial operation safety challenges associated with HF lixiviant. The reported valorization process can be a sustainable tantalum recycling process that simultaneously can address UNO sustainable development goal, WEEE directive, and UNEP E-Waste Management goal.


Asunto(s)
Residuos Electrónicos , Administración de Residuos , Residuos Electrónicos/análisis , Industrias , Reciclaje , Semiconductores , Tantalio
20.
Waste Manag ; 144: 543-551, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35379528

RESUMEN

Most two-dimensional plastic packaging materials are thermally recovered, which does not add to the recycling quota of 50 % required by EU legislation for all lightweight packaging until 2025. Furthermore, the separation processes for 2D materials cannot reach the same level of accuracy, which is possible in the sorting of rigid plastic packaging. This study proposes new adaptations to existing sorting aggregates to increase the near-infrared spectral quality of two-dimensional materials. It aims to improve the spectral quality, which was defined by the deviation of the spectra from a reference spectrum and the variability of the recorded spectra, which can be achieved by installing reflectors behind the material made up of copper or aluminium. This setup enables detection in transflection rather than reflection mode. The variability could be reduced by a factor of 6 through the use of a reflective background. Meanwhile, the spectral fidelity to the reference spectrum could be enhanced, in some cases decreasing the deviation from the reference spectrum by 30 %, which means enhancing a spectrum from unrecognisable to useable. Apart from using reflective materials, the effects of emitter intensity, material and thickness were evaluated.


Asunto(s)
Plásticos , Reciclaje , Aluminio , Cobre , Embalaje de Productos
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